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Laboratory Safety

Chemical Hygiene Plan

Preface

Chemicals are part of many work environments. Approximately 25 million workers nationwide are exposed to 500,000 chemical products in the work place. Hundreds of new chemicals are introduced annually, posing a significant problem to exposed workers. Chemicals must be treated with respect. Exposure to chemicals can cause serious health effects such as skin rashes, burns, organ damage, cancer, sterility, and birth defects. In addition some chemicals are safety hazards with the potential to cause fires, explosions, and other accidents.

Because these problems are serious, and there is often a lack of information available to workers concerning chemicals, OSHA has adopted a Hazard Communication Standard and a Laboratory Safety Standard. OSHA's Hazard Communication Standard is intended to protect workers in industrial operations. The Lab Standard is specifically designed to protect workers exposed to chemicals in laboratories. A Chemical Hygiene Plan must be developed to implement the provisions of the Lab Standard. It must include all procedures and policies necessary to protect workers from hazardous chemicals used in laboratories. The goal of both standards is to reduce the incidence of occupational illness and injuries from exposure to hazardous chemicals.

Injury to laboratory workers can result from carelessness, unfamiliarity with hazards of chemicals and equipment, or a lack of proper precautions. Accidents involving injuries and illness from exposure to corrosives, toxins, flammable liquids and explosives are far to common in laboratories. To reduce these accidents, personnel must be trained in the hazards of the chemicals they work with and methods to reduce exposures. Individuals must develop good personal safety habits such as wearing proper eye protection and not smoking or eating in areas where chemicals are present.

The university is committed to providing students, faculty, and staff an environment that is free from recognized hazards. This manual provides information on chemical hazards and procedures for the safe handling of hazardous chemicals commonly used in laboratories. Physical hazards such as flammable liquids, reactives, explosives, compressed gas cylinders, and cryogenic liquids are covered. Health hazards associated with chemicals such as corrosives, toxins, carcinogens and embryotoxins are included. Information is also presented on personal protective equipment, safety equipment that can reduce exposures and prevent accidents, and protection from other hazards commonly found in laboratories such as electrical equipment.

1.0 Laboratory Facilities

Poor design and layout of laboratories and equipment are often the underlying cause of accidents. This aspect of laboratory safety is often the most neglected. A safe laboratory is well designed. It has proper access and the layout is conductive to the free movement of personnel in the event of an emergency. Adequate ventilation and appropriate equipment for the operation of the laboratory are available and well maintained. The laboratory is kept clean and uncluttered. Provisions are made for special hazards. Hazardous areas are posted with the appropriate warning signs and safety equipment is present and conveniently located.

Design

Approval. New construction and renovations must be approved by Facilities Management and the Safety Office.

Organization.  The space within a laboratory should be organized as much as possible to separate areas of high and low risk activities. It should not be necessary to routinely pass through high risk areas. In the event of an emergency, escape routes should be placed through the safest area within the laboratory. Traffic flow should be minimized near equipment that generates fumes, e.g., fume hoods and distillation apparatus. Flammable materials should be separated by as much distance as possible from sources of ignition. Emergency equipment should be readily accessible from every point within the laboratory.

Aisles.  A minimum aisle clearance of 36 inches must be maintained in all laboratories. Dead end aisles should be avoided. In emergencies, equipment cluttering up aisles can lead to accidents. Caution must be taken to ensure that portable equipment, carts, gas cylinders and similar items are not allowed to restrict aisle clearance.

Exits.  Teaching laboratories that use flammable or combustible liquids or other fire hazards are required to have at least two exits with doors that swing in the direction of exit travel. Existing, small, one or two person research laboratories are exempted from this requirement but should be organized to reduce fire hazards between the normal work station and the single exit. For example, flammable liquids or storage cabinets should not be stored along a required exit path. All exits must be marked with a readily visible sign. Any door, passage, or stairwell that might be mistaken for an exit must be labeled "Not an Exit".

Emergency equipment.  Appropriate emergency equipment such as deluge showers, eye-wash stations, fire extinguishers, and first aid kits must be readily available. Access to this equipment must not be blocked. All laboratories should be equipped with an audible evacuation alarm system. Safety equipment should be periodically inspected to ensure they are in good working order.

Housekeeping.  Equipment should be organized in an orderly and stable manner in the laboratory. Clutter on the bench, in hoods, and in aisles should be eliminated. Equipment must not block exits and emergency equipment. Electrical cords, wires, or hoses should not run across aisles.

Furniture and Surfaces

Furniture.  Laboratory furniture should meet appropriate safety standards and be functional, durable, and economical. Furniture should be selected in cooperation with the Safety Office.

Floors.  Laboratory floors should be seamless, slip resistant, easily cleaned or decontaminated, and resistant to spills of water or common chemicals such as solvents. Tile floors should be avoided because spills can run into the joints, making clean up very difficult.

Benches and countertops.  Work surfaces should be built to facilitate decontamination if needed. The surfaces should be relatively impervious, such as Formica, and free of cracks and seams. The construction materials should be fire resistant, non-reactive, and not subject to corrosion from the chemicals being used.

Cabinets.  Cabinets should be designed to provide safe, secure storage for chemicals. They should be constructed of non-reactive, corrosion resistant material, have a non-skid surface and edge protection to prevent bottles from falling off accidentally. Access to the chemicals should not be difficult. High wall-mounted units or free standing cupboards should be discouraged.

Ventilation

Air changes.  Laboratory activities involving work with toxic, flammable, or irritating materials must be provided with adequate ventilation. This is necessary to provide makeup air for the fume hoods and to provide clean air for breathing. The ventilation system should be capable of independently providing 4-12 air changes per hour with 100 percent exhaust. Other types of laboratories may require additional ventilation.

Consultation.  Consultation on ventilation problems may be obtained from the Safety Office. Advice and design for ventilation systems can be obtained from Facilities Management.

Intake and exhaust.  Intake and exhaust ventilation should be balanced to maintain a slight negative pressure with respect to adjacent areas to ensure that air movement is into the laboratory. Air must be exhausted outdoors and not recycled. Exhaust discharges must not be located near air intakes of buildings.

Special Facilities

General.  Specialized laboratories must meet requirements based on the type of research and the degree of hazard associated with the research. These facilities will require evaluation on a case-by-case basis. Examples include laboratories using OSHA regulated carcinogens, or highly infectious agents. The Safety Office should be called for consultation.

Recombinant DNA facilities.  Laboratory containment and facilities must be in accordance with the current safety levels and practices specified in the NIH Guideline for Recombinant DNA Research.

Warning Signs

General.  Laboratories that have special or unusual hazards should be posted with the appropriate warning signs. In some instances, access to an area will be restricted. Following is a partial list of signs or symbols that may be required. Usually, the sign will be preceded by the words "Caution", "Warning", or "Danger" depending on the degree of hazard. Information on the size, color and required symbol may be obtained from the Safety Manager.

Airborne radioactivity.  Some uses of radioactivity could lead to the generation of airborne radioactivity. If levels in excess of those legally permitted could occur, this sign must be posted at the boundaries of the area.

Authorized admission only.  This sign should be posted, accompanied by a sign identifying the hazard, in highly hazardous areas.

Biological hazard.  An area in which a biologically active agent that could lend to human illness is used (Class II or III etiologic agent) must be posted with a standard biological hazard sign.

Carcinogenic agent.  Entrances to areas in which known or suspect carcinogens are used or stored in significant quantities should be posted with this sign. Laboratories using OSHA regulated carcinogens that may exceed an action level must post this sign.

Chemical splash goggles required.  This sign should be posted at entrances to areas where active wet chemical operations are in progress. Normally this will be posted on the door to laboratories and goggles would be required upon entering the room. Goggles are not required, however, in areas in the laboratory set aside for non-laboratory work such as study areas.

Cryogenic liquids.  All containers of cryogenic liquids (liquid nitrogen, helium, air, etc.) should be labeled with a caution sign.

Flammable solvents.  Laboratories in which flammable solvents in quantities greater than five gallons are stored or used must be posted with this sign. In addition, a NO SMOKING sign must be posted.

High voltage.  The entrance to electrical closets, breaker rooms and maintenance rooms with accessible high voltage circuits must be labeled with this sign.

Interlocks on.  Devices with internal hazards are often interlocked to prevent access while they are on. Many of these, such as x-ray diffraction units, legally require warning signs.

Lasers.  Standard warning signs are required on the entrance to rooms where lasers of class 3b and above are operating.

Microwave.  Areas in which it is possible to exceed the occupational limit for microwave energy must be posted with this sign.

No eating, drinking or smoking.  This sign must be posted in areas where highly toxic substances, carcinogens, mutagens, or embryotoxins are used.

No smoking.  This sign must be posted where highly toxic substances, carcinogens, mutagens, embryotoxins, or flammables are in use or stored. No smoking signs may be posted in other areas at the discretion of personnel working in the area.

Not for use on electrical fires.  This sign must be posted on all fire extinguishers containing water.

Radiation area.  This sign accompanied by the standard radiation symbol, must be posted in areas where the radiation levels may exceed levels defined by the Nuclear Regulatory Commission.

Radioactive materials.  Areas in which radioactive materials are stored must be identified with this sign.

Radioactive waste.  All radioactive waste must be placed in standard waste containers labeled with this sign.

Refrigerator not to be used for storage of chemicals.  Refrigerators used only to store food for human consumption should be posted with this sign.

Refrigerator not to be used for storage of food for human consumption.   Laboratory refrigeration units used for storage of chemicals and biological materials should be posted with this sign to prevent the storage of food and chemicals in the same refrigerator.

Refrigerator unsafe for storage of flammables.  Standard refrigerators must be posted with this sign. Only explosion-safe and explosion-proof refrigerators are to be used for the storage of flammable liquids.

Respiratory protective equipment required.  This sign must be posted wherever airborne levels are present that exceed the action levels specified by OSHA.

Safety glasses required.  This sign must be posted in areas where a risk to eyesight exists which is exclusively due to impact.

Toxic chemicals.  Laboratories that store or use significant quantities of highly toxic chemicals should be posted with this sign.

Toxic gas.  This sign should be posted in all laboratories that use or store highly toxic gas cylinders.

Ultra-violent light.  This sign should be posted in laboratories if there is a possibility of exposure to ultra-violet light.

X-ray.  This sign must be posted in all areas where x-ray equipment is located.

The following signs are generic. The researcher is responsible for identifying the special risks and providing the appropriate warnings.

(Specific item) personnel protective equipment required.  Areas in which risks exist that would require specific items of protection must be posted with the appropriate warning sign.

(Specific) toxic or hazardous material.  OSHA has identified several chemicals that require specific warnings to users. Among these are ethylene oxide, PCBs, lead, and ethylene dibromide.

(Specific) waste chemical only.  The chemical waste disposal program requires that chemicals be segregated. Waste collection containers must be labeled with this sign.

2.0 Laboratory Safety Equipment

Laboratory safety equipment is designed to protect personnel from injury and minimize damage if an accident occurs. Safety equipment should be in useable condition and available to all laboratories. Laboratory workers should know the location, operation and limitations of safety equipment in the work area.

Fire Extinguishers

Portable fire extinguishers are the first line of defense against a laboratory fire. Fire extinguishers are rated for their suitability in combating four types of fires.

Class A.  Class A fire extinguishers are used to extinguish fires in ordinary combustibles such as wood, paper, cloth, rubber, and plastics. These extinguishers should not be used on electrical, flammable liquid or combustible metal fires. Extinguishers effective against type A fires contain water or a special dry chemical agent.

Class B.  Class B fire extinguishers are effective against flammable liquids and gas fires such as solvents, oil, gasoline, and grease. Dry chemical agents, carbon dioxide, and halogenated agents are typically used. Water will only spread a flammable liquid fire and should not be used as an extinguishing agent for Class B fires.

Class C.  Class C fire extinguishers are used to extinguish fires involving energized electrical equipment. Non-conducting agents such as dry chemical, carbon dioxide, or halogen compounds are used. Water should never be used to extinguish an electrical fire.

Class D.  Class D fire extinguishers contain a special granular formulation that is effective against combustible metal fires such as sodium, potassium, magnesium, and lithium. Normal extinguishing agents must not be used against combustible metal fires because they may increase the intensity of the fire.

Training.  Personnel should be trained yearly in the basic operation of fire extinguishers and know what type of extinguisher to use on a particular fire.

Laboratories.  All chemical laboratories should be provided with carbon dioxide and/or dry chemical fire extinguishers. Laboratories working with flammable solvents must have an appropriate fire extinguisher. Class D fire extinguishers or other suitable extinguishing media should be readily available to laboratories working with reactive metals or metal hydrides.

Labeling.  Every extinguisher should be clearly labeled to indicate the classification of the fires it is effective against. Water fire extinguishers must be labeled to indicate that they cannot be used on electrical fires.

Access.  Fire extinguishers should be readily accessible and the location of the extinguisher should be clearly identified. Fire extinguishers must be mounted off the floor and no higher than 5 feet. Extinguishers weighing over 40 lbs. should not be mounted higher than 3 1/2 ft.

Inspections.  Fire extinguishers should be maintained in operating condition, inspected monthly, checked against tampering, and recharged as required.

Flammable Storage Cabinets

Quantities of flammable liquids greater than 10 gallons must be stored in flammable storage cabinets, approved safety cans, or a properly designed flammable storage room. Approved storage cabinets are designed to protect flammable liquids from involvement in an external fire for 10 minutes. This is the time it would normally take for an area to become seriously involved in a fire.

Approval.  All cabinets must comply with OSHA and NFPA requirements.

Fire resistance.  Cabinets must be capable of limiting the internal temperature to less than 325 F when subjected to a 10-minute standard fire test.

Metal cabinets.  The bottom, top, door, and sides of metal cabinets shall be constructed of at least No. 18 gage sheet iron, and double walled with one and a half inch air space. The door sill shall be raised at least 2 inches above the bottom of the cabinet.

Wooden cabinets.  The bottom, top, and sides of wooden cabinets shall be constructed of at least 1-inch thick high density plywood. When more than one door is used, there shall be a rabbeted overlap of not less than one inch. Hinges shall be mounted so that they will not loosen during the fire test. The door sill shall be raised at least 2 inches above the bottom of the cabinet.

Storage limits.  Maximum storage limits for flammable liquids in approved storage cabinets are 120 gallons of Class I, Class II, and Class IIIA liquids. Of this total, only 50 gallons of Class I and Class II liquids are allowed. No more than three such cabinets may be stored in a fire area.

Venting.  Storage cabinets are not required to be vented unless required by the local Fire Marshal. Venting a cabinet may defeat the cabinet's purpose of protecting the contents from involvement in a fire for 10 minutes.

Labeling.  Cabinets must be labeled in conspicuous lettering "Flammable-Keep Fire Away."

Safety Cans

Portable approved safety cans can be used to safely store, carry, and pour flammable and combustible liquids. The main purpose of the safety can is to prevent an explosion of the container when it is heated. Safety cans are constructed of terne plate steel, stainless steel, or high density polyethylene. The type of can purchased is determined by the chemical properties of the flammable liquid and how it will be used. Terne-plate steel cans are designed to store petroleum solvents if the purity and color of the solvents are not critical. Some solvents may also dissolve the paint from the outside of these cans. Stainless steel cans are recommended when high purity solvents are needed. High density polyethylene cans are resistant to many solvents but may cause discoloration of the solvent.

Approval.  Safety cans must be UL listed and FM approved, and properly labeled to identify contents.

Construction.  All approved cans must have a lid that is spring loaded to close automatically after filling or pouring. The lid also acts as a relief valve when pressure builds up. A flame arrestor screen must be inside the cap spout to prevent fire flashback into the can.

Refrigerators

Confined vapors from flammable liquids are easily ignited and represent a major hazard in laboratory refrigeration units. There are a number of potential ignition sources in a normal refrigerator or freezer. Spark producing devices include the thermostat, light switch, defrost mechanism and compressor. In addition, self-defrosting units have a drain hole at the bottom. Vapors can escape through the hole and be ignited by the compressor.

Standard refrigerators.  Because of the danger of fires and explosion, standard refrigerators and freezers may not be used for storage of flammable liquids. These refrigerators should be posted as unsafe for storage of flammable liquids.

Acceptable units.  The following types of refrigerators are safe for the storage of flammable materials:

  • Explosion-Safe or flammable storage refrigerators and freezers, which have been modified to eliminate the spark producing mechanisms.
  • Explosion-Proof refrigerators and freezers, which not only protect against flammable vapors inside the unit, but may also be operated in rooms that have an explosive atmosphere. These units must be permanently wired to the laboratory electrical system.

The extra protection afforded by Explosion-Proof units is not necessary for solvent storage under ordinary laboratory conditions. Explosion-Safe units are recommended for this purpose. However, if large amounts of ether are stored, the former should be considered.

Eyewash Fountains and Emergency Showers

Suitable eye-wash facilities and emergency showers must be available to laboratories using hazardous chemicals that may be harmful to the eyes or skin or can be absorbed through the skin. In addition to providing protection from chemical splashes, emergency showers can be used to extinguish clothing fires. Emergency showers and eye-wash stations should always be installed at the same location because injuries to the eyes and skin often occur together. All personnel should be familiar with the location and operation of emergency showers and eye-wash stations before beginning hazardous procedures.

Location.  Units shall be located in readily accessible areas within 10 seconds of a laboratory using injurious chemicals. In extremely hazardous areas, units may be required to be closer. Eyewash and emergency showers should not be located near electrical apparatus, power outlets or water reactive chemicals. The area around the equipment must be kept clear to ensure immediate access.

Valve.  The valve must be designed so that the water remains on without the user holding the valve open. Injured personnel must be able to hold both eyelids open or take their clothes off. The valve actuator should be large enough to be easily located and operated by the user. A self-closing valve on emergency showers may be used in teaching laboratories and low hazard research laboratories if approved by the Safety Office.

Pull devices.  Overhead chains are most commonly used to activate showers. The chain should be within reach of anyone working in the lab. The chain should never be tied out of the way. Rod-type pull activators are preferable to chains because they are easily accessible and cannot be tied out of the way.

Water flow.  Eye-wash equipment should be capable of delivering to both eyes simultaneously at least 0.4 gallons of potable water per minute for 15 minutes. The velocity should be low enough so that it will not injure the user. Nozzles must be protected from airborne contaminants. The removal of the protective device should not require a separate motion by the user. Shower heads shall be between 82 and 96 inches from the floor. Emergency shower heads must be capable of delivering a minimum of 20 gallons of water per minute.

Signs.  The location of eyewash units and emergency showers should be identified with a highly visible sign.

Inspections.  Laboratory personnel should flush eye-wash units for a few minutes weekly to ensure they are in operating condition and to clean out the water lines. The Safety Office will inspect and flush eye wash units four times a year. Emergency showers will be flushed twice a year.

Back-up units.  Small squeeze bottles of water are not acceptable as a primary eyewash unit because they do not supply the flow necessary for repeated washings and cannot flush both eyes simultaneously. Drench hoses are acceptable only as a back up system because they cannot flush both eyes simultaneously and the user cannot hold both eyes open. In addition, hand-held drench hoses cannot provide the full flow associated with an emergency shower. Small eye-wash units mounted on the ends of faucets are intended only to supplement, but not replace standard plumbed in eye-wash equipment. These units can be difficult to operate in an emergency.

Laboratory Fume Hoods

Laboratory fume hoods are ventilated enclosures in which toxic, offensive, or flammable materials can be handled safely. Operations that involve hazardous reactions, heating or evaporating solvents, and transfer of hazardous chemicals from one container to another should be performed in a fume hood. The purpose of a hood is to capture gases, dust, vapors, or fumes from these operations and prevent them from escaping into the laboratory where they could injure personnel. This is accomplished by an exhaust fan on the roof which draws hazardous material into the hood away from the operators breathing zone and exhausts it safely away from the building. In addition to providing protection from gases and dust, the sliding sash on the hood offers protection from chemical splashes and explosions of hazardous materials within the hood. The hood can also act as a containment device in case of chemical spills.

Laboratory fume hoods are divided into two classes: general purpose and special purpose hoods. General purpose hoods are suitable for most chemicals used in the laboratory. Special purpose hoods requiring additional safety features are used for substances posing unusual hazards, such as hot perchloric acid, highly toxic chemicals, carcinogens, radioactive materials, and flammable solvents and gases. Perchloric acid poses special problems because it is a highly reactive substance which forms explosive residues when allowed to dry, especially when mixed with organic materials. Because of the possibility of acid fumes contaminating the duct work and forming explosive residues, hot perchloric acid must be used in specially designed hoods.

Approval.  The Safety Office must be notified before purchasing a hood to ensure that the proper hood has been ordered and that it will be installed correctly.

Construction.  Fume hoods should be constructed of heat and corrosion resistant materials such as epoxy resins, fiberglass, cement-asbestos, and stainless steel. Control valves, electrical receptacles, and other fixtures should be located outside the hood to minimize the need to reach into the hoods, and to reduce explosion hazards.

Ducts. Each hood should be independently ducted to the roof of the building. This eliminates the possibility that toxic vapors released into one hood could enter into an unused hood. Ducts from hoods in the same room may be combined. The exit duct should be of the updraft type and designed to discharge the effluent away from the building and air intakes. The exhaust duct should never discharge out the side of the building. This could allow potentially hazardous fumes to collect near the building. Ducts penetrating a floor must be encased in a 2-hour fire rated enclosure that extends to the ground. The motor must be located on the roof. This ensures that the ducts within the building are under negative pressure and that leakage will occur into the duct.

Sash.  The sash insures safe operation, reaction containment and proper airflow. To maximize the capture efficiency of hazardous fumes the sash opening should not be greater than 18 inches. The sash should be opened fully only when placing large items in or removing them from the hood. The sash should be closed when conducting procedures that produce high velocity aerosols, particulate contamination or when conducting experiments with high pressure systems that produce gases and vapors.

Face velocity.  To provide adequate protection from hazardous chemicals, the face velocity of air entering the hood must be between 75-150 feet per minute (fpm). Air flow greater than 150 fpm will create turbulence that can allow fumes to escape back into the room. At velocities less than 75 fpm, leakage from the hood is likely. Whenever maintenance is performed on a hood, the face velocity must be measured by the Safety Office before the unit is returned to service. Face velocities will be measured every four months by the Safety Office and acceptable sash limits marked.

General ventilation.  The performance of the hood is strongly influenced by the general ventilation system in the laboratory. Sufficient make-up air must be available so the hood will draw properly.

Flow monitor.  New installations should include an air flow monitor. As a minimum alternative to ensure proper air flow in existing installations, a light should be connected with the motor to warn users if the power fails. If the light goes out users should assume that the hood is inoperable and call Facilities Management.

Location.  Hoods should be located in draft-free low traffic areas away from exits, walkways, doors, windows and air conditioning and heating ducts. Cross drafts from the movement of people or air currents can exceed the face velocity of the hood and draw hazardous materials from the hood into the room. Walking, for example, can generate air speeds of 200 fpm. Fume hoods should also be located so that an accident in the hood will not block egress from the laboratory. Location of the hoods within a facility must be done in cooperation with the Safety Office and Facilities Management.

Proper use.  To increase the effectiveness of the hood, work should be done as deeply within the hood as possible (at least 8 inches from the edge). Equipment should be arranged in the hood as far back as possible without blocking the rear baffles. Operations producing gases should be vented toward the rear of the hood. Possible sources of ignition should be eliminated from the hood if there is a potential for an explosion. As a rule of thumb use a hood when working with volatile substances that have a permissible exposure limit of less than 50 ppm.

Storage in hood.  Chemicals and equipment stored in a hood should be kept to a minimum. Excessive storage can create unnecessary turbulence which reduces the effectiveness of the hood and may allow fumes to escape into the laboratory. The hood must run continuously if highly toxic and volatile chemicals are stored in the hood. It is preferable to provide separate vented cabinets for the storage of these chemicals. Placing of containers in the hood that are continuously emitting toxic contaminants should be avoided. A malfunction in the hood could allow contaminants to enter the laboratory.

Effluents.  If highly toxic, corrosive, or offensive vapors will be produced local scrubbing of the effluent should be done before exhausting the vapors into the duct work. If this is impossible, then HEPA filters and activated charcoal filters should be installed at the exit duct to trap particulates and absorb gases.

Perchloric acid hood.  Only hoods that are specifically designated as perchloric acid hoods are to be used for operations with hot perchloric acid. These hoods are equipped with a water wash down system that removes residue from the duct work. It must be constructed of relatively inert materials such as stainless steel, ceramic coated material, or PVC. All duct work should be a short and straight as possible to prevent residues from collecting at any point. The hood must be exhausted through a special external duct which carries the effluent well away from the building. All hoods must be permanently labeled "For Perchloric Acid Use."

Radioisotope hood.  Hoods used for radioactive material must be designated as a radioisotope fume hood by the vendor. The interior shall be of a seamless material, preferably stainless steel, with coved corners free of joints, cracks, or gaskets to facilitate decontamination. Ducts shall be of stainless steel. Hoods must be ducted independently directly to the roof. Blowers shall be roof mounted, spark-proof and explosion-proof. A HEPA filter must be installed in the exhaust duct if the hood is used for radioisotope work that may present a particulate problem. New units must be installed with a flow monitor and alarm to ensure proper air velocity and direction. As a minimum, older units shall have a red warning light indicating that the motor is working. Hoods shall be labeled "For Radioisotope Use."

Explosion-proof hood.  Hoods used for flammable materials, particularly solvents, explosive gases and other highly reactive chemicals, must be equipped with explosion-proof light fixtures and fan motors if the discharge can exceed 25% of the LEL. Switches and outlets should be located outside the hood to eliminate spark sources. Hot plates and fixed wiring in the hood shall be in good repair. The interior of the hood and ducts must be either a glass-cement composition or stainless steel. Work with very reactive or potentially explosive substances will require a horizontal sash unit or an additional protective shield.

Carcinogen hood.  Chemical carcinogen hoods must meet the requirements for radioactive use hoods.

Self-contained hood.  Self-contained units may be used when venting a hood is not practical and the chemical is of moderate hazard. These units recirculate air through activated charcoal filters and remove small quantities of solvents, acids, and annoying odors from the air. Filters should be designed to release a pungent odor when they become saturated. Purchase of these hoods must be approved by the Safety Office.

Biological Safety Cabinets

Biological safety cabinets are among the most effective and commonly used primary containment devices in laboratories working with infectious agents. Primary barriers are important because most laboratory techniques produce aerosols that can be readily inhaled. The majority of reported laboratory acquired infections for which no specific cause was identified, have been attributed to exposure to aerosols. There are three basic types of biological safety cabinets: Class I, Class II, and Class III. Class I and II cabinets generally provide an equivalent level of personal protection. Class II cabinets provide the additional benefit of protecting the work area from contamination. The Class III cabinet provides the highest level of personnel, product, and environmental protection.

Class I.  The Class I cabinet is a partial containment enclosure that is basically a modified chemical fume hood. Room air flows through a fixed front opening preventing microbial aerosols from entering the room. Exhaust air from the cabinet is filtered through a high efficiency particulate air (HEPA) filter that removes 99.97% of all particles 0.3 microns or greater in size. The cabinet does not protect the work area or the operator's hands and arms from contamination, because the inward flow of air can carry microbial contaminants into the cabinet.

Class II.  The Class II, or laminar flow, biological safety cabinet is a partial containment enclosure that protects the worker and the research material. Instead of passing over the product, inward air passes downward in front of the work area and joins a recirculating air stream in the back. Part of this air passes downward through a HEPA filter toward the work area providing a contamination free zone. The remainder of the air is exhausted out of the facility through another HEPA filter.

Class II cabinets are divided into two types, type A and type B, that differ mainly in the amount of air they recirculate. Type A cabinets recirculate approximately 70% of the total exhaust air. Type B cabinets are divided into two subgroups, B1 and B2. Type B1 cabinets recirculate approximately 30% of the total cabinet air. Because a higher dilution rate is achieved before exhausting the air to the atmosphere, Type B1 cabinets may be used with a wider range of chemicals than the type A cabinet. Type B2 cabinets exhaust all inflow and downflow air to the atmosphere through a HEPA filter without recirculation in the cabinet. Hazardous volatiles may be used in this type of cabinet.

Class III.  The Class III cabinet is a totally enclosed, gas tight, ventilated, negative pressure cabinet. Operations within the cabinet are conducted through attached rubber gloves. Supply air is drawn through HEPA filters and air is exhausted outdoors through two HEPA filters in series. All procedures involving infectious agents are contained within the cabinet, providing the highest level of personnel, product, and environmental protection. Class III cabinets are also known as glove boxes, however, not all glove boxes are Class III biological cabinets.

Biological agents.  Class I and II cabinets are designed for general research operations with low and moderate risk biological agents (Biosafety levels 1, 2, and 3). Class I and II cabinets are not recommended for use with highly infectious agents (Biosafety level 4) because an interruption in the inward air flow could allow aerosols to escape from the cabinet. Work with high risk biological agents (Biosafety level 4) must be performed in a Class III cabinet.

Volatile solvents.  Work with biological agents involving volatile solvents must be performed in Class II, type B cabinets. The selection of a B1 or B2 cabinet will depend on the amounts and hazards of solvents used. Substantial quantities of hazardous volatiles should be used in a B2 cabinet.

Exhaust.  All type B cabinets must be ducted to the outside. Class I and Class II type A cabinets may discharge exhaust air to the room although it is preferable to discharge exhaust air outdoors.

Certification.  The design of Class II cabinets must meet National Sanitation Foundation Standard 49. The integrity of Class II cabinets must be certified upon receipt, any time the cabinet is moved, and at least annually.

Carcinogens.  A specifically modified Class I cabinet that exhausts to the outside, a Class II type B1 or B2, or Class III biological safety cabinet may be used for chemical carcinogens.

Miscellaneous Safety Equipment

First aid kits.  First aid kits should contain adequate first aid instructions and an assortment of material packaged in single disposable packages. Bottles of antiseptic liquids or tubes of antiseptic creams that can break or leak should be avoided. A kit should be readily available when work is performed. The location of the kit should be clearly identified and access should not be blocked. Phone numbers for emergency personnel should be posted in the same area. The kit should be inspected periodically and re-supplied as necessary.

Machine guards.  Mechanical equipment, such as vacuum pumps, must be adequately guarded to prevent access to rotating parts, pulleys or electrical connections. Guards on fan blades shall have openings no larger than one-half inch.

Safety shields.  Transparent safety shields made of shatter-proof glass, polycarbonate, acrylic, or similar material should be used to protect the worker from potentially explosive reactions. This includes highly exothermic reactions, evaporation of ethers, and the heating of chemicals such as polynitro compounds, diazo compounds, diazonium compounds, peroxides, metallic acetylides, and perchlorates. Portable shields may be used to protect against limited hazards such as small splashes and fires. Fixed shields that surround the process on all available sides should be used if detonation is possible.

Fire blankets.  Fire blankets should only be used as a last resort to extinguish clothing fires because they may hold the heat in and increase the severity of burns. Fire blankets should be used primarily to prevent shock in an accident victim.

Local exhaust.  Laboratory apparatus that discharges toxic vapors such as vacuum pumps, gas chromatographs, distillation columns, and Kjeldahl units, should be vented to an auxiliary local exhaust system. Venting outside a window is not acceptable.

3.0 Handling Laboratory Equipment

Although attention is usually concentrated on chemical hazards in laboratories, consideration must be given to the safe use of laboratory equipment. Equipment in the laboratory must be set up and operated properly to ensure that accidents are minimized. Cuts and burns from handling glassware are among the most common sources of laboratory accidents. Breaking glassware may cause a chemical spill and possible injury. Chemicals exploding in glassware can send fragments of glass flying into the laboratory. Vacuum systems may implode, sending flying glass and chemicals across the room. Flammable vapors contacting sparking electrical equipment may cause an explosion. Laboratory workers may be electrocuted if they handle electrical equipment improperly. The following safety procedures should reduce the potential for accidents in laboratories.

Glassware

Training.  Inexperienced users should receive training in the proper handling of glassware, especially with systems that present unusual risks such as excess pressure or vacuums.

Glassware selection.  The proper selection of glassware is very important because glassware is designed with unique characteristics and for specific operations. Systems containing custom glassware should be evaluated to ensure the integrity of the glass under all operational parameters. Only glassware specially designed for vacuum work should be used for that purpose.

Handling.  Careful handling and storage of glassware is necessary to prevent damage to the glassware and injury to the worker. Damaged glassware should be properly discarded. Care must be used while inserting glass tubing through a stopper or when connecting flexible tubing to the glass. The glass tubing should be polished, or rounded and lubricated with glycerine or stopcock grease. Hands must be protected with cloth or leather gloves. Hands should be held close together to reduce pressure on the tubing, and out of the direct line of the glass should it break. Vacuum glass apparatus should be handled with extreme caution. Dewar flasks and other glass vacuum vessels should be taped or shielded to protect against flying glass in case of an implosion.

Broken glass.  Gloves must be used to pick up broken glass, especially if the glass is contaminated. Small slivers should be picked up with a dustpan and broom. The custodial staff should not be asked to pick up contaminated broken glass. Broken glass should never be placed in a trash bag. Place broken glass in a box clearly marked "Broken Glass" and contact the custodial staff for proper disposal.

Distillation Apparatus

Water supply.  Most distillation units operate with water cooled condensers. Water pressure can change however, and cause unexpected problems. Inadequate water supply can allow distillate vapors to escape. Too high a flow can cause the tubing connectors to burst, flooding the laboratory. All flexible hoses should be free of cracks, slits, or kinks and kept away from hot plates and flames. All hose connections should be firm and clamped or wired for prolonged use. Flow rates should be approximately one liter per minute. For unattended operations, the water pressure should be regulated automatically.

Heating supply.  Heating mantles must be used to heat distillation flasks. A variable voltage transformer should be used. The temperature of the mantle must be monitored carefully. If left unattended the mantle must be connected to a thermal cut-off device that turns the heater off if too high a temperature is reached.

Distilled water supply units.  These units are usually intended to operate automatically and are left unattended for long periods. This unit must be equipped with a thermal cut off, independent of the temperature controlling devices. This feature is needed to prevent overheating that could cause a fire. When a still is set up, or ceases to operate, the Safety Office should be notified.

Vacuum Equipment

In a vacuum system the pressure on the outside of the containment vessel is greater than on the inside. A break in the container will cause an implosion, resulting in flying glass, splattered chemicals, and a possible fire. Even equipment under moderate pressure, such as those achieved in water aspirators, can be potentially hazardous. Another hazard associated with vacuum equipment is rapid pressure change that can draw hazardous liquids and gases into the building vacuum system or equipment.

Eye protection.  Depending on the hazard, safety goggles, impact resistant glasses, or face shields must be worn when working with vacuum equipment.

Glass vessels.  Glass flasks should be taped with friction tape or placed in a metal container large enough to hold the flask. If this is not possible, a safety shield should be placed between the flask and the operator. The vessel should be inspected for cracks or scratches before use. Only round bottomed or thick walled flat bottomed flasks specifically designed for vacuum work should be used. Ordinary glass ware, especially flat bottomed flasks, is not intended for vacuum work and may burst.

Dewar flasks.  Dewar flasks are capable of imploding from thermal shock or a very slight scratch. They should be wrapped with friction tape all the way up the neck or shielded in a wooden or metal container to guard against flying glass in case of an implosion.

Vacuum desiccators.  Glass vacuum desiccators should be made of glass specifically designed for vacuum work. They should be enclosed in a shield or wrapped in friction tape.

Vacuum distillations.  The reaction flask should be taped and placed in a wire cage. The distillation should be performed behind an explosion shield. Operators should wear a face shield. A safety trap should be used to protect equipment (such as a manometer) and the vacuum source from contamination. Pressure should be equalized slowly after the experiment is over and the flask has cooled to room temperature.

Water aspirator.  A trap or check valve should be placed between the aspirator and the container under vacuum to prevent water from being drawn back from the aspirator into the container.

Vacuum pump.  A safety trap should be placed between the apparatus and the pump to prevent solvents and corrosives from getting into the pump oil or the atmosphere of the laboratory. Exhaust from pumps should be vented to a hood.

Mercury manometers.  A sudden change in pressure may cause the mercury to break the closed end of the glass tube and scatter the mercury. A capillary section should be incorporated into the manometer that will prevent surges or a bleeder arrangement should be installed into the trap. The manometer should be placed in a container that will hold any spilled mercury.

Electrical Hazards

The improper use of electrical equipment is a common source of accidents in laboratories. Electrical shocks, fires, and explosions are some of the potential hazards found in the laboratory. Effects of contact with electrical circuits range from a mild tingling sensation to painful shock and burns to cardiac arrest. Because electrical shorts often get worse, any equipment that produces a mild shock should be reported immediately and removed from service. Proper design of equipment, maintenance, and training of personnel should reduce these hazards.

Shock hazards.  To reduce shock hazards, all electrical equipment must be properly grounded. Electrical outlets in the laboratory will be tested periodically for proper grounding. Equipment that does not have a three-prong plug should be re-wired unless it is double insulated. Electrical equipment should not be handled with wet hands or while standing on a wet floor. Wet equipment should never be turned on. Any electrical equipment that emits noises and odors should be turned off and unplugged. Safety devices or interlocks on electrical equipment should not be bypassed.

CPR.  As an added precaution in case of electrical shock, several individuals in each department should be trained in CPR.

Location.  Electrical equipment should be located to reduce the possibility that water or chemicals could be spilled into the equipment.

Repairs.  The power must be turned off before modifying any circuit or servicing any equipment. Electrical equipment should only be serviced by qualified individuals. High voltage equipment must be serviced by qualified electricians. A sign must be posted if an interlock or safety device has been bypassed for repair purposes.

Equipment used with flammables.  Arcing electrical equipment may cause an explosion in laboratories where volatile flammable solvents are used. Equipment with non-sparking induction motors and enclosed electrical contact must be used with volatile flammable solvents. This applies to the motors used in vacuum pumps, mechanical shakers, heating devices, magnetic stirrers and rotary evaporators. Kitchen appliances such as mixers and blenders are not equipped with induction motors and should not be used in labs if flammable materials are present. Electrical fixtures may need to be explosion-proof if flammable vapors or gases reach high concentrations. Flammable liquids must be stored in explosion-safe or explosion-proof refrigerators or freezers.

Guards.  Live parts of electrical equipment operating at 50 volts or more shall be guarded against accidental contact.

Power cords.  Equipment should never be unplugged by pulling or jerking on the power cord. Electrical cords should be inspected periodically to ensure the integrity of insulators and contacts. All frayed or damaged line cords must be replaced.

Extension cords.  Extension cords are for temporary use only and are not designed to replace permanent wiring. Insulation and wire size should be adequate for the voltage and current carried. Extension cords should be as short as possible and protected so they do not present a trip hazard.

Access.  Sufficient access and working space shall be provided around electrical equipment to permit safe operation of the equipment. Access to switch boards, control panels, switches and circuit breakers shall not be obstructed. Breaker panels must properly identify the circuits within the lab.

Receptacles.  All 110 V receptacles in labs should be of the standard design that accept a three-prong plug and provides a ground connection. All electrical wiring in labs must meet specifications of the National Electrical Code. An adequate number of receptacles should be provided at the laboratory bench to remove the need for extension cords and long lengths of cords. Receptacles that provide electric power for operation in hoods should be located outside of the hood. This location prevents the production of electrical sparks inside the hood. Circuits should not be overloaded by using multiple sockets and extension cords.

Heating Devices

Heating devices are the most common type of electrical device found in the laboratory. Although much safer than Bunsen burners, these devices pose electrical and fire hazards if used improperly.

Variable transformer.  Variable transformers control the temperature on many laboratory heating devices. Because some sparking may occur when the control knob is turned, transformers should be located where they will not be exposed to flammable liquids or vapors. Connections from the variable transformer to the heating device should not be done with alligator clips because of the potential shock and spark hazard. Heating devices left unattended overnight should be equipped with a device that turns the power off if a preset temperature is exceeded.

Heating element.  The heating element in any laboratory heating device should be enclosed in an insulated case that prevents contact with the worker and protects against sparks.

Laboratory hot plates.  Laboratory hot plates are normally used when solutions must be heated above 100 C. Hot plates should be designed specifically for laboratory use. Household type units should never be used in the laboratory. Hot plates with exposed heating elements or spark producing switches should not be used to heat flammable liquids. Care should be exercised when heating solvents on hot plates with enclosed elements to ensure that the liquid does not boil over into the electrical heating equipment.

Hot air blowers.  Hot air blowers are used to dry glassware and samples, heat plastic tubing, and to heat the upper parts of a distillation apparatus. Although hot-air blowers provide flameless heat, they are potentially hazardous because the heating element is open and the switches and motor are usually not spark free. Hot air blowers should not be used near open containers of flammable liquids or where there may be appreciable concentrations of flammable vapors. Household hair dryers should only be used if they are double insulated or have a three-prong plug.

Heating mantles.  Heating mantles consist of an insulated electric heating element enclosed in several layers of fiberglass cloth. They are commonly used to heat round bottom flasks, and related reaction vessels. Heating mantles should always be used with a variable auto-transformer. Exceeding the voltage recommended by the manufacturer may cause the mantle to melt and expose the bare heating element. Fiberglass mantles protected by outer metal cases should be grounded to protect the worker in case the heating element shorts against the metal case. Precautions should be taken to prevent water or other chemicals from spilling into the mantle and creating a shock hazard.

Oil baths.  Electrically heated oil baths are commonly used when a constant temperature is needed. Mineral oil, paraffin and glycerin are used for temperatures below 200 C. Silicon oil is used for temperatures up to 300 C. Oil baths must be carefully monitored to ensure that the temperature has not approached the flash point of the oil vapor. If the oil bath thermostat fails, the oil will overheat and a fire may start. Heating baths containing combustible liquids must have an independent thermal cut-off to ensure that the system will not reach a temperature high enough to ignite the oil bath.

Heated oil should be contained in a metal pan or heavily-walled porcelain dish; never in a glass dish or beaker. The oil bath should be mounted on a stable horizontal support such as a laboratory jack. Because of its instability, an oil bath should never be mounted on a ring stand. Water should never contact the hot oil. Highly oxidizing substances (perchlorates, nitrates, peroxides) should never be heated in an oil bath.

Laboratory ovens.  Electrically heated ovens are commonly used in the laboratory to remove water or solvents from chemicals and to dry glassware. Because these ovens are usually improperly vented, gases and vapors produced in them will discharge into the laboratory atmosphere. It is also possible for dangerous concentrations of explosive and flammable mixtures to build up inside the oven. Many fires have started by placing solvents with low flash points in ovens at temperatures where they will ignite.

Ovens should never be used to dry toxic chemicals that are even moderately volatile unless the oven is properly vented. Glassware rinsed with an organic solvent should be rinsed with distilled water before being placed in the oven to dry. Because of the explosion hazard, laboratory ovens should be constructed so that the heating element and temperature controls are physically separated from the interior atmosphere. Ovens not meeting these requirements should be posted with a sign stating "This oven is not safe for flammable liquids."

4.0 Handling Chemicals

Accidents associated with the handling of chemicals in laboratories can occur during storage, use, and disposal of the chemical. Personnel may be exposed to hazardous chemicals that present health hazards, such as toxins and corrosives, and physical hazards that may result in fires and explosions. These risks can be minimized by following the general precautions recommended below. Recommendations for handling specific classes of chemicals are presented in the succeeding chapters.

Ordering

The potential hazards of a chemical should be known before ordering. Personnel must receive adequate training in handling the material, and plans must be made to store and dispose of the chemical properly before it is received. Chemicals should be properly labeled, inventoried, and a material safety data sheet (MSDS) should be available. Preferably, all chemicals should be received in a central location.

Quantity.  To reduce waste disposal costs, only the smallest quantity of a chemical needed for the experiment should be ordered.

Material safety data sheets.  Hazardous chemicals should not be accepted unless a MSDS is on file with the Department or the Safety Office.

Labels.  In accordance with Globally Harmonized System of Classification and Labeling of Chemicals (GHS), and in compliance with OHSA 1910.1200; labels on incoming chemicals must contain the name of the product or chemical, identify hazardous ingredents or components, display the appropriate signal word, appropriate physical, health, environmental hazard statements, supplemental information, precautionary measures & pictograms, first aid statements, and the name and address of the manufacturer. Unlabeled chemicals must not be accepted.

Inventory.  All departments should maintain an inventory of hazardous chemicals.

Free materials.  The recipient should limit the amount of free material to that needed. The donor should agree in writing to dispose of any excess material in a legal and safe manner. If the free material poses any safety or health risks or would cause any storage or disposal problems, the Safety Office should be notified to resolve the problems posed by the gift.

Controlled substances.  Authorization to use controlled substances for research purposes is normally held by the department head. The holder of the license must sign all purchases and maintain records of the purchase. Copies of the license must be provided to the Safety Office. Contact the Safety Office for information on obtaining a Controlled Substance Registration. 

Radioisotopes.  All orders for radioisotopes must originate from an Authorized User approved by the Radiation Safety Committee. The Authorized User's name must be on the requisition. The requisition must be signed by the department head and sent to the Safety Office for approval. Purchasing will return unapproved requisition to the initiating department.

The Safety Office should be notified to arrange for prompt delivery of short half-life materials. Phone orders must be approved by the Safety Office. Phone orders will be made by the Safety Office or the purchasing department.

All radioactive material will be shipped to the Safety Office. The Safety Office will maintain records of the transaction, perform a radiological survey of the package and deliver the package to the Authorized User. Radioactive materials cannot be mailed directly to Authorized Users.

Regulated carcinogens.  The use of OSHA regulated carcinogens can involve a long list of requirements concerning recordkeeping, posting, containment, facilities, training, monitoring, contamination control, and medical surveillance. To ensure that regulated carcinogens are used properly the Safety Office should be notified before ordering these materials.

Ethers.  Ethers pose a special problem because they often form highly explosive peroxides as they age. The smallest amount needed for immediate use should be purchased. Containers must be dated when purchased and disposed of after 12 months if unopened, or after six months if opened.

Perchloric acid.  Perchloric acid is an extremely corrosive agent that requires special precautions. It becomes explosive under a variety of conditions, such as heating, dehydrating, combination with organic materials, and shock. Because of these hazards the Safety Manager should be notified when ordering perchloric acid in concentrations greater than 72%.

Flammable liquids.  Flammable and combustible liquids must be purchased and stored in containers that do not exceed the following sizes:

Class Glass or Plastic Metal (non DOT) Metal (DOT) Safety Cans
Class IA 1 pt 1 gal 60 gal 2 gal
Class IB 1 qt 5 gal 60 gal 5 gal
Class IC 1 gal 5 gal 60 gal 5 gal
Class II 1 gal 5 gal 60 gal 5 gal
Class III 1 gal 5 gal 60 gal 5 gal

Chemical Storage

Numerous hazards are associated with the storage of chemicals. Accidents can be reduced by the careful planning of storage procedures and facilities. Chemical containers should be periodically inspected to ensure that labels are legible and intact, containers are not leaking or rusting, and that chemicals have not dangerously deteriorated or peroxidized. Containers should always be kept tightly sealed. Storage in laboratories should be minimized. Chemicals should be inventoried periodically and unnecessary chemicals returned to the stock room or disposed of through the Safety Office. Individual chapters on chemical classes should be consulted for additional information on storage procedures.

Location.  Chemicals should be stored in a definite storage area and returned to that location after each use. Chemicals should be stored on shelves with a one-half inch retaining lip. Shelves should not be above shoulder height. Shelves should be sturdy and coated with chemically resistant paint. Chemicals should not be stored on bench tops or in hoods. Storage areas should be cool, dry, well ventilated, and out of direct sunlight.

Incompatibles.  Every effort should be made to separate chemicals that may react together and create a hazardous situation. A common and unsafe practice is storing chemicals alphabetically. This practice often allows explosions, or the release of toxic vapors. Chemicals should be stored according to chemical class. Further information is available from the Safety Office on incompatible chemicals.

Carcinogens.  Stock quantities of carcinogens should be stored in a designated area or cabinet and posted with the appropriate hazard sign. Volatile chemicals should be stored in a ventilated storage area in a secondary container having sufficient volume to contain the material in case of an accident. Storage areas should be separated from flammable solvents and corrosive liquids.

Toxic chemicals.  Toxic chemicals should be stored away from fire hazards, heat, and moisture, and isolated from acids, corrosives, and reactive chemicals. Special care should be taken to ensure that toxic chemicals are not released into the environment. Access to the storage area should be restricted for highly toxic chemicals. Highly toxic chemicals should be stored in unbreakable secondary containers.

Corrosives.  Corrosive chemicals should not be stored with combustibles, flammables, organics, and other highly reactive and toxic compounds. Acid and bases should not be stored together. Organic acids should be separated from sulfuric, nitric, perchloric acid and other strong oxidizers.

Flammable liquids.  Storage in laboratories is limited to 10 gallons outside of flammable storage cabinets or safety cans. Storage in glass containers is limited to 1 pint for Class IA liquids and 1 quart for Class IB liquids unless permission has been obtained from the Safety Manager.

Flammable liquids should not be stored near exits, sources of heat, ignition, or near strong oxidizing agents, explosives, or reactives. Smoking is prohibited in storage areas. Storage areas should be adequately ventilated to prevent vapor building up. Adequate fire extinguishers should be readily available. Metal dispensing and receiving containers should be grounded and bonded together by a suitable conductor to prevent static sparks.

Reactives.  Reactive chemicals should be protected from shock, heat, ignition sources, and rapid temperature changes. Containers should be separated from corrosives, flammables, organic materials, toxins, and other reactive chemicals. Depending on the quantity, explosives may need to be stored in specially constructed magazines. Water reactive chemicals should be separated from sprinkler systems, emergency showers, eyewash stations and other water sources. Keep containers well sealed. Store water reactives under an inert non-flammable solvent.

Explosion hazards.  Ethers, picric acid, and perchloric acid that have deteriorated in storage present potential explosion hazards. Ethers older than one year and picric acid and perchloric acid with visible crystal formation should not be touched or opened. The Safety Manager should be called for proper disposal of these items.

Compressed gases.  Cylinders must be secured, and stored upright with the valve protector in place. Storage areas should be well ventilated and dry. Cylinders should be stored away from ignition sources, heat, and combustibles. Flammable gas cylinders and oxidizing cylinders in storage must be separated by 20 feet or a 5-foot high wall with a half-hour fire rating. Highly toxic gas cylinders must be stored in occupied areas in a way that will not contaminate breathing air.

Drugs.  Individuals holding licenses to use drugs in their research must provide safe secure storage for these drugs. The storage must be lockable and difficult to move.

Radioisotopes.  The license to use radioisotopes requires the university to rigorously enforce the rules of the NRC. The rules require that all radioisotopes be kept in locked, secure storage when not in use or when an unauthorized user is not physically present.

Ethers.  Ethers should be ordered only in small quantities, dated upon arrival and discarded within six months of opening. Unopened containers should be disposed of after one year.

General Safety Practices

Most laboratory chemicals are hazardous and should be handled with precautions. These hazards include toxic and corrosive chemicals that can damage health, and chemicals that can cause fires and explosions. Many accidents occur because the hazard was not known or it was underestimated. However, most laboratory accidents occur because workers became careless with commonly used substances with known hazards. To reduce accidents in laboratories, individuals must accept responsibility for carrying out their work according to good safety practices. Personnel should always strive to minimize their exposure to chemicals. The following general safety procedures are designed to minimize the likelihood of an accident while working with hazardous chemicals.

Planning.  Work should be planned carefully; appropriate planning can substantially reduce the risks in using chemicals. Always know the potential hazards and safety procedures associated with any chemical or operation before beginning the work. Consult this manual for general information on chemical classes and the Material Safety Data Sheet for detailed information for specific chemicals. The following factors should be considered before using hazardous chemicals in research projects or classrooms:

  • Hazards associated with the use of the chemicals.
  • Alternate chemicals or procedures that would be safer to use.
  • Safety training for personnel.
  • Personal protective equipment.
  • Safety equipment.
  • Modifications to the facility.
  • Storage facilities.
  • Hazardous waste disposal.
  • Chemical spills.

Training.  Personnel working with, or potentially exposed to, hazardous chemicals must receive training on the hazards of chemicals in their work area and safety procedures. Training will be provided at the time of the employee's initial assignment and prior to exposure to new hazards. Training must contain the following information:

  • Methods and observations to detect the presence of hazardous chemicals in the work place.
  • Physical and health hazards of chemicals including signs and symptoms of an overexposure.
  • Procedures to protect against hazards including proper work practices, emergency procedures, safety equipment, personal protective equipment, and first aid procedures.
  • Contents of the Chemical Hygiene Plan.

Emergencies.  Telephone numbers of emergency personnel and supervisors should be prominently posted in each laboratory.

Reference materials.  MSDSs, reference materials on hazardous chemicals, and permissible exposure limits are available in the Safety Office.

Inspections.  The Safety Office will periodically inspect laboratories to ensure that the use of hazardous chemicals conforms with University regulations. Preliminary discussion with the Safety Director is encouraged to reduce potential problems associated with new research. 

Chemical Hygiene Officer.  The Safety Director will serve as the Chemical Hygiene Officer for the university. This person is qualified by training or experience to provide technical guidance in chemical and laboratory safety. The Chemical Hygiene Officer will develop and implement a chemical hygiene plan for the safe use of chemicals in laboratories at the university.

Laboratory supervisor.  The laboratory supervisor is responsible for daily chemical hygiene in the laboratory. Specific duties are to ensure that employees are trained properly in chemical hazards, wear appropriate protective equipment and follow the rules in the Chemical Hygiene Plan.

Chemicals spills.  Appropriate equipment for the proper handling of chemical spills (sand, soda ash, sodium bicarbonate, or a commercially available spill kit) should be readily available.

Transportation.  Glass bottles of flammable solvents, corrosive, and toxic chemicals should be transported in rubber buckets or similar protective carriers.

Hygiene.  Since most chemicals are harmful, chemicals should not come in contact with the skin. Wash thoroughly with soap and water if chemicals contact the skin, before leaving the laboratory, and before eating.

Eating & drinking.  Many chemicals used in the laboratory are extremely dangerous if ingested. Contamination of food and drinks is a potential route of exposure to these toxic chemicals. A well defined area within the laboratory may be established for the storage, handling, and consumption of food. Chemicals or chemical equipment must not be allowed in this area. Food should never be consumed in laboratory glassware. The storage, handling, and consumption of food is prohibited in certain high risk laboratories such as carcinogenic research laboratories, levels 3 & 4 biological laboratories, pesticide laboratories, and laboratories working with highly toxic compounds. Food meant for human consumption and chemicals or biological specimens must not be stored in the same refrigerator. A refrigerator should be designated for food storage only and appropriately labeled.

Housekeeping.  Work areas should be kept clean and orderly, chemicals should be properly labeled, and equipment and chemicals should be properly stored. Chemicals should be used in a systematic way. Reagents should be capped and returned to their normal storage location after use. Unlabeled containers and chemical waste should be disposed of promptly using established procedures. Chemicals that are no longer needed should be disposed of properly. Chemicals should not be stored in aisles where they could be knocked over. Spilled chemicals should be cleaned up immediately. The Safety Manager should be notified immediately in the event of a large spill or one involving toxic materials. Laboratory benches and floors should be cleaned daily to reduce the quantities of accumulated chemicals that could pose respiration hazards.

Pipetting.  Mouth pipetting of chemicals is strictly prohibited. Always use a pipet bulb or similar mechanical device.

Personal protective equipment.  Exposure to hazardous chemicals should be avoided. Appropriate eye protection must be worn at all times by anyone working or visiting an area of the laboratory where experiments are underway. Other protective equipment such as face shields, gloves, protective clothing, and respirators should be worn as necessary.

Personal apparel.  Long hair should be confined. Shoes should be worn at all times. Workers should not wear sandals, perforated shoes, or sneakers.

Shielding.  Any reaction that has the potential for explosion or splashing should be guarded on all accessible sides with a safety shield.

Labels.  In accordance with Globally Harmonized System of Classification and Labeling of Chemicals (GHS), and in compliance with OHSA 1910.1200; labels on incoming chemicals must contain the name of the product or chemical, identify hazardous ingredents or components, display the appropriate signal word, appropriate physical, health, environmental hazard statements, supplemental information, precautionary measures & pictograms, first aid statements, and the name and address of the manufacturer. Carefully read the label, noting the name and hazard information. Many chemicals have similar names. Secondary chemicals not intended for immediate use during the work shift must be labeled with the name of the chemical and the appropriate hazard warnings. Containers with illegible or missing labels should not be accepted or used. These chemicals should be disposed of by calling the Safety Office.

Material safety data sheets (MSDS).  MSDSs must be maintained for all incoming shipments of chemicals and made readily accessible to employees.

Smoking.  Smoking is prohibited in laboratories that use or store flammable solvents.

Working alone.  Hazardous experiments and work with chemicals that may be immediately dangerous to life and health should not be conducted alone.

Unattended operations.  Reactions that may continue overnight should be posted with a warning sign containing the name and phone number of the operator. These operations should contain safety equipment that will shut the reaction off in case of an emergency, e.g., automatic water regulators and thermal cut-off devices.

Flammables.  Open flames should not be used to heat flammable liquids. Before lighting an open flame ensure that all flammables have been removed from the area and that all flammables are tightly closed. Use only non-sparking electrical devices to heat flammable liquids.

Fume hoods.  Potentially explosive reactions and operations involving the release of hazardous toxic or flammable vapors, or reactions releasing noxious vapors must be performed in a fume hood.

Medical consultation.  Personnel must receive medical attention whenever symptoms associated with a possible overexposure are noted or when monitoring shows an exposure routinely above the action level for an OSHA regulated substance.

Air monitoring.  Routine monitoring of airborne concentrations of chemicals is normally not warranted in laboratories. Monitoring may be necessary, however for work with certain OSHA regulated carcinogens.

Horseplay.  Practical jokes or other behavior that might startle, confuse, or distract another worker must be avoided.

Handling Major Spills

Initial Response and Notifications

1. Any incident which could endanger facility occupants, property, or the environment should be treated as a major spill. If you are unsure about the severity of the spill or the hazards are unknown, treat it as a major spill. In addition, any fires involving hazardous chemicals or spills that causes any injury such as unconsciousness should be considered a major spill.

2. The following are examples of spills that should be considered major:

Type of spill Amount Examples
Extremely flammable liquids (flash point <0 F) > 1 pint ethyl ether
Flammable liquids (flash point <100 F) > 1 quart toluene
Combustible liquids ( flash point >100 F) > 1 quart mineral spirits
Highly toxic liquids > 1 pint acrylonitrile
Toxic liquids > 1 quart ammonia
Concentrated acids > 1 gallon sulfuric acid
Concentrated alkalis > 1 gallon lye solution
Concentrated Hydrofluoric Acid any amount Hydrofluoric Acid
Poisonous, reactive materials any amount cyanides, sulfides
Oxidizing agents > 1 pound concentrated nitric acid
Leaks from gas cylinders uncontrolled chlorine, acetylene

3. Do not attempt to clean up a major spill. Only individuals who have received the 40-hour HAZWOPER training course and are part of an emergency response team should clean up major spills.

4. If flammable or combustible liquids are spilled, immediately turn off all sources of ignition.

5.  Evacuate persons in the immediate vicinity of the spill. Remove injured personnel to fresh air or an emergency shower or eyewash. If occupants in the building are in danger, pull the fire alarm to evacuate the building. Evacuate to an upwind location for toxic gases such as chlorine. Assemble in a designated area well away from the building. Distances from the building will be determined from the DOT Emergency Response Guidebook based upon the type of spilled material. Individuals trained to at least the first responder operations level (Level II) will determine the evacuation distance.

6. On your way out, open windows and turn on a hood, if possible. Close the sash if the spill was in a hood. Close the door and turn off the air conditioning and ventilation systems to prevent vapors from spreading throughout the building. Do not put yourself in danger.

7. Report the spill to the University Police Department. The Police Department will call the Safety Manager. If appropriate, the Police Department will also call the Vice President for Finance and Administration. If deemed appropriate, the Vice President of Finance and Administration will notify the President.

8. Provide the following information. Wait in a safe place for emergency personnel to arrive and direct them to the spill:

  • Name and telephone number of the caller
  • Location of the spill
  • Name and quantity of materials involved
  • Extent of injuries, if any
  • Environmental concerns, such as the location of storm drains & streams
  • Any unusual features such as foaming, odor, fire, etc.

9. If you have been properly trained (at least Level III training) and can do so without putting yourself in danger, don appropriate PPE and attempt to stop the leak or reduce contamination by quickly doing the following:

  • Close a valve
  • Upright a drum
  • Roll a drum to point the leak up
  • Put a container under the leak
  • Surround the leak with spill booms
  • Surround storm drains and sanitary drains with spill booms
  • Place an oil-only boom in streams to absorb petroleum products

10. The Safety Office will obtain the MSDS during normal hours if the identity of the spill is known. The Police Department will obtain the MSDS after hours.

11. A Police Officer will proceed to the site and cautiously evaluate the situation while waiting for the Safety Manager. The officer will evacuate the building if there is clear danger to the occupants of the building. If the spill is clearly beyond the capabilities of the university to handle, the Police Officer will immediately call the Radford City Fire Department.

12. The Safety Office and Police Department will evaluate the hazards. The Safety Office will attempt to clean up the spill if it is within the capabilities of university personnel. Safety Office personnel will wear proper personal protective equipment based on the nature of the spill.

13. If the Safety Office cannot handle the spill they will call the Radford City Fire Department and a spill response contractor.

14. The Safety Office will notify the City of Radford and Pepper's Ferry Treatment Authority as soon as possible, but within four hours, of an accidental discharge into the sanitary sewer system. This notification will include the location, type of waste, concentration and volume, and corrective actions being taken. A written report must be submitted within five days describing the incident and the measures taken to prevent a future occurrence.

Specific Emergency Procedures

1. The Police Director is the Campus Emergency Coordinator and has overall responsibility at the spill site until the arrival of the Fire Chief. The Police Director will ensure that appropriate emergency responders have been called.

2. The Chief of the Radford City Fire Department or his designate will be the initial senior emergency response official at the scene and direct the clean-up operation.

3. Until the arrival of the Fire Chief, the Safety Manager will serve as the Incident Commander for a hazardous chemical spill. The Safety Manager will also serve as the safety official at the site and will be familiar with the emergency plan, facilities, emergency equipment, hazardous materials, chemical storage sites, and records. The Safety Manager has the authority to stop operations that pose an immediate threat to lives, property, or the environment.

4. The following monitoring equipment is available to the Safety Manager to take air samples to assess the spill and determine proper respiratory protection if needed:

  • Confined space meter that measures oxygen, LEL, CO, and H2S.
  • Photoionization detector for measuring VOCs.
  • Personal air sampling pump.
  • Natural-gas meter.

5. The Radford Fire Department in cooperation with university personnel will assess the severity of the spill, level of personal protective equipment needed, and implement appropriate emergency operations. If necessary, assistance will be requested from:

  • Department of Environmental Quality.
  • Radford University Police Department.
  • Radford City Police Department.
  • State Hazardous Waste Emergency Response Team.
  • Hazardous materials response teams from Giles County, Roanoke County, or Salem.
  • Radford University Facilities Management.
  • Local environmental contractors.
  • Virginia Tech Safety Office.

6.  An evacuation of the building may be ordered by the Fire Chief or the University Police Director.

7.  Site security and crowd control to prevent entry into the hot zone will be provided by the Radford University Police Department.

8. Assistance with university facilities and equipment will be provided by Facilities Management.

9.  As other emergency response teams arrive, the most senior emergency response official at the site will be in charge. All emergency responders and operations will be coordinated through this individual.

10.  Spills requiring Level A or B protection will be handled by an outside hazardous materials team. SCBAs and chemical resistant suits will be worn. Spills requiring Level C or D protection may be handled by properly trained individuals from the Fire Department or Radford University. Proper PPE will be worn. Operations in hazardous areas will be performed using a buddy system.

11. Victims of a chemical spill will be taken to the Carilion New River Valley Medical Center.

12. Emergency medical treatment will be provided by the Radford City EMS squad. First aid for emergency responders will be provided by RUEMS.

13. Decontamination of victims, equipment, and emergency responders will be performed under the supervision of the Safety Manager in cooperation with the Fire Department and outside contractors. Individuals performing decontamination will wear proper PPE and be trained in decontamination procedures. Decontamination equipment is stored in the paint room next to the Allen Building.

14. The Safety Office will notify the National Response Center if a reportable quantity is released and file a report with the Department of Environmental Quality if required.

15. Immediately after the emergency, the Safety Office will ensure that recovered waste and contaminated materials are properly disposed.

16. Within a week of the incident, the Safety Office will contact all parties involved in the incident and critique the emergency response. Necessary changes will be made to the plan.

Handling Minor Spills

Initial Response and Notification

  1. Spills that can be cleaned up by personnel on the spot are defined as minor spills. Minor spills are releases of low toxicity liquids or solids not generating dangerous gases or fumes, e.g., small acid and solvent spills, hydraulic fluids, fuel oils, etc. Minor spills are limited in quantity and pose no emergency or significant threat to the safety and health of employees.
  2. Notify persons in the immediate area and prevent access to the spill if possible. Evacuate persons in the immediate vicinity of the spill if they are in danger.
  3. If flammable or combustible liquids are spilled immediately turn off all sources of ignition.
  4. Avoid breathing vapors from the spill. Open windows and turn on a hood. Close the sash if the spill was in a hood.
  5. Contact the Safety Office if assistance is needed in cleaning up the spill.

Specific Emergency Procedures

  1. Determine the chemical name of the spilled material by checking labels and shipping papers. Obtain the MSDS and identify the hazards associated with the spill. Is it flammable, combustible, reactive, toxic, corrosive, or an oxidizing agent?
  2. Do not touch spilled materials. Consult the MSDS. Wear appropriate gloves, eye protection, and protective clothing if necessary. For concentrated acids and alkalis, a face shield is needed in addition to goggles. Wear an air-purifying respirator if hazardous gases, fumes, or dusts are present that are within the range of protection of the respirator. Ensure that proper cartridges are used. Anyone who wears an air-purifying respirator must be properly trained and medically evaluated.
  3. Stop the leak at the source and try to prevent the spill from spreading. Prevent the spill from entering drains or leaking onto the ground. Upright overturned containers. Turn the container so that a hole points up. Transfer liquids from leaking containers to new ones. Plug or patch a leaking drum. Surround the spill with an inert absorbent such as vermiculite or spill booms.
  4. Absorb small spills of acids, caustics, solvents, oil, and aqueous solutions with paper towels, spill pads, or spill control pillows. Paper towels should not be used for more than tiny amounts of volatile liquids because the paper will aid evaporation. Using tongs, carefully place the towels, pads, or pillows onto the spill. Pick up flammable liquid spill control materials using sparkproof tools (e.g. plastic, aluminum). Carefully pick up the saturated material with a scoop or tongs, place in a plastic bag, label, and dispose as hazardous waste. Keep oxidizers away from combustible materials (wood, paper towels, oil, etc.).
  5. For a large liquid spill, use a squeegee to bring the liquid into contact with absorbents. Always work toward the center of the spill. If an absorbent is not readily available cover the spill with a plastic sheet to reduce vaporization.
  6. Carefully push solids into a pile with a plastic scraper. Brushes and brooms may create an unacceptable dust hazard and should be used with caution.
  7. Acid and base residues that were not absorbed by the vermiculite or spill pillows should be removed with neutralizers. Small acid spills can be neutralized with sodium bicarbonate or sodium carbonate and alkali spills with sodium bisulfate, citric acid or vinegar. Commercial adsorbent spill control materials can also be used. Wash the contaminated area with soap and water to remove any remaining residues.

Mercury Spills

  1. To prevent spills, always store mercury in unbreakable plastic containers. Place instruments containing mercury in a tray large enough to hold the contents.
  2. Because mercury is toxic and volatilizes easily, clean spills up immediately. Wear appropriate gloves, eye protection, and respirator. Use mercury cleanup sponges or powder to amalgamate mercury droplets and prevent the emission of mercury vapors. Scoop up the amalgamated mercury and place it and all other contaminated items in a plastic bag for disposal as hazardous waste.
  3. A mercury vacuum, aspirator bulb, or suction flask may be necessary for large spills or droplets that are in hard-to-reach areas. Use mercury indicator powder to verify that all the mercury has been cleaned up. Wear a mercury vapor mask when cleaning up large quantities of mercury.
  4. Check for the presence of mercury vapors with an instrument or mercury vapor detector.

Hydrofluoric (HF) Acid Spills

  1. To prevent spills, always store mercury in unbreakable plastic containers. Place instruments containing mercury in a tray large enough to hold the contents.
  2. Because mercury is toxic and volatilizes easily, clean spills up immediately. Wear appropriate gloves, eye protection, and respirator. Use mercury cleanup sponges or powder to amalgamate mercury droplets and prevent the emission of mercury vapors. Scoop up the amalgamated mercury and place it and all other contaminated items in a plastic bag for disposal as hazardous waste.
  3. A mercury vacuum, aspirator bulb, or suction flask may be necessary for large spills or droplets that are in hard-to-reach areas. Use mercury indicator powder to verify that all the mercury has been cleaned up. Wear a mercury vapor mask when cleaning up large quantities of mercury.
  4. Check for the presence of mercury vapors with an instrument or mercury vapor detector.

5.0 Toxic Chemicals

Toxic chemicals are chemicals that can produce injury or death when inhaled, ingested, or absorbed through the skin. Damage may result from acute or chronic exposures and involve local tissue or internal organs. The extent of the injury depends on the dose administered, duration of the exposure, physical state, solubility, and interaction with other chemicals. Toxic chemicals include corrosives, systemic poisons, carcinogens, mutagens, and embryotoxins.

Dosage

The dose is the most important factor that determines if damage will result from exposure to a chemical. Chemicals vary tremendously in their toxicity. An excess of almost any chemical can be harmful and a sufficiently small amount of most chemicals will not cause injury. There is a threshold or no effects level that must be exceeded before toxic effects will be noticeable for most chemicals.

Although the toxicity and chemical structure of a compound are generally related, each compound must be studied independently to determine its toxicity. In determining the toxicity of chemicals it is common to use standardized terms called the median lethal dose (LD50) or the median lethal concentration (LC50). The LD50 is defined as the dose of a chemical that will result in the death of 50% of a group of test animals when ingested or applied to the skin in a single dose. It is expressed in milligrams of the chemical per kilogram (ppm) of body weight of the test animal. The LC50 refers to the concentration of a gas or vapor that will result in the death of 50% of the animals when inhaled.

A substance is considered toxic if the LD50 in test animals is between 50 ppm and 500 ppm when ingested, or between 200 ppm and 2000 ppm when in contact with the skin. The substance is also considered toxic if the LC50 is between 200 ppm and 20,000 ppm when inhaled. Examples of toxic chemicals include acrylonitrile, benzene, chloroform, hydrofluoric acid, and mercury. A substance is considered highly toxic if it has an LD50 in test animals of less than 50 ppm by ingestion, less than 200 ppm by skin contact, or the LC50 is less than 200 ppm. Examples of highly toxic chemicals include arsenic, hydrogen cyanide, fluorine, and phosgene.

Exposure

The toxicity of chemicals is also related to the duration of the exposure. Exposure to toxic chemicals is divided into two classes; acute toxicity and chronic toxicity.

Acute toxicity. An acutely toxic chemical causes damage in a relatively short time after a single concentrated dose. Irritation, burns, illness, or death may result. Hydrogen cyanide, hydrogen sulfide, nitrogen dioxide, carbon monoxide, chlorine, and ammonia are examples of acutely toxic poison gases commonly used in the laboratory. These substances may cause severe inflammation, shock, collapse or even sudden death when inhaled in high concentrations. Corrosive materials such as acids and bases may cause irritation, burns, and serious tissue damage.

Chronic toxicity. A chemical that is a chronic toxin produces long term effects. Damage may result after repeated exposures to low doses over time, as from the slow accumulation of mercury in the body, or after a long latency period from exposure to a carcinogen. Chronic exposure to solvents may result in reproductive problems and behavioral changes. The symptoms from exposure to chronic toxins are usually different from those seen in acute poisoning from the same chemical. Since the level of contamination is low workers may not be aware of the exposure.

Chronic toxicity also includes exposure to embryotoxins, teratogenic agents, and mutagenic agents. Embryotoxins are substances that cause any adverse effects on the fetus (death, malformations, retarded growth, functional problems). Teratogenic compounds specifically cause malformations of the fetus. Examples of embryotoxic compounds include organomercurials and lead compounds. Mutagenic compounds cause changes in the gene structure of the sex cells that can result in the occurrence of a mutation in a future generation. Approximately 90% of carcinogenic compounds are also mutagens.

Effects

Toxic effects are based on the site of action and are classified into local and systemic effects.

Local. The action of a toxin on the skin or mucous membrane at the point of contact is termed local toxicity or corrosivity. For example, acids have a local or direct irritating effect on the skin, eyes, nose, throat, and lungs. The skin may be severely burned or vision impaired. The lungs may be damaged as a result of inhaling toxic gases. Exposure may be through inhalation, ingestion, or direct contact with the skin or eyes.

Systemic. When a toxin is absorbed into the blood stream and distributed throughout the body, systemic or indirect toxicity may occur. Several sites may be damaged or the toxin may act on only one site. Arsenic, for example, may damage the blood, nervous system, liver, and kidneys when absorbed in toxic amounts. However, benzene only acts on one site, the blood forming bone marrow. Absorption may take place through the lungs, skin, or gastrointestinal tract.

Routes of Exposure

Toxic chemicals may enter the body through three routes: inhalation, ingestion, or contact with the skin and eyes.

Inhalation.  Inhalation of toxic substances represents the most common means by which injurious substances enter the body. Air contaminants in the workplace present both acute and chronic dangers to health. Inhalation of toxins can cause local damage to the mucous membranes of the mouth, throat, and lungs or pass through the lungs into the circulatory system and produce systemic poisoning at remote sites.

Thousands of deaths per year are attributed to occupational exposure from dust, fumes, gases, vapors, and mists. Exposure to organic dusts such as coal dust can cause asthma, chronic bronchitis, and emphysema. Mineral dusts such as asbestos can cause asbestosis, characterized by coughing and breathlessness, or mesothelioma, a cancer of the lung lining. Exposure to toxic chemical dusts may result in irritation, bronchitis, and cancer depending on the nature of the chemical. The poisoning effect may be fast or slow depending on the toxicity and concentration inhaled.

Breathing the fumes generated from the heating of heavy metals may result in metal fume fever characterized by irritation of the lungs, dry throat, chills, fever, and pain in the limbs. Cadmium fumes may cause emphysema. Exposure of hydrocarbons, chromium, beryllium, and arsenic fumes may cause lung cancer.

Exposure to acid and alkaline gases such as hydrochloric acid and ammonia will cause extreme local irritation to the lungs. Some gases such as carbon monoxide may pass into the blood stream and cause systemic injuries. Other gases such as vinyl chloride may cause cancer.

Vapors are the gaseous state of liquids. Exposure to vapors may cause nose and throat irritation, pulmonary edema or cancer.

Mists are fine suspensions of liquid in air and can cause chemical burns of the lungs, lung disease and cancer. Common mists include chromic acid, sulfuric acid, and sodium hydroxide from oven cleaners.

Many gases can be detected by their odor or irritating effect which results in an immediate warning so that injury can be averted. Ammonia, for example, is highly irritating and has an offensive odor. Other toxic gases, such as carbon monoxide, however, may have no odor or irritating effects. Deadening of the sense of smell may occur from exposure to some gases, such as hydrogen sulfide, and prevent the detection of toxic quantities. Pain may be delayed for several hours from exposure to other gases, such as hydrogen fluoride. Although sensory warnings may give adequate warnings sometimes, it should not be relied on as a primary defense.

Ingestion.  Anything ingested may be absorbed into the blood and cause systemic poisoning. Oral toxicity is generally lower than inhalation toxicity because of the relatively poor absorption of many chemicals from the intestines into the blood stream. The ingestion of laboratory chemicals may cause severe local damage to the lining of the mouth, throat, and gastrointestinal tract. In addition, if the chemical is absorbed into the blood stream, systemic poisoning may result. Ingestion of chemicals may occur from eating contaminated food, smoking cigarettes contaminated with chemicals, or swallowing chemicals deposited in the throat through inhalation.

Skin contact.  Chemical damage to the skin of the hands and arms is a common occupational injury in laboratories. Damage to the skin may include inflammation, burning, blistering, and complete destruction of the skin. The extent of the damage depends on the type of chemical, its concentration, and the duration of the contact. Chemicals that affect the skin are divided into two classes: irritants and sensitizers. Exposure to irritants can result in contact dermatitis, the most common occupational skin disease. Contact dermatitis is any local inflammation of the skin following exposure to damaging substances. Most organic and inorganic acids and metallic salts are strong irritants. Exposure to these chemicals can result in serious local damage to the skin often requiring medical attention. Exposure to milder irritants such as detergents and solvents may cause redness, burning, and swelling. The irritation is usually confined to the area of skin that contacted the chemical and may heal in a few days.

Initial contact with a chemical sensitizer may produce no reaction. Once sensitized, however, subsequent exposures may result in an allergic-type of response called contact allergic dermatitis. Reactions usually develop several hours after re-exposure and may last for several days. Skin reactions may also appear at sites remote from the initial contact. Once a worker has become sensitized to a chemical, very small amounts of it may trigger a reaction. Typical sensitizers include arsenic, mercury, nickel compounds, trichloroethylene, carbon disulfide, petroleum distillates, detergents, and many pesticides.

Skin contact is also the primary route of entry into the body for many hazardous chemicals. Chemicals such as organophosphates, aniline, hydrocyanic acid, and phenol may pass through the skin and cause serious or even fatal poisoning. The largest problem associated with skin absorption of chemicals occurs with organic solvents. Solvents such as benzene, carbon tetrachloride, and methyl alcohol may be absorbed in sufficient quantities to cause systemic injury or even cancer at other organ sites. In addition, some solvents such as DMSO may act as vehicles that carry other chemicals through the skin.

Eye contact.  The effects of accidentally splashing corrosive chemicals into the eye can range from minor irritation, to scarring of the cornea and loss of vision. Injury to the eye from bases is much more damaging than acid burns. Acids cause a protein barrier to form in the eye preventing further penetration of the acid. Bases, however, continue to soak into the eye and cause further damage. In addition, mists, vapors, and gases may produce varying degrees of damage to the eyes. Some chemicals may be absorbed by the eye and produce systemic poisoning.

Interactions

It is common in laboratories for workers to be exposed to a wide range of chemicals. Consideration must be given to the possible interaction of these chemicals and how they may affect personnel. There is growing evidence that many chemicals may have a synergistic effect and produce toxic effects that are much greater in combination than would be predicted from their individual effects. Since standards for permissible levels of chemicals are based on the effects of a chemical acting alone, it is prudent to keep exposures to the lowest possible level. Another possible hazard involves the interaction of chemicals with cigarettes. Cigarettes can convert chemicals in the atmosphere into more harmful forms. For example, chloroform can be converted by the heat from a cigarette into the highly toxic gas phosgene. Interactions may also occur inside the body of the worker, producing harmful metabolites.

Threshold Limit Values

Exposure limits to airborne concentrations of common chemicals are published yearly by the American Conference of Governmental Industrial Hygienists (ACGIH). These limits are recommendations, not legal standards, and represent conditions to which nearly all workers may be exposed without experiencing significant adverse effects. They are based on the best currently available data from industrial experiences, human population studies, and animal experiments. Three categories of Threshold Limit Values (TLV) are specified: Time Weighted Average (TWA), Short Term Exposure Limit (STEL), and Ceiling Value. TLV's are expressed in parts per million (ppm) or mg/cubic meter.

TWA.  The TWA is the concentration of an airborne chemical averaged over an eight-hour workday to which workers may be exposed to daily without sustaining injury. Exposure to concentrations above the limit is allowed as long as they are balanced by exposures below the limit and do not exceed the STEL or Ceiling Limit.

STEL.  The STEL is the maximum concentration a worker can be exposed to for fifteen minutes without suffering from irritation, chronic or irreversible tissue damage, or narcosis of sufficient degree to cause impairment.

Ceiling limit.  The Ceiling Limit is the concentration that should never be exceeded for any time.

PEL.  The legal maximum levels of airborne chemicals are determined by OSHA and are called Permissible Exposure Levels (PEL). Most of the OSHA Permissible Exposure Levels are adopted from the ACGIH Threshold Limit Value list. OSHA values are not updated yearly as are the ACGIH Threshold Limit Values.

The TLV and PEL should only be used as guidelines for good practice and should not be used as fine lines between safe and unsafe concentrations. It is always prudent to keep exposures to airborne contaminants as low as possible.

Classes

Lung irritants.  Lung irritants are chemicals that irritate or damage pulmonary tissue. Chemical irritants are classified as primary or secondary. Primary irritants exert their effect locally, for example, acid fumes burning the lungs. Secondary irritants, such as mercury vapors, may exhibit some local irritation but the main hazard is from systemic effects resulting from absorption of the chemical.

Irritation of the lungs may produce acute pulmonary edema (fluid in the lungs). Symptoms include shortness of breath and coughing that produces large amounts of mucous. Reactions to some chemicals may produce an allergic sensitization that causes asthmatic-type symptoms following additional exposures. Short term exposure to irritants is usually reversible with no permanent damage, however, systemic poisoning may persist and cause permanent damage.

The solubility of an irritant gas influences the part of the respiratory tract affected. For example, soluble gases such as ammonia, hydrogen chloride, and sulfur dioxide mainly irritate the upper respiratory tract. Insoluble gases such as nitrogen dioxide, carbon monoxide, and phosgene travel deeply into the lungs and cause irritation of the bronchi and air sacs. These gases are then absorbed into the blood stream and damage various organ sites. Some gases such as chlorine and hydrogen sulfide may affect the entire respiratory tract.

Skin irritants.  Although not as destructive as corrosive chemicals, skin irritants can cause severe rashes and dermatitis to the hands upon significant and repeated contact. Many common laboratory solvents, such as toluene and xylene, are irritants.

Asphyxiants.  Chemical asphyxiants prevent or interfere with the uptake and transformation of oxygen. Examples include carbon monoxide which prevents oxygen transportation, and hydrogen cyanide which inhibits enzyme systems and interferes with the transportation of oxygen to the tissues. At sufficiently high concentrations, both chemicals can result in immediate collapse and death.

Narcotics.  Narcotics affect the central nervous system causing symptoms that range from mild anesthesia reactions to loss of consciousness and death at high doses. Examples include acetone, methyl ethyl ketone, and chloroform.

Neurotoxins.  Neurotoxins interfere with the transfer of signals between nerves and may cause a collapse of the nervous system. Effects include narcosis, behavior changes, and decreases in motor function. Examples include ethanol, methanol, general anesthetics, mercury, carbon disulfide, and tetraethyl lead.

Hepatotoxins.  Chemicals that damage the liver. Effects include jaundice and liver enlargement. Examples include bismuth, mercury, uranium, carbon tetrachloride, heavy metals, and chlorinated hydrocarbons.

Nephrotoxins.  Chemicals that produce kidney damage. Effects include anemia, excessive amounts of protein in the urine and renal failure. Examples include arsenic, bismuth, chromium, lead, mercury, cadmium, glycols, phenols, halogenated hydrocarbons, and vinyl chloride.

Agents that act on the blood.  Chemicals that cause decreased hemoglobin function which deprives the tissues of oxygen. Symptoms include cyanosis and loss of consciousness. Examples include carbon monoxide, cyanides, metal carbonyls, nitrobenzene, and arsine.

Hematopoietic system.  Chemicals that interfere with the production of red blood cells. Symptoms include anemia and leukemia. Examples include arsenic, benzene, fluoride, iodide, and various nitro compounds.

Reproductive toxins.  Chemicals that can cause birth defects, spontaneous abortions, or sterility. Examples include lead, PCBs, selenium compounds, and vinyl chloride.

Organic solvents.  The vapor pressure of a chemical determines if it has the potential to be a hazard from inhalation. The vapor pressure is the pressure of the vapor in equilibrium with its liquid or solid form. The more volatile a chemical the higher its vapor pressure and the lower its boiling point. Solvents are a problem because they vaporize easily and produce high concentrations of vapor in the air. Common solvents have vapor pressures that can produce concentrations in the breathing zones of workers in the rage of 10 to 1000 ppm. Carbon tetrachloride, for example, has a TLV of 10 ppm and should always be used in a hood.

Inhalation of the vapors from organic solvents can pass to the heart and central nervous system very rapidly and cause a toxic reaction. An acute exposure to very high concentrations can cause unconsciousness and death. Chronic exposure can cause nausea, headaches, fatigue, and mental impairment. Injury to the organs of the body and damage to the blood may also occur. Studies have shown that low concentrations of common laboratory solvents in the air can adversely affect behavior, judgement and coordination. There is also evidence that chronic exposure to some solvents can cause cancer (e.g., benzene, carbon tetrachloride, and chloroform).

Contact with the skin may cause irritation, dermatitis, or an allergic reaction. Some solvents such as benzene and xylene may be absorbed through the skin and enter the bloodstream. Common laboratory solvents include toluene, xylene, benzene, carbon tetrachloride, formaldehyde, chloroform, and methyl alcohol.

Organic solvents are commonly divided into two classes: chlorinated and non-chlorinated solvents. Chlorinated solvents are usually non-flammable. Examples include carbon tetrachloride, chloroform, and trichloroethylene. Non-chlorinated solvents are generally flammable. Examples include xylene, benzene, and toluene.

Corrosive chemicals.  Corrosive chemicals cause visible destruction or irreversible alternations in living tissue at the site of contact. These chemicals can burn the skin, cause severe bronchial irritation, and blindness if splashed into the eyes. Examples include sulfuric acid, hydrochloric acid, sodium hydroxide, phosphorus pentoxide, fluorine, and perchloric acid.

Heavy metals and their compounds.  Heavy metals are relatively harmless in the metallic state, but their fumes, dust, and soluble compounds are well-known toxins. Some are carcinogenic, others are nephrotoxins, hepatotoxins, or neurotoxins. The most common heavy metals are arsenic, beryllium, cadmium, chromium, lead, mercury, nickel, and silver. Acute toxic effects from exposure to heavy metals result from inhalation and ingestion of dusts or inhalation of fumes. Metal fumes are generally more hazardous than dusts because the particles in fumes can enter the bloodstream easier. Bronchitis, chemical pneumonia, and pulmonary edema may result. Beryllium and cadmium are two of the most toxic metals when inhaled. Symptoms include nausea, vomiting, abdominal pain, and diarrhea.

Chronic exposure to heavy metals may lead to long-term effects. For example, chronic exposure to lead may damage the nervous system, brain and kidneys. Exposure to mercury over a long period can permanently damage the liver, kidney, and brain. Chronic inhalation of cadmium can cause emphysema and kidney damage. Carcinogenic effects have been shown from exposure to chromium, nickel, arsenic, cadmium, and beryllium. Prenatal effects have been observed from exposure to methyl mercury. In addition, some lead compounds are embryotoxic.

Some metals and their compounds can be absorbed through the skin. Mercury metal, and tetraethyl lead for example can enter the bloodstream through this route. Nickel, arsenic, chromium, and beryllium cannot penetrate the skin but they can damage the skin or cause allergic-type reactions.

Phosphorus and its compounds.  White phosphorus is highly toxic by ingestion and inhalation and is a fire and explosion hazard. Several inorganic phosphorus compounds are very corrosive. Examples include phosphorus pentoxide, phosphorus pentafluoride, and phosphorus pentachloride. Some compounds such as phosphine, phosphorus trioxide, and phosphorus tribromide are extremely toxic. Organic phosphorus compounds are widely used as pesticides. These compounds may cause acute and chronic poisoning. Poisoning may result from ingestion, inhalation, or absorption through the skin. Organophosphates act by inhibiting an enzyme called cholinesterase. Examples include malathion, diazinon, parathion, and TEPP.

Cyanides.  The simple metallic cyanides are highly toxic by ingestion. Cyanides are readily absorbed through the skin, mucous membranes, and by inhalation. Alkali salts are toxic by ingestion. Even small amounts of sodium and potassium cyanide are highly toxic and death may occur within minutes from ingestion. Inhalation of toxic fumes from hydrogen cyanide gas may result in death in a few seconds. Symptoms of poisoning include dizziness, headaches, tightness in the chest, palpitation of the heart, and difficulty in breathing.

Safety Procedures

Alternate reagents.  Before a chemical is used, information about its toxicity should be obtained. If the chemical is highly toxic, alternate reagents should be used if possible. For example, toluene or xylene can often be substituted for benzene. If the material must be used then adequate personal protection and containment are required.

Ventilation.  The best way to avoid exposure is to prevent the escape of toxic materials into the workplace by using adequate ventilation such as exhaust hoods. Solvent distillations, column chromatography, heating or evaporating solvents, and transfers from one container to another should only be done in a hood. Respirators may need to be worn if local exhaust ventilation cannot be provided. Respirators must be approved by the Safety Manager.

Hygiene.  To prevent the ingestion of toxic chemicals, workers should wash their hands immediately after using toxic chemicals, before leaving the laboratory, and before eating, drinking, smoking, or applying cosmetics.

Eating, drinking, or smoking.  Eating, drinking, or smoking is prohibited in areas where toxic chemicals are used or stored. Food and drinks should not be stored with toxic chemicals. Chemicals should never be poured into food or drink containers.

Mouth pipetting.  Mouth pipetting of toxic chemicals is prohibited.

Personal protection.  Skin and eye contact with chemicals should be avoided by using the appropriate eye protection equipment, gloves, respirators, and laboratory coats. Personal protective equipment must be approved by the Safety Manager.

Highly toxic chemicals.  Safety procedures for carcinogens should be followed when working with highly toxic chemicals.

Storage.  Storage areas should be well ventilated and away from sources of heat or ignition. Incompatible chemicals should not be stored together. For example, potassium cyanide should not be stored with acids because of the possibility of the formation of the extremely toxic gas, hydrogen cyanide.

Solvents.  Contact with solvents should be avoided by wearing appropriate eye protection and gloves. Tongs or a basket should be used to hold parts in a solvent bath. Hands should never be washed with a solvent. Inhalation of solvent vapors should be kept to a minimum. Work with volatile solvents should be done in a hood. Volatile solvents should not be used to any extent on the open bench. Open containers of volatile solvents should not be allowed on the laboratory bench.

Cyanides.  Cyanides should not be stored with acids or exposed to the air. Gloves, eye protection and protective clothing should be worn when working with cyanides. Personnel working with large quantities of cyanides should not work alone. Respirators and appropriate first-aid supplies should be readily available.

Heavy metals.  Inhalation of heavy metal dust should be avoided. Work must be conducted in a carefully controlled manner. Adequate exhaust ventilation is the most important factor in reducing exposure to heavy metals. Fine powders should be handled in a hood and care must be taken to avoid dispensing the metal into the laboratory atmosphere. For the most toxic compounds, a totally enclosed system may be required. Protective clothing such as gloves, laboratory coat, dust masks and eye protection must be worn. Respirators must be worn if engineering controls are not feasible. Removal of dust should never be done by dry sweeping or with an air hose. Surfaces should be cleaned by vacuuming with a special HEPA vacuum or wetting down the surface prior to sweeping. Water sprays should be used to prevent the formation of dust and to prevent dust from becoming airborne.

Mercury.  Every effort should be made to prevent spills of metallic mercury. Mercury flows easily and gets into cracks and crevices where it can be extremely difficult to pick up. Mercury also vaporizes very easily and creates an inhalation hazard. Under static conditions 0.03 grams (about 1/100 the volume contained in a standard laboratory thermometer) can volatilize into the air in a standard laboratory and exceed the threshold limit value. Mercury should be stored in unbreakable plastic bottles. Containers should be sealed, kept in a cool, well-ventilated area, and stored in secondary containers. Instruments containing mercury should be placed in a tray that is large enough to contain the mercury. Transfers of mercury from one container to another should be done in a hood over a tray to hold spills. Spills should be cleaned up immediately. Droplets should be pushed together and collected by suction using an aspirator bulb or a suction flask. Alternatively a commercial mercury clean-up kit that includes special pads for picking up mercury may be used.

When there is a danger of mercury volatilizing, adequate local exhaust ventilation should be installed. Workers should be protected with respiratory equipment if this is not possible. Toxic dust respirators do not offer protection from mercury fumes. Gas respirators only offer minimal protection. The most effective protection is a supplied air respirator if the process cannot be enclosed and local exhaust is not possible.

6.0 Corrosive Chemicals

Chemicals that cause severe local injury to living tissue are called corrosive chemicals. Accidents involving splashes of corrosive chemicals are very common in the work place. Damage to the skin, respiratory system, digestive system and the eyes may result from contact with these substances or their vapors. The seriousness of the damage depends on the type and concentration of corrosive material, length of the exposure, the body part contacted, and first aid measures taken.

Usually minor exposure to corrosive materials is reversible and healing is normal. However, severe exposure may cause permanent damage. Depending on the severity of the exposure, damage to the skin may range from redness and peeling to severe burns and blistering. Chronic exposure may result in dermatitis. Exposure to the respiratory system may range from mild irritation, to inflammation, chest pain, difficulty in breathing, pulmonary edema, and death. Mild exposure to the eyes may cause pain, tearing, and irritation while severe exposure may cause ulcerations, burns and blindness. Ingestion of corrosive chemicals may cause immediate pain and burning in the mouth, throat, and stomach followed by vomiting and diarrhea. Perforation of the esophagus and stomach is possible.

The concentration of a corrosive material also determines the extent of damage to the tissues. For example, a weak solution of acetic acid (vinegar) can be ingested and contact the skin without any harmful effects. However, concentrated acetic acid is highly corrosive and can cause serious burns to the tissues.

First aid measures must be taken immediately if corrosive chemicals contact the tissues. Corrosive chemicals that contact the skin or eyes should be immediately washed off with water for at least fifteen minutes. Inhalation victims should be moved to fresh air and artificial respiration started if breathing has stopped. If a corrosive material has been ingested, call the poison control center immediately.

If mixed or stored incorrectly corrosive chemicals can generate excessive heat, pressure, flammable, and toxic gases that can damage equipment, ignite combustibles, and lead to injury. During a fire, highly toxic gases may be released. Many corrosive chemicals have other serious hazards and may be classified as flammables, reactives, or toxins. For example, perchloric acid is a strong oxidizing agent that can explode under the right conditions.

Classes

Strong acids.  All concentrated strong acids can attack the skin and permanently damage the eyes. Acids usually cause irritation and pain immediately. Adding water to acids can cause the contents to be violently ejected. In general, inorganic acids are more hazardous than organic acids. Organic acids, however, can cause deep-seated burns on prolonged contact with the skin. Burns from acids are typically more painful, though less destructive than alkaline burns. Acids react differently in contact with the skin. Nitric acid, for example, reacts with the skin and forms a yellow burn. Sulfuric acid reacts with the moisture on the skin leaving a severe burn. Hydrofluoric acid has a delayed action and causes painful deep burns hours after the initial exposure. In addition to burns, exposure to hydrofluoric acid may cause a crippling disease due to fluoride deposition in bone. The vapors from many acids such as hydrochloric acid are soluble in water and cause irritation of the nose and upper respiratory tract. Vapors from other acids, however, are not soluble in water and do not cause irritation. For example, vapors from nitric acid may travel deep into the lungs and cause permanent damage and not be immediately noticed.

Strong acids are also hazardous because they can combine with other chemicals in storage and cause fires and explosions. Common strong acids include hydrochloric, nitric, sulfuric, hydrofluoric, and perchloric acids.

Strong alkalis.  The metal hydroxides, especially the alkali metal hydroxides, are extremely hazardous to the skin and the eyes. In contact with water considerable heat can be generated that can cause splattering of the material. Burns from alkaline substances are less painful than acid burns but possibly more damaging. The healing of serious alkaline burns is extremely difficult. Concentrated alkaline gases such as ammonia can cause severe damage to the skin, eyes, and respiratory tract. Dry bases can react with the moisture on the skin, eyes, and mucous membranes, causing serious burns. Examples of strong alkalis include sodium hydroxide, potassium hydroxide, and ammonia.

Non-metal chlorides.  Phosphorus trichloride, boron trichloride, aluminum trichloride, and silicon tetrachloride and their bromides are a common source of accidents. These chemicals react violently with water and are extremely hazardous to the eyes.

Dehydrating agents.  Because of their affinity for water, these compounds can cause severe burns to the eyes and skin. Violent reactions and splattering can occur when added to water. The strong dehydrating agents include concentrated sulfuric acid, sodium hydroxide, phosphorus pentoxide, calcium oxide, and glacial acetic acid.

Halogens.  The halogens are toxic and corrosive to the skin, mucous membranes, and the eyes. Fluorine gas is highly reactive with organic matter and will cause deep penetrating burns on contact with the skin. Chlorine is less reactive but still extremely hazardous. Bromine is a common source of eye damage because of its prevalence in teaching laboratories. In contact with the skin it can also cause severe, long lasting burns. Iodine vapor is irritating to the eyes and respiratory tract and may cause pulmonary edema. Skin contact may produce burns.

Oxidizing agents.  In addition to being corrosive to the skin, mucous membranes, and eyes, oxidizing agents are also fire and explosion hazards. Oxidizing agents readily release oxygen, increasing the ease of ignition of flammable and combustible materials and increasing the intensity of burning. Some compounds give up their oxygen at room temperatures while others require the application of heat. Powerful oxidizers such as perchloric, chromic, nitric, and sulfuric acids may react with organic compounds and readily oxidizable materials causing fires and explosions. Oxidizers include chlorates, perchlorates, bromates, peroxides, nitrates, and permanganates. The halogens are also considered oxidizing agents because they react the same as oxygen under some conditions.

Safety Procedures

Transportation.  Corrosive chemicals should always be transported in unbreakable safety containers. Carts used for moving chemicals should have a lip to prevent accidents.

Reactions.  Acids should always be added to water to prevent excessive heat generation and splashing. All corrosives should be mixed slowly. Many acids are also oxidizers and react violently with organic compounds and other acids. Nitric acid, for example, should never be mixed with Chromerge or a chromic acid/sulfuric acid mixture. Reaction vessels should not be heated in oil baths.

Personnel protective equipment.  Chemical goggles, aprons, and rubber gloves must be worn when handling corrosive chemicals. Gauntlets (sleeve coverings) may also need to be worn. Goggles should be supplemented with a face mask if the possibility of significant splashing exists. Contact lenses must never be worn when working with corrosive chemicals because they can trap chemicals against the eye. Suitable respiratory equipment should be available if a danger exists from inhaling toxic fumes.

Eye wash and emergency shower.  An OSHA approved eye-wash unit and emergency shower must be located in areas where corrosive chemicals are used. If corrosive chemicals contact the skin or the eyes, the area should be immediately washed with large amounts of water for 15 minutes.

Storage.  Storage should be in a cool, dry, and well-ventilated area away from direct sunlight. Corrosive chemicals should not be stored with combustibles, flammables, organics, and other highly reactive and toxic compounds. Acids and bases should not be stored together. Fire, explosion, or the release of dangerous gases or vapors may result if these chemicals combine. Organic acids should be separated from sulfuric, nitric, perchloric acid, and other strong oxidizers.

Corrosive chemicals should be stored below eye level to prevent splashes in the eyes or face. Shelving should be non-corroding. Strong oxidizing agents should be stored and used in glass or other inert container. Corks and rubber stoppers should not be used.

Ventilation.  Corrosive chemicals producing hazardous vapors and corrosive gases should be used with adequate exhaust ventilation. Chromic acid solutions must always be used in a hood because of the possible formation of volatile chromyl chloride, a serious toxic hazard and recognized carcinogen.

Perchloric acid.  Perchloric acid is an extremely corrosive chemical and strong oxidizing agent that requires special precautions. It becomes explosive under a variety of conditions, such as heating, dehydrating, combination with organic material, and shock. Consult the chapter on Reactive Chemicals for specific handling procedures.

Spills.  Neutralizing chemicals, absorbant materials, and cleaning supplies should be readily available to clean up corrosive chemical spills. All spills should be cleaned up immediately.

7.0 Carcinogens, Mutagens, Embryotoxins

Carcinogens

Cancer is the second leading cause of death in the United States. Approximately one person in four will develop some form of cancer during their lifetime. Cancer is not one disease, but a group of diseases characterized by uncontrolled growth of abnormal cells. These cells are destructive and often capable of migrating to new sites to form secondary growths. Among the causes of cancer, environmental agents acting with genetic susceptibilities are believed to be the most prominent. Approximately 60% to 90% of all cancers may be related to environmental factors such as sunlight, radiation, chemicals, diet, and viruses.

Agents that cause cancer or increase the risk of cancer either by initiating or promoting it, are called carcinogens. Carcinogens can enter the body through the skin, lungs, or the digestive system and act directly or indirectly to cause cancer. Direct acting carcinogens usually cause cancer at the site of exposure, for example, skin contact with coke oven emissions may cause skin cancer. Indirect acting carcinogens are changed by the body into carcinogenic substances that cause cancer at sites other than the initial exposure site. Benzidine, for example, entering the body through the skin does not cause skin cancer. Instead it is transformed to a reactive species in the body and eliminated in the urine causing bladder cancer. Other substances, called promoters, do not cause cancer themselves but are necessary for some chemicals to express their carcinogenicity.

Chemical carcinogens were among the first agents associated with an increased incidence of cancer. In 1775, a positive association was demonstrated between exposure to soot and scrotum cancer among chimney sweeps in England. Since then, chemical components of tar, smoke, air pollution, and automobile exhausts have been shown to be carcinogenic. Several occupational chemicals have also been demonstrated to be carcinogens, including asbestos, arsenic, vinyl chloride, ethylene oxide, and cadmium.

Carcinogens differ in the length of time necessary for the cancer to develop after the initial exposure. This latency period may be as short as five years for the development of leukemia from benzene exposure to as long as 30 years to develop bladder cancer from benzidine.

The existence of a safe level or threshold has not been demonstrated for most carcinogens. Because of this, it must be assumed that low doses can cause cancer also but at a proportionately lower rate than high doses. Therefore, it is prudent to reduce exposures to known or suspected carcinogens to the lowest level possible. Exposure to several carcinogens at once may result in cancer rates higher than would be expected by adding the risks from each carcinogen separately. This is known as a synergistic effect. For example, both cigarette smoking and exposure to asbestos have been show to cause cancer. The cancer rate among asbestos workers who smoke is much greater than would be expected by adding the risk from smoking to the risk from exposure to asbestos.

Mechanism

The mechanism that causes a normal cell to become cancerous is not well understood. The process is usually characterized by three stages: initiation, promotion, and progression. During the initiation stage, the DNA in the cell that carries the genetic information for cell division is altered spontaneously or by an external agent. This altered cell may replicate during the promotion stage into a malignant tumor. The appearance of the tumor following initiation may take 5-30 years. This latency period is probably related to a gradual weakening of the immune system or hormonal changes as the body ages. Another theory states that the cells remain dormant until another stimulus from an environmental agent causes it to start dividing. During the progression stage, the tumor invades adjoining tissue and may spread throughout the body.

Testing

OSHA considers a chemical to be a carcinogen if the chemical causes cancer in humans, or two different mammal species, or one mammal species if the results are reproduced in a separate study, or one mammal species if the results are supported by a mutagenicity test such as the Ames test.

The carcinogenic potential of a chemical in humans is usually discovered through epidemiological (population) studies. In these studies, the incidence of cancer in a group of exposed workers is compared to a comparable unexposed population. For example, when compared to unexposed workers, an excess of liver cancer was found among polyvinyl chloride workers and an excess of lung cancer was found in asbestos workers. Another study on members of the American Chemical Society demonstrated a significantly higher incidence of cancer deaths among chemists when compared to the general population.

Human population studies are not always adequate to determine if a chemical is carcinogenic. Large populations are needed, cancers may not develop for 30 years, and there are many variables that must be controlled. Therefore, tests are usually performed on experimental animals under controlled conditions. Tests on animals can identify human carcinogens because chemicals that cause cancer in one mammalian species are likely to cause cancer in another. With the exception of arsenic, all human carcinogens have also been shown to cause cancer in animals. It must be assumed that agents that cause cancers in animals are likely to be carcinogenic in humans also.

Animal studies are performed to demonstrate the potential for a chemical to cause cancer. Because small populations are used, it is necessary to use large doses of chemicals to demonstrate an effect. This does not mean that only large doses of the chemical will cause cancer. Smaller doses would cause cancer also but in proportionately smaller numbers, numbers so small that they might be missed in a small population.

Screening tests using cells growing in laboratory cultures, require only a few days or weeks to provide preliminary results on the carcinogenic potential of chemicals. The suspect chemical is added to the cells and any mutagenesis is noted. Approximately 90% of chemicals found to be carcinogenic in humans or animals have also shown mutagenesis in these tests. This procedure is the basis for the Ames test.

Classes

Although not all inclusive, chemical carcinogens are commonly classified into the following groups. Carcinogenic chemicals should also be considered mutagenic.

Polycyclic aromatic hydrocarbons (PAHs).  PAHs were the first group of chemicals shown to be carcinogenic in man. They are produced from the combustion of fossil fuels and tobacco. PAHs are probably the most widespread chemical carcinogens in the environment and some of the most powerful carcinogens are found in this group. Examples include benzo(a)pyrene and methylcholantrene.

Aromatic amines.  Aromatic amines result from the addition of an amine group to a polycyclic aromatic hydrocarbon. For example, adding an amine group to the non-carcinogen anthracene produces a well-known carcinogen, 2-anthranine. Other examples include the OSHA regulated carcinogens, benzidine, and 2-naphthylamine.

Aminoazo compounds.  Aminoazo compounds were frequently used as dyes in polish, soap, cooking oils, and margarine. An example is 4-Dimethylaminoazobenzene.

n-Nitroso compounds.  n-Nitroso compounds are widely distributed in the environment and can also form in the body. These compounds may be one of the most important groups of carcinogens in man. Sodium nitrite is a commonly used preservative in meat that is converted by heat to nitrous acid which reacts with amines in the meat to form nitrosamines. A common example is methyl benzyl nitrosamine.

Alkylating agents.  Alkylating agents represents one of the largest classes of carcinogens. They are subdivided based on their functional groups and include compounds such as the aziridines, nitrogen, sulfur, and oxygen mustards, epoxides, lactones, and aldehydes. A common aziridine is the OSHA regulated carcinogen ethylenimine. Alkylating agents commonly used in laboratories include ethylene oxide, propylene oxide, formaldehyde, acetaldehyde, and acrolein.

Aliphatic halogenated hydrocarbons.  Several of these compounds are commonly used in the laboratory as solvents. Examples include carbon tetrachloride, chloroform, trichloroethylene, methylene chloride, and ethylene dibromide.

Inorganic metals and minerals.  Several carcinogens are known among metals or their salts. Examples of these include beryllium, cadmium, nickel, cobalt, and chromium. Only two minerals are known to cause cancer; asbestos and arsenic.

Naturally occurring.  Several natural occurring carcinogens are known. Among these is aflatoxin, probably the most potent of all carcinogens. Aflatoxins are produced by molds that grow on peanuts and corn. Other naturally occurring carcinogens are present in sassafrass and chili peppers.

Mutagenic Substances

Mutagenic substances cause an alteration in the genetic instructions on the DNA molecule. If the alteration occurred on a somatic (non-sex cell) the results could be the development of cancer. An alteration of a germ cell (sex cell) in either sex can produce genetic defects that will be transmitted to the next generation. Because all mammalian genes are composed of DNA, a mutagenic substance that can produce alterations in one species is considered capable of producing alterations in another species.

Because approximately 90% of chemical carcinogens have been demonstrated to be mutagenic, the carcinogenic potential of a chemical can be determined by assessing its ability to produce mutations. The potential mutagenic potential of a chemical can be rapidly determined by performing short term "in-vitro" (in the tube) tests. In-vitro tests use a microbial organism, such as a bacterium, to assess the potential of a chemical to produce alterations in the genetic material and produce mutations.

Long term "in-vivo" (in the animal) studies are only needed for a few chemicals. Insects, mice, rats, and hamsters are used for these tests to evaluate mutagenicity in an animal system. Chemicals producing positive animal results are considered to represent a genetic risk for humans.

Embryotoxins

Women of child bearing potential must be especially concerned about exposure to hazardous chemicals because many chemicals may be hazardous to the embryo or fetus. Embryotoxins are substances that may kill, deform, retard the growth, affect the development of specific functions in the unborn child, or cause postnatal functional problems. Agents that only produce malformations of the embryo are called teratogenic. Approximately 60-70% of all malformations are the result of chemical, physical and infectious agents. The developing embryo depends on the environment to supply the substances needed for growth and differentiation of the tissues and organs of the embryo. The result is that various chemical, physical, and infectious agents may alter or arrest growth in the developing embryo.

The influence of embryotoxins depends on the phase of growth the exposure took place. The period of greatest susceptibility to embryotoxins is the first trimester, which includes a period when the woman may not know she is pregnant. The embryo is undergoing rapid growth and differentiation and significant malformations can be produced. Although the development of the fetus is not as sensitive as the embryo, alterations may still occur, particularly in the nervous system.

Classes

Medicines.  Medicines that have demonstrated embryotoxic properties in humans include thalidomide, diethylstilbestriol, male hormones similar to methyltestosterone, and cytotoxic drugs such as chlorambucil.

Solvents.  Dimethylsulphoxide and formamide have demonstrated both embryotoxic and teratogenic action. Other solvents, however, are less dangerous. Growth retardation and abortions, but not malformations, were shown in animals exposed to chloroform, carbon tetrachloride, trichloroethylene, perchloroethylene, benzene, xylene, cyclohexanone, and propylene glycol.

Heavy metals.  Organomercurials and lead compounds are embryotoxic to humans. Cadmium, arsenic, selenium, chromium, and nickel compounds have been shown to be embryotoxic in animals and are classified as potentially harmful to the human embryo.

Pesticides.  Pesticides producing malformations in animals include parathion, demeton, paraquat, and penthion.

Anesthetic gases.  Anesthetic gases demonstrating embryotoxic properties in animals include, halothane, ethylene oxide, nitrous oxide, and metofane.

Organic compounds.  Organic compounds that have shown embryotoxic properties in animals include azo dyes, formaldehyde, hydrazine, ethylenethiourea, pentachlorobenzene, and thiurams.

Safety Procedures for Handling Carcinogens

The following procedures should also be used when working with highly toxic chemicals, mutagens, and embryotoxins.

Protective clothing.  Protective clothing such as a fully fastened laboratory coat and disposable gloves should be worn to prevent contact of carcinogenic chemicals with the skin. Care should be exercised in the proper selection of gloves. Although a glove may be resistant to a pure carcinogen it may be permeable to the carrier solvent. Contaminated clothing should be decontaminated before laundering. Contaminated clothing should never be worn out of the work area.

Protective equipment.  Appropriate eye protection should be available and used in the laboratory work area. Contact lenses should not be worn. Personnel working with animals or other procedures that could generate airborne particulates should wear an appropriate face mask or respirator. The face mask or respirator should not be worn out of the work area.

Eating, drinking, & smoking.  There shall be no eating, drinking, smoking, chewing of gum or tobacco, or application of cosmetics in areas where carcinogenic chemicals are used or stored. Storage of food or food containers in these areas is also prohibited.

Pipetting.  Under no circumstances is oral pipetting of carcinogenic chemicals permitted. Pipetting should always be performed with the aid of a mechanical pipetting device.

Personal hygiene.  Laboratory workers should wash their hands immediately after the completion of any procedure involving the use of carcinogenic materials.

Storage.  Stock quantities of carcinogens should be stored in a designated area or cabinet and posted with the appropriate hazard sign. Volatile chemicals should be stored in a ventilated storage area in a secondary container having sufficient volume to contain the material in case of an accident. Storage areas should be separated from flammable solvents and corrosive liquids.

Labeling.  All containers should be labeled as to contents and bear the appropriate hazard warning information.

Work areas.  Procedures involving the use of volatile chemical carcinogens or procedures that may generate aerosols should be conducted in a chemical fume hood, glove box, or a Class I Biological Safety Cabinet. Examples of aerosol producing procedures include the opening of containers, transferring procedures, weighing and preparation of food mixtures, blending and the application, injection, or intubation of chemicals into animals. Biological procedures involving carcinogens should be conducted in a Class II type B1 or B2, or Class III Biological Safety Cabinet. A Class II-type A Cabinet may be used with carcinogenic chemicals in low concentrations. Procedures involving non-volatile compounds and procedures with a low aerosol potential should be done in a controlled area of the laboratory designated for carcinogenic materials.

Transport.  Carcinogens should be transported in unbreakable outer covers such as metal cans. Contaminated materials transported to a disposal area should be placed in a plastic bag or other impervious material, sealed, and labeled appropriately.

Housekeeping.  To reduce the production of aerosols, dry mopping and dry sweeping should not be done in areas where finely divided solid carcinogens are used. Wet mopping or a vacuum cleaner equipped with a HEPA filter should be used.

Vacuum lines.  A disposable HEPA filter and liquid trap should be used to prevent the entry of carcinogens into the vacuum system. Separate vacuum pumps placed in or vented to a laboratory hood should be used when working with volatile agents.

Local exhaust.  Operations producing aerosols that cannot be accommodated in a primary containment device must be captured by a local exhaust system and exhausted into a chemical fume hood or appropriate Biological Safety Cabinet. Examples include analytical instruments, dosage preparation areas, and necropsy areas.

Working quantities.  Working quantities should be kept to a minimum and not exceed the amounts required for use in one week.

Spill control.  Spills and accidents must be immediately reported to supervisory personnel and to the Safety Office. Because of aerosol production, the area should be evacuated immediately unless the spill is small and well contained. Personnel performing decontamination should wear adequate protective clothing including respirators or self-contained breathing apparatus. As much of the spill as possible should be absorbed into paper towels, rags or sponges. Dry solids should be covered with paper towels moistened with water or an appropriate solvent. Care should be taken not to generate aerosols. Large spills may require a HEPA filtered vacuum cleaner. Decontamination of the spill should be attempted only after the bulk of the spill has been removed by mechanical means.

Disposal.  Volatile carcinogens should never be disposed of by evaporation in a hood. Chemicals and contaminated materials should be decontaminated or removed for subsequent disposal. Chemical inactivation is preferred to incineration because of the possibility of incomplete combustion. Contaminated waste, cleaning devices, and animal carcasses should be collected in plastic bags or other impervious containers, sealed, labeled as to contents and hazard and disposed of by approved methods.

Handwashing facilities.  Handwashing facilities should be available in the work area where carcinogens are used. Foot or elbow operated faucets are preferable. 

Eye-wash & deluge showers.  OSHA approved eye-wash units and deluge showers should be readily available to personnel working with carcinogens having corrosive properties or that can penetrate the skin. Depending on the hazard, these units may be required in the laboratory. A regular shower should be available to laboratories doing extensive work with carcinogens.

Exhaust ventilation.  Air movement should be controlled by a mechanical exhaust system that moves air from clean areas to potentially contaminated areas. Exhaust air should be discharged in a way that reduces the possibility of entry into air intake ducts. Exhaust air from laboratory hoods in which carcinogens are used should be treated by filtration through a HEPA filter to remove contaminated aerosols.

Work area identification.  Entrances to work areas where carcinogens are used or stored should be posted with a sign stating "Danger Carcinogen - Authorized Personnel Only." In addition, the area should also be posted with a sign stating "No Eating, Drinking, or Smoking."

Access.  Only authorized personnel should be allowed in areas where carcinogens are used and stored. Casual visitors should be prohibited. Doors should be closed at all times.

Work surfaces.  Work surfaces on which carcinogenic chemicals are handled should be protected from contamination by using an impervious material such as stainless steel, plastic trays or absorbent plastic backed paper. Work surfaces should be decontaminated or disposed of properly after the procedure has been completed.

OSHA Regulated Carinogens

OSHA publishes a list of known carcinogens that are strictly regulated. The regulations on each are specific and detailed. Their use involves a long list of requirements concerning recordkeeping, posting, monitoring, facilities, training, contamination control and medical surveillance. The following chemicals are on OSHA's list:

  • 2-Acetylaminofluorene(AAF)
  • Acrylonitrile
  • 4-Aminodiphenyl
  • Arsenic
  • Asbestos
  • Benzene
  • Benzidine
  • Bis and Methy Chloromethyl Ether
  • Coke Oven Emissions
  • 1,2,-Dibromo-3-chloropropane(DBCP)
  • 3,3'-Dichlorobenzidine(DCB) and salts
  • 4-Dimethylaminoazobenzene(DAB)
  • Ethylenemine
  • Ethylene Oxide
  • Formaldehyde
  • Alpha and Beta Naphthylamine
  • 4-Nitrobiphenyl
  • Beta-Propiolactone
  • Vinyl Chloride

Monitoring.  Air monitoring must be conducted if there is reason to believe that exposure to the regulated carcinogen may exceed an action level or permissible exposure level (PEL). The relevant OSHA standard will be followed if initial monitoring exceeds an action level or PEL.

Exclusions.  Since many of these compounds cannot be completely removed from commercial preparations, OSHA has excluded from its standards preparations containing less than 1.0% of some regulated carcinogens and less than 0.1% for other regulated carcinogens. Consult the Safety Manager for further information.

Approval.  A complete evaluation of the facilities, procedures, and measures to protect workers should be conducted by the Safety Manager before using regulated carcinogens. Requirements for use may be expensive and mandate extensive facility and labor commitments. It is strongly recommended that alternate reagents be employed if possible.

Experimental Animals

Working with animals is particularly hazardous because of the possibility of the formation of aerosols and dusts containing carcinogenic chemicals. These dust and aerosols can easily contaminate the work area through the animal feed, urine, or feces if proper procedures are not followed. Procedures should be implemented to handle potentially contaminated material in a controlled manner to reduce the possible exposure of personnel.

The principal routes of exposure to workers from chemicals occur through inhalation or direct contact. These exposures can occur during the initial handling of the chemicals, dosage preparations and administration, post-treatment, holding and examination of animals, and disposal of waste.

Initial handling.  Activities involving the storage, dispensing and aliquotting of stock quantities of chemicals provide a significant opportunity for release of contaminants. Contaminants typically occur on the outer surface of the containers, floors and bench tops, the balance, on protective clothing, and in adjacent rooms. Solid test materials should be handled with extra caution because they can be easily released and dispersed into the work area. Liquids are less likely to disperse but local contamination is still possible. Another route of exposure may come from solids and liquids that volatilize easily. Even materials with a moderate vapor pressure can expose workers to significant vapor concentrations of the chemical. Procedures involving chemicals that volatilize easily or procedures that produce aerosols should be performed in a hood.

Dosage preparation.  The worst contamination problem typically occurs in the dosage preparation areas. Aerosol production occurs when the pure chemical is added to the appropriate feed vehicle and vigorously mixed. To reduce aerosol formation all mixing procedures should be done within closed containers and within a hood.

Administration of dose.  Animal holding areas can easily become contaminated when the material is being administered. The greatest potential to create contamination of the facility occurs during feed studies, followed by dosed water, gavage, skin painting, and injection. Filling of the feed hoppers generates large amounts of aerosols that can contaminate the work area. Volatilization of the dose material and exhalation by the test animal may occur when the test material is administered by gavage. To reduce contamination, administration of the dose to the animal should be performed in a hood, biological safety cabinet or controlled by local exhaust ventilation.

Animal holding.  Experimental animals need to be held under controlled conditions after the treatment because hazardous metabolites or the parent compound may be eliminated in the urine or feces. The removal of contaminated bedding and cage matting can create large amounts of aerosols and dust. Vacuum cleaners equipped with HEPA filters and wetting the bedding to reduce dusts should be used. If the caging system does not protect personnel from contamination workers should wear completely closed jump suits, booties, head covers, and a respirator. Under no circumstances should protective clothing and respirators be allowed out of the work area. Large scale studies should be carried out in special facilities or rooms having restricted access.

Disposal of waste.  The Safety Manager should be consulted for proper disposal strategies. Proper disposal will depend on the particular carcinogen, its concentration, the fate of the carcinogen within the biological system, its toxic properties, and if the waste contains radioactive materials.

8.0 Flammable Liquids

Flammable liquids are a common hazard found in laboratories. These materials can easily vaporize and form flammable and explosive mixtures in air. The degree of hazard is determined by the flash point of the liquid, the concentration of the air-fuel mixture, and the availability of ignition sources. In addition, many flammable chemicals react violently with oxidizing compounds and may start a fire. The flammability properties of a chemical should be checked before a flammable liquid is used. The danger of fire and explosions can be eliminated or reduced by using strict handling, dispensing, and storage procedures.

Definitions

Flash point.  The fire hazard associated with a flammable liquid is usually based on its flash point. The flash point is the lowest temperature at which a liquid in an open vessel will give off sufficient concentration of vapors to form an ignitable mixture with air. Many common laboratory chemicals have flash points below room temperature. Ethyl ether for example has a flash point of minus 45 C.

Explosive range.  An important factor in determining the fire hazard of a flammable liquid is its flammable or explosive range. Once the flash point has been reached, flammable vapors will be given off that can mix with air to form an explosive mixture. Every flammable liquid has an upper and lower limit that defines the range of concentrations of the liquid in air that will ignite and propagate a flame. The lower explosive limit (LEL) is the minimum concentration of the vapor in air that will sustain the spread of a flame. Below this concentration, the mixture is too lean to burn. The upper explosive limit (UEL) is the maximum concentration of vapors in air that will propagate a flame. The mixture is too rich to burn above this concentration. The range is usually expressed as a percentage by volume of vapor in air. Acetaldehyde, for example, has a very wide explosive range extending from an LEL of 4% to an UEL of 60%.

If the lower limit is small it only takes a small amount of vapors in the air to form an ignitible mixture. Flammable liquids with an LEL of less than 10% are considered especially hazardous. Liquids having flash points below room temperature and a wide flammability range, for example, ethyl ether, are among the most hazardous flammable liquids.

Ignition temperature.  Once the flammability range has been reached, the vapors will ignite at the proper ignition temperature. The ignition temperature of a substance is the lowest temperature necessary to cause the vapor-air mixture over the liquid to ignite and continue to burn in the absence of the heat source. If the vapor-air mixture is confined and there is an ignition source, an explosion will result. The ignition temperature is often misleading because it is a relatively large number, often in the hundreds of degrees. However, it only takes a short duration of contact with a potential ignition source to reach this temperature and ignite a flammable vapor. For example, a spark contacting a few molecules of a flammable vapor can raise the temperature above the ignition point in only a few thousandths of a second. A hot light bulb can ignite some chemicals. Carbon disulfide, for example, will ignite at a temperature of 80 C.

Sources of ignition.  Three conditions must exist before a fire can occur: fuel concentration that is within the explosive range for the substance, air, and a source of ignition. To prevent fires, it is necessary to remove one of these conditions. The easiest way to prevent fires is usually to separate the flammable vapors from an ignition source. Many sources such as sparking electrical equipment, open flames, static electricity, and hot surfaces can ignite flammable vapors. Close attention must be given to all sources of ignition when using flammable liquids, especially those at a lower level than the liquid. The vapors of most flammable liquids are heavier than air and can travel considerable distances.

Spontaneous ignition.  Spontaneous ignition takes place when a substance generates heat faster than it can be dissipated and reaches its ignition temperature independent of an ignition source. Materials susceptible to spontaneous ignition include oil or paint soaked rags, organic materials mixed with strong oxidizing agents, alkali metals, phosphorus, and finely divided pyrophoric metals.

Classes

Flammable and combustible liquids are divided into the following classes; based on flash points and boiling points. Flammable liquids are defined as those with flash points below 100 F and combustible liquids have flash points at or above 100 F. Flammable and combustible liquids are further subdivided into the following classes:

Class IA.  Flash point below 73 F (22.8 C) and boiling point below 100 F. (37.8 C). Examples include acetaldehyde, diethyl ether, pentane, ethyl chloride, ethyl mercaptan, hydrocyanic acid, and gasoline.

Class IB.  Flash point below 73 F (22.8 C) and boiling point at or above 100 degrees F (37.8 C). Examples include acetone, benzene, carbon disulfide, cyclohexane, ethyl alcohol, heptane, hexane, isopropyl alcohol, methyl alcohol, methyl ethyl ketone, toluene, petroleum ether, acetonitrile, and tetrahydrofuran.

Class IC.  Flash point at or above 73 F (22.8 C) and below 100 F (37.8 C). Examples include glacial acetic acid, acetic anhydride, cyclohexanone, and dichloroethylether.

Class II.  Flash point at or above 100 F (37 C) and below 140 F (60 C). Examples include kerosene, diesel fuel, hydrazine, and cyclohexanone.

Class IIIA.  Flash point at or above 140 F (60 C) and below 200 F (93.4 C). Examples include aniline, cyclohexanol, phenol, o-cresol, naphthalene, nitrobenzene, and p-dichlorobenzene.

Class IIIB.  Flash point at or above 200 F (93.4 C). Examples include diethyl sulfate, diethylene glycol, and p-cresol.

Safety Procedures

Ventilation.  Ventilation is essential to prevent the buildup of vapors that could lead to flammable liquid fires and vapor-air explosions. Vapors must be controlled by confinement, local exhaust, or general room ventilation. Ventilation systems should be designed to keep the vapor concentration below 25% of the lower flammability level. Room ventilation should be adequate to prevent the accumulation of dangerous concentrations of vapors if only very small quantities are released. All laboratories that use or store flammable or combustible liquids should have six-room air changes per hour with 100% exhaust.

Hoods.  An exhaust hood should be used if significant quantities of flammable liquids are being transferred from one container to another or being heated or allowed to stand in an open vessel. Only hoods that are properly designed to handle flammable solvents should be used. Hoods must be equipped with explosion-proof light fixtures. The motor must be explosion-proof if the fumes will pass through it. Switches and outlets should be located outside the hood to reduce sparking.

Ignition sources.  Flammable liquids should never be heated with an open flame. Steam baths, water baths, oil baths, or heating mantles should be used. Containers should always be kept closed to reduce the possibility of flammable vapors contacting an ignition source. When flammable liquids are used, all unnecessary ignition sources should be removed. Ignition sources include open flames, nonexplosion proof electrical equipment, hot surfaces, and static sparks.

Smoking.  Smoking is prohibited in laboratories where flammable liquids are used or stored.

Fire extinguishers.  Appropriate fire extinguishers must be located in laboratories using flammable liquids.

Warning signs.  "No Smoking" and "Flammable Liquids" signs shall be prominently posted in areas where flammable liquids are used or stored.

General storage.  Flammable liquids should not be stored near heat, ignition sources, powerful oxidizing agents, or other reactive chemicals. Flammable liquids should not be stored near an exit, stairway, or any area normally used for the safe egress of people. Storage in glass bottles should be avoided if possible. If glass must be used, the bottle should be protected against breakage. The quantity of flammable liquids in the laboratory should be limited to what is immediately needed. As much as possible of working quantities should be stored in safety cans. Flammable liquids should not be stored above eye level.

Refrigerators.  Flammable solvents must not be stored in standard refrigerators; explosions may result from the ignition of confined flammable vapors by sparking electrical contacts. Only explosion-proof or explosion-safe refrigerators may be used.

Container size.  Flammable and combustible liquids must be stored in containers  that do not exceed the following sizes:

Class Glass or Plastic Metal (non DOT) Metal (DOT) Safety Cans
Class IA 1 pt 1 gal 60 gal 2 gal
Class IB 1 qt 5 gal 60 gal 5 gal
Class IC 1 gal 5 gal 60 gal 5 gal
Class II 1 gal 5 gal 60 gal 5 gal
Class III 1 gal 5 gal 60 gal 5 gal

Storage limits in laboratories.  The maximum amount that may be stored within a laboratory outside approved safety cans, storage cabinets, or flammable storage rooms is 10 gallons. Approved flammable storage cabinets may contain a maximum of 50 gallons of Class I and II liquids, or 120 gallons of Class I, II, and III combined. Only three cabinets are allowed in a fire area.

Inside storage rooms.  Bulk quantities of flammable liquids, such as 30 or 55 gallon drums, must be stored in properly designed indoor storage rooms or outside storage areas. Indoor storage rooms containing flammable and combustible liquids must meet the requirements of OSHA Standard 1910-106(d). These standards include spill control measures, spark-proof electrical fixtures, fire suppression equipment, and ventilation requirements.

Electrical grounding.  Transferring liquids from one metal container to another may produce static electricity sparks capable of igniting the flammable vapors. To discharge the static electricity, dispensing drums should be adequately grounded and bonded to the receiving container before pouring. Bonding between containers may be made by means of a conductive hose or by placing the nozzle of the dispensing container in contact with the mouth of the receiving container. If the container cannot be grounded, then the liquid should be poured slowly to allow the charge time to disperse.

Spills.  Appropriate spill kits should be available to laboratories using flammable liquids. Materials should absorb the solvent and reduce the vapor pressure so that ignition is impossible.

Transportation.  Flammable solvents should be transported in metal or other protective containers.

9.0 Reactive Chemicals

Reactive chemicals are substances that can explode or enter into violent reactions releasing large amounts of light, heat, and gases. A number of reactive chemicals are recognized explosives, requiring only a mild initiating force for detonation. Other reactive chemicals are capable of detonation but require a stronger initiating force. Some reactive chemicals will not detonate but can enter violent reactions producing large quantities of heat and explosive gases. Reactive chemicals must be handled with extreme care, even milligram quantities of some chemicals can result in violent explosions.

Classes

Reactive chemicals are classified as explosives, strong oxidizing agents, acid sensitives, water reactives, air reactives, and special organic compounds.

Explosives.  Explosives are substances that can detonate or decompose rapidly and violently at room temperatures and pressure with an essentially instantaneous release of large quantities of gases and heat. Gentle heat, light, mild shock, and chemical action can initiate these explosive reactions. Many of these compounds become more sensitive as they age or dry out. Hydrogen and chlorine for example will react violently in the presence of light. Acetylides, azides, organic nitrates, nitrocompounds, and peroxides are shock sensitive. Hydrogen peroxide will undergo violent decomposition in the presence of many metals. Picric acid and picryl chloride should always be kept damp. Examples of chemical groups containing explosives include certain aromatic and aliphatic polynitro compounds, nitroamines, organic nitrates, peroxides, and azides, metal salts of nitrophenols, acetylides and azides of heavy metals.

Peroxides.  Among the most hazardous chemicals normally handled in the laboratory are the organic peroxides. Peroxides are dangerous because of their extreme sensitivity to shock, heat, friction, and strong oxidizing and reducing agents. Many peroxides normally handled in laboratories are more sensitive to shock than TNT. In addition, all organic peroxides are highly flammable. Ethers, especially isopropyl ether, ethyl ether, dioxane, and tetrahydrofuran (THF), can form explosive peroxides in the presence of air and light during storage. The ether-peroxide solution can explode if heated, or subjected to shock or friction. Peroxides may also form on potassium metal.

Strong oxidizing agents.  Many strong oxidizing agents are capable of detonation or explosive decomposition under conditions of strong heat, confinement, or a strong shock. Violent reactions can occur when strong oxidizers are mixed with combustibles such as wood or paper. Strong oxidizing agents that can cause explosions include perchloric acid, organic and inorganic perchlorates, inorganic nitrates, peroxides, permanganates, chlorates, perchlorates, persulfates, chromates and the halogens. Strong oxidizing agents will also react violently with most organic compounds, powdered metals, sulphur, phosphorus, boron, silicon, and carbon.

Acid sensitives.  Acid sensitive chemicals react with acids to produce heat, flammable, explosive, and/or toxic gases. Examples include alkali metals, hydroxides, carbonates, carbides, arsenic, cyanides, sulfides, and most metals.

Water reactives.  Chemicals that combine with water or moisture in the air to produce heat, flammable, explosive or toxic gases are termed water reactive chemicals. These chemicals present a severe fire hazard because sufficient heat is often released to self ignite the chemical or ignite nearby combustibles. In addition, contact with the skin can cause severe thermal and alkali burns. Common examples include strong acids and bases, acid anhydrides and sulfides that only liberate heat; and alkali metals, hydrides, carbides and anhydrous metal salts that also release flammable gases.

Air reactives.  Air reactives (also called pyrophoric materials) ignite spontaneously in air at temperatures below 130 F. Finely divided metal powders that do not have a protective oxide coat may ignite when a specific surface area is exceeded. The degree of reaction depends on the size of the particle, its distribution, and surface area. Examples include aluminum trialkls, white phosphorus, fine zirconium powder, activated zinc, and silanes.

Special organic compounds.  These chemicals are unstable and may decompose spontaneously or by contact with the air, water, or other chemicals. Examples include diazonium compounds, diazomethane, butadiene, organic sulfates, polymerization reactions, and highly nitrated compounds.

Safety Procedures

Planning.  The procedures and risks involved should be thoroughly reviewed before working with reactive chemicals. Work should be performed with the smallest possible amount of the chemical.

Personal protective equipment.  Safety glasses, face shield, gloves, and a laboratory coat should be worn at all times when handling, transporting, or manipulating reactive chemicals.

Safety equipment.  Adequate portable fire extinguishers should be immediately available in the laboratory. Approved eye-wash stations and emergency showers must be in the work area. Safety shields should be used as necessary.

Explosives.  Explosives should be protected from heat and shock. Large quantities of explosives may need to be stored in heavily constructed magazines. Explosives should be stored in a cool, dry area, separated from flammables, corrosives, and other reactive chemicals. Operating systems involving explosives should be surrounded by a safety shield made of shatterproof glass or 0.25 inch thick acrylic. Two safety shields should be used if the properties of the explosive are unknown. Protective devices such as long-handled tongs should be available for handling explosives at a distance. Areas in which explosives are handled or stored should be posted with a sign stating "Caution Explosion Hazard." Access to the laboratory should be restricted while experiments are being conducted. Efforts should be made to reduce static electricity discharges such as using cotton gloves, wearing conductive-soled shoes, and working on conductivity mats.

Peroxides.  Peroxides should not be stored near strong oxidizing agents, ignition sources or sources of heat. Peroxides should be stored at the lowest possible temperature above their freezing or precipitation temperature. The peroxide should not be allowed to freeze or precipitate. Peroxides in these forms are extremely hazardous. Unused peroxides should not be returned to their original containers. Aliphatic hydrocarbons can be added to most peroxides to reduce their sensitivity to shock and heat (toluene should not be added to diacyl peroxides). Solutions of peroxides should not be allowed to evaporate and increase the peroxide concentration. Metal spatulas should not be used with peroxides. Friction, grinding, and impact should be avoided. Glass containers with screw top lids must be avoided. Spilled peroxides should be absorbed on vermiculite as quickly as possible. Organic peroxides should never be flushed down the drain or mixed with other chemicals for disposal.

Ethers.  Ethers should not be distilled unless known to be free of peroxides. Ethers should not be stored in clear bottles. Storage should be in a cool place, preferably an explosion safe refrigerator. Ethers should be dated when purchased and discarded after six months if opened, or after one year if unopened. Inhibitors such as copper mesh or BHT may be ineffective and should not be relied on to prevent peroxide formation. Ethers that do not have an inhibitor, such as those used for anesthesia, should be handled with particular caution. The Safety Manager should be notified to dispose of old containers of ether.

Picric acid.  Picric acid should be stored with greater than 10% water at room temperature. Metal spatulas should never be used with picric acid. Explosive salts may form. After each use, the cap and threads should be cleaned with a damp cloth to prevent dry crystal formation. Bottles containing dry crystalline picric acid or with evidence of crystal formation around the cap should not be used. Call the Safety Manager for disposal.

Perchloric acid.  Only hoods that are specifically designated as perchloric acid hoods are to be used for operations with hot perchloric acid. Cold perchloric acid may be used in a standard fume hood. Flammable solvents or organic materials should not be stored in a perchloric acid hood. If perchloric acid is frequently used, the hood and ventilation duct should be washed down weekly to remove potentially explosive residues. Perchloric acid should be purchased in minimum quantities, no more than one pound should be stored in a laboratory. Perchloric acid should not be purchased in concentrations greater than 72%.

Perchloric acid should not be stored with strong dehydrating agents such as concentrated sulfuric acid or phosphorus pentoxide. Highly unstable anhydrous perchloric acid may form which can explode with tremendous force. Perchloric acid should be stored in a perchloric acid hood in a glass tray deep enough to hold the contents of the bottle. Perchloric acid should not come in contact with rubber gloves, corks, rubber stoppers, and oil or grease. Never heat perchloric acid with an oil bath. Organic matter should be digested with nitric acid before perchloric acid is added. Explosive crystals may form in bottles stored for more than one year. Bottles with visible crystal formation should be disposed of by calling the Safety Manager. Do not attempt to open or move the container.

85% perchloric acid.  If concentrations greater than 72% are needed, additional safety precautions must be used. Operations must be conducted behind a safety shield to protect against a possible explosion. Safety goggles, face shield, thick gauntlets, and a rubber apron must be worn. Only freshly prepared acid should be used. Contact with organic materials will usually result in an explosion. Any discoloration of the anhydrous acid requires immediate disposal. A second person should be nearby to provide routine and emergency assistance.

Water reactives.  Water reactive chemicals should be stored in an air and watertight container in an area free of combustibles and flammable solvents. Storage areas should be free from sources of water such as automatic sprinklers and deluge showers. Sodium and potassium should be stored in a closed container under kerosene, toluene, or mineral oil. Vessels containing potassium or sodium should be embedded in an outer container of sand as an added precaution in the event of explosion. Sodium and potassium should be transferred from storage areas in metal containers with a tight cover. Work with these materials should be within a fume hood behind an explosion shield. Personnel should wear safety goggles, face mask, and gauntlets. Proper fire extinguishing agents such as a Class D fire extinguisher, special dry powders developed for metal fires, dry sand, dry sodium chloride, or dry soda ash should be readily available where water reactive metals are used.

Air reactives.  Combustibles and flammable liquids must be kept out of the storage area. White or yellow phosphorus should be stored under water in a tightly stoppered glass container, placed in a metal container, and stored in a secure area. All operations should be carried out in an exhaust hood. Large volumes of water should be available in the area to extinguish fires. Pyrophoric gases should be used with equipment that has been purged with an inert gas before administering gas from the cylinder. Store and use with adequate ventilation at all times. Back-flow into the cylinder may cause an explosion. A vacuum break or other protective apparatus should be used in line to prevent back-flow. When working with metal powders, information on how the powder will react in the presence of air is essential to prevent fires and explosions.

Peroxide Forming Chemicals

Chemicals that decompose into peroxides present a serious hazard. After the peroxides form they may dry in the threads on the container's top or they may become concentrated if the chemical is distilled. Dry or concentrated peroxides formed in this manner are highly explosive and have caused serious explosions in laboratories.

All storage containers of chemicals that may form peroxides must be labeled with the date the container was
opened. Laboratory personnel are responsible for dating containers when they are first opened.

Group A - High hazard - (3 month storage after opening)
These chemicals form explosive levels of peroxides without concentration and are severe hazard after prolonged storage, especially after exposure to air.  All have been responsible for fatalities.
Test for peroxide formation (see testing section) or discard after three (3) months from open date.  If peroxides are not present, the discard date can be reset as per Group A schedule (otherwise discard promptly via RU EHS). This group includes the following compounds:

divinely acetylene

isopropyl (diisopropyl) ether

potassium amide

potassium metal

sodium amide

vinylidene chloride six

Butadiene *1

Chloroprene *1

Tetrafluoroethylene *1

*1 - when stored as a liquid monomer

Group B - Concentration peroxides - (12 month storage after opening)
These are a peroxide hazard upon concentration (distillation or evaporation). Test for peroxide before distillation, evaporation or if concentration is suspected.
Test for peroxide formation or discard after 12 month from open date.   If test shows peroxides are not present, the discard date can be reset to 6 months from test date (otherwise discard promptly via RU EHS).  This group includes the following:

Acetal

Acetaldehyde

Benzyl alcohol

Butadiyne (butadiene)

2-Butanol

Cellosolves

Chlorofluoroethylene

Cumene

Cyclohexene

Cyclohexanol

2-Cyclohexen-1-ol

Cyclopentene

Decahydronaphthalene

Decalin

Diacetylene (butadiene)

Dicyclopentadiene

Diethyl ether

Diethylene glycol dimethyl ether

Diglyme

Dioxanes

Ethyl ether

Ethylene glycol dimethyl ether

Ethylene glycol ether acetate

Furan

Glyme

4-Heptanol

2-Hexanol

Isopropyl alcohol

Isopropyl benzene

Methyl acetylene

3-Methyl-1-butanol

Methylcyclopentane

Methyl isobutyl ketone

4-Methyl-2-Pentanol

4-Methyl-2-Pentanone

2-Pentanol

4-Penten-1-ol

1-Phenylethanol

2-Phenylethanol

2-Propanol

Tetrahydrofuran

Tetrahydronaphthalene

Tetralin

Vinyl ethers

(Other Secondary Alcohols)

Group C - Autopolymerizers - (12 month storage after opening)
These peroxide former are unsaturated materials, especially those of low molecular weight, which may autopolymerize violently and hazardously due to peroxide initiation.  These should not be stored under inert atmosphere after opening.

Test inhibited chemicals*2 for peroxide formation (see test procedure) or discard after 12 month from open date.  If test shows peroxides are not present, the discard date can be reset to 12 months from test date (otherwise discard promptly via RU EHS). This group includes the following:

acrylic acid

acrylonitrile

1,3-butadiene*3

2-chloro-1, 3-butadiene

chloroprene *3

chlorotrifluoroethylene

dibenzocyclopentadiene

9,10-dihydroanthracene

indene

methyl methacrylate

styrene

tetrafluoroethylene*3

vinyl acetate

vinyl acetylene

vinyl chloride

vinylidene chloride

vinyl pyridine

 

*2 - Uninhibited autopolymerizers should not be stored over 24 hours (add polymerizer inhibitor).
*3 - When stored as a gas

10.0 Compressed Gas Cylinders

Compressed gas cylinders are especially dangerous because they possess both mechanical and chemical hazards. Due to the large amount of potential energy resulting from compression of the cylinder, gas cylinders should be handled as high energy sources and as a potential explosive. If a cylinder falls and breaks a valve, the energy released is sufficient to propel the cylinder through concrete walls.

In addition, the gases contained in the cylinders are hazardous because of their flammable, toxic and corrosive properties. The most common hazard associated with gas cylinders is leakage from regulators which allows the gas to diffuse throughout the room. Flammable gases can mix with air causing fires and explosions. Most flammable gases have explosive ranges greater than flammable liquid vapors.

Additional hazards arise from the high toxicity and corrosive properties of many of the gases. Usually, there is no visual warning or odor associated with the escaping gases. Some gases are toxic at concentrations below the odor threshold and some gases can quickly paralyze the sense of smell. Even harmless gases such as nitrogen may displace the oxygen in an unventilated room and cause asphyxiation. The best protection against accidents is knowledge of proper handling and storage techniques.

Classes

Compressed gas cylinders may be classified into the following six groups based on similar chemical and physical properties, storage compatibility, and handling procedures. Common examples are included.

Highly toxic gases.  Phosgene, phosphene, arsine, nitric oxide, nitrogen dioxide, chlorine, fluorine, carbonyl fluoride, diborane, hydrogen cyanide, hydrogen selinide, nickel carbonyl, ozone.

Non-flammable, non-corrosive, low toxicity gases.  Air, argon, helium, krypton, neon, carbon dioxide, nitrogen, nitrous oxide, oxygen.

Flammable, non-corrosive, low toxicity gases.  Acetylene, butane, cyclopropane, ethane, ethylene, hydrogen, isobutane, methane, natural gas, propane, propylene.

Flammable, toxic, corrosive gases.  Carbon monoxide, ethylene oxide, hydrogen sulfide, methyl bromide, methyl chloride, propylene oxide.

Acid and alkaline gases.  Ammonia, hydrogen bromide, hydrogen chloride, hydrogen fluoride, boron trichloride, boron trifluoride, dimethylamine, nitrosyl chloride, trimethylamine, ethylamine, methylamine, sulfur dioxide.

Spontaneously flammable gases.  Silane.

Safety Procedures

Identification.  The contents of compressed gas cylinders should be clearly identified and bear the appropriate DOT hazard label. Labels should not be removed or defaced. Color coding systems used to identify contents are not reliable because cylinder colors vary among manufacturers. If the labeling on a cylinder becomes defaced, the cylinder should be marked "contents unknown" and returned to the manufacturer.

Transportation.  Manual transportation of cylinders (excluding lecture bottles) should always be done with a handtruck. Cylinders should be securely fastened with a strap or rope. The valve cap must be in place. Cylinders should never be lifted by the valve cap or dragged, rolled, dropped, or permitted to strike hard objects or another cylinder.

Training.  Persons who handle corrosive and toxic gas cylinders should be adequately trained in the physical and chemical properties of the gas and the proper methods to use the cylinders.

General storage.  Cylinders shall be stored upright where they are unlikely to be knocked over, or secured by a heavy chain, strap, or base support. Cylinders cannot be stored in stairwells or within a required exit corridor. The valve protection cap must always be in place when the cylinder is not being used. Cylinders should never be stored on their sides or near a heat or ignition source. Storage areas shall be posted with the name of the gases stored. Storage areas should be well ventilated (one-half to one air change per hour minimum) and dry. Storage rooms should be of fire resistive construction. Temperatures shall not exceed 130 F. Some rupture devices may release at approximately 160 F. Lecture bottles are usually not fitted with rupture devices and may explode if exposed to high temperatures. Cylinders shall not be stored near readily ignitable substances such as gasoline, waste, or bulk combustibles.

Outdoor storage.  Cylinders may be stored outdoors if they are adequately protected from the weather and direct sunlight. It is recommended that cylinders be stored under a non-combustible canopy and protected from the ground by a concrete pad.

Handling flammable gas cylinders.  Flammable gas cylinders stored inside occupied buildings shall be separated from flammable liquids, highly combustible materials, and oxidizing cylinders by at least 20 ft. or a 5 ft. high wall with a 1/2-hour fire rating. Flammable gas cylinders in storage and in use should be kept away from arcing electrical equipment, open flames, or other sources of ignition. Adequate portable fire extinguishers shall be located in storage areas and No Smoking signs shall be posted. Spontaneously flammable gases should be used only with equipment purged with an inert gas. A vacuum break or other protective device should be used to prevent back-flow into the cylinder.

Handling oxidizing gases.  Oxidizing gas cylinders in storage shall be separated from flammable gas cylinders or combustible materials such as oil or grease by at least 20 feet or by a 5-foot high wall with a 1/2-hour fire rating. Oxidizing gas cylinders, valves, regulators, and hoses shall be kept free from oil or grease.

Handling acid and alkaline gases.  Proper protective clothing such as goggles, face shields, rubber gloves, and aprons shall be worn when working with acid and alkaline gases. Areas in which acid and alkaline gases are used shall be equipped with an OSHA approved deluge shower and eye-wash station. Acid and alkaline gases should be used in a well ventilated area. Corrosive gases should be used only with compatible equipment. The total quantity of gases on site should be kept to a minimum. Proper respiratory equipment shall be readily available for use in an emergency. When discharging gases into a liquid, a trap should be used to prevent back-flow of liquids into the regulator or cylinder.

Handling highly toxic gases.  Highly toxic gas cylinders (except lecture bottles) shall be stored outdoors or in an unoccupied building or room with a one-hour fire rating. Lecture bottles may be stored in a laboratory if they cannot contaminate breathing air. Storage, for example, in a constantly running hood is appropriate. Areas in which toxic gas cylinders are used or stored should be posted with an appropriate warning sign. The quantity of highly toxic gas cylinders should be kept to a minimum. Highly toxic gas cylinders shall be used only in forced ventilation areas or preferably in hoods with forced ventilation. Highly toxic gases should be used only with compatible equipment. Gases emitted in high concentrations shall be discharged into appropriate scrubbing equipment. Users shall only be exposed to concentrations of highly toxic gases that are below OSHA permissible levels. When discharging gases into a liquid, a trap should be used to prevent back-flow of liquids into the regulator or cylinder. Proper respiratory equipment shall be readily available for use during an emergency.

Dispensing contents.  The proper regulator should be connected. Be careful not to cross thread or over tighten the connections. Never stand in front of or behind the pressure gauge as the main tank valve is opened. Pressure gauges can explode. When opening the valve on a cylinder containing a corrosive or toxic gas, stand on the side opposite the valve opening. Safety glasses should be worn when dispensing compressed gases to prevent eye damage from equipment failure.

Regulators.  Always use the appropriate regulator. Regulators for non-corrosive gases are usually made of brass. Corrosion resistant regulators should be used with gases such as ammonia, boron trifluoride, chlorine, hydrogen chloride, hydrogen sulfide, and sulfur dioxide. Special regulators should be used with carbon dioxide because of potential freeze-up and corrosion problems. Connections should never be forced. Regulators and valves should never be oiled or greased, a fire or explosion could result. Pressure should be removed from the regulator when not in use. The main tank valve should be closed and the pressure bled off from the regulator valves. To prevent explosions, regulators made of brass or copper should not be used with acetylene.

Traps.  A trap, check valve, or vacuum break should be used to prevent the back-flow of contamination into the cylinder.

Empty cylinders.  Cylinders should not be completely emptied. Approximately 25 pounds of pressure should remain in the cylinder. The tank valve should be closed to prevent contamination from air and water. Empty cylinders should never be refilled by the user. Remove the regulator, replace the cap, mark the cylinder empty, and return it to the storeroom and vendor when possible. Segregate empty cylinders from full cylinders to reduce handling by the supplier. The cylinder should be securely fastened in the storeroom.

11.0 Cryogenic Liquids

Cryogenic liquids are liquified gases. The primary risks associated with the use of these materials are physical injuries caused by exposure of tissue to extreme cold, typically below -150 F, the potential for fires and explosions, and asphyxiation.

Even very brief skin contact with a cryogenic liquid is capable of causing frostbite injury. Prolonged contact may result in blood clots. Flooding the affected tissue with warm water as soon as possible is the recommended treatment for exposure to cryogenic liquids.

Gases such as hydrogen, methane, and acetylene present obvious fire and explosion hazards. Liquid oxygen greatly increases the flammability of ordinary combustibles and may even cause non-combustibles to burn. Because oxygen has a higher boiling point than nitrogen, helium, or hydrogen it can condense out of the atmosphere during the use of these lower boiling cryogenic liquids. Conditions may exist for an explosion, particularly with hydrogen.

Liquid nitrogen is commonly transported in vacuum flasks called Dewars containing from 15 to 50 liters at atmospheric pressure. If the vacuum in the Dewar flask should fail, the nitrogen would rapidly escape and could displace enough air in a small confined space to asphyxiate someone. However, the most likely consequence of a sudden vacuum loss would be an implosion that could result in flying glass. Water vapor condensing to ice on vents or pressure relief valves blocking the route of gas escape can also result in a pressure explosion in these vessels.

Safety Procedures

Personal protection.  Personnel should wear suitable eye protection such as chemical splash goggles or a face shield. Long sleeves, long pants and hand protection should be worn. Adequate hand protection must be worn to prevent contact with the cold liquid. Pads or pot holders should be used instead of gloves to prevent the cold fluid from being trapped inside the glove.

Containers.  All exposed glass surfaces of vacuum flasks used to transport or store cryogenic fluids must be taped to guard against flying glass from an implosion. Containers should be handled and stored in an upright position. Containers must not be dropped, tipped, or rolled on their sides. Containers and systems should be periodically inspected to guard against ice buildup on vents and pressure relief valves. Vessels used for the storage and handling of liquified gases should not be filled to more than 80% capacity to reduce the likelihood of expansion of the contents and rupture of the vessel. Cryogenic liquids should be handled in multi-wall, vacuum insulated containers specifically designed for cryogenic liquid. Store bought glass thermos bottles are not appropriate.

Pressure relief devices.  Containers shall be provided with pressure relief devices adequate to prevent excessive pressure within the container.

Ventilation.  Cryogenic fluids should be used and stored in well ventilated areas to prevent excessive accumulation of the gas.

Liquid air.  The use of liquid air as a substitute for liquid nitrogen is prohibited. The concentration of oxygen in liquid air containers can increase over time creating an explosion hazard.

Liquid oxygen.  Liquid oxygen poses a serious fire hazard and should only be used if absolutely essential. Liquid oxygen must be used with a monitoring device. Ignition sources or flammable liquids are not allowed near liquid oxygen systems. Containers, piping, and equipment should be free of grease, oil, and organic material to prevent the possibility of an explosion. The Safety Office should be notified before using liquid oxygen.

Liquid hydrogen.  Smoking, open flames, and arcing electrical equipment are prohibited in areas where liquid hydrogen is used or stored. Liquid hydrogen shall be stored and transferred under positive pressure to prevent air from entering the system.

Liquified natural gas.  Smoking, open flames, and arcing electrical equipment are prohibited in areas where liquified natural gas is used or stored. Liquified natural gas shall be stored and transferred under positive pressure to prevent air from entering the system.

Liquid helium and neon.  Liquid helium and neon shall be stored and transferred under positive pressure.

Liquified inert gases.  Gases such as argon, carbon dioxide, helium, krypton, neon, nitrogen, and xenon are asphyxiants that can displace the oxygen in a room and cause suffocation. Self-contained breathing apparatus must be worn when entering an area suspected or being oxygen deficient.

Appendix A - Glossary

Acid:  A compound that releases hydrogen ions in the presence of solvents or water. Acids react with bases to form salts and water.

ACGIH:  American Conference of Governmental Industrial Hygienists

Acute toxicity:  A substance that causes injury because of a short term exposure, usually in minutes or hours.

Aerosols:  Liquid droplets or solid particles that can remain dispersed in air for a period of time.

Auto-ignition temperature:  The lowest temperature at which a flammable gas mixture will ignite from its own heat source without the necessity of a spark or flame.

Benign:  A tumor that does not metastasize.

Blood toxin:  Chemicals that damage blood cells or decrease the ability of the blood cells to deliver oxygen.

Boiling point:  The temperature at which the vapor pressure of a liquid and the atmospheric pressure is the same.

Bronchitis:  Inflammation of the trachea (windpipe) and its branches.

Cancer:  Cancer is characterized by uncontrolled growth of abnormal cells. These cells are destructive and often capable of migrating to new sites to form secondary growths.

Canister:  A container filled with sorbents that removes gases and vapors drawn through the device.

Carcinogen:  A chemical that causes malignant tumors. It must be listed as a carcinogen or potential carcinogen in one of the following sources: Annual Report on Carcinogens, published by the National Toxicology Program, or Monographs, published by the International Agency for Research on Cancer, or it is regulated by OSHA.

Caustic:  A chemical that is strongly irritating or corrosive.

Ceiling limit:  The concentration of a chemical that exposure to should never be exceeded.

CFR:  Code of Federal Regulations

Chronic toxicity:  A substance that causes injury because of long term (months or years) exposure or causes injury after months or years following an acute exposure.

Class IA flammable liquid:  Flash point below 73 F(22.8 C). Boiling point below 100 F (37.8 C).

Class IB flammable liquid:  Flash point below 73 F (22.8 C). Boiling point at or above 100 F (37.8 C).

Class IC flammable liquid:  Flash point at or above 73 F (22.8 C) and below 100 F (37.8 C).

Class II combustible liquid:  Flash point at or above 100 F (37.8 C) and below 140 F (60 C).

Class IIIA combustible liquid:  Flash point at or above 140 F (60 C) and below 200 F (93.4 C).

Class IIIB combustible liquid:  Flash point at or above 200 F (93.4 C).

CNS:  Central Nervous System

Combustible Liquid:  A liquid having a flash point at or above 100 F but below 200 F.

Container:  Any bag, barrel, bottle, box, can, cylinder, drum, reaction vessel, storage tank, or the like that contains a hazardous chemical. Pipes or piping systems are not considered containers.

Corrosive:  A chemical that causes visible destruction or irreversible damage to living tissue by chemical action at the site of contact.

Critical organ:  The organ that receives the greatest concentration of the chemical.

Cryogenic liquids:  Liquified gases which are handled at very low temperatures, typically below -150 F.

Density:  The mass of a substance divided by its volume.

Dermatitis:  Inflammation of the skin.

Desiccant:  A substance that absorbs water.

Duct:  A conduit that air travels through.

Dyspnea:  Shortness of breath or difficulty in breathing.

Eczema:  Skin disease or disorder.

Edema: Swelling of body tissue from excess water.

Embryo:  The stage of gestation from conception to the end of the third month.

Embryotoxic:  Substances that act during pregnancy to cause adverse effects on the fetus.

Epidemiology:  Study of the cause of diseases in human populations.

Erythema:  Reddening of the skin.

Exhaust ventilation:  The removal of air from an area by mechanical means.

Experimental carcinogen:  A substance that has been shown by statistically scientific studies to cause cancer in animals.

Explosive:  A chemical that causes a sudden, almost instantaneous release of pressure, gas, and heat when subjected to sudden shock, pressure, or high temperature.

Face velocity:  Air velocity at the opening of a hood.

Fetus:  The stage of gestation from the end of the fourth month to birth.

Flammable liquid:  A liquid having a flashpoint below 100 F.

Flammable solid:  A solid, other than an explosive, that can cause fire through friction, absorption of moisture, spontaneous chemical change, or which can be ignited readily and create a serious hazard.

Flash point:  The minimum temperature at which a liquid gives off a vapor in sufficient concentration to ignite.

Fume:  Minute solid particles dispersed in the air because of heating a solid.

Gas:  State of matter characterized by very low density and viscosity.

Gastro:  Referring to the stomach.

Glove box:  A sealed enclosure in which all operations are carried out through long impervious gloves sealed to the box.

Hazard warning:  Any words, pictures, or symbols appearing on a label that conveys the hazards of the chemical in the container.

Hazardous chemical:  A chemical that is a physical or health hazard.

Health hazard:  A chemical for which there is statistically significant evidence based on at least one scientific study that acute or chronic health effects may occur in exposed individuals. Health hazards include chemicals that are carcinogens, mutagens, teratogens, corrosives, toxic and highly toxic agents, irritants, and sensitizers.

Hemato:  Referring to the blood.

Hematopoietic toxins:  Chemicals that interfere with the production of red blood cells.

HEPA filter:  High efficiency particulate air filter. Removes 99.97% of particles with a diameter greater than 0.3 microns.

Hepatotoxins:  Chemicals that damage the liver.

Highly toxic: A chemical is considered highly toxic if it has an LD50 in test animals of less than 50 mg/kg by ingestion, or less than 200 mg/kg by skin contact, or the LC50 is less than 200 ppm.

Human carcinogen:  A substance that has been shown by statistically significant epidemiological evidence to cause cancer in humans.

Hydrocarbon:  Organic compounds consisting solely of hydrogen and carbon.

IARC:  International Agency for Research on Cancer.

Ignition temperature:  The lowest temperature necessary to cause the vapor-air mixture over the liquid to ignite and continue to burn without the heat source.

Inorganic:  Compounds from a source other than animal or vegetable that generally do not contain carbon.

Irritant:  A chemical that causes a reversible inflammatory effect on living tissue by chemical action at the site of contact.

Ischemia:  Loss of blood supply to a part of the body.

Label:  Any written, printed, or graphic material displayed on or affixed to containers of hazardous chemicals.

LC50:  The air concentration of a chemical that causes the death of 50% of the test animals.

LD50:  The quantity of a material that will result in the death of 50% of the test animals when ingested, injected, or applied to the skin.

Leukemia:  Blood disease characterized by an overproduction of white blood cells.

Lower flammability limit:  The minimum concentration of the vapor in air that will sustain the spread of a flame.

Makeup air:  Clean, tempered outdoor air that replaces air removed by exhaust ventilation.

Material safety data sheet:  Written or printed material concerning a hazardous chemical that is prepared according to the Hazard Communication Standard.

Metastases:  The process by which a malignant tumor establishes new sites.

Mists:  Finely divided liquid suspended in air. Created by condensation or by breaking up a liquid.

MSDS:  Material safety data sheet.

Mucous membranes:  Lining of the hollow organs of the body such as the nose, mouth, stomach, intestines, and bronchial tubes.

Mutagenic:  Chemicals that cause a change in the gene structure that can be passed on to offspring.

Myelo:  Referring to bone marrow.

Narcosis:  Loss of consciousness.

Necrosis:  Death of body tissues.

Neoplasm:  A new growth that may be benign or malignant.

Nephrotoxins:  Chemicals that produce kidney damage.

Neurotoxins:  Chemicals that produce their primary effect on the central nervous system.

NFPA:  National Fire Protection Association.

NIOSH:  National Institute for Occupational Safety and Health.

NTP:  National Toxicology Program.

Oncogenic:  Chemicals that cause tumors.

Organic matter:  Compounds containing carbon.

OSHA:  Occupational Safety and Health Administration.

Oxidizer:  A chemical that initiates or promotes combustion in other materials by releasing oxygen, causing a fire.

Palpitation:  Rapid or fluttering heartbeat that the person is very conscious of.

Particulate matter:  Suspension of fine solid or liquid matter in air.

PEL: Permissible exposure limit established as legal limit by OSHA to which nearly all workers may be exposed to as an eight-hour time-weighted average without adverse effects.

Personal protective equipment:  Equipment such as respirators, gloves, and eye goggles, worn by workers to protect themselves from hazards.

Physical hazard:  A chemical that is a combustible liquid, compressed gas, explosive, flammable, organic peroxide, oxidizer, pyrophoric, or reactive.

Plenum:  A space filled with air as opposed to a vacuum.

Poison:  A chemical with an oral LD50 of 50 mg/kg or less.

ppb:  parts per billion.

ppm:  parts per million.

Pyrophoric:  A chemical that will ignite in air at a temperature of 130 F or below.

RCRA:  Resource Conservation & Recovery Act.

Reactive:  A chemical that will decompose, condense, or will become self-reactive under conditions of shock, pressure or temperature.

Reproductive toxins:  Chemicals that can cause birth defects, spontaneous abortions, or sterility.

Respirator:  A device worn by workers to protect themselves from breathing harmful contaminants.

Safety can:  Designed to safely relieve internal pressure when exposed to a fire. Has a spring-closing lid and a flame arrestor in the spout.

Sensitizer:  A chemical that causes many exposed people to develop an allergic reaction after repeated exposure to the chemical.

Solvent:  A substance that dissolves another substance. Most commonly water but often an organic compound.

Sorbent:  A material that removes toxic gases and vapors from air inhaled through a respirator.

Specific gravity:  The mass of a substance divided by the mass of an equal volume of water.

STEL:  Short term exposure limit. The maximum amount that a worker may be exposed to for 15 minutes.

Synergism:  Substances combining to cause an effect that is greater than the sum of the parts.

Teratogenic:  A substance that may produce a malformation of the embryo or fetus.

TLV-TWA:  The threshold limit value established by the ACGIH that represents the eight hour time-weighted average concentration to which nearly all workers may be exposed without suffering adverse effects.

Toxic:  A chemical is considered toxic if the LD50 in test animals is between 50 mg/kg and 500 mg/kg when ingested or between 200 mg/kg and 2000 mg/kg when in contact with the skin. The substance is also considered toxic if the LC50 is between 200 ppm and 20,000 ppm when inhaled.

TWA:  Time weighted average.

Upper flammability limit:  The maximum concentration of vapors in air that will propagate a flame.

Vapor pressure:  The pressure of a vapor in equilibrium with its liquid or solid. The higher the vapor pressure the greater the volatility.

Vapors:  The gaseous form of a material that is normally in the solid or liquid state.

Viscosity:  The internal friction or resistance to flow in a liquid or gas.

Volatile:  The ability of a liquid to vaporize. A highly volatile liquid, such as gasoline, has a high vapor pressure and will vaporize easily.

Water-reactive:  A chemical that will react with water to release gas that is either flammable or presents a health hazard.

 

Appendix B - NFPA Hazard Identification Labeling System

The National Fire Protection Association (NFPA) diamond symbol is designed to show at a glance the hazards of chemicals under emergency conditions such as spills and fires. It can also be used as a guide to provide information about non-emergency hazards associated with chemicals. Information on the presence of acute health, flammability, and reactivity (stability) hazards and the relative severity of the hazards are shown on the symbol by numerical designations from 0 to 4. In general the numbers represent the following hazards:

0- no significant hazard

1- slight

2- moderate

3- serious

4- severe

The diamond symbol is subdivided into four smaller diamonds. Health hazards are identified on the left in a blue diamond, flammability at the top in a red diamond, and reactivity on the right in a yellow diamond. The bottom section is used to identify special hazards such as water reactives, oxidizers, or radioactive materials. Following is a summary of the meaning of the numbers in each hazard category:

Health Hazards

4- Materials that are deadly and could be fatal on very short exposure. Special protective equipment required.

3- Materials that are extremely hazardous and could produce serious injury on short exposure. Skin contact or inhalation should be avoided. Protective clothing required.

2- Materials that are hazardous and may be harmful to health if inhaled or absorbed.

1- Materials that are slightly hazardous may cause irritation.

0- Materials that present no unusual hazard.

Flammability

4- Extremely flammable liquids. Flash points below 73 F. Includes Class IA and IB flammable liquids.

3- Flammable liquids. Flash points between 73 F and 100 F. Includes Class IC flammable liquids.

2- Combustible liquids with flashpoints between 100 F and 200 F that require moderate heating to ignite. Includes Class II and IIIA combustible liquids.

1- Combustible materials that must be heated strongly to ignite. Flashpoints above 200 F. Class IIIB combustible liquids.

0- Non-combustible materials.

Reactivity

4- Materials that can readily explode at room temperature and pressure. Includes shock sensitive materials.

3- Materials that may explode when heated under confinement or mixed with water. Includes materials that are sensitive to shock under elevated temperatures and pressures.

2- Materials that are unstable and may undergo violent chemical change but do not explode. May react violently with water.

1- Materials that are normally stable but may react if heated or mixed with water.

0- Materials that are stable and do not react with water.

Appendix C - Incompatible Chemicals

Incompatible chemicals are chemicals that can react violently with each other creating fires, explosions, or the release of toxic gases. These chemicals should always be handled, stored, and disposed of in a manner that ensures that they do not accidentally come in contact with each other.

Acids:  Bases, metals, cyanides, sulfides, selenides

Acetic Acid:  Chromic acid, nitric acid, hydroxyl compounds, ethylene glycol, perchloric acid, peroxides, permanganates

Acetylene:  Chlorine, bromine, copper, fluorine, silver, mercury, or their compounds

Acetone:  Concentrated sulfuric and nitric acid mixtures

Alkali & Alkaline Earth (carbides, hydrides, hydroxides, metals, oxides, peroxides):  Water, acids, halogenated organic compounds, carbon dioxide, halogens

Ammonia (anhydrous):  Mercury, chlorine, calcium hypochlorite, iodine, bromine, hydrofluoric acid (anhydrous)

Ammonium nitrate:  Acids, metal powders, flammable liquids, chlorates, nitrites, sulfur, finely divided organic or combustible materials

Aniline:  Nitric acid, hydrogen peroxide, strong oxidizing agents

Azides, inorganic:  acids, heavy metals and their salts, oxidizing agents

Bases:  Acids

Bromine:  Ammonia, acetylene, butadiene, butane (or other petroleum gases), hydrogen, sodium carbide, turpentine, benzene, finely divided metals

Calcium oxide:  Water

Carbon, activated:  Calcium hypochlorite, all oxidizing agents

Carbon tetrachloride:  Sodium

Chlorates:  Ammonium salts, acids, metal powders, sulfur, finely divided organic or combustible materials

Chromic acid:  Acetic acid, naphthalene, camphor, glycerol, flammable liquids

Chlorine:  Ammonia, acetylene, butadiene, butane, methane, propane (or other petroleum gases), hydrogen, sodium carbide, turpentine, benzene, finely divided metals

Chlorine dioxide:  Ammonia, methane, phosphine, hydrogen sulfide

Copper:  Acetylene, hydrogen peroxide

Cumene hydroperoxide:  Acids (organic or inorganic)

Cyanides, inorganic:  Acids, strong bases

Flammable liquids:  Ammonium nitrate, chromic acid, hydrogen peroxide, nitric acid, sodium peroxide, halogens, strong oxidizing agents

Fluorine:  Separate from everything

Hydrocarbons:  Fluorine, chlorine, bromine, chromic acid, sodium peroxide

Hydrocyanic acid:  Nitric acid, alkali

Hydrofluoric acid, anhydrous:  Ammonia (aqueous or anhydrous)

Hydrogen peroxide:  Copper, chromium, iron, most metals and their salts, alcohols, acetone, organic materials, aniline, nitromethane, flammable liquids, combustible materials

Hydrogen sulfide:  Fuming nitric acid, oxidizing gases

Hypochlorites:  Acids, activated carbon

Iodine:  Acetylene, hydrogen, ammonia

Mercury and its amalgams:  Acetylene, fulminic acid, ammonia, nitric acid, sodium azide

Nitrates:  Sulfuric acid

Nitric acid:  Acetic acid, aniline, bases, chromic acid, chromates, hydrocyanic acid, sulfides, sulfuric acid, carbon, flammable liquids, flammable gases, metals, permanganates, reducing agents

Nitrites, inorganic:  Acids, oxidizing agents

Nitro compounds, organic:  Strong bases

Nitroparaffins:  Inorganic bases, amines

Oxalic acid:  Silver and its salts, mercury and its salts

Oxidizing agents:  Reducing agents (e.g., alkaline metals, ammonia, carbon, metals, metal hydrides, nitrites, organic compounds, phosphorus, silicon, sulfur), flammable & combustible materials

Oxygen:  Oils, grease, hydrogen, flammable liquids, solids, and gases

Perchloric acid: Acetic anhydride, bismuth and its alloys, alcohol, paper, wood, other organic materials

Peroxides, organic:  Acids, friction, heat

Phosphorus pentoxide:  Water, alcohols, strong bases

Phosphorus, white:  Air, oxygen, alkalis, reducing agents

Potassium:  Carbon tetrachloride, carbon dioxide, water

Potassium chlorate & perchlorate:  Sulfuric and other acids

Potassium permanganate:  Glycerine, ethylene glycol, benzaldehyde, sulfuric acid

Reducing agents:  Oxidizing agents (e.g., bromates, chlorates, chromates, chromium trioxide, dichromates, halogens, hydrogen peroxide, hypochlorites, iodates, nitric acid, nitrates, perchlorates, peroxides, permangnates, persulfates)

Selenides:  Reducing agents

Silver:  Acetylene, oxalic acid, tartaric acid, ammonium compounds

Sodium:  Carbon tetrachloride, carbon dioxide, water

Sodium nitrite:  Ammonium nitrate, and other ammonium salts

Sodium peroxide:  Oxidizable substances such as: methanol, glacial acetic acid, acetic anhydride, benzaldehyde, carbon disulfide, glycerine, ethylene glycol, ethylacetate

Sulfides, inorganic:  Acids

Sulfuric acid:  Bases, chlorates, perchlorates, permanganates, water

Tellurides:  Reducing agents

Appendix D - Gloves: Chemical Resistance Guide

Acetaldehyde:  Neoprene, Natural Rubber

Acetic Acid, Glacial:  Nitrile, PVC

Acetic Acid, 50%:  Nitrile, Neoprene, Natural Rubber, PVC

Acetone:  Neoprene, Natural rubber

Acetonitrile:  Neoprene

Ammonium Hydroxide, 29%:  Nitrile, Neoprene, PVC, Natural Rubber

Aniline:  Neoprene, Nitrile, Natural Rubber

Aroclor 1254/50% TCB:  Neoprene, Nitrile

Benzene:  Nitrile

Benzene Chloride:  Nitrile

Bis(2-Hydroxyethyl) Amine:  Nitrile, Neoprene, PVC, Natural Rubber

2-Butanone:  Neoprene

2-Butoxyethanol:  Nitrile, Neoprene, Natural Rubber

Butyl Acetate:  Nitrile, Neoprene

Butyl Cellosolve:  Nitrile, Neoprene, Natural Rubber

Carbolic Acid:  Neoprene, Nitrile, Natural Rubber

Carbon Dichloride:  Nitrile

Carbon Disulfide: Nitrile

Carbon Tetrachloride:  Nitrile

Cellosolve:  Nitrile, Neoprene, Natural Rubber

Cellosolve Acetate:  Nitrile, Neoprene

Chlorobenzene:  Nitrile

Chloroform:  Neoprene

Chlorothene:  Nitrile

o-Chlorotoluene:  Nitrile

p-Chlorotoluene:  Nitrile

Chromic Acid 50%:  Nitrile

m-Cresol:  Neoprene, PVC

Cumene:  Nitrile

Cyclohexane:  Nitrile, Neoprene

Diamine:  Nitrile, Neoprene, PVC, Natural Rubber

1,2-Dichlorobenzene:  Nitrile

1,3-Dichlorobenzene: Nitrile

1,2-Dichloroethane:  Neoprene

Dichloromethane:  Neoprene

Diethanolamine:  Nitrile, Neoprene, PVC, Natural Rubber

Diethyl Ether:  Nitrile, Neoprene

1,4-Diethylene Dioxide:  Neoprene

Dimethyl Acetamide:  Natural Rubber

Dimethyl Formadmide:  Neoprene, Natural Rubber

Dimethyl sulfoxide:  Neoprene, Natural Rubber

1,4-Dioxane:  Neoprene

2-Ethoxyethanol:  Neoprene, Natural Rubber

2-Ethoxyethyl Acetate:  Neoprene

Ethyl Acetate:  Neoprene

Ethyl Alcohol:  Nitrile, Neoprene, PVC, Natural Rubber

Ethyl Ether:  Nitrile, Neoprene

Ethylene Dichloride:  Nitrile, Neoprene

Ethylene Glycol:  Nitrile, Natural Rubber

Ethylene Oxide:  Nitrile, Neoprene

Formaldehyde 37%:  Nitrile, Neoprene, PVC, Natural Rubber

Formalin Solution:  Nitrile, Neoprene, Natural Rubber

Gasoline:  Nitrile, Neoprene

Heptane:  Nitrile, Neoprene

Hexane:  Nitrile, Neoprene

Hydrazine:  Nitrile, Natural Rubber, PVC, Neoprene

Hydrochloric Acid 37%:  Nitrile, Neoprene, PVC, Natural Rubber

Hydroflouric Acid 48%:  Neoprene, PVC, Natural Rubber

Isoamyl Acetate:  Neoprene

Isopropyl Alcohol:  Nitrile, Neoprene, PVC, Natural Rubber

Isopropylbenzene:  Nitrile

Kerosene:  Nitrile, Neoprene

Lacquer Thinner:  Nitrile

Methane Dichloride:  Neoprene

Methyl Alcohol:  Nitrile, Neoprene, Natural Rubber

Methylchloroform:  Nitrile

Methyl Cyanide:  Neoprene

Methyl Ethyl Ketone:  Neoprene, Natural Rubber

Methyl Iodide:  Neoprene

Methylene Chloride:  Neoprene

m-Methylphenol:  Neoprene, PVC

Mineral Spirits:  Nitrile, Neoprene

Naptha:  Nitrile, Neoprene

Nitric Acid 50%:  Neoprene, PVC

Nitrobenzene:  Nitrile, Neoprene

Oleic Acid:  Nitrile, Neoprene

Paint thinner:  Neoprene, Nitrile

Pentane:  Neoprene

Perchloroethylene:  Nitrile

Petroleum Ether:  Nitrile, Neoprene

Petroleum Distillates:  Neoprene, Nitrile

Phenol Sat.:  Neoprene, Natural Rubber

Phosphoric Acid 85%:  Nitrile, Neoprene, PVC, Natural Rubber

Polychlorinated Biphenyls:  Neoprene

Potassium Hydroxide 50%:  Nitrile, Neoprene, PVC, Natural Rubber

Pyridine:  Neoprene

Sodium Hydroxide 50%:  Nitrile, Neoprene, PVC, Natural Rubber

Sulfuric Acid 50%:  Nitrile, Neoprene, PVC, Natural Rubber

1,1,2,2-Tetrachloroethane:  Neoprene

1,1,2,2-Tetrachloroethylene:  Nitrile

Tetrahydrofuran:  Nitrile, Neoprene

Toluene:  Nitrile

Toluene Diisocyanate:  Nitrile, PVC, Natural Rubber

1,1,1-Trichloroethane:  Nitrile, Neoprene

Trichloroethylene:  Neoprene

Trichlorotrifluoroethane:  Nitrile, Neoprene

Triethanolamine:  Nitrile, Neoprene, PVC, Natural Rubber

Trifluoroethanol:  Neoprene

Trihydroxytriethylamine:  Nitrile, Neoprene, PVC, Natural Rubber

Turpentine:  Nitrile, Neoprene

Varsol:  Neoprene, Nitrile

Vinyl Acetate:  Nitrile, Neoprene

Xylenes (Xylols):  Nitrile

Hazard Communication Manual

1.0 Safety Equipment

Safety equipment is designed to protect personnel from injury and minimize damage to property if an accident occurs. Safety equipment should be in useable condition and available to all workers who use chemicals. Personnel should know the location, operation and limitations of safety equipment in the work area.

Fire Extinguishers

Portable fire extinguishers are the first line of defense against a fire. Fire extinguishers are rated for their suitability in combating the following four types of fires:

Class A.   Class A fire extinguishers are used to extinguish fires in ordinary combustibles such as wood, paper, cloth, rubber, and plastics. These extinguishers should not be used on electrical, flammable liquid or combustible metal fires. Extinguishers effective against type A fires contain water or a special dry chemical agent.

Class B.  Class B fire extinguishers are effective against flammable liquids and gas fires such as solvents, oil, gasoline, and grease. Dry chemical agents, carbon dioxide, and halogenated agents are typically used. Water will only spread a flammable liquid fire and should not be used as an extinguishing agent for Class B fires.

Class C.  Class C fire extinguishers are used to extinguish fires involving energized electrical equipment. Non-conducting agents such as dry chemical, carbon dioxide, or halogen compounds are used. Water should never be used to extinguish an electrical fire.

Class D.  Class D fire extinguishers contain a special granular formulation that is effective against combustible metal fires such as sodium, potassium, magnesium, and lithium. Normal extinguishing agents must not be used against combustible metal fires because they may increase the intensity of the fire.

Rating numbers are also used on the labels of extinguishers for Class A and Class B fires to indicate their ability to handle different sizes of fires. An extinguisher rated 1A will extinguish 64 square feet of wood and a 1B unit will extinguish 2.5 square feet of a flammable liquid. The rating numeral also gives the relative extinguishing effectiveness of the fire extinguisher. For example, an extinguisher rated 2A should extinguish twice as much fire as an extinguisher rated 1A. Class C and D fire extinguishers have no numerical ratings. Extinguishers that are effective on more than one class of fire have multiple letter and numeral ratings. No extinguisher is suitable for all four classes of fires.

Recently the National Fire Protection Association has recommended a labeling system that uses picture-symbol labels. Types of fires that the extinguisher should be used for are shown by blue symbols. Black symbols crossed with a red diagonal line show fires that the extinguisher should not be used against.

Training.  Personnel should be trained in the basic operation of fire extinguishers and know what type of extinguisher to use on a particular fire.

Location.
  Areas in which flammable solvents are used must have an appropriate fire extinguisher.

Labeling.
  Every extinguisher should be clearly labeled to show the classification of the fires it is effective against. Water fire extinguishers must be labeled to indicate that they cannot be used on electrical fires.

Access.  Fire extinguishers should be readily accessible and the location of the extinguisher should be clearly identified. Access to the fire extinguisher should not be blocked. Fire extinguishers must be mounted off the floor and no higher than five feet. Extinguishers weighing over 40 lbs. should be mounted no higher than three 1/2 feet.

Inspections.
Fire extinguishers should be maintained in operating condition, inspected monthly, checked against tampering, and recharged as required.

Flammable Storage Cabinets

Quantities of flammable liquids greater than 10 gallons must be stored in flammable storage cabinets, approved safety cans, or a properly designed flammable storage room. Approved storage cabinets are designed to protect flammable liquids from involvement in an external fire for 10 minutes. This is the time it would normally take for an area to become seriously involved in a fire.

Approval.  All cabinets must comply with OSHA and NFPA requirements. Cabinets can be made of metal or wood if properly constructed.

Storage limits.
  Maximum storage limits for flammable liquids in approved storage cabinets are 120 gallons. Of this total, only 60 gallons of Class I and Class II liquids are allowed. No more than three such cabinets may be stored in a fire area.

Venting.
  Storage cabinets are not required to be vented. Venting a cabinet may defeat the cabinet's purpose of protecting the contents from involvement in a fire for 10 minutes.

Labeling.  Cabinets must be labeled in conspicuous lettering "Flammable-Keep Fire Away."

Safety Cans

Portable approved safety cans are used to safety store, carry, and pour flammable and combustible liquids. The main purpose of the safety can is to prevent an explosion of the container when it is heated. Safety cans are constructed of terne plate steel, stainless steel, or high density polyethylene. The type of can purchased is determined by the chemical properties of the flammable liquid and how it will be used. Terne-plate steel cans are designed to store petroleum solvents if the purity and color of the solvent are not critical. Some solvents may also dissolve the paint from the outside of these cans. Stainless steel cans are recommended when high purity solvents are needed. High density polyethylene cans are resistant to many solvents but may cause discoloration of the solvent.

Approval.  Safety cans must be UL listed and FM approved, and properly labeled to identify contents.

Construction.  All approved cans must have a lid that is spring loaded to close automatically after filling or pouring. The lid also acts as a relief valve when pressure builds up in the can. A flame arrestor screen must be inside the cap spout to prevent fire flashback into the can.

Refrigerators

Confined vapors from flammable liquids are easily ignited and represent a major hazard in laboratory refrigeration units. There are several potential ignition sources in a normal refrigerator or freezer. Spark producing devices include the thermostat, light switch, defrost mechanism and compressor. In addition, self-defrosting units have a drain hole at the bottom and vapors can escape through the hole and be ignited by the compressor.

Standard refrigerators.  Because of the danger of fires and explosion, standard refrigerators and freezers may not be used for storage of flammable liquids. These refrigerators should be posted as unsafe for storage of flammable liquids.

Acceptable units.  The following types of refrigerators are safe for the storage of flammable materials:

  1. Explosion-Safe or flammable storage refrigerators and freezers, which have been modified to eliminate the spark producing mechanisms.
  2. Explosion-Proof refrigerators and freezers, which not only protect against flammable vapors inside the unit, but may also be operated in rooms that have an explosive atmosphere. These units must be permanently wired to the electrical system.

Eyewash Fountains and Emergency Showers

Suitable eyewash facilities and emergency showers must be available in areas that use hazardous chemicals that may be harmful to the eyes or skin or that can be absorbed through the skin. Besides providing protection from chemical splashes, emergency showers can be used to extinguish clothing fires. Emergency showers and eyewash stations should always be installed at the same location because injuries to the eyes and skin often occur together. All personnel should be familiar with the location and operation of emergency showers and eyewash stations before beginning hazardous procedures.

Location.  Units shall be located in readily accessible areas within 10 seconds of an area using injurious chemicals. In extremely hazardous areas, units may be required to be within 10-20 feet of the hazard. Eyewash units and emergency showers should not be located near electrical apparatus, power outlets or water reactive chemicals. The area around the equipment must be kept clear to ensure immediate access.

Valve.  The valve should be designed so that the water remains on without requiring the user to hold the valve open. Injured personnel must have the ability to hold both eyelids open or take their clothes off. The valve actuator should be large enough to be easily located and operated by the user. A self-closing valve on emergency showers may be used in low hazard areas if approved by the Safety Manager.

Pull devices.  Overhead chains are most commonly used to activate showers. The chain should be at such a height that anyone working in the area could reach the chain. The chain should never be tied up out of the way. Rod-type pull activators are preferable to chains because they are easily accessible and cannot be tied out of the way.

Water flow.  Eye-wash equipment should be capable of delivering to both eyes simultaneously at least 0.4 gallons of potable water per minute for 15 minutes. The velocity should be low enough so that it will not injure the user. Nozzles must be protected from airborne contaminants. The removal of the protective device should not require a separate motion by the user. Shower heads shall be between 82 and 96 inches from the floor. Emergency shower heads must be capable of delivering a minimum of 20 gallons of water per minute.

Signs.  The location of eyewash units and emergency showers should be identified with a highly visible sign.

Inspections.  Eye-wash stations should be flushed weekly for a few minutes to ensure that they are in operating condition and to clean out the water lines. Deluge showers should be tested and flushed yearly.

Back-up units.  Small squeeze bottles of water or saline solutions are not acceptable as a primary eyewash unit because they do not supply the flow necessary for repeated washings and cannot flush both eyes simultaneously. Drench hoses are acceptable only as a back up system because they cannot flush both eyes simultaneously and the user cannot hold both eyes open. In addition, hand-held drench hoses cannot provide the full flow associated with an emergency shower and can only be used to support an approved emergency shower. Small eye-wash units mounted on the ends of faucets are intended only to supplement, but not replace standard plumbed in eye-wash equipment. These units can be difficult to operate in an emergency.

Miscellaneous Safety Equipment

First aid kits. First aid kits should contain adequate first aid instructions and an assortment of material packaged in single disposable packages. Bottles of antiseptic liquids or large tubes of antiseptic creams that can break or leak should be avoided. A kit should be readily available at all times work is being performed. The location of the kit should be clearly identified and access should not be blocked. Phone numbers for emergency personnel should be posted in the same area. The kit should be inspected periodically and re-supplied as necessary.

Machine guards.  Mechanical equipment must be adequately guarded to prevent access to rotating parts, pulleys or electrical connections. Guards on fan blades shall have openings no larger than one-half inch.

Fire blankets.  Fire blankets should only be used as a last resort to extinguish clothing fires because they may hold the heat in and increase the severity of burns. Fire blankets should be used primarily to prevent shock in accident victims.

2.0 Handling Chemicals

Accidents associated with the handling of chemicals can occur during, storage, use, and disposal. Personnel may be exposed to hazardous chemicals that present health hazards, such as toxins and corrosives, and physical hazards that may result in fires and explosions. These risks can be minimized by following the general precautions recommended below. Recommendations for handling specific classes of chemicals are presented in the succeeding chapters.

Ordering

The potential hazards of a chemical should be known before ordering. Personnel should receive adequate training in handling the material, and plans must be made to store and dispose of the chemical properly before it is received. Chemicals must be properly labeled, inventoried, and a material safety data sheet must be available. Preferably, all chemicals should be received in a central location.

Quantity.  To reduce waste disposal costs, only the smallest quantity of a chemical should be ordered.

Material safety data sheets.  Hazardous chemicals should not be accepted unless an MSDS has been sent with the shipment, is being sent, or is on file with the Safety Office.

Labels.  In accordance with Globally Harmonized System of Classification and Labeling of Chemicals (GHS), and in compliance with OSHA 1910.1200; Labels on incoming chemicals must contain the name of the product or chemical, identify hazardous ingredients or components, display the appropriate signal word, appropriate physical, health, environmental hazard statements, supplemental information, precautionary measures & pictograms, first aid statements, and the name and address of the manufacturer. Unlabeled chemicals must not be accepted.

Inventory.  All departments must maintain an inventory of incoming hazardous chemicals.

Free materials.  The recipient should limit the amount of free material to that actually needed. The donor should agree in writing to dispose of any excess material in a legal and safe manner. If the free material poses any safety or health risks or would cause any storage or disposal problems, the Safety Manager should be notified to resolve the problems posed by the gift.

Flammable materials.  Containers of flammable and combustible liquids are limited to the following sizes:

Class Glass or Metal Plastic Metal Safety Cans
(non DOT)
Metal Safety Cans (DOT)
Class IA 1 pt 1 gal 60 gal 2 gal
Class IB 1 qt 5 gal 60 gal 5 gal
Class IC 1 gal 5 gal 60 gal 5 gal
Class II 1 gal 5 gal 60 gal 5 gal
Class III 1 gal 5 gal 60 gal 5 gal

Chemical Storage

Many hazards are associated with the storage of chemicals. Accidents can be reduced by careful planning, following procedures, and properly designing facilities. Chemical containers should be periodically inspected to ensure that labels are legible and intact, containers are not leaking or rusting, and chemicals have not dangerously deteriorated. Containers should always be kept tightly sealed. Storage should be minimized. Chemicals should be inventoried periodically and unneeded chemicals disposed of through the Safety Office. Individual chapters on chemical classes should be consulted for additional information on storage procedures.

Location.  Chemicals should be stored in a definite storage area and returned to that location after each use. Chemicals should be stored on shelves with a one-half inch retaining lip. Shelves should not be above shoulder height. Shelves should be sturdy and coated with a chemically resistant paint. Chemicals should not be stored on bench tops. Storage areas should be cool, dry, well ventilated, and out of direct sunlight.

Incompatibles.  Every effort should be made to separate chemicals that may react together and create a hazardous situation. A common and unsafe practice is storing chemicals alphabetically. This practice can cause explosions, or the release of toxic vapors. Chemicals should be stored according to chemical class. Further information on incompatible chemicals is available from the Safety Office.

Carcinogens.  Carcinogens should be stored in a designated area or cabinet and posted with the appropriate hazard sign. Volatile chemicals should be stored in a ventilated storage area in a secondary container having sufficient volume to contain the material in case of an accident. Storage areas should be separated from flammable solvents and corrosive liquids.

Toxic chemicals.  Toxic chemicals should be stored away from fire hazards, heat, and moisture, and isolated from acids, corrosives, and reactive chemicals. Special care should be taken to ensure that toxic chemicals are not released into the environment. Access to the storage area should be restricted for highly toxic chemicals. Highly toxic chemicals should be stored in unbreakable secondary containers.

Corrosives.  Corrosive chemicals should not be stored with combustibles, flammables, organics, and other highly reactive and toxic compounds. Acid and bases should not be stored together.

Flammable liquids.  Storage in work areas is limited to 10 gallons outside flammable storage cabinets or approved safety cans. Storage in glass containers is limited to one pint for Class IA liquids and one quart for Class IB liquids, unless permission has been obtained from the Safety Manager.

Flammable liquids should not be stored near exits, sources of heat, ignition, or near strong oxidizing agents, explosives, or reactives. Smoking is prohibited in storage areas. Storage areas should be adequately ventilated to prevent vapor building up. Adequate fire extinguishers should be readily available. Metal dispensing and receiving containers should be grounded and bonded together by a suitable conductor to prevent static sparks.

Reactives.  Reactive chemicals should be protected from shock, heat, ignition sources, and rapid temperature changes. Containers should be separated from corrosives, flammables, organic materials, toxins, and other reactive chemicals. Depending on the quantity, explosives may need to be stored in specially constructed magazines. Water reactive chemicals should be separated from sprinkler systems, emergency showers, eyewash stations and other water sources. Keep containers well sealed. Store water reactives under an inert non-flammable solvent.

Compressed gases.  Cylinders must be secured, and stored upright with the valve protector in place. Storage areas should be well ventilated and dry. Cylinders should be stored away from ignition sources, heat, and combustibles. Flammable gas cylinders and oxidizing cylinders must be separated by 20 feet or a five-foot high wall with a half-hour fire rating. Highly toxic gas cylinders must be stored in occupied areas in a way that will not contaminate breathing air.

General Safety Practices

Most chemicals are hazardous and should be handled with precautions. These hazards include toxic and corrosive chemicals that can damage health, and chemicals that can cause fires and explosions. Many accidents occur because the hazard was not known or it was underestimated. However, most accidents occur because workers become careless with commonly used substances with known hazards. To reduce accidents individuals must accept responsibility for carrying out their work according to good safety practices. Personnel should always strive to minimize their exposure to chemicals. The following general safety procedures are designed to minimize the likelihood of an accident when working with hazardous chemicals.

Planning.  Work should be planned carefully; appropriate planning can substantially reduce the risks in using chemicals. Always know the potential hazards and safety procedures associated with any chemical or operation before beginning the work. Consult this manual for general information on chemical classes and the Material Safety Data Sheet for detailed information for specific chemicals. The following factors should be considered before using hazardous chemicals:

  • Hazards associated with the use of the chemicals
  • Alternative chemicals or procedures that would be safer to use
  • Safety training for personnel
  • Personal protective equipment
  • Safety equipment
  • Modifications to the facility
  • Storage facilities
  • Hazardous waste disposal
  • Chemical spills

Training.  Personnel working with, or potentially exposed to, hazardous chemicals must receive training on the hazards of chemicals in their work area and safety procedures. Training is to be provided at the time of the employee's initial assignment and before exposure to new hazards. Training must contain the following information:

  • Methods and observations to detect the presence of hazardous chemicals in the work place.
  • Physical and health hazards of chemicals including signs and symptoms of an overexposure.
  • Procedures to protect against hazards including proper work practices, emergency procedures, safety equipment, personal protective equipment, and first aid procedures.

Emergencies.  Telephone numbers of emergency personnel and supervisors should be prominently posted in each work area.

Reference materials.  MSDSs, reference materials on hazardous chemicals, and permissible exposure limits are available in the Safety Office.

Inspections.  The Safety Manager will periodically inspect work areas to ensure that the use of hazardous chemicals conforms with University regulations. Preliminary discussion with the Safety Manager is encouraged to reduce potential problems associated with the use of new chemicals.

Chemical Hygiene Officer.  The Safety Manager will serve as the Chemical Hygiene Officer for the university. This person is qualified by training or experience to provide technical guidance in chemical and laboratory safety. The Chemical Hygiene Officer will develop and implement a chemical hygiene plan for the safe use of chemicals in laboratories and other work areas at the university.

Supervisors.  Supervisors are responsible for daily chemical hygiene in their work area. Specific duties are to ensure that employees are trained properly in chemical hazards, wear appropriate protective equipment and follow university rules for the safe use of chemicals.

Chemical spills.  Appropriate equipment for the proper handling of chemical spills (sand, soda ash, sodium bicarbonate, or a commercially available spill kit) should be readily available to personnel.

Transportation.  Glass bottles of flammable solvents, corrosive, and toxic chemicals should be transported in rubber buckets or similar protective carriers.

Hygiene.  Since most chemicals are harmful, chemicals should not come in contact with the skin. Wash thoroughly with soap and water if chemicals contact the skin, before leaving the work area, and before eating.

Eating & drinking.  Many chemicals are extremely dangerous if ingested. Contamination of food and drinks is a potential route of exposure to these toxic chemicals. A well-defined area within the work area must be established for the storage, handling, and consumption of food. Chemicals or chemical equipment must not be allowed in this area. Chemicals should never be stored in glassware designed to handle food or beverages. The storage, handling, and consumption of food are prohibited in certain high risk areas such as pesticide facilities. Food meant for human consumption and chemicals must not be stored in the same refrigerator. A refrigerator should be designated for food storage only and appropriately labeled.

Housekeeping.  Work areas should be kept clean and orderly, chemicals should be properly labeled, and equipment and chemicals should be properly stored. Chemicals should be used in a systematic way. Reagents should be capped and returned to their normal storage location after use. Unlabeled containers and chemical waste should be disposed of promptly using established procedures. Chemicals that are no longer needed should be disposed of properly. Chemicals should not be stored in aisles where they could be knocked over. Spilled chemicals should be cleaned up immediately. The Safety Manager should be notified immediately in the event of a large spill or one involving toxic materials. Benches and floors should be cleaned daily to reduce the quantities of accumulated chemicals that could pose respiratory hazards.

Personal protective equipment.  Exposure to hazardous chemicals should be avoided. Appropriate eye protection must be worn at all times by anyone working or visiting an area where hazardous chemicals are used. Other protective equipment such as face shields, gloves, protective clothing, and respirators should be worn as necessary.

Personal apparel.  Long hair should be confined. Shoes should be worn at all times. Workers should not wear sandals, perforated shoes, or sneakers.

Labels.   In accordance with Globally Harmonized System of Classification and Labeling of Chemicals (GHS), and in compliance with OHSA 1910.1200; labels on incoming chemicals must contain the name of the product or chemical, identify hazardous ingredents or components, display the appropriate signal word, appropriate physical, health, environmental hazard statements, supplemental information, precautionary measures & pictograms, first aid statements, and the name and address of the manufacturer. Unlabeled chemicals must not be accepted. Carefully read the label, noting the name and hazard information. Many chemicals have similar names. Secondary chemicals not intended for immediate use during the work shift must be labeled with the name of the chemical and the appropriate hazard warnings. Containers with illegible or missing labels should not be used. These chemicals should be disposed of by calling the Safety Office.

Material safety data sheets (MSDS).  MSDSs must be maintained for all incoming shipments of chemicals and made readily accessible to employees.

Smoking.  Smoking is prohibited in areas that use or store flammable solvents.

Working alone.  Work with chemicals that may be immediately dangerous to life and health should not be conducted alone.

Flammables.  Open flames should not be used to heat flammable liquids. Before lighting an open flame, ensure that all flammables have been removed from the area and that all flammables are tightly closed. Use only non-sparking electrical devices to heat flammable liquids.

Medical consultation.  Personnel must receive medical attention whenever symptoms associated with a possible overexposure are noted, or when monitoring shows an exposure routinely above the action level for an OSHA regulated substance.

Air monitoring.  Routine monitoring of airborne concentrations of chemicals is not normally warranted. Monitoring may be necessary, however, for work with certain carcinogens and when using chemicals in areas with inadequate ventilation.

Horseplay.  Practical jokes or other behavior that might startle, confuse, or distract another worker should be avoided.

3.0 Toxic Chemicals

Toxic chemicals are chemicals that can produce injury or death when inhaled, ingested, or absorbed through the skin. Damage may result from acute or chronic exposures and involve local tissue or internal organs. The extent of the injury depends on the dose administered, duration of the exposure, physical state, solubility, and interaction with other chemicals. Toxic chemicals include corrosives, systemic poisons, carcinogens, mutagens, and embryotoxins.

Dosage

The dose of a chemical is the most important factor that determines whether damage will result from exposure to the chemical. Chemicals vary tremendously in their toxicity. An excess of almost any chemical can be harmful and a sufficiently small amount of most chemicals will not cause injury. There is a threshold, or no effects level, that must be exceeded before toxic effects will be noticeable for most chemicals. Although the toxicity and chemical structure of a compound are generally related, each compound must be studied independently to determine its toxicity. In determining the toxicity of chemicals it is common to use standardized terms called the median lethal dose (LD50) or the median lethal concentration (LC50).

The LD50 is the dose of a chemical that will result in the death of 50% of a group of test animals when ingested or applied to the skin in a single dose. It is expressed in milligrams of the chemical per kilogram of body weight of the test animal. The LC50 refers to the concentration of a gas or vapor that will result in the death of 50% of the animals when inhaled and is expressed in parts per million (ppm).

A substance is considered toxic if the LD50 in test animals is between 50 mg/kg and 500 mg/kg when ingested, or between 200 mg/kg and 2000 mg/kg when in contact with the skin. The substance is also considered toxic if the LC50 is between 200 ppm and 20,000 ppm when inhaled. Examples of toxic chemicals include ammonia, bromine, sodium hydroxide, and methanol. A substance is considered highly toxic if it has an LD50 in test animals of less than 50 mg/kg by ingestion, less than 200 mg/kg by skin contact, or the LC50 is less than 200 ppm. Examples of highly toxic chemicals include chlorine, fluorine, and hydrogen sulfide.

Exposure

The toxicity of chemicals is also related to the duration of the exposure. Exposure to toxic chemicals is divided into two classes; acute toxicity and chronic toxicity.

Acute toxicity.  An acutely toxic chemical causes damage in a relatively short time (within minutes or hours) after a single concentrated dose. Irritation, burns, illness, or death may result. Commonly used acutely toxic poisons include chlorine and ammonia. These substances may cause severe inflammation, shock, collapse or even sudden death when inhaled in high concentrations. Corrosive materials such as acids and bases may cause irritation, burns, and serious tissue damage if splashed onto the skin or eyes.

Chronic toxicity.  A chemical that is a chronic toxin produces long term effects. Damage may result after repeated exposures to low doses over time, as from the slow accumulation of mercury or lead in the body, or after a long latency period from exposure to a carcinogen. Chronic exposure to solvents may also result in reproductive problems and behavioral changes. The symptoms from exposure to chronic toxins are usually different from those seen in acute poisoning from the same chemical. Since the level of contamination is low the worker may not be aware of the exposure to the toxin.

Chronic toxicity also includes exposure to embryotoxins, teratogenic agents, and mutagenic agents. Embryotoxins are substances that cause any adverse effects on the fetus (death, malformations, retarded growth, functional problems). Teratogenic compounds specifically cause malformation of the fetus. Examples of embryotoxic compounds include mercury and lead compounds. Mutagenic compounds can cause changes in the gene structure of the sex cells that can result in the occurrence of a mutation in a future generation. Approximately 90% of carcinogenic compounds are also mutagens.

Effects

Toxic effects are based on the site of action and are classified into local and systemic effects.

Local.  The action of a toxin on the skin or mucous membrane at the point of contact is termed local toxicity or corrosivity. For example, acids have a local or direct irritating effect on the skin, eyes, nose, throat, and lungs. The skin may be severely burned or vision impaired. The lungs may be damaged because of inhaling toxic gases. Exposure may be through inhalation, ingestion, or direct contact with the skin or eyes.

Systemic.  When a toxin is absorbed into the blood stream and distributed throughout the body systemic or indirect toxicity may occur. Absorption may take place through the lungs, skin, or gastrointestinal tract. Several sites may be damaged or the toxin may act on only one site. For example, arsenic may damage the blood, nervous system, liver, and kidneys. However, benzene acts on one site, the blood forming bone marrow. Pesticides are an example of systemics poisons commonly found in the work place.

Routes of Exposure

Toxic chemicals may enter the body through three routes: inhalation, ingestion, or contact with the skin and eyes.

Inhalation.  Inhalation of toxic substances represents the most common means by which injurious substances enter the body. Air contaminants in the workplace present both acute and chronic dangers to health. Inhalation of toxic substances can cause serious local damage to the mucous membranes of the mouth, throat, and lungs; or pass through the lungs into the circulatory system producing systemic poisoning at sites remote from the point of entry.

Several thousand deaths per year are attributed to exposure to dust, fumes, gases, vapors, and mist in the work place. Exposure to organic dusts such as coal dust can cause asthma, chronic bronchitis, and emphysema. Mineral dusts such as asbestos can cause asbestosis, characterized by coughing and breathlessness, or mesothelioma, a cancer of the lung lining. Exposure to toxic chemical dusts may result in irritation, bronchitis, and cancer depending on the nature of the chemical. The poisoning effect may be fast or slow depending on the toxicity and concentration inhaled.

Breathing the fumes generated from the heating of heavy metals may result in metal fume fever characterized by irritation of the lungs, dry throat, chills, fever, and pain in the limbs. Cadmium fumes may cause emphysema. Exposure to hydrocarbons, chromium, beryllium, and arsenic fumes may cause lung cancer.

Exposure to acid and alkaline gases such as hydrochloric acid and ammonia will cause extreme local irritation to the lungs. Some gases such as carbon monoxide may pass into the blood stream and cause systemic injuries.

Vapors are the gaseous state of liquids. Inorganic vapors are generally harmless. Exposure to organic vapors, however, may cause nose and throat irritation, pulmonary edema or cancer.

Mists are fine suspensions of liquid in air and can cause chemical burns of the lungs, lung disease and cancer. Common mists include sulfuric acid and sodium hydroxide from oven cleaners.

Many gases can be detected by their odor or irritating effect which results in an immediate warning so that injury can be averted. Ammonia, for example, is highly irritating and has an offensive odor. Other toxic gases, such as carbon monoxide, however, may have no odor or irritating effects. Deadening of the sense of smell may occur with some gases, such as hydrogen sulfide, and prevent the detection of toxic quantities, or the pain may be delayed for several hours as from exposure to hydrogen fluoride. Although sensory warnings may give adequate warnings occasionally, it should not be relied on as a primary defense.

Ingestion.  The ingestion of chemicals may cause severe local damage to the lining of the mouth, throat, and gastrointestinal tract. In addition, if the chemical is absorbed into the blood stream, systemic poisoning may result. Ingestion of chemicals may occur from eating contaminated food, smoking cigarettes contaminated with chemicals, or swallowing chemicals deposited in the throat through inhalation. Oral toxicity is generally lower than inhalation toxicity because of the relatively poor absorption of many chemicals from the intestines into the blood stream.

Skin contact.  Chemical damage to the skin of the hands and arms is the most common occupational injury. Damage to the skin may include inflammation, burning, blistering, and complete destruction of the skin. The extent of the damage depends on the type of chemical, its concentration, and the duration of the contact. Chemicals that affect the skin are divided into two classes: irritants and sensitizers. Exposure to irritants can result in contact dermatitis, the most common occupational skin disease. Contact dermatitis is any local inflammation of the skin following exposure to damaging substances. Most organic and inorganic acids and bases are strong irritants. Exposure to these chemicals can result in serious local damage to the skin often requiring medical attention. Exposure to milder irritants such as detergents and solvents may cause redness, burning, and swelling. The irritation is usually confined to the area of skin that contacted the chemical and may heal in a few days.

Initial contact with a chemical sensitizer may produce no reaction. Once sensitized, however, subsequent exposures may result in an allergic-type of response called contact allergic dermatitis. Reactions usually develop several hours after re-exposure and may last for several days. Skin reactions may also appear at sites remote from the initial contact. Once a worker has become sensitized to a chemical, very small amounts of it may trigger a reaction. Typical sensitizers include arsenic, mercury, nickel compounds, petroleum distillates, detergents, and many pesticides.

Skin contact is also the primary route of entry into the body for many hazardous chemicals. Many pesticides, for example, may pass through the skin and cause serious or even fatal poisoning. The largest problem associated with skin absorption of chemicals, however, occurs with organic solvents. Solvents such as benzene, carbon tetrachloride, and methyl alcohol may be absorbed in sufficient quantities to cause systemic injury or even cancer at other organ sites. In addition, some solvents such as DMSO may act as vehicles that carry other chemicals through the skin.

Eye contact.  The effects of accidentally splashing corrosive chemicals into the eye can range from minor irritation, to scarring of the cornea and loss of vision. Injury to the eye from bases is much more damaging than acid burns. Acids cause a protein barrier to form in the eye preventing further penetration of the acid. Bases, however, continue to soak into the eye and cause further damage. In addition, mists, vapors, and gases may produce varying degrees of damage to the eyes. Some chemicals may be absorbed by the eye and produce systemic poisoning.

Interactions

It is common for workers to be exposed to a wide range of chemicals. Consideration must be given to the possible interaction of these chemicals and how they may affect personnel. There is growing evidence that many chemicals may have a synergistic effect and produce toxic effects that are much greater in combination than would be predicted from their individual effects. Since standards for maximum permissible levels of chemicals are based on the effects of a chemical acting alone it is prudent to keep exposures to chemicals to the lowest possible level. Another possible hazard involves the interaction of chemicals with cigarettes. Cigarettes can convert chemicals in the atmosphere into more harmful forms. For example, chloroform can be converted by the heat from a cigarette into the highly toxic gas phosgene. Interactions may also occur inside the body of the worker, producing harmful substances.

Threshold Limit Values

Exposure limits to airborne concentrations of common chemicals are published yearly by the American Conference of Governmental Industrial Hygienists (ACGIH). These limits are recommendations, not legal standards, and represent conditions to which nearly all workers may be exposed without experiencing significant adverse effects. They are based on the best currently available data from industrial experiences, human population studies, and animal experiments. Three categories of Threshold Limit Values (TLV) are specified: Time Weighted Average (TWA), Short Term Exposure Limit (STEL), and Ceiling Value. TLV's are expressed in parts per million (ppm) or mg/cubic meter.

TWA.  The TWA is the concentration of an airborne chemical averaged over an eight-hour workday that workers may be exposed to daily without sustaining injury. Exposure to concentrations above the limit is allowed as long as they are balanced by exposures below the limit and do not exceed the STEL or Ceiling Limit.

STEL.  The STEL is the maximum concentration a worker can be exposed to for fifteen minutes without suffering from irritation, chronic or irreversible tissue damage, or narcosis of sufficient degree to cause impairment.

Ceiling limit.  The Ceiling Limit is the concentration that should never be exceeded for any period of time.

PEL.  The legal maximum levels of airborne chemicals are determined by OSHA and are called Permissible Exposure Levels (PEL). Most of the OSHA Permissible Exposure Levels are adopted from the ACGIH Threshold Limit Value list. OSHA values are not updated yearly as are the ACGIH Threshold Limit Values.

The TLV and PEL should only be used as guidelines for good practice and should not be used as fine lines between safe and unsafe concentrations. It is always prudent to keep exposures to airborne contaminants as low as possible.

Classes

Lung irritants. Lung irritants are chemicals that irritate or damage pulmonary tissue. Chemical irritants are classified as primary or secondary. Primary irritants exert their effect locally, for example, acid fumes burning the lungs. Secondary irritants, such as mercury vapors, may exhibit some local irritation but the main hazard is from systemic effects resulting from absorption of the chemical.

Irritation of the lungs may produce acute pulmonary edema (fluid in the lungs). Symptoms include shortness of breath and coughing that produces large amounts of mucous. Reactions to some chemicals may produce an allergic sensitization that causes asthmatic-type symptoms following additional exposures. Short term exposure to irritants is usually reversible with no permanent damage, however, systemic poisoning may persist and cause permanent damage.

The solubility of an irritant gas influences the part of the respiratory tract that is affected. For example, soluble gases such as ammonia, hydrogen chloride, and sulfur dioxide mainly irritate the upper respiratory tract. Insoluble gases such as carbon monoxide and phosgene travel deeply into the lungs and cause irritation of the bronchi and air sacs. These gases are then absorbed into the blood stream and damage various organ sites. Some gases such as chlorine and hydrogen sulfide may affect the entire respiratory tract.

Skin irritants.  Although not as destructive as corrosive chemicals, skin irritants can cause severe rashes and dermatitis to the hands upon significant and repeated contact. Many common solvents, such as toluene and xylene, are irritants.

Asphyxiants.  Chemical asphyxiants prevent or interfere with the uptake and transformation of oxygen. Examples include carbon monoxide, which prevents oxygen transportation, and hydrogen cyanide which inhibits enzyme systems and interferes with the transportation of oxygen to the tissues. At sufficiently high concentrations, both chemicals can result in immediate collapse and death.

Narcotics.  Narcotics affect the central nervous system causing symptoms that range from mild anesthesia reactions to loss of consciousness and death at high doses. Examples include acetone, toluene, xylene, and chloroform.

Neurotoxins.  Neurotoxins interfere with the transfer of signals between nerves and may cause a collapse of the nervous system. Effects include narcosis, behavior changes, and decreases in motor function. Examples include ethanol, methanol, general anesthetics, mercury, and tetraethyl lead.

Hepatotoxins.  Chemicals that damage the liver. Effects include jaundice and liver enlargement. Examples include mercury, uranium, carbon tetrachloride, heavy metals, and chlorinated hydrocarbons.

Nephrotoxins.  Chemicals that produce kidney damage. Effects include anemia, excessive amounts of protein in the urine and renal failure. Examples include arsenic, uranium, chromium, lead, mercury, cadmium, and halogenated hydrocarbons.

Agents that act on the blood.  Chemicals that cause decreased hemoglobin function that deprives the tissues of oxygen. Symptoms include cyanosis and loss of consciousness. Examples include carbon monoxide and cyanides.

Hematopoietic system.  Chemicals that interfere with the production of red blood cells. Symptoms include anemia, and leukemia. Examples include arsenic, benzene, fluoride, and iodide.

Reproductive toxins.  Chemicals that can cause birth defects, spontaneous abortions, or sterility. Examples include lead and PCBs.

Organic solvents.  The vapor pressure of a chemical determines if it has the potential to be a hazard from inhalation. The vapor pressure is the pressure of the vapor in equilibrium with its liquid or solid form. The more volatile a chemical the higher its vapor pressure and the lower its boiling point. Solvents are a problem because they vaporize easily and produce high concentrations of vapor in the air. Common solvents have vapor pressures that can produce concentrations in the breathing zones of workers between 10 to 1000 ppm.

Inhalation of the vapors from organic solvents can pass to the heart and central nervous system very rapidly and cause a toxic reaction. An acute exposure to very high concentrations can cause unconsciousness and death. Chronic exposure can cause nausea, headaches, fatigue, and mental impairment. Injury to the organs of the body and damage to the blood may also occur. Studies have shown that low concentrations of common solvents in the air can adversely affect behavior, judgement and coordination. There is also evidence that chronic exposure to some solvents can cause cancer (e.g., benzene, carbon tetrachloride, and chloroform).

Contact with the skin may cause irritation, dermatitis, or an allergic reaction. Some solvents such as benzene and xylene may be absorbed through the skin and enter the bloodstream. Common solvents include toluene, xylene, benzene, carbon tetrachloride, formaldehyde, chloroform, and methyl alcohol.

Organic solvents are commonly divided into two classes: chlorinated and non-chlorinated solvents. Chlorinated solvents are usually non-flammable. Examples include carbon tetrachloride, chloroform, and trichloroethylene. Non-chlorinated solvents are generally flammable. Examples include xylene, benzene, and toluene.

Corrosive chemicals.  Corrosive chemicals cause visible destruction or irreversible alternations in living tissue at the site of contact. These chemicals can burn the skin, cause severe bronchial irritation, and blindness if splashed into the eyes. Examples include sulfuric acid, hydrochloric acid, sodium hydroxide, and bromine.

Heavy metals and their compounds.  Heavy metals are relatively harmless in the metallic state, but their fumes, dust, and soluble compounds are well-known toxins. Some are carcinogenic, others are nephrotoxins, hepatotoxins, or neurotoxins. The most common heavy metals are arsenic, beryllium, cadmium, chromium, lead, mercury, nickel, and silver. Acute toxic effects from exposure to heavy metals result from inhalation and ingestion of dusts or inhalation of fumes. Metal fumes are generally more hazardous than dusts because the particles in fumes can enter the bloodstream easily. Bronchitis, chemical pneumonia, and pulmonary edema may result. Beryllium and cadmium are two of the most toxic metals when inhaled. Symptoms include nausea, vomiting, abdominal pain, and diarrhea.

Chronic exposure to heavy metals may lead to long-term effects. For example, chronic exposure to lead may damage the nervous system, brain and kidneys. Exposure to mercury over a long time can permanently damage the liver, kidney, and brain. Chronic inhalation of cadmium can cause emphysema and kidney damage. Carcinogenic effects have been shown from exposure to chromium, nickel, arsenic, cadmium, and beryllium. Prenatal effects have been observed from exposure to methyl mercury. In addition, some lead compounds are embryotoxic.

Some metals and their compounds can be absorbed through the skin. Mercury metal, and tetraethyl lead for example can enter the bloodstream through this route. Nickel, arsenic, chromium, and beryllium cannot penetrate the skin but they can damage the skin or cause allergic-type reactions.

Phosphorus.  Organic phosphorus compounds are widely used as pesticides. These compounds may cause acute and chronic poisoning. Poisoning may result from ingestion, inhalation, or absorption through the skin. Organophosphates act by inhibiting an enzyme called cholinesterase. Examples include malathion, diazinon, parathion, and TEPP.

Safety Procedures

Alternative reagents. Before a chemical is used, information about its toxicity should be obtained. If the chemical is highly toxic, alternative reagents should be used if possible. For example, toluene or xylene can often be substituted for benzene. If the material must be used then adequate personal protection and containment are required.

Ventilation.  The best way to avoid exposure is to prevent the escape of toxic materials into the workplace by using adequate ventilation such as dilution and local exhaust ventilation. Respirators may need to be worn if local exhaust ventilation cannot be provided. Respirators must be approved by the Safety Manager.

Hygiene.  To prevent the ingestion of toxic chemicals, workers should wash their hands immediately after using toxic chemicals, before leaving the work area, and before eating, drinking, smoking, or applying cosmetics.

Eating, drinking, or smoking.  Eating, drinking, or smoking is prohibited in areas where toxic chemicals are used or stored. Food and drinks should not be stored with toxic chemicals. Chemicals should never be poured into food or drink containers.

Mouth pipetting.  Mouth pipetting of toxic chemicals is prohibited.

Personal protection.  Skin and eye contact with chemicals should be avoided by using the appropriate eye protection equipment, gloves, respirators, and laboratory coats. Personal protective equipment must be approved by the Safety Manager.

Highly toxic chemicals.  Safety procedures for carcinogens should be followed when working with highly toxic chemicals.

Storage.  Storage areas should be well ventilated and away from sources of heat or ignition. Incompatible chemicals should not be stored together. For example, ammonia should not be stored with bleach because of the possibility of the formation of the extremely toxic gas, chlorine.

Solvents.  Contact with solvents should be avoided by wearing appropriate eye protection and gloves. Tongs or a basket should be used to hold parts in a solvent bath. Hands should never be washed with a solvent. Inhalation of solvent vapors should be kept to a minimum. Work with volatile solvents should be done with adequate ventilation. Containers of volatile solvents should be kept closed.

Heavy metals.  Inhalation of heavy metal dust should be avoided. Work must be conducted in a carefully controlled manner. Adequate exhaust ventilation is the most important factor in reducing exposure to heavy metals. Fine powders should be handled in a hood and care must be taken to avoid dispensing the metal into the atmosphere. For the most toxic compounds, a totally enclosed system may be required. Protective clothing such as gloves, laboratory coat, dust masks and eye protection must be worn. Respirators must be worn if engineering controls are not feasible. Removal of dust should never be done by dry sweeping or with an air hose. Surfaces should be cleaned by vacuuming with a special fume vacuum or wetting down the surface before sweeping. Water sprays should be used to prevent the formation of dust and to prevent dust from becoming airborne.

4.0 Corrosive Chemicals

Chemicals that cause severe local injury to living tissue are called corrosive chemicals. Accidents involving splashes of corrosive chemicals are very common in the work place. Damage to the skin, respiratory system, digestive system and the eyes may result from contact with these substances or their vapors. The seriousness of the damage depends on the type and concentration of corrosive material, length of the exposure, the body part contacted, and first aid measures taken.

Usually minor exposure to corrosive materials is reversible and healing is normal. However, severe exposure may cause permanent damage. Depending on the severity of the exposure, damage to the skin may range from redness and peeling to severe burns and blistering. Chronic exposure may result in dermatitis. Exposure to the respiratory system may range from mild irritation, to inflammation, chest pain, difficulty in breathing, pulmonary edema, and death. Mild exposure to the eyes may cause pain, tearing, and irritation. Severe exposure may cause ulcerations, burns and blindness. Ingestion of corrosive chemicals may cause immediate pain and burning in the mouth, throat, and stomach followed by vomiting and diarrhea. Perforation of the esophagus and stomach is possible.

The concentration of a corrosive material also determines the extent of damage to the tissues. For example, a weak solution of acetic acid (vinegar) can be ingested and contact the skin without any harmful effects. However, concentrated acetic acid is highly corrosive and can cause serious burns to the tissues.

First aid measures must be taken immediately if corrosive chemicals contact the tissues. Corrosive chemicals that contact the skin or eyes should be immediately washed off with water for at least fifteen minutes. Inhalation victims should be moved to fresh air and artificial respiration started if breathing has stopped. If a corrosive material has been ingested, 2-4 glasses of water should be administered to the victim and the poison control center called immediately.

If mixed or stored incorrectly corrosive chemicals can generate excessive heat, pressure, flammable, and toxic gases that can damage equipment, ignite combustibles, and lead to injury. During a fire, highly toxic gases may be released. Many corrosive chemicals have other serious hazards and may be classified as flammables, reactives, or toxins.

Classes

Strong acids.  All concentrated strong acids can attack the skin and permanently damage the eyes. Acids usually cause irritation and pain immediately. Adding water to acids can cause the contents to be violently ejected. Burns from acids are typically more painful, though less destructive than alkaline burns. The vapors from many acids such as hydrochloric acid are soluble in water and cause irritation of the nose and upper respiratory tract. Vapors from other acids, however, are not soluble in water and do not cause irritation. For example, vapors from nitric acid may travel deep into the lungs and cause permanent damage and not be immediately noticed.

Strong acids are also hazardous because they can combine with other chemicals in storage and cause fires and explosions. Common strong acids include hydrochloric, nitric, and sulfuric.

Strong alkalis.  The metal hydroxides, especially the alkali metal hydroxides, are extremely hazardous to the skin and the eyes. In contact with water considerable heat can be generated that can cause splattering of the material. Burns from alkaline substances are less painful than acid burns but possibly more damaging. The healing of serious alkaline burns is extremely difficult. Concentrated alkaline gases such as ammonia can cause severe damage to the skin, eyes, and respiratory tract. Dry bases can react with the moisture on the skin, eyes, and mucous membranes, causing serious burns. Examples of strong alkalis include sodium hydroxide, potassium hydroxide, and ammonia.

Halogens.  The halogens are toxic and corrosive to the skin, mucous membranes, and the eyes. Fluorine gas is highly reactive with organic matter and will cause deep penetrating burns on contact with the skin. Chlorine is less reactive but still extremely hazardous. Bromine is a common source of eye damage because of its use as a pool disinfectant. In contact with the skin it can also cause severe, long lasting burns. Iodine vapor is irritating to the eyes and respiratory tract and may cause pulmonary edema. Skin contact may produce burns.

Oxidizing agents.  Besides being corrosive to the skin, mucous membranes, and eyes, oxidizing agents are also fire and explosion hazards. Oxidizing agents readily release oxygen, increasing the ease of ignition of flammable and combustible materials and increasing the intensity of burning. Some compounds give up their oxygen at room temperatures while others require the application of heat. Powerful oxidizers such as nitric and sulfuric acids may react with organic compounds and readily oxidizable materials causing fires and explosions. Oxidizers include chlorates, perchlorates, bromates, peroxides, and nitrates. The halogens are also considered oxidizing agents because they react the same as oxygen under some conditions.

Safety Procedures

Transportation. Corrosive chemicals should always be transported in unbreakable safety containers. Carts used for moving chemicals should have a lip to prevent accidents.

Reactions.  Acids should always be added to water to prevent excessive heat generation and splashing. All corrosives should be mixed slowly. Many acids are also oxidizers and react violently with organic compounds and other acids.

Personnel protective equipment.  Chemical goggles, aprons, and rubber gloves must be worn when handling corrosive chemicals. Gauntlets (sleeve coverings) may also need to be worn. Goggles should be supplemented with a face mask if the possibility of significant splashing exists. Contact lenses must never be worn when working with corrosive chemicals because they can trap chemicals against the eye. Suitable respiratory equipment should be available if a danger exists from inhaling toxic fumes.

Eye-wash and emergency shower.  An OSHA approved eye-wash unit and emergency shower must be located in areas where corrosive chemicals are used. If corrosive chemicals contact the skin or the eyes, the area should be immediately washed with large amounts of water for 15 minutes.

Storage.  Storage should be in a cool, dry, and well ventilated area away from direct sunlight. Corrosive chemicals should not be stored with combustibles, flammables, organics, and other highly reactive and toxic compounds. Acids and bases should not be stored together. Fire, explosion, or the release of dangerous gases or vapors may result if these chemicals combine.

Corrosive chemicals should be stored below eye level to prevent splashes in the eyes or face. Shelving should be non-corroding. Strong oxidizing agents should be stored and used in glass or other inert containers. Corks and rubber stoppers should not be used.

Ventilation.  Corrosive chemicals producing hazardous vapors and corrosive gases should be used with adequate exhaust ventilation.

Spills.  Neutralizing chemicals, absorbent materials, and cleaning supplies should be readily available to clean up corrosive chemical spills. All spills should be cleaned up immediately.

5.0 Carcinogens, Mutagens, Embryotoxins

Carcinogens

Cancer is the second leading cause of death in the United States. Approximately 25% of the population will develop some form of cancer during their lifetime. Cancer is not a single disease, but a group of diseases characterized by uncontrolled growth of abnormal cells. These cells are destructive and often can migrate to new sites to form secondary growths. Among the causes of cancer, environmental agents acting in combination with genetic susceptibilities are believed to be the most prominent. Approximately 60% to 90% of all cancers may be related to environmental factors such as sunlight, radiation, chemicals, diet, and viruses.

Agents that cause cancer or increase the risk of cancer either by initiating or promoting it, are called carcinogens. Carcinogens can enter the body through the skin, lungs, or the digestive system and interact with the body by direct or indirect means. Direct acting carcinogens usually cause cancer at the site of exposure, for example, skin contact with coke oven emissions may cause skin cancer. Indirect acting carcinogens are changed by the body into carcinogenic substances that cause cancer at sites other than the initial exposure site. Common examples include solvents such as benzene and carbon tetrachloride. Other substances, called promoters, do not cause cancer themselves but are necessary for some chemicals to express their carcinogenicity.

Chemical carcinogens were among the first agents associated with an increased incidence of cancer. In 1775, a positive association was demonstrated between exposure to soot and scrotum cancer among chimney sweeps in England. Since then, chemical components of tar, smoke, air pollution, and automobile exhausts have been shown to be carcinogenic. Several occupational chemicals are carcinogens, including asbestos, arsenic, benzene, beryllium, and cadmium.

Carcinogens differ in the length of time needed for the cancer to develop after the initial exposure. This latency period may be as short as five years for the development of leukemia from benzene exposure to as long as 20 years to develop lung cancer from cigarette smoking.

The existence of a safe level or threshold has not been demonstrated for most carcinogens. Because of this, it must be assumed that low doses can cause cancer also but at a proportionately lower rate than high doses. Therefore, it is prudent to reduce exposures to known or suspected carcinogens to the lowest level possible. Exposure to several carcinogens at once may result in cancer rates higher than would be expected by adding the risks from each carcinogen separately. This is known as a synergistic effect. For example, both cigarette smoking and exposure to asbestos have been show to cause cancer. The cancer rate among asbestos workers who smoke is much greater than would be expected by adding the risk from smoking to the risk from asbestos.

Mechanism

The mechanism that causes a normal cell to become cancerous is not well understood. The process is usually characterized by three stages: initiation, promotion, and progression. During the initiation stage, the DNA in the cell that carries the genetic information for cell division is altered either spontaneously or by an external agent. This altered cell may replicate during the promotion stage into a malignant tumor. The appearance of the tumor following initiation may take 5-30 years. This latency period is probably related to a gradual weakening of the immune system or hormonal changes as the body ages. Another theory states that the cells remain dormant until another stimulus from an environmental agent causes it to start dividing. During the progression stage, the tumor invades adjoining tissue and may spread throughout the body.

Testing

OSHA considers a chemical to be a carcinogen if the chemical causes cancer in humans or two different mammal species. The carcinogenic potential of a chemical in humans is usually discovered through epidemiological (population) studies. In these studies, the incidence of cancer in a group of exposed workers is compared to a comparable unexposed population. For example, when compared to unexposed workers, an excess of liver cancer was found among PVC workers and an excess of lung cancer was found in asbestos workers. Another study on members of the American Chemical Society has shown a significantly higher incidence of cancer deaths among chemists than would be expected in the general population.

Human population studies are not always adequate to determine if a chemical is carcinogenic. Large populations are needed, cancers may not develop for 30 years, and there are many variables that must be controlled. Therefore, tests are usually performed on experimental animals under controlled conditions. Tests on animals can identify human carcinogens because chemicals that cause cancers in one mammalian species are likely to cause cancers in another. Except arsenic, all human carcinogens have also been demonstrated to be carcinogenic in animals. It must be assumed that agents that cause cancers in animals are likely to be carcinogenic in humans.

Animal studies are performed to demonstrate the potential for a chemical to cause cancer. Because small populations are used, it is necessary to use large doses of chemicals to demonstrate an effect. This does not mean that only large doses of the chemical will cause cancer. Smaller doses would cause cancer also but in proportionately smaller numbers, numbers so small that they might be missed in a small population.

Screening tests using cells growing in laboratory cultures, require only a few days or weeks to provide preliminary results on the carcinogenic potential of chemicals. The suspect chemical is added to the cells and any mutation is noted. Approximately 90% of chemicals found to be carcinogenic in humans or animals have also shown mutagenic changes in these tests.

Classes

Chemical carcinogens are commonly found in the following groups. Carcinogenic chemicals should also be considered mutagenic.

Polycyclic aromatic hydrocarbons (PAHs).  PAHs were the first group of chemicals shown to be carcinogenic in man. PAHs are produced from the combustion of fossil fuels and tobacco. PAHs are probably the most widespread chemical carcinogens in the environment and some of the most powerful carcinogens are found in this group.

Nitroso compounds.  Nitroso compounds are widely distributed in the environment and can also form in the body. These compounds may be one of the most important groups of carcinogens in man. Sodium nitrite is a commonly used preservative in meat that is converted to carcinogenic nitrosamines in the body.

Halogenated hydrocarbons.  Several of these compounds are commonly used as solvents. Examples include carbon tetrachloride, chloroform, trichloroethylene, and methylene chloride.

Inorganic metals and minerals.  Several carcinogens are known among metals or their salts. Examples of these include beryllium, cadmium, nickel, cobalt, and chromium. Only two minerals are known to cause cancer: asbestos and arsenic.

Naturally occurring.  Several natural occurring carcinogens are known. Among these is aflatoxin, probably the most potent of all carcinogens. Aflatoxins are produced by molds that grow on peanuts and corn. Other naturally occurring carcinogens are present in sassafrass and chili peppers.

Mutagenic Substances

Mutagenic substances cause an alteration in the genetic instructions on the DNA molecule. If the alteration occurred on a somatic (non-sex cell) the results could be the development of cancer. An alteration of a germ cell (sex cell) in either sex can produce genetic defects that will be transmitted to the next generation. Since all genes are composed of DNA, a mutagenic substance that can produce alterations in one species is considered capable of producing alterations in another.

Because approximately 90% of chemical carcinogens have been shown to be mutagenic, the carcinogenic potential of a chemical can be determined by assessing its ability to produce mutations. The potential mutagenic potential of a chemical can be rapidly determined by performing short term "in vitro" (in the tube) tests. In vitro tests use a microbial organism, such as a bacterium, to assess the potential of a chemical to produce alterations in the genetic material and produce mutations. This procedure is commonly known as the Ames Test.

Long term "in vivo" (in the animal) studies are only needed for a few chemicals. Insects, mice, rats, and hamsters are used for these tests to evaluate mutagenicity in an animal system. Chemicals producing positive animal results can be considered a genetic risk for humans.

Embryotoxins

Women of child bearing potential must be especially concerned about exposure to hazardous chemicals because many chemicals may be hazardous to the embryo or fetus. Embryotoxins are substances that may kill, deform, retard the growth, affect the development of specific functions in the unborn child, or cause postnatal functional problems. Agents that only produce malformations of the embryo are called teratogenic. Approximately 60-70% of all malformations are the result of chemical, physical and infectious agents. The developing embryo depends on the environment to supply the substances needed for growth and differentiation of the tissues and organs of the embryo. Because of this, various chemical, physical, and infectious agents may alter or arrest growth in the developing embryo.

The influence of embryotoxins depends on when the exposure took place. The period of greatest susceptibility to embryotoxins is the first trimester, which includes a period when the woman may not know she is pregnant. The embryo is undergoing rapid growth and differentiation and significant malformations can be produced. Although the development of the fetus is not as sensitive as the embryo, alterations may still occur, particularly in the nervous system.

Classes

Medicines.  Medicines that have been shown to be embryotoxic in humans include thalidomide, diethylstilbestriol, some male hormones similar to methyltestosterone, and some anticancer drugs.

Solvents.  Growth retardation and abortions, but not malformations, have been shown in animals exposed to chloroform, carbon tetrachloride, trichloroethylene, perchloroethylene, benzene, xylene, and propylene glycol.

Heavy metals.  Organomercurials and lead compounds have demonstrated embryotoxic properties in humans. Cadmium, arsenic, selenium, chromium, and nickel compounds have been shown to be embryotoxic in animals and are classified as potentially harmful to the human embryo.

Pesticides.  Pesticides producing malformations in animals include parathion, demeton, paraquat, and penthion.

Anesthetic gases.  Anesthetic gases demonstrating embryotoxic properties in animals include ethylene oxide, and nitrous oxide.

Organic compounds.  Organic compounds that have shown embryotoxic properties in animals include azo dyes, and formaldehyde.

Safety Procedures for Handling Carcinogens

The following procedures should also be used when working with highly toxic chemicals, mutagens, and embryotoxins.

Protective clothing.  Protective clothing such as a fully fastened laboratory coat and disposable gloves should be worn to prevent contact of carcinogenic chemicals with the skin. Contaminated clothing should not be worn out of the work area.

Protective equipment.  Appropriate eye protection should be available and used in the work area. Contact lenses should not be worn. Appropriate respiratory equipment should be worn if the procedure generates airborne particulates or gases. The face mask or respirator should not be worn out of the work area.

Eating, drinking, & smoking.  There shall be no eating, drinking, smoking, chewing of gum or tobacco, or application of cosmetics in areas where carcinogenic chemicals are used or stored. Storage of food or food containers in these areas is also prohibited.

Pipetting.  Under no circumstances is oral pipetting of carcinogenic chemicals permitted. Pipetting should always be performed with the aid of a mechanical pipetting device.

Personal hygiene.  Workers should wash their hands immediately after the completion of any procedure involving the use of carcinogenic materials.

Storage.  Carcinogens should be stored in a designated area or cabinet and posted with the appropriate hazard sign. Volatile chemicals should be stored in a ventilated storage area in a secondary container having sufficient volume to contain the material in case of an accident. Storage areas should be separated from flammable solvents and corrosive liquids.

Labeling.  All containers should be labeled as to contents and bear the appropriate hazard warning information.

Containment.  Procedures involving the use of volatile chemical carcinogens or procedures that may generate aerosols should be conducted in a chemical fume hood or glove box. Procedures involving non-volatile compounds and procedures with a low aerosol potential should be done in a controlled area that is designated for carcinogenic materials.

Transport.  Carcinogens should be transported in unbreakable outer covers such as metal cans. Contaminated materials that are to be transported to a disposal area should be placed in a plastic bag or other impervious material, sealed, and labeled appropriately before transport.

Housekeeping.  To minimize the production of aerosols, dry mopping and dry sweeping should not be done in areas where finely divided solid carcinogens are used. Wet mopping or a vacuum cleaner equipped with a HEPA filter should be used.

Working quantities.  Working quantities (outside of storage) should be kept to a minimum and should not exceed the amounts required for use in one week.

Spill control.  Spills and accidents must be immediately reported to supervisory personnel and to the Safety Office. Because of aerosol production, the area should be evacuated immediately unless the spill is small and well contained. Personnel performing decontamination should wear adequate protective clothing including respirators or self-contained breathing apparatus. As much of the spill as possible should be absorbed into paper towels, rags or sponges. Dry solids should be covered with paper towels moistened with water or an appropriate solvent. Care should be taken not to generate aerosols. Large spills may require a HEPA filtered vacuum cleaner. Decontamination of the spill should be attempted only after the bulk of the spill has been removed by mechanical means.

Disposal.  Volatile carcinogens should never be disposed of by evaporation. Chemicals and contaminated materials should be decontaminated or removed for subsequent disposal. Contaminated waste, and cleaning devices should be collected in plastic bags or other impervious containers, sealed, labeled as to contents and hazard and disposed of by approved methods.

Handwashing facilities.  Handwashing facilities should be available in the work area where carcinogens are used. Foot or elbow operated faucets are preferable.

Eye-wash & deluge showers.  OSHA approved eye-wash units and deluge showers should be readily available to personnel working with carcinogens having corrosive properties or that can penetrate the skin.

Work area identification.  Entrances to work areas where significant quantities of carcinogens are used or stored should be posted with a sign stating "Danger Carcinogen - Authorized Personnel Only." In addition, the area should also be posted with a sign stating "No Eating, Drinking, or Smoking."

Access.  Only authorized personnel should be allowed in areas where carcinogens are used and stored. Casual visitors should be prohibited. Doors should be closed at all times.

Work surfaces.  Work surfaces on which carcinogenic chemicals are handled should be protected from contamination by using an impervious material such as stainless steel, plastic trays or absorbent plastic backed paper. Work surfaces should be decontaminated or disposed of properly after the procedure has been completed.

6.0 Flammable Liquids

Flammable liquids are among the most common occupational hazards found in the work place. Flammable liquids can easily vaporize and form flammable and explosive mixtures in air. The degree of hazard is determined by the flash point of the liquid, the concentration of the air-fuel mixture, and the availability of ignition sources. In addition, many flammable chemicals react violently with oxidizing compounds and may start a fire. The flammability properties of a chemical should be checked before a flammable liquid is used. The danger of fire and explosions can be eliminated or reduced by strict handling, dispensing, and storage procedures.

Definitions

Flash point.  The fire hazard associated with a flammable liquid is usually based on its flash point. The flash point is the lowest temperature at which a liquid in an open vessel will give off sufficient concentration of vapors to form an ignitable mixture with air. Many common solvents have flash points below room temperature. Acetone, for example, has a flash point of 15 F.

Flammable or explosive range.  An important factor in determining the fire hazard of a flammable liquid is its flammable or explosive range. Once the flash point has been reached, flammable vapors will be given off that can mix with air to form a flammable or explosive mixture. Every flammable liquid has an upper and lower limit that defines the range of concentrations of the liquid in air that will ignite and propagate a flame. The lower flammability limit is the minimum concentration of the vapor in air that will sustain the spread of a flame; below this concentration, the mixture is too lean to burn. The upper flammability limit is the maximum concentration of vapors in air that will propagate a flame. Above this concentration, the mixture is too rich to burn. The range is usually expressed as a percentage by volume of vapor in air. Ethyl ether, for example, has a wide flammability range extending from a minimum of 2% by volume in air to an upper limit of 48%. If the lower limit is small it only takes a small amount of vapors in the air to form an ignitable mixture. Flammable liquids with a lower flammability limit of less than 10% are considered especially hazardous.

Ignition temperature.  Once the flammability range has been reached, the vapors will ignite at the proper ignition temperature. The ignition temperature of a substance is the lowest temperature necessary to cause the vapor-air mixture over the liquid to ignite and continue to burn without the heat source. If the vapor-air mixture is confined and there is an ignition source, an explosion will result. The ignition temperature is often misleading because it is a relatively large number, often in the hundreds of degrees. However, it only takes a short duration of contact with a potential ignition source to reach this temperature and ignite a flammable vapor. For example, a spark contacting a few molecules of a flammable vapor can raise the temperature above the ignition point in only a few thousandths of a second. A hot light bulb can ignite some chemicals.

Sources of ignition.  Three conditions must exist before a fire can occur: fuel concentration that is within the flammability range for the substance, air, and a source of ignition. To prevent fires, it is necessary to remove one of these conditions. The easiest way to prevent fires is usually to separate the flammable vapors from an ignition source. Many sources such as sparking electrical equipment, open flames, static electricity, and hot surfaces can ignite flammable vapors. Close attention must be given to all sources of ignition when using flammable liquids, especially those at a lower level than the liquid. The vapors of most flammable liquids are heavier than air and can travel considerable distances.

Spontaneous ignition.  Spontaneous ignition takes place when a substance generates heat faster than it can be dissipated and reaches its ignition temperature independent of an ignition source. Materials susceptible to spontaneous ignition include oil or paint soaked rags, organic materials mixed with strong oxidizing agents, alkali metals, phosphorus, and finely divided pyrophoric metals.

Classes

Flammable and combustible liquids are divided into the following classes; based on flash points and boiling points. Flammable liquids are defined as those with flash points below 100 F and combustible liquids have flash points at or above 100 F. Flammable and combustible liquids are further subdivided into the following classes:

Class IA.  Flash point below 73 F. Boiling point below 100 F. Examples include ethyl ether, and gasoline.

Class IB.  Flash point below 73 F. Boiling point at or above 100 F. Examples include acetone, benzene, ethyl alcohol, isopropyl alcohol, methyl alcohol, toluene, and petroleum ether.

Class IC.  Flash point at or above 73 F and below 100 F. Examples include xylene and turpentine.

Class II.  Flash point at or above 100 F and below 140 F. Examples include kerosene, mineral spirits, and diesel fuel.

Class IIIA.  Flash point at or above 140 F and below 200 F. Examples include pine tar oil, fuel oil no. 6, and phenol.

Class IIIB.  Flash point at or above 200 F. Examples include mineral, motor, and tung oil.

Safety Procedures

Ventilation. Ventilation is essential to prevent the buildup of vapors that could lead to flammable liquid fires and vapor-air explosions. Vapors must be controlled by confinement, local exhaust, or general room ventilation. Ventilation systems should be designed to keep the vapor concentration below 25% of the lower flammability level. Room ventilation should be adequate to prevent the accumulation of dangerous concentrations of vapors if only very small quantities are released.

Ignition sources.  Flammable liquids should never be heated with an open flame. Steam baths, water baths, oil baths, heating mantles, and hot air baths should be used. Containers should always be kept closed to reduce the possibility of flammable vapors contacting an ignition source. When flammable liquids are used, all unnecessary ignition sources should be removed. Ignition sources include open flames, nonexplosion proof electrical equipment, hot surfaces, and static sparks.

Smoking.  Smoking is prohibited in areas where flammable liquids are used or stored.

Fire extinguishers.  Appropriate fire extinguishers must be located in work areas using flammable liquids.

Warning signs.  "No Smoking" and "Flammable Liquids" signs shall be prominently posted in areas where flammable liquids are used or stored.

General storage.  Flammable liquids should not be stored near heat, ignition sources, powerful oxidizing agents, or other reactive chemicals. Flammable liquids should not be stored near an exit, stairway, or any area normally used for the safe egress of people. Storage in glass bottles should be avoided if possible. If glass must be used, the bottle should be protected against breakage. The quantity of flammable liquids should be limited to what is immediately needed. As much as possible of working quantities should be stored in safety cans. Flammable liquids should not be stored above eye level.

Refrigerators.  Flammable solvents must not be stored in standard refrigerators; explosions may result from the ignition of confined flammable vapors by sparking electrical contacts. Only explosion-proof or explosion-safe refrigerators may be used.

Container size.  Flammable and combustible liquids must be stored in appropriate containers according to their classification. See Chapter 4 for proper container sizes.

Storage limits.  The maximum amount that may be stored within a fire area outside approved safety cans, storage cabinets, or flammable storage rooms is 10 gallons. Approved flammable storage cabinets may contain a maximum of 60 gallons of Class I or II liquids, or 120 gallons of Class I, II, and III liquids combined. Only three cabinets are allowed in a fire area.

Inside storage rooms.  Bulk quantities of flammable liquids, such as 30 or 55 gallon drums, must be stored in properly designed indoor storage rooms or outside storage areas. Indoor storage rooms containing flammable and combustible liquids must meet the requirements of OSHA Standard 1910-106(d). These standards include spill control measures, spark-proof electrical fixtures, fire suppression equipment, and ventilation requirements.

Electrical grounding.  Transferring liquids from one metal container to another may produce static electricity sparks capable of igniting the flammable vapors. To discharge the static electricity, dispensing drums should be adequately grounded and bonded to the receiving container before pouring. Bonding between containers may be made by means of a conductive hose or by placing the nozzle of the dispensing container in contact with the mouth of the receiving container. If the container cannot be grounded, then the liquid should be poured slowly to allow the charge time to disperse.

Spills.  Appropriate spill kits should be available in work areas using flammable liquids. Materials should absorb the solvent and reduce the vapor pressure so that ignition is impossible.

Transportation.  Flammable solvents should be transported in metal or other protective containers.

7.0 Reactive Chemicals

Reactive chemicals are substances that can explode or enter violent reactions releasing large amounts of light, heat, and gases. Several reactive chemicals are recognized explosives, requiring only a mild initiating force for detonation. Other reactive chemicals are capable of detonation but require a stronger initiating force. Some reactive chemicals will not detonate but can enter into violent reactions producing large quantities of heat and explosive gases. Reactive chemicals must be handled with extreme care. Even milligram quantities of some chemicals can result in explosions.

Classes

Reactive chemicals are classified as explosives, strong oxidizing agents, acid sensitives, water reactives, air reactives, and special organic compounds.

Explosives.  Explosives are substances that can detonate or decompose rapidly and violently at room temperatures and pressure with an essentially instantaneous release of large quantities of gases and heat. Gentle heat, light, mild shock, and chemical action can initiate these explosive reactions. Many of these compounds become more sensitive as they age or dry out. Examples include peroxides, nitroglycerin, and TNT.

Strong oxidizing agents.  Many strong oxidizing agents are capable of detonation or explosive decomposition under conditions of strong heat, confinement, or a strong shock. Violent reactions can occur when strong oxidizers are mixed with combustibles such as wood or paper. Strong oxidizing agents that can cause explosions include perchlorates, inorganic nitrates, chlorates, chromates and the halogens. Strong oxidizing agents will also react violently with most organic compounds, powdered metals, sulphur, phosphorus, boron, silicon, and carbon.

Water reactives.  Chemicals that combine with water or moisture in the air to produce heat, flammable, explosive or toxic gases are termed water reactive chemicals. These chemicals present a severe fire hazard because sufficient heat is often released to self ignite the chemical or ignite nearby combustibles. In addition, contact with the skin can cause severe thermal and alkali burns. Common examples include strong acids and bases, alkali metals such as sodium and potassium, hydrides, and carbides.

Air reactives.  Air reactives (also called pyrophoric materials) ignite spontaneously in air at temperatures below 130 degrees F. Finely divided metal powders that do not have a protective oxide coat may ignite when a specific surface area is exceeded. The degree of reaction depends on the size of the particle, its distribution, and surface area. Examples include white phosphorus, fine zirconium powder, and activated zinc.

Safety Procedures

Planning. The procedures and risks involved should be thoroughly reviewed before working with reactive chemicals. Work should be performed with the smallest possible quantity of the chemical.

Personal protective equipment.  Safety glasses, face shield, gloves, and a laboratory coat should be worn at all times when handling, transporting, or manipulating reactive chemicals.

Safety equipment.  Adequate portable fire extinguishers should be immediately available. Approved eye-wash stations and emergency showers must be in the work area. Safety shields should be used as necessary.

Explosives.  Explosives should be protected from heat and shock. Large quantities of explosives may need to be stored in heavily constructed magazines. Explosives should be stored in a cool, dry area, separated from flammables, corrosives, and other reactive chemicals. Areas in which explosives are handled or stored should be posted with a sign stating "Caution Explosion Hazard." Access to the area should be restricted. Efforts should be made to reduce static electricity discharges such as using cotton gloves, wearing conductive-soled shoes, and working on conductivity mats.

Ethers.  Ethers should not be stored in clear bottles. Storage should be in a cool place, preferably an explosion safe refrigerator. Ethers should be dated when purchased and discarded after six months if opened, or after one year if unopened. Inhibitors such as copper mesh or BHT may be ineffective and should not be relied on to prevent peroxide formation. Ethers that do not have an inhibitor, such as those used for anesthesia, should be handled with particular caution. Old containers of ether should not be handled. The Safety Manager should be notified to dispose of these containers.

8.0 Compressed Gas Cylinders

Compressed gas cylinders are especially dangerous because they possess both mechanical and chemical hazards. Due to the large amount of pressure resulting from compression of the cylinder, gas cylinders should be handled as high energy sources and as a potential explosive. If a cylinder falls and breaks a valve, the energy released is sufficient to propel the cylinder through concrete walls.

In addition, the gases contained in the cylinders are hazardous because of flammable, toxic or corrosive properties. The most common hazard associated with gas cylinders is leakage from regulators that can allow the gas to diffuse throughout the room. Flammable gases can mix with the air and present fire and explosion risks. Most flammable gases have explosive ranges greater than flammable liquid vapors.

Additional hazards arise from the high toxicity and corrosive properties of many gases. Usually, there is no visual warning or odor associated with the escaping gases. Some gases are toxic at concentrations below the odor threshold and some gases with strong odors can quickly paralyze the sense of smell. Even harmless gases such as nitrogen may displace the oxygen in an unventilated room and cause asphyxiation. The best protection against accidents is knowledge of proper handling and storage techniques.

Classes

Compressed gas cylinders may be classified into the following six groups based on similar chemical and physical properties, storage compatibility, and handling procedures. Common examples of each group are included.

Highly toxic gases.  Phosgene, phosphene, nitric oxide, nitrogen dioxide, chlorine, fluorine, hydrogen cyanide, ozone

Non-flammable, non-corrosive, low toxicity gases.  Air, argon, helium, neon, carbon dioxide, nitrogen, nitrous oxide, oxygen

Flammable, non-corrosive, low toxicity gases.  Acetylene, butane, ethylene, hydrogen, isobutane, methane, natural gas, propane

Flammable, toxic, corrosive gases.  Carbon monoxide, ethylene oxide, hydrogen sulfide

Acid and alkaline gases.  Ammonia, hydrogen chloride, hydrogen fluoride, sulfur dioxide

Spontaneously flammable gases.  Silane

Safety Procedures

Identification. The contents of compressed gas cylinders should be clearly identified and bear the appropriate DOT hazard label. Labels should not be removed or defaced. Color coding systems used to identify contents are not reliable because cylinder colors vary among manufacturers. If the labeling on a cylinder becomes defaced, the cylinder should be marked "contents unknown" and returned to the manufacturer.

Transportation.  Manual transportation of cylinders should always be done with a handtruck. Cylinders should be securely fastened with a strap or rope. The valve cap must be in place. Cylinders should never be lifted by the valve cap or dragged, rolled, dropped, or permitted to strike hard objects or another cylinder.

Training.  Persons who handle flammable, corrosive, or toxic gas cylinders should be adequately trained in the physical and chemical properties of the gas and the proper methods to use the cylinders.

General storage.  Cylinders shall be stored upright where they are unlikely to be knocked over, or secured by a heavy chain, strap, or base support. Cylinders cannot be stored in stairwells or within a required exit corridor. The valve protection cap must always be in place when the cylinder is not being used. Cylinders should never be stored on their sides or near a heat or ignition source. Storage areas shall be posted with the name of the gases stored. Storage areas should be well ventilated and dry. Storage rooms should be of fire resistive construction. Temperatures shall not exceed 130 degrees F. Containers shall not be stored near readily ignitable substances such as gasoline, waste, or bulk combustibles.

Outdoor storage.  Cylinders may be stored outdoors if adequately protected from the weather and direct sunlight. It is recommended that cylinders be stored under a non-combustible canopy and protected from the ground by a concrete pad.

Handling flammable gas cylinders.  Flammable gas cylinders stored inside occupied buildings shall be separated from flammable liquids, highly combustible materials, and oxidizing cylinder by at least 20 ft. or a five ft. high wall with a 1/2-hour fire rating. Flammable gas cylinders in storage and in use should be kept away from arcing electrical equipment, open flames, or other sources of ignition. Adequate portable fire extinguishers shall be located in storage areas and "No Smoking" signs posted. Hydrogen gas systems shall not exceed 400 cubic feet unless the Safety Manager has approved the system.

Handling oxidizing gases.  Oxidizing gas cylinders in storage shall be separated from flammable gas cylinders or combustible materials such as oil or grease by at least 20 feet or by a five foot high wall with a 1/2-hour fire rating. Oxidizing gas cylinders, valves, regulators, and hoses shall be kept free from oil or grease.

Handling acid and alkaline gases.  Proper protective clothing such as goggles, face shields, rubber gloves, and aprons shall be worn when working with acid and alkaline gases. Areas in which acid and alkaline gases are used shall be equipped with an OSHA approved deluge shower and eye-wash station. Acid and alkaline gases should be used in a well ventilated area. Corrosive gases should be used only with compatible equipment. The total quantity of gases on site should be kept to a minimum. Proper respiratory equipment shall be readily available for use in an emergency.

Handling highly toxic gases.  Highly toxic gas cylinders shall be stored outdoors or in an unoccupied building or room with a one-hour fire rating. Areas in which toxic gas cylinders are used or stored should be posted with an appropriate warning sign. The quantity of highly toxic gas cylinders should be kept to a minimum. Highly toxic gas cylinders shall be used only in forced ventilation areas. Highly toxic gases should be used only with compatible equipment. Gases emitted in high concentrations shall be discharged into appropriate scrubbing equipment. Users shall only be exposed to concentrations of highly toxic gases that are below OSHA permissible levels. Proper respiratory equipment shall be readily available for use during an emergency.

Dispensing contents.  The cylinder should be secured, and the protective cap removed. The proper regulator should be connected being careful not to cross thread or over tighten the connections. Never stand in front of or behind the pressure gauge as the main tank valve is opened. Pressure gauges can explode. When opening the valve on a cylinder containing a corrosive or toxic gas, the user should stand on the side opposite the valve opening. Safety glasses should be worn when dispensing compressed gases to prevent eye damage from equipment failure.

Regulators.  Always use the appropriate regulator. Regulators for non-corrosive gases are usually made of brass. Corrosion resistant regulators should be used with gases such as ammonia, chlorine, hydrogen chloride, hydrogen sulfide, and sulfur dioxide. Special regulators should be used with carbon dioxide because of potential freeze-up and corrosion problems. Connections should never be forced. Regulators and valves should never be oiled or greased. A fire or explosion could result. Pressure should be removed from the regulator when not in use. The main tank valve should be closed and the pressure bled off from the regulator valves. To prevent explosions, regulators made of brass or copper should not be used with acetylene.

Traps.  A trap, check valve, or vacuum break should be used to prevent the back-flow of contamination into the cylinder.

Empty cylinders.  Cylinders should not be completely emptied. Approximately 25 pounds of pressure should remain in the cylinder. The tank valve should be closed to prevent contamination from air and water. Empty cylinders should never be refilled by the user. Remove the regulator, replace the cap, mark the cylinder empty, and return it to the storeroom and vendor as soon as possible. Segregate empty cylinders from full cylinders to reduce handling by the supplier. The cylinder should be securely fastened in the storeroom.

9.0 Cryogenic Liquids

Cryogenic liquids are liquefied gases that are handled at very low temperatures, typically below -150 degrees F. The primary risks associated with the use of these materials are the physical injuries caused by exposure of tissue to extreme cold, the potential for fires and explosions, and asphyxiation.

Even very brief skin contact with a cryogenic liquid is capable of causing frostbite injury. Prolonged contact may result in blood clots. Flooding the affected tissue with warm water as soon as possible is the recommended treatment for exposure to cryogenic liquids.

Gases such as hydrogen, methane, and acetylene present obvious fire and explosion hazards. Liquid oxygen greatly increases the flammability of ordinary combustibles and may even cause non-combustibles to burn. Because oxygen has a higher boiling point than nitrogen, helium, or hydrogen it can be condensed out of the atmosphere during the use of these lower boiling cryogenic liquids. Conditions may exist for an explosion, particularly with hydrogen.

Water vapor condensing to ice on vents or pressure relief valves blocking the route of gas escape can result in a pressure explosion in the vessel. Liquid nitrogen is commonly transported in vacuum flasks called Dewars. If the vacuum in the Dewar flask should fail, the nitrogen would rapidly escape and could displace enough air in a small confined space to asphyxiate someone. However, the most likely consequence of a sudden vacuum loss would be an implosion that could result in flying glass.

Safety Procedures

Personal protection. Personnel should wear suitable eye protection such as chemical splash goggles or a face shield. Long sleeves, long pants and hand protection should be worn. Adequate hand protection must be worn to prevent contact with the cold liquid. It is recommended that pads or pot holders be used instead of gloves to prevent the cold fluid from being trapped inside the glove.

Containers.  All exposed glass surfaces of vacuum flasks used to transport or store cryogenic fluids must be taped to guard against flying glass from an implosion. Containers should be handled and stored in an upright position. Containers must not be dropped, tipped, or rolled on their sides. Containers and systems should be periodically inspected to guard against ice buildup on vents and pressure relief valves. Vessels used for the storage and handling of liquefied gases should not be filled to more than 80% capacity to reduce the likelihood of expansion of the contents and rupture of the vessel. Cryogenic liquids should be handled in multi-wall, vacuum insulated containers specifically designed for cryogenic liquid. Store-bought glass thermos bottles are not appropriate.

Pressure relief devices.  Containers shall be provided with pressure relief devices adequate to prevent excessive pressure within the container.

Ventilation.  Cryogenic fluids should be used and stored in well ventilated areas to prevent excessive accumulation of the gas.

Hazard Communication Manual Glossary

Acid:  A compound that releases hydrogen ions in the presence of solvents or water. Acids react with bases to form salts and water.

ACGIH:  American Conference of Governmental Industrial Hygienists

Acute toxicity:  A substance that causes injury because of a short term exposure, usually in minutes or hours.

Aerosols:  Liquid droplets or solid particles that can remain dispersed in air for a period of time.

Auto-ignition temperature:  The lowest temperature at which a flammable gas mixture will ignite from its own heat source without the necessity of a spark or flame.

Benign:  A tumor that does not metastasize.

Blood toxin:  Chemicals that damage blood cells or decrease the ability of the blood cells to deliver oxygen.

Boiling point:  The temperature at which the vapor pressure of a liquid and the atmospheric pressure is the same.

Bronchitis:  Inflammation of the trachea (windpipe) and its branches.

Cancer:  Cancer is characterized by uncontrolled growth of abnormal cells. These cells are destructive and often capable of migrating to new sites to form secondary growths.

Canister:  A container filled with sorbents that removes gases and vapors drawn through the device.

Carcinogen:  A chemical that causes malignant tumors. It must be listed as a carcinogen or potential carcinogen in one of the following sources: Annual Report on Carcinogens, published by the National Toxicology Program, or Monographs, published by the International Agency for Research on Cancer, or it is regulated by OSHA.

Caustic:  A chemical that is strongly irritating or corrosive.

Ceiling limit:  The concentration of a chemical that exposure to should never be exceeded.

CFR:  Code of Federal Regulations

Chronic toxicity:  A substance that causes injury because of long term (months or years) exposure or causes injury after months or years following an acute exposure.

Class IA flammable liquid:  Flash point below 73 F(22.8 C). Boiling point below 100 F (37.8 C).

Class IB flammable liquid:  Flash point below 73 F (22.8 C). Boiling point at or above 100 F (37.8 C).

Class IC flammable liquid:  Flash point at or above 73 F (22.8 C) and below 100 F (37.8 C).

Class II combustible liquid:  Flash point at or above 100 F (37.8 C) and below 140 F (60 C).

Class IIIA combustible liquid:  Flash point at or above 140 F (60 C) and below 200 F (93.4 C).

Class IIIB combustible liquid:  Flash point at or above 200 F (93.4 C).

CNS:  Central Nervous System

Combustible Liquid:  A liquid having a flash point at or above 100 F but below 200 F.

Container:  Any bag, barrel, bottle, box, can, cylinder, drum, reaction vessel, storage tank, or the like that contains a hazardous chemical. Pipes or piping systems are not considered containers.

Corrosive:  A chemical that causes visible destruction or irreversible damage to living tissue by chemical action at the site of contact.

Critical organ:  The organ that receives the greatest concentration of the chemical.

Cryogenic liquids:  Liquified gases which are handled at very low temperatures, typically below -150 F.

Density:  The mass of a substance divided by its volume.

Dermatitis:  Inflammation of the skin.

Desiccant:  A substance that absorbs water.

Duct:  A conduit that air travels through.

Dyspnea:  Shortness of breath or difficulty in breathing.

Eczema:  Skin disease or disorder.

Edema: Swelling of body tissue from excess water.

Embryo:  The stage of gestation from conception to the end of the third month.

Embryotoxic:  Substances that act during pregnancy to cause adverse effects on the fetus.

Epidemiology:  Study of the cause of diseases in human populations.

Erythema:  Reddening of the skin.

Exhaust ventilation:  The removal of air from an area by mechanical means.

Experimental carcinogen:  A substance that has been shown by statistically scientific studies to cause cancer in animals.

Explosive:  A chemical that causes a sudden, almost instantaneous release of pressure, gas, and heat when subjected to sudden shock, pressure, or high temperature.

Face velocity:  Air velocity at the opening of a hood.

Fetus:  The stage of gestation from the end of the fourth month to birth.

Flammable liquid:  A liquid having a flashpoint below 100 F.

Flammable solid:  A solid, other than an explosive, that can cause fire through friction, absorption of moisture, spontaneous chemical change, or which can be ignited readily and create a serious hazard.

Flash point:  The minimum temperature at which a liquid gives off a vapor in sufficient concentration to ignite.

Fume:  Minute solid particles dispersed in the air because of heating a solid.

Gas:  State of matter characterized by very low density and viscosity.

Gastro:  Referring to the stomach.

Glove box:  A sealed enclosure in which all operations are carried out through long impervious gloves sealed to the box.

Hazard warning:  Any words, pictures, or symbols appearing on a label that conveys the hazards of the chemical in the container.

Hazardous chemical:  A chemical that is a physical or health hazard.

Health hazard:  A chemical for which there is statistically significant evidence based on at least one scientific study that acute or chronic health effects may occur in exposed individuals. Health hazards include chemicals that are carcinogens, mutagens, teratogens, corrosives, toxic and highly toxic agents, irritants, and sensitizers.

Hemato:  Referring to the blood.

Hematopoietic toxins:  Chemicals that interfere with the production of red blood cells.

HEPA filter:  High efficiency particulate air filter. Removes 99.97% of particles with a diameter greater than 0.3 microns.

Hepatotoxins:  Chemicals that damage the liver.

Highly toxic: A chemical is considered highly toxic if it has an LD50 in test animals of less than 50 mg/kg by ingestion, or less than 200 mg/kg by skin contact, or the LC50 is less than 200 ppm.

Human carcinogen:  A substance that has been shown by statistically significant epidemiological evidence to cause cancer in humans.

Hydrocarbon:  Organic compounds consisting solely of hydrogen and carbon.

IARC:  International Agency for Research on Cancer.

Ignition temperature:  The lowest temperature necessary to cause the vapor-air mixture over the liquid to ignite and continue to burn without the heat source.

Inorganic:  Compounds from a source other than animal or vegetable that generally do not contain carbon.

Irritant:  A chemical that causes a reversible inflammatory effect on living tissue by chemical action at the site of contact.

Ischemia:  Loss of blood supply to a part of the body.

Label:  Any written, printed, or graphic material displayed on or affixed to containers of hazardous chemicals.

LC50:  The air concentration of a chemical that causes the death of 50% of the test animals.

LD50:  The quantity of a material that will result in the death of 50% of the test animals when ingested, injected, or applied to the skin.

Leukemia:  Blood disease characterized by an overproduction of white blood cells.

Lower flammability limit:  The minimum concentration of the vapor in air that will sustain the spread of a flame.

Makeup air:  Clean, tempered outdoor air that replaces air removed by exhaust ventilation.

Material safety data sheet:  Written or printed material concerning a hazardous chemical that is prepared according to the Hazard Communication Standard.

Metastases:  The process by which a malignant tumor establishes new sites.

Mists:  Finely divided liquid suspended in air. Created by condensation or by breaking up a liquid.

MSDS:  Material safety data sheet.

Mucous membranes:  Lining of the hollow organs of the body such as the nose, mouth, stomach, intestines, and bronchial tubes.

Mutagenic:  Chemicals that cause a change in the gene structure that can be passed on to offspring.

Myelo:  Referring to bone marrow.

Narcosis:  Loss of consciousness.

Necrosis:  Death of body tissues.

Neoplasm:  A new growth that may be benign or malignant.

Nephrotoxins:  Chemicals that produce kidney damage.

Neurotoxins:  Chemicals that produce their primary effect on the central nervous system.

NFPA:  National Fire Protection Association.

NIOSH:  National Institute for Occupational Safety and Health.

NTP:  National Toxicology Program.

Oncogenic:  Chemicals that cause tumors.

Organic matter:  Compounds containing carbon.

OSHA:  Occupational Safety and Health Administration.

Oxidizer:  A chemical that initiates or promotes combustion in other materials by releasing oxygen, causing a fire.

Palpitation:  Rapid or fluttering heartbeat that the person is very conscious of.

Particulate matter:  Suspension of fine solid or liquid matter in air.

PEL: Permissible exposure limit established as legal limit by OSHA to which nearly all workers may be exposed to as an eight-hour time-weighted average without adverse effects.

Personal protective equipment:  Equipment such as respirators, gloves, and eye goggles, worn by workers to protect themselves from hazards.

Physical hazard:  A chemical that is a combustible liquid, compressed gas, explosive, flammable, organic peroxide, oxidizer, pyrophoric, or reactive.

Plenum:  A space filled with air as opposed to a vacuum.

Poison:  A chemical with an oral LD50 of 50 mg/kg or less.

ppb:  parts per billion.

ppm:  parts per million.

Pyrophoric:  A chemical that will ignite in air at a temperature of 130 F or below.

RCRA:  Resource Conservation & Recovery Act.

Reactive:  A chemical that will decompose, condense, or will become self-reactive under conditions of shock, pressure or temperature.

Reproductive toxins:  Chemicals that can cause birth defects, spontaneous abortions, or sterility.

Respirator:  A device worn by workers to protect themselves from breathing harmful contaminants.

Safety can:  Designed to safely relieve internal pressure when exposed to a fire. Has a spring-closing lid and a flame arrestor in the spout.

Sensitizer:  A chemical that causes many exposed people to develop an allergic reaction after repeated exposure to the chemical.

Solvent:  A substance that dissolves another substance. Most commonly water but often an organic compound.

Sorbent:  A material that removes toxic gases and vapors from air inhaled through a respirator.

Specific gravity:  The mass of a substance divided by the mass of an equal volume of water.

STEL:  Short term exposure limit. The maximum amount that a worker may be exposed to for 15 minutes.

Synergism:  Substances combining to cause an effect that is greater than the sum of the parts.

Teratogenic:  A substance that may produce a malformation of the embryo or fetus.

TLV-TWA:  The threshold limit value established by the ACGIH that represents the eight hour time-weighted average concentration to which nearly all workers may be exposed without suffering adverse effects.

Toxic:  A chemical is considered toxic if the LD50 in test animals is between 50 mg/kg and 500 mg/kg when ingested or between 200 mg/kg and 2000 mg/kg when in contact with the skin. The substance is also considered toxic if the LC50 is between 200 ppm and 20,000 ppm when inhaled.

TWA:  Time weighted average.

Upper flammability limit:  The maximum concentration of vapors in air that will propagate a flame.

Vapor pressure:  The pressure of a vapor in equilibrium with its liquid or solid. The higher the vapor pressure the greater the volatility.

Vapors:  The gaseous form of a material that is normally in the solid or liquid state.

Viscosity:  The internal friction or resistance to flow in a liquid or gas.

Volatile:  The ability of a liquid to vaporize. A highly volatile liquid, such as gasoline, has a high vapor pressure and will vaporize easily.

Water-reactive:  A chemical that will react with water to release gas that is either flammable or presents a health hazard.

 

Hazard Communication Program

1.0 Introduction

Approximately one worker in four is exposed to chemical hazards on the job. Exposure to chemicals can cause serious health effects such as skin rashes, burns, organ damage, birth defects, and cancer. In addition, many chemicals are fire and explosion hazards. Recognizing the seriousness of these problems, OSHA has adopted a Hazard Communication or Right-To-Know Standard. This Standard requires employers to inform workers of chemical hazards in the work place and to provide measures to minimize exposures. The goal of the Standard is to reduce the incidence of illness and injuries due to chemical exposure.

2.0 Program

  1. The Safety Manager will manage, review, and update the Hazard Communication Program as necessary to ensure compliance with OSHA regulations. The effectiveness of the Program will be reviewed annually by the Safety Manager.
  2. Copies of the program, chemical inventory, MSDSs, and further information on chemical hazards may be obtained from the Safety Office by calling 831-7790.
  3. A copy of the university's written Hazard Communication Program will be made available to contractors upon request.

3.0 Chemical Inventory

  1. Departments using chemicals, other than laboratories and the warehouse, will maintain a list of all hazardous chemicals used in their area. Chemicals generated by a work process will also be included in the inventory.
  2. The identity of the chemicals on the list will correspond to the MSDS and label.

4.0 Material Safety Data Sheets

  1. An MSDS will be maintained for all hazardous chemicals used at the university. Departments will maintain files for chemicals used in their work areas to provide employees with immediate access to MSDSs.
  2. MSDSs will be reviewed by supervision or the Safety Manager to ensure that they are complete and clearly written. If necessary, the Safety Manager will write a letter to the manufacturer requesting additional information or a complete MSDS. The university will rely upon the hazard determinations provided by the manufacturer.
  3. The Safety Manager will attempt to obtain an MSDS from the manufacturer or MSDSonline as soon as possible if one is not on file. The local OSHA office will be notified if the manufacturer fails to respond after three documented requests.
  4. The university will not use a hazardous chemical unless an MSDS can be obtained. Hazardous chemicals that omit physical properties and health effects on the MSDS because of trade secrets shall not be used.
  5. A properly prepared MSDS will accompany any hazardous material shipped from the university.
  6. The university contracts with KellerOnline to provide MSDSs to employees. Employees may obtain MSDSs by calling the Safety Manager during normal working hours at 831-7790 or 831-7800. After hours accessibility is available by calling the University Police Department at 831-5500.
  7. In addition, employees can request an MSDS through the internet.
  8. MSDS files will be updated by the Safety Manager if new information is provided by the manufacturer concerning health hazards of the chemical. Affected employees will be retrained if necessary.

5.0 Labels and Other Forms of Warning

  1. Supervisors will ensure that hazardous chemicals received at the university are properly labeled with the name of the chemical, appropriate hazard warning and the name and address of the manufacturer, importer, or other responsible party. Chemicals without proper labeling will not be accepted. If a chemical is regulated by OSHA, the Safety Manager shall verify that the label meets the requirements of the standard. Labels must not be removed or defaced unless the container is immediately marked with the appropriate information. Chemicals shipped from the university will be properly labeled.
  2. Secondary containers not intended for use during the work shift must be labeled with the name of the chemical and appropriate hazard warnings. Signs will be posted near stationary process containers that have similar contents and hazards rather than labeling individual containers.
  3. Pipes and piping system will not be labeled but their contents will be described in training sessions. Processes that generate hazardous chemicals shall be properly labeled.
  4. In-house labels will allow hazards to be communicated in writing and/or by NFPA coding. Secondary labels will correspond to the information on the primary label and MSDS. These labels will be reviewed and updated as necessary by the Safety Manager.

6.0 Employee Information and Training

  1. Employees working with, or potentially exposed to, hazardous chemicals will receive information and training on the hazards of chemicals in their work area, safety procedures, and the requirements of the Hazard Communication Standard. Training shall be performed at the time of the employee's initial assignment and whenever a new hazard is introduced into the work area.
  2. The Safety Manager will supervise the employee training program. Training shall consist of lectures, handouts, video tapes and/or slides, and contain the following information:
    1. Hazard Communication Standard.
    2. Methods and observations to detect the presence of hazardous chemicals in the work place.
    3. Physical and health hazards of chemicals including signs and symptoms of overexposure.
    4. Procedures to protect against hazards including proper work practices, emergency procedures, safety equipment, personal protective equipment, and first aid procedures.
    5. Location of MSDSs, understanding MSDSs, and where additional information may be obtained.
  3. Information presented in the initial training session will be reviewed during regular safety meetings. Employees will have the opportunity to ask questions. Supervisors shall receive extensive training so they can answer employee questions and monitor safe work practices.
  4. Records of participation in training classes will be maintained by the Safety Manager. The Safety Manager will periodically review and update the training program and solicit ideas from employees.
  5. Employees required to perform non-routine tasks (e.g., cleaning tanks, entering confined spaces) that could involve exposure to hazardous chemicals shall be informed of the potential hazards and proper safety procedures. Employees will be informed of the hazardous chemicals in unlabeled pipes in their work area and the safety precautions to prevent exposure.
  6. The Safety Manager, upon notification by the responsible supervisor, will inform outside contractors of the hazards associated with on-site chemicals, appropriate safety procedures, labeling system in use, and the location of MSDSs. Contractors will be responsible for training their employees in the hazards of chemicals they bring to the work area.

Laboratory Safety Rules

View the PDF version of Radford University's Laboratory Safety Rules.

The following rules must be followed to reduce the risk of accidents and injuries in laboratories.

  1. Know the location and operation of safety showers, eye wash units and fire extinguishers.
  2. Always wear eye protection and closed toe shoes while working in the laboratory.  Wear a protective apron or laboratory coat. If any chemical is spilled on your skin or clothing, wash it off immediately and remove any contaminated clothing.
  3. Never bring food or beverages into the laboratory. Do not taste or smell chemical. Smoking is not allowed in the lab. Never bring chemicals near your face.
  4. Do not use the lab burner until your instructor has explained how it is to be operated. Never leave your burner unattended. When heating test tubes, do not point the open end of the tube towards yourself or someone else.
  5. Do not attempt to insert glass tubing or thermometers into rubber stoppers until your instructor has shown you the proper procedure. Do not use broken, chipped, or cracked glassware.
  6. Dispose of chemicals properly. Ask about a chemical waste container if you don't see one.
  7. Never perform any unauthorized lab experiments or procedure. Do not take chemicals, supplies, or equipment out of the lab area.
  8. Handle chemical with caution. Read labels carefully. Only take as much as you need. Leave reagent bottles in their place. Clean up all spills immediately.
  9. Immediately report all accidents to your instructor, no matter how minor.
  10. Clean your lab bench, put away all equipment and reagents, and wash your hands at the end of the work session.

Pesticides

1.0 Storage

  1. A prominent warning sign, stating "Danger- Pesticides- Keep Out!"  should be posted over the entrance to the pesticide storage area. "No Smoking" signs should also be posted. Storage doors should be kept locked at all times.
  2. Storage areas should be ventilated with an exhaust fan. Ten air changes per hour are recommended.
  3. Pesticides that present fire or explosion hazards should be stored separately from other pesticides. Storage should be away from heat and possible ignition sources.
  4. Highly toxic pesticides should be stored separately from other pesticides to prevent cross contaminations and mistakes in identity.
  5. Supplies such as absorptive clay or vermiculite, shovel, broom, and dust pan should be readily available to clean up spills.
  6. A ten pound ABC fire extinguisher should be located near the door.
  7. Dusters and sprayers should not be stored with any pesticides left in them. A label should be placed on the equipment listing the name of the last used pesticide.
  8. A partly empty container of pesticides containing chlorates should not be stored for a long period.
  9. Pesticides should be stored in their original containers with their proper labels. Never store pesticides in coke bottles, canning jars, or unmarked containers.
  10. Routine checks should be made for leaks and spills.
  11. Wetable powders packaged in paper bags should not be stored on concrete floors.
  12. Storage should be in a cool, dry, airy room or building which is fireproof.
  13. Do not store pesticide containers (especially glass and aerosols) in front of windows.
  14. Never store food, feed, or fertilizer in the pesticide storage area as it may become contaminated.
  15. The different groups of pesticides (herbicide, insecticide, fungicide, rotenticide, etc.) should be kept separate to prevent cross-contamination.
  16. Metal shelves are advisable because they are much easier to decontaminate than wooden shelves. Leak proof plastic trays placed on the shelves will contain spillage.
  17. Gloves, aprons, respirators should be stored nearby but not inside the pesticide storage area.
  18. A steel cabinet may be used for small quantities of pesticides. Locate the cabinet along an outside wall in an area away from extreme heat and freezing temperatures. Pesticides should be separated by type and stored on shelves in plastic leakproof trays. The cabinet should be locked and identified as a place of pesticide storage.

2.0 Mixing Procedures

  1. All pesticides should be mixed and prepared in the open or in a well ventilated area. When handled in close quarter, highly toxic pesticides may cause poisoning through inhalation. Volatile liquid pesticides may cause fires or explosions.
  2. Always wear unlined rubber gloves when handling concentrates. Proper care of gloves must be maintained to prevent contamination. Rinse the gloves well with water before removing them. Do not turn gloves inside out when removing.
  3. To safely mix and prepare some pesticides, it may be necessary to wear a respirator and protective clothing. The container label must be followed in detail for safety equipment and directions for use.
  4. If it is necessary to use the same equipment for several types of pesticides, the supervisor should see that the following precautions are observed:
    1. When opening a liquid or dust pesticide container, keep your face away from the cap or lid.
    2. Guard against the hazard of mixing incompatible chemicals. The equipment should be cleaned and/or decontaminated after completion of each pesticide application.
    3. Workers need to be warned of the possible toxic hazards to themselves and the environment from mixing incompatible chemicals.
    4. An up to date compatibility chart must be posted or readily available for reference on all pesticide materials currently used.
    5. The sprayer agitator should be in operation while mixing pesticides in the sprayer tank. This will ensure proper distribution of the material and will keep suspended particles in suspension for more effective and safer application.

3.0 Spills

  1. The contaminated area should be roped off and warning signs posted. Only people wearing proper personal protective equipment should be allowed in the contaminated area. In case of obvious spread of hazardous material, local authorities must be warned of the possible danger. If contamination of water supplies exist, State and Federal health authorities must be notified. All toxic residues must be disposed of in accordance with waste disposal recommendations.
  2. Every precaution should be taken to prevent accidental contamination of water sources. The cleaning and maintenance of application equipment should be performed in controlled and marked section of the work site away from wells, lakes, and streams. The cleaning equipment site should not be used for any other work activity and should be posted with warning signs to keep unauthorized people out of the contaminated area.

4.0 Disposal of Empty Containers

  1. Punch holes in containers to prevent reuse or water collection. The containers are not safe for reuse and should be properly disposed.
  2. Do not dispose of pesticides in the dump. Unwanted pesticides should be declared as hazardous waste.
  3. Containers should be triple rinsed before disposal. This will reduce the residual pesticide contamination by greater than 90%. The rinse should be added back to the prepared formulation.
  4. Never burn a pesticide container. Toxic and/or flammable vapors may be produced.
  5. Large containers should be crushed.

5.0 Personal Hygiene

  1. Personal cleanliness is the first step in the prevention of pesticide poisoning. Pesticide handlers should wear clean clothes each day. An extra change of clothes should be available at the work site so the worker can change immediately if necessary. All pesticide contaminated clothing should be cleaned separately from other clothing with a very strong detergent and liquid chlorine bleach before reuse. Clothing that has been badly contaminated with a highly toxic pesticide should be disposed of as hazardous waste.
  2. Workers should be provided with facilities to wash thoroughly after exposure to pesticides. Workers should wash their hands thoroughly before eating, drinking, or smoking.

6.0 Personal Protective Equipment

  1. Workers required to handle pesticides should wear the proper personal protective equipment as necessary to ensure that the health of the employee is not compromised.
  2. 2. Workers handling pesticides that can be absorbed through the skin should wear rubber gloves in addition to the appropriate personal protective equipment recommended on the label.
  3. 3. The following personal equipment is recommended:
    1. Boots- rubber, knee-length and unlined
    2. Coverall- lined tyvek
    3. Gloves- rubber, unlined and long enough to wear inside sleeves
    4. Hat- wide brim, waterproofed
    5. Hood- should be used for protection of head,, eyes, face and neck while dusting overhead
    6. Goggles- should be unventilated or indirect vented with anti-fog coating
  4. To ensure adequate eye protection all workers handling pesticides will be furnished with goggles. Goggles must be worn when mixing, spraying, dusting, or when handling any concentrated highly toxic pesticide.
  5. A source of water to irrigate the eyes should be readily available to pesticide operators in the field.

7.0 Respirators

  1. Dust respirators do not offer protection from toxic gases and vapors given off by many pesticides.
  2. Most pesticides are applied as either dusts or sprays. In many instances the pesticide formulation is very volatile. Pesticide applicators are often exposed to a combination of gaseous and particulate hazards. Adequate protection is provided by utilizing an appropriate gas or vapor absorber in conjunction with a high efficiency particulate filter. Chemical cartridges are available with particulate filters assembled as a integral part. Other units offer the chemical and particulate cartridge as separate units. These units are more economical because the dust filter usually clogs before the chemical cartridge.
  3. Pesticide applicators using respirators must be certified by the Safety Office.

GHS Hazard Classifications

Physical Hazards

  • Explosives
  • Flammable Gases
  • Flammable Aerosols
  • Oxidizing Gases
  • Gases Under Pressure
  • Flammable Liquids
  • Flammable Solids
  • Self-Reactive Substances
  • Pyrophoric Liquids
  • Pyrophoric Solids
  • Self-Heating Substances
  • Substances which, in contact with water emit flammable gases
  • Oxidizing Liquids
  • Oxidizing Solids
  • Organic Peroxides
  • Corrosive to Metals

Explosives
An explosive substance (or mixture) is a solid or liquid which is in itself capable by chemical reaction of producing gas at such a temperature and pressure and at such a speed as to cause damage to the surroundings. Pyrotechnic substances are included even when they do not evolve gases. A pyrotechnic substance (or mixture) is designed to produce an effect by heat, light, sound, gas or smoke or a combination of these as the result of non-detonative, self-sustaining, exothermic chemical reactions.

Classification as an explosive and allocation to a division is a three-step process:

  • Ascertain if the material has explosive effects (Test Series 1);
  • Acceptance procedure (Test Series 2 to 4);
  • Assignment to one of six hazard divisions (Test Series 5 to 7).

Table 3.1 Explosives

Division

Characteristics

1.1

Mass explosion hazard

1.2

Projection hazard

1.3

Fire hazard or minor projection hazard

1.4

No significant hazard

1.5

Very insensitive substances with mass explosion hazard

1.6

Extremely insensitive articles with no mass explosion hazard

Explosive properties are associated with certain chemical groups that can react to give very rapid increases in temperature or pressure. The GHS provides a screening procedure that is aimed at identifying the presence of such reactive groups and the potential for rapid energy release. If the screening procedure identifies the substance or mixture to be a potential explosive, the acceptance procedure has to be performed.

Substances, mixtures and articles are assigned to one of six divisions, 1.1 to 1.6, depending on the type of hazard they present. See, UN Manual of Tests and Criteria Part I Test Series 2 to 7. Currently, only the transport sector uses six categories for explosives.

Flammable Gases
Flammable gas means a gas having a flammable range in air at 20°C and a standard pressure of 101.3 kPa. Substances and mixtures of this hazard class are assigned to one of two hazard categories on the basis of the outcome of the test or calculation method (ISO 10156:1996).

Flammable Aerosols
Aerosols are any gas compressed, liquefied or dissolved under pressure within a non-refillable container made of metal, glass or plastic, with or without a liquid, paste or powder. The container is fitted with a release device allowing the contents to be ejected as solid or liquid particles in suspension in a gas, as a foam, paste or powder or in a liquid or gaseous state.

Aerosols should be considered for classification as either a Category 1 or Category 2 Flammable Aerosol if they contain any component classified as flammable according to the GHS criteria for flammable liquids, flammable gases, or flammable solids. Classification is based on:

  • Concentration of flammable components;
  • Chemical heat of combustion (mainly for transport/storage);
  • Results from the foam test (foam aerosols) (mainly for worker/consumer);
  • Ignition distance test (spray aerosols) (mainly for worker/consumer);
  • Enclosed space test (spray aerosols) (mainly for worker/consumer).

Aerosols are considered:

  • Nonflammable, if the concentration of the flammable components < 1% and the heat of combustion is < 20 kJ/g.
  • Extremely flammable, if the concentration of the flammable components >85% and the heat of combustion is > 30 kJ/g to avoid excessive testing.

See the UN Manual of Tests and Criteria for the test method.

Oxidizing Gases
Oxidizing gas means any gas which may, generally by providing oxygen, cause or contribute to the combustion of other material more than air does. Substances and mixtures of this hazard class are assigned to a single hazard category on the basis that, generally by providing oxygen, they cause or contribute to the combustion of other material more than air does. The test method is ISO 10156:1996. Currently, several workplace hazard communication systems cover oxidizers (solids, liquids, gases) as a class of chemicals.

Gases under Pressure
Gases under pressure are gases that are contained in a receptacle at a pressure not less than 280 Pa at 20°C or as a refrigerated liquid. This endpoint covers four types of gases or gaseous mixtures to address the effects of sudden release of pressure or freezing which may lead to serious damage to people, property, or the environment independent of other hazards the gases may pose.

For this group of gases, the following information is required:

  • vapor pressure at 50°C;
  • physical state at 20°C at standard ambient pressure;
  • critical temperature.

Criteria that use the physical state or compressed gases will be a different classification basis for some workplace systems.

Table 3.2 Gases under Pressure

Group

Criteria

Compressed gas

Entirely gaseous at -50°C

Liquefied gas

Partially liquid at temperatures > -50°C

Refrigerated liquefied gas

Partially liquid because of its low temperature

Dissolved gas

Dissolved in a liquid phase solvent

Data can be found in the literature, and calculated or determined by testing. Most pure gases are already classified in the UN Model Regulations. Gases are classified, according to their physical state when packaged, into one of four groups as shown in Table 3.2.

Flammable Liquids
Flammable liquid means a liquid having a flash point of not more than 93°C. Substances and mixtures of this hazard class are assigned to one of four hazard categories on the basis of the flash point and boiling point (See Table 3.3). Flash Point is determined by closed cup methods as provided in the GHS document, Chapter 2.5, paragraph 11.

Table 3.3 Flammable Liquids

Category

Criteria

1

Flash point < 23°C and initial boiling point ≤ 35°C (95°F)

2

Flash point < 23°C and initial boiling point > 35°C (95°F)

3

Flash point ≥ 23°C and ≤ 60°C (140°F)

4

Flash point ≥ 60°C (140°F) and ≤ 93°C (200°F)

Flammable Solids
Flammable solids are solids that are readily combustible, or may cause or contribute to fire through friction. Readily combustible solids are powdered, granular, or pasty substances which are dangerous if they can be easily ignited by brief contact with an ignition source, such as a burning match, and if the flame spreads rapidly.

Substances and mixtures of this hazard class are assigned to one of two hazard categories (Table 3.4) on the basis of the outcome of the UN Test N.1 (UN Manual of Tests and Criteria). The tests include burning time, burning rate and behavior of fire in a wetted zone of the test sample.

Table 3.4 Flammable Solids

Category

Criteria

1

Metal Powders: burning time ≤ 5 minutes
Others: wetted zone does not stop fire & burning time < 45 seconds or burning > 2.2 mm/second

2

Metal Powders: burning time > 5 and ≤ 10 minutes
Others: wetted zone stop fire for at least 4 minutes & burning time < 45 seconds or burning rat > 2.2mm/second

Self-Reactive Substances
Self-reactive substances are thermally unstable liquids or solids liable to undergo a strongly exothermic thermal decomposition even without participation of oxygen (air). This definition excludes materials classified under the GHS as explosive, organic peroxides or as oxidizing. These materials may have similar properties, but such hazards are addressed in their specific endpoints. There are exceptions to the self-reactive classification for material: (i) with heat of decomposition <300 J/g or (ii) with self-accelerating decomposition temperature (SADT) > 75°C for a 50 kg package.

Substances and mixtures of this hazard class are assigned to one of the seven 'Types', A to G, on the basis of the outcome of the UN Test Series A to H (UN Manual of Tests and Criteria). Currently, only the transport sector uses seven categories for self-reactive substances (Table 3.5).

Table 3.5 Self-Reactive Substances

Type

Criteria

A

Can detonate or deflagrate rapidly, as packaged.

B

Possess explosive properties and which, as packaged, neither detonates nor deflagrates, but is liable to undergo a thermal explosion in that package.

C

Possess explosive properties when the substance or mixture as package cannot detonate or deflagrate rapidly or undergo a thermal explosion.

D

  • Detonates partially, does not deflagrate rapidly and shows no violent effect when heated under confinement; or
  • Does not detonate at all, deflagrates slowly and shows no violent effect when heated under confinement; or
  • Does not detonate or deflagrate at all and shows a medium effect when heated under confinement.

E

Neither detonates nor deflagrates at all and shows low or no effect when heated under confinement.

F

Neither detonates in the cavitated bubble state nor deflagrates at all and shows only a low or no effect when heated under confinement as well as low or no explosive power.

G

Neither detonates in the cavitated state nor deflagrates at all and shows non effect when heated under confinement nor any explosive power, provided that it is thermally stable (self-accelerating decomposition temperature is 60°C to 75°C for a 50 kg package), and, for liquid mixtures, a diluent having a boiling point not less than 150°C is used for desensitization.

Pyrophorics

Pyrophoric Liquids
A pyrophoric liquid is a liquid which, even in small quantities, is liable to ignite within five minutes after coming into contact with air. Substances and mixtures of this hazard class are assigned to a single hazard category on the basis of the outcome of the UN Test N.3 (UN Manual of Tests and Criteria).

Pyrophoric Solids
A pyrophoric solid is a solid which, even in small quantities, is liable to ignite within five minutes after coming into contact with air. Substances and mixtures of this hazard class are assigned to a single hazard category on the basis of the outcome of the UN Test N.2 (UN Manual of Tests and Criteria).

Self-Heating Substances
A self-heating substance is a solid or liquid, other than a pyrophoric substance, which, by reaction with air and without energy supply, is liable to self-heat. This endpoint differs from a pyrophoric substance in that it will ignite only when in large amounts (kilograms) and after long periods of time (hours or days). Substances and mixtures of this hazard class are assigned to one of two hazard categories on the basis of the outcome of the UN Test N.4 (UN Manual of Tests and Criteria).

3.1.12 Substances which on Contact with Water Emit Flammable Gases

Substances that, in contact with water, emit flammable gases are solids or liquids which, by interaction with water, are liable to become spontaneously flammable or to give off flammable gases in dangerous quantities. Substances and mixtures of this hazard class are assigned to one of three hazard categories on the basis of test results (UN Test N.5 UN Manual of Tests and Criteria) which measure gas evolution and speed of evolution.

Category

Criteria

1

≥10 L/kg/1 minute

2

≥20 L/kg/ 1 hour + < 10 L/kg/1 min

3

≥1 L/kg/1 hour + < 20 L/kg/1 hour

Not classified

< 1 L/kg/1 hour

Oxidizing Liquids
An oxidizing liquid is a liquid which, while in itself not necessarily combustible, may, generally by yielding oxygen, cause or contribute to the combustion of other material. Substances and mixtures of this hazard class are assigned to one of three hazard categories on the basis of test results (UN Test O.2 UN Manual of Tests and Criteria) which measure ignition or pressure rise time compared to defined mixtures.

Oxidizing Solids
An oxidizing solid is a solid which, while in itself not necessarily combustible, may, generally by yielding oxygen, cause or contribute to the combustion of other material. Substances and mixtures of this hazard class are assigned to one of three hazard categories on the basis of test results (UN Test O.1 UN Manual of Tests and Criteria) which measure mean burning time and re compared to defined mixtures. Currently, several workplace hazard communication systems cover oxidizers (solids, liquids, gases) as a class of chemicals.

Organic Peroxides
An organic peroxide is an organic liquid or solid which contains the bivalent -0-0- structure and may be considered a derivative of hydrogen peroxide, where one or both of the hydrogen atoms have been replaced by organic radicals. The term also includes organic peroxide formulations (mixtures). Such substances and mixtures may:

  • be liable to explosive decomposition;
  • burn rapidly;
  • be sensitive to impact or friction;
  • react dangerously with other substances.

Substances and mixtures of this hazard class are assigned to one of seven 'Types', A to G, on the basis of the outcome of the UN Test Series A to H (UN Manual of Tests and Criteria). Currently, only the transport sector uses seven categories for organic peroxides.

Table 3.7 Organic Peroxides

Type

Criteria

A

Can detonate or deflagrate rapidly, as packaged.

B

Possess explosive properties and which, as packaged, neither detonates nor deflagrates rapidly, but is liable to undergo a thermal explosion in that package.

C

Possess explosive properties when the substance or mixture as packaged cannot detonate or deflagrate rapidly or undergo a thermal explosion.

D

  • Detonates partially, does not deflagrate rapidly and shows no violent effect when heated under confinement; or
  • Does not detonate at all, deflagrates slowly and shows no violent effect when heated under confinement; or
  • Does not detonate or deflagrate at all and shows a medium effect when heated under confinement.

E

Neither detonates nor deflagrates at all and shows low or no effect when heated under confinement.

F

Neither detonates in the caviated bubble state nor deflagrates at all and shows only a low or no effect when heated under confinements as well as low or non explosive power.

G

Neither detonates in the caviated state nor deflagrates at all and shows no effect when heated under confinement nor any explosive power, provided that it is thermally stable (self-accelerating decomposition temperature is 60°C to 75°C for a 50 kg package), and, for liquid mixtures, a diluent having a boiling point not less than 150°C is used for desensitization.

Substances Corrosive to Metal
A substance or a mixture that by chemical action will materially damage, or even destroy, metals is termed 'corrosive to metal'. These substances or mixtures are classified in a single hazard category on the basis of tests (Steel: ISO 9328 (II): 1991 - Steel type P235; Aluminum: ASTM G31-72 (1990) - non-clad types 7075-T6 or AZ5GU-T66). The GHS criteria are a corrosion rate on steel or aluminum surfaces exceeding 6.25 mm per year at a test temperature of 55°C.

The concern in this case is the protection of metal equipment or installations in case of leakage (e.g., plane, ship, tank), not material compatibility between the container/tank and the product. This hazard is not currently covered in all systems.

Health Hazard

  • Acute Toxicity
  • Skin Corrosion/Irritation
  • Serious Eye Damage/Eye Irritation
  • Respiratory or Skin Sensitization
  • Germ Cell Mutagenicity
  • Carcinogenicity
  • Reproductive Toxicology
  • Target Organ Systemic Toxicity - Single Exposure
  • Target Organ Systemic Toxicity - Repeated Exposure
  • Aspiration Toxicity

 

Environmental Hazard

  • Hazardous to the Aquatic Environment
    •   Acute aquatic toxicity
    •   Chronic aquatic toxicity
      •   Bioaccumulation potential
      •   Rapid degradability

Acute Toxicity
Five GHS categories have been included in the GHS Acute Toxicity scheme from which the appropriate elements relevant to transport, consumer, worker and environment protection can be selected. Substances are assigned to one of the five toxicity categories on the basis of LD50 (oral, dermal) or LC50 (inhalation). The LC50 values are based on 4-hour tests in animals. The GHS provides guidance on converting 1-hour inhalation test results to a 4-hour equivalent. The five categories are shown in the Table 3.8 Acute Toxicity.

Table 3.8 Acute Toxicity

Acute
toxicity

Cat. 1

Cat. 2

Cat. 3

Cat. 4

Category 5

Oral
(mg/kg)

≤ 5

> 5
≤ 50

> 50
≤ 300

> 300
≤ 2000

Criteria:

  • Anticipated oral LD50 between 2000 and 5000 mg/kg;
  • Indication of significant effect in humans;*
  • Any mortality at class 4;*
  • Significant clinical signs at class 4;*
  • Indications from other studies.*

*If assignment to more hazardous class is not warranted.

Dermal
(mg/kg)

≤ 50

> 50
≤ 200

> 200
≤ 1000

> 1000
≤ 2000

Gases
(ppm)

≤ 100

> 100
≤ 500

> 500
≤ 2500

> 2500
≤ 5000

Vapors
(mg/l)

≤ 0.5

> 0.5
≤ 2.0

> 2.0
≤ 10

> 10
≤ 20

Dust & mists
(mg/l)

≤ 0.05

> 0.05
≤ 0.5

> 0.5
≤ 1.0

> 1.0
≤ 5



Category 1, the most severe toxicity category, has cut-off values currently used primarily by the transport sector for classification for packing groups. Some Competent Authorities may consider combining Acute Categories 1 and 2. Category 5 is for chemicals which are of relatively low acute toxicity but which, under certain circumstances, may pose a hazard to vulnerable populations. Criteria other than LD50/LC50 data are provided to identify substances in Category 5 unless a more hazardous class is warranted.

Skin Corrosion
Skin corrosion means the production of irreversible damage to the skin following the application of a test substance for up to 4 hours. Substances and mixtures in this hazard class are assigned to a single harmonized corrosion category. For Competent Authorities, such as transport packing groups, needing more than one designation for corrosivity, up to three subcategories are provided within the corrosive category. See the Skin Corrosion/Irritation Table 3.9.

Several factors should be considered in determining the corrosion potential before testing is initiated:

  • Human experience showing irreversible damage to the skin;
  • Structure/activity or structure property relationship to a substance or mixture already classified as corrosive;
  • pH extremes of £ 2 and ³ 11.5 including acid/alkali reserve capacity.

Skin Corrosion
Category 1

Skin Irritation
Category 2

Mild Skin Irritation
Category 3

Destruction of dermal tissue: visible necrosis in at least one animal

Reversible adverse effects in dermal tissue

Draize score: ≥ 2.3 < 4.0
or persistent inflammation

Reversible adverse effects in dermal tissue

Draize score: ≥ 1.5 < 2.3

Subcategory 1A
Exposure < 3 min.
Observation < 1hr,

Subcategory 1B
Exposure < 1hr.
Observation < 14 days

Subcategory 1C
Exposure < 4 hrs. Observation < 14 days

         



Skin Irritation
Skin irritation means the production of reversible damage to the skin following the application of a test substance for up to 4 hours. Substances and mixtures in this hazard class are assigned to a single irritant category. For those authorities, such as pesticide regulators, wanting more than one designation for skin irritation, an additional mild irritant category is provided. See the Skin Corrosion/Irritation Table 3.9.

Several factors should be considered in determining the irritation potential before testing is initiated:

  • Human experience or data showing reversible damage to the skin following exposure of up to 4 hours;
  • Structure/activity or structure property relationship to a substance or mixture already classified as an irritant.

Eye Effects
Several factors should be considered in determining the serious eye damage or eye irritation potential before testing is initiated:

  • Accumulated human and animal experience;
  • Structure/activity or structure property relationship to a substance or mixture already classified;
  • pH extremes like < 2 and > 11.5 that may produce serious eye damage.

Table 3.10 Eye Effects

Category 1
Serious eye damage

Category 2
Eye Irritation

Irreversible damage 21 days after exposure

Draize score:
    Corneal opacity ≥ 3
    Iritis > 1.5

Reversible adverse effects on cornea, iris, conjunctiva

Draize score:
   Corneal opacity ≥ 1
   Iritis > 1
   Redness ≥ 2
   Chemosis ≥ 2

Irritant
Subcategory 2A
Reversible in 21 days

Mild Irritant
Subcategory 2B
Reversible in 7 days

Serious eye damage means the production of tissue damage in the eye, or serious physical decay of vision, following application of a test substance to the front surface of the eye, which is not fully reversible within 21 days of application. Substances and mixtures in this hazard class are assigned to a single harmonized category.

Eye irritation means changes in the eye following the application of a test substance to the front surface of the eye, which are fully reversible within 21 days of application. Substances and mixtures in this hazard class are assigned to a single harmonized hazard category. For authorities, such as pesticide regulators, wanting more than one designation for eye irritation, one of two subcategories can be selected, depending on whether the effects are reversible in 21 or 7 days.

Sensitization
Respiratory sensitizer means a substance that induces hypersensitivity of the airways following inhalation of the substance. Substances and mixtures in this hazard class are assigned to one hazard category.

Skin sensitizer means a substance that will induce an allergic response following skin contact. The definition for "skin sensitizer" is equivalent to "contact sensitizer". Substances and mixtures in this hazard class are assigned to one hazard category. Consideration should be given to classifying substances which cause immunological contact urticaria (an allergic disorder) as contact sensitizers.

Germ Cell Mutagenicity
Mutagen means an agent giving rise to an increased occurrence of mutations in populations of cells and/or organisms. Substances and mixtures in this hazard class are assigned to one of two hazard categories. Category 1 has two subcategories. See the Germ Cell Mutagenicity (Table 3.11) below.

Table 3.11 Germ Cell Mutagenicity

Category 1
Known/Presumed

Category 2
Suspected/Possible

Known to produce heritable mutations in human germ cells

  • May include heritable mutations in human germ cells
  • Positive evidence from tests in mammals and somatic cell tests
  • In vivo somatic genotoxicity supported by in vitro mutagenicity

Subcategory 1A

Positive evidence from epidemiological studies

Subcategory 1B

Positive results in:

  • In vivo heritable germ cell tests in mammals
  • Human germ cell tests
  • In vivo somatic mutagenicity tests, combined with some evidence of germ cell mutagenicity
     



Carcinogenicity
Carcinogen means a chemical substance or a mixture of chemical substances which induce cancer or increase its incidence. Substances and mixtures in this hazard class are assigned to one of two hazard categories. Category 1 has two subcategories. The Carcinogenicity Guidance Section in the GHS Document includes comments about IARC.

Table 3.12 Carcinogenicity

Category 1
Known or Presumed Carcinogen

Category 2
Suspected Carcinogen

Subcategory 1A

Known Human Carcinogen Based on human evidence

Subcategory 1B

Presumed Human Carcinogen
Based on demonstrated animal carcinogenicity

Limited evidence of human or animal carcinogenicity

Reproductive Toxicity
Reproductive toxicity includes adverse effects on sexual function and fertility in adult males and females, as well as developmental toxicity in offspring.  Substances and mixtures with reproductive and/or developmental effects are assigned to one of two hazard categories, 'known or presumed' and 'suspected'. Category 1 has two subcategories for reproductive and developmental effects. Materials which cause concern for the health of breastfed children have a separate category, Effects on or Via Lactation.

Table 3.13 Reproductive Toxicity

Category 1
 

Category 2
Suspected

Additional
Category

Known or presumed to cause effects on human reproduction or on development

Human or animal evidence possibly with other information

Effects on or via lactation

Category 1A
Known

Based on human
evidence

Category 1B

Presumed
Based on
experimental animals

       



Target Organ Systemic Toxicity (TOST): Single Exposure & Repeated Exposure
The GHS distinguishes between single and repeat exposure for Target Organ Effects. Some existing systems distinguish between single and repeat exposure for these effects and some do not. All significant health effects, not otherwise specifically included in the GHS, that can impair function, both reversible and irreversible, immediate and/or delayed are included in the non-lethal target organ/systemic toxicity class (TOST). Narcotic effects and respiratory tract irritation are considered to be target organ systemic effects following a single exposure.

Substances and mixtures of the single exposure target organ toxicity hazard class are assigned to one of three hazard categories in Table 3.14.

Table 3.14 TOST : Single Exposure

Category 1

Significant toxicity in humans

- Reliable, good quality human case studies or epidemiological studies
Presumed significant toxicity in humans
- Animal studies with significant and/or severe toxic effects relevant to humans at generally low exposure (guidance)

Category 2

Presumed to be harmful to human health

- Animal studies with significant toxic effects relevant to humans at generally moderate exposure (guidance)
- Human evidence in exceptional cases

Category 3

Transient target organ effects

- Narcotic effects
- Respiratory tract irritation

Substances and mixtures of the repeated exposure target organ toxicity hazard class are assigned to one of two hazard categories in Table 3.15.

Table 3.15 TOST : Repeated Exposure

Category 1

Significant toxicity in humans

- Reliable, good quality human case studies or epidemiological studies
Presumed significant toxicity in humans
- Animal studies with significant and/or severe toxic effects relevant to humans at generally low exposure (guidance)

Category 2

Presumed to be harmful to human health

- Animal studies with significant toxic effects relevant to humans at generally moderate exposure (guidance)
- Human evidence in exceptional cases

In order to help reach a decision about whether a substance should be classified or not, and to what degree it would be classified (Category 1 vs. Category 2), dose/concentration 'guidance values' are provided in the GHS. The guidance values and ranges for single and repeated doses are intended only for guidance purposes. This means that they are to be used as part of the weight of evidence approach, and to assist with decisions about classification. They are not intended as strict demarcation values. The guidance value for repeated dose effects refer to effects seen in a standard 90-day toxicity study conducted in rats. They can be used as a basis to extrapolate equivalent guidance values for toxicity studies of greater or lesser duration.

Aspiration Hazard
Aspiration toxicity includes severe acute effects such as chemical pneumonia, varying degrees of pulmonary injury or death following aspiration. Aspiration is the entry of a liquid or solid directly through the oral or nasal cavity, or indirectly from vomiting, into the trachea and lower respiratory system. Some hydrocarbons (petroleum distillates) and certain chlorinated hydrocarbons have been shown to pose an aspiration hazard in humans. Primary alcohols, and ketones have been shown to pose an aspiration hazard only in animal studies.

Table 3.16 Aspiration Toxicity

Category 1: Known (regarded) human

- human evidence
- hydrocarbons with kinematic viscosity ? 20.5 mm2/s at 40° C.

Category 2: Presumed human

- Based on animal studies
- surface tension, water solubility, boiling point
- kinematic viscosity ? 14 mm2/s at 40°C & not Category 1

Substances and mixtures of this hazard class are assigned to one of two hazard categories this hazard class on the basis of viscosity.

Environmental Hazards

Hazardous to the Aquatic Environment
The harmonized criteria are considered suitable for packaged goods in both supply and use in multi-modal transport schemes. Elements of it may be used for bulk land transport and bulk marine transport under MARPOL (International Convention for the Prevention of Pollution from Ships) insofar as this uses aquatic toxicity. Two Guidance Documents (Annexes 8 and 9 of the GHS Document) cover issues such as data interpretation and the application of the criteria to special substances. Considering the complexity of this endpoint and the breadth of the application, the Guidance Annexes are important in the application of the harmonized criteria.

Acute Aquatic Toxicity
Acute aquatic toxicity means the intrinsic property of a material to cause injury to an aquatic organism in a short-term exposure. Substances and mixtures of this hazard class are assigned to one of three toxicity categories on the basis of acute toxicity data: LC50 (fish) or EC50 (crustacea) or ErC50 (for algae or other aquatic plants). In some regulatory systems these acute toxicity categories may be subdivided or extended for certain sectors.

Chronic Aquatic Toxicity
Chronic aquatic toxicity means the potential or actual properties of a material to cause adverse effects to aquatic organisms during exposures that are determined in relation to the lifecycle of the organism. Substances and mixtures in this hazard class are assigned to one of four toxicity categories on the basis of acute data and environmental fate data: LC50 (fish) or EC50 (crustacea) or ErC50 (for algae or other aquatic plants) and degradation/bioaccumulation.

While experimentally derived test data are preferred, where no experimental data are available, validated Quantitative Structure Activity Relationships (QSARs) for aquatic toxicity and log KOW may be used in the classification process. The log KOW is a surrogate for a measured Bioconcentration Factor (BCF), where such a measured BCF value would always take precedence.

Chronic Category IV is considered a "safety net" classification for use when the available data do not allow classification under the formal criteria, but there are some grounds for concern.

Table 3.17 Acute & Chronic Aquatic Toxicity

Acute Cat. I
Acute toxicity ≤ 1.00 mg/l

Acute Cat. II
Acute toxicity > 1.00 but ≤ 10.0 mg/l

Acute Cat. III
Acute toxicity ≤ 10.0 but < 100 mg/l

Chronic Cat. I
Acute toxicity
≤ 1.00 mg/l and lack of rapid degradability and log Kow ≥ 4 unless BCF < 500

Chronic Cat. II
Acute toxicity
> 1.00 but ≤ 10.0 mg/l and lack of rapid degradability and log Kow ≥ 4 unless BCF < 500 and unless chronic toxicity > 1 mg/l

Chronic Cat. III
Acute toxicity
> 10.0 but ≤ 100.0 mg/l and lack of rapid degradability and log Kow ≥ 4 unless BCF < 500 and unless chronic toxicity > 1 mg/l

Chronic Cat. IV
Acute toxicity
> 100 mg/l and lack of rapid degradability and log Kow ≥ 4 unless BCF < 500 and unless chronic toxicity > 1 mg/l

GHS Model MSDS

What is the GHS Safety Data Sheet (SDS)?
The (Material) Safety Data Sheet (SDS) provides comprehensive information for use in workplace chemical management. Employers and workers use the SDS as sources of information about hazards and to obtain advice on safety precautions. The SDS is product related and, usually, is not able to provide information that is specific for any given workplace where the product may be used. However, the SDS information enables the employer to develop an active program of worker protection measures, including training, which is specific to the individual workplace and to consider any measures that may be necessary to protect the environment. Information in a SDS also provides a source of information for other target audiences such as those involved with the transport of dangerous goods, emergency responders, poison centers, those involved with the professional use of pesticides and consumers.

The SDS should contain 16 headings (Figure 4.14). The GHS MSDS headings, sequence and content are similar to the ISO, EU and ANSI MSDS/SDS requirements, except that the order of sections 2 and 3 have been reversed. The SDS should provide a clear description of the data used to identify the hazards. Figure 4.14 and the GHS Purple Book provide the minimum information that is required in each section of the SDS. Examples of draft GHS SDSs are provided in Appendix B of this guidance document.

The revised Purple Book contains guidance on developing a GHS SDS (Annex 4).  Other resources for SDSs include:

  • ILO Standard under the Recommendation 177 on Safety in the Use of Chemicals at Work,
  • International Standard 11014-1 (1994) of the International Standard Organization (ISO) and ISO Safety Data Sheet for Chemical Products 11014-1: 2003 DRAFT,
  • American National Standards Institute (ANSI) Standard Z400.1,
  • European Union SDS Directive 91/155/-EEC.

Figure 4.14 - Minimum information for an MSDS

1.

Identification of the substance or mixture and of the supplier

  • GHS product identifier.
  • Other means of identification.
  • Recommended use of the chemical and restrictions on use.
  • Supplier's details (including name, address, phone number, etc.).
  • Emergency phone number.

2.

Hazards identification

  • GHS classification of the substance/mixture and any national or regional information.
  • GHS label elements, including precautionary statements. (Hazard symbols may be provided as a graphical reproduction of the symbols in black and white or the name of the symbol, e.g., flame, skull and crossbones.)
  • Other hazards which do not result in classification (e.g., dust explosion hazard) or are not covered by the GHS.

3.

Composition/information on ingredients

Substance

  • Chemical identity.
  • Common name, synonyms, etc.
  • CAS number, EC number, etc.
  • Impurities and stabilizing additives which are themselves classified and which contribute to the classification of the substance.

Mixture

  • The chemical identity and concentration or concentration ranges of all ingredients which are hazardous within the meaning of the GHS and are present above their cutoff levels.

NOTE: For information on ingredients, the competent authority rules for CBI take priority over the rules for product identification.

4.

First aid measures

  • Description of necessary measures, subdivided according to the different routes of exposure, i.e., inhalation, skin and eye contact, and ingestion.
  • Most important symptoms/effects, acute and delayed.
  • Indication of immediate medical attention and special treatment needed, if necessary.

5.

Firefighting measures

  • Suitable (and unsuitable) extinguishing media.
  • Specific hazards arising from the chemical (e.g., nature of any hazardous combustion products).
  • Special protective equipment and precautions for firefighters.

6.

Accidental release measures

  • Personal precautions, protective equipment and emergency procedures.
  • Environmental precautions.
  • Methods and materials for containment and cleaning up.

7.

Handling and storage

  • Precautions for safe handling.
  • Conditions for safe storage, including any incompatibilities.

8.

Exposure controls/personal protection.

  • Control parameters, e.g., occupational exposure limit values or biological limit values.
  • Appropriate engineering controls.
  • Individual protection measures, such as personal protective equipment.

9.

Physical and chemical properties

  • Appearance (physical state, color, etc.).
  • Odor.
  • Odor threshold.
  • pH.
  • melting point/freezing point.
  • initial boiling point and boiling range.
  • flash point.
  • evaporation rate.
  • flammability (solid, gas).
  • upper/lower flammability or explosive limits.
  • vapor pressure.
  • vapor density.
  • relative density.
  • solubility(ies).
  • partition coefficient: n-octanol/water.
  • autoignition temperature.
  • decomposition temperature.

10.

Stability and reactivity

  • Chemical stability.
  • Possibility of hazardous reactions.
  • Conditions to avoid (e.g., static discharge, shock or vibration).
  • Incompatible materials.
  • Hazardous decomposition products.

11.

Toxicological information

Concise but complete and comprehensible description of the various toxicological (health) effects and the available data used to identify those effects, including:

  • information on the likely routes of exposure (inhalation, ingestion, skin and eye contact);
  • Symptoms related to the physical, chemical and toxicological characteristics;
  • Delayed and immediate effects and also chronic effects from short- and long-term exposure;
  • Numerical measures of toxicity (such as acute toxicity estimates).

12.

Ecological information

  • Ecotoxicity (aquatic and terrestrial, where available).
  • Persistence and degradability.
  • Bioaccumulative potential.
  • Mobility in soil.
  • Other adverse effects.

13.

Disposal considerations

  • Description of waste residues and information on their safe handling and methods of disposal, including the disposal of any contaminated packaging.

14.

Transport information

  • UN Number.
  • UN Proper shipping name.
  • Transport Hazard class(es).
  • Packing group, if applicable.
  • Marine pollutant (Yes/No).
  • Special precautions which a user needs to be aware of or needs to comply with in connection with transport or conveyance either within or outside their premises.

15.

Regulatory information

  • Safety, health and environmental regulations specific for the product in question.

16.

Other information including information on preparation and revision of the SDS

 

GHS Labeling Elements

The standardized label elements included in the GHS are:

  • Symbols (hazard pictograms): Convey health, physical and environmental hazard information, assigned to a GHS hazard class and category.
  • Signal Words: "Danger" or "Warning" are used to emphasize hazards and indicate the relative level of severity of the hazard, assigned to a GHS hazard class and category.
  • Hazard Statements: Standard phrases assigned to a hazard class and category that describe the nature of the hazard.

The symbols, signal words, and hazard statements have all been standardized and assigned to specific hazard categories and classes, as appropriate. This approach makes it easier for countries to implement the system and should make it easier for companies to comply with regulations based on the GHS. The prescribed symbols, signal words, and hazard statements can be readily selected from Annex 1 of the GHS Purple Book. These standardized elements are not subject to variation, and should appear on the GHS label as indicated in the GHS for each hazard category/class in the system. The use of symbols, signal words or hazard statements other than those that have been assigned to each of the GHS hazards would be contrary to harmonization.
 

GHS Label Elements, product name, signal word, physical, health, environmental hazard statements, precautionary measures and pictograms, first aid, name address and telephone of manufacturer

Symbols/Pictograms
The GHS symbols have been incorporated into pictograms for use on the GHS label. Pictograms include the harmonized hazard symbols plus other graphic elements, such as borders, background patterns or colors which are intended to convey specific information. For transport, pictograms (Table 4.10) will have the background, symbol and colors currently used in the UN Recommendations on the Transport of Dangerous Goods, Model Regulations. For other sectors, pictograms (Table 4.9) will have a black symbol on a white background with a red diamond frame. A black frame may be used for shipments within one country. Where a transport pictogram appears, the GHS pictogram for the same hazard should not appear.

Signal Words
The signal word indicates the relative degree of severity a hazard. The signal words used in the GHS are

"Danger"  for the more severe hazards, and
"Warning" for the less severe hazards.

Signal words are standardized and assigned to the hazard categories within endpoints. Some lower level hazard categories do not use signal words. Only one signal word corresponding to the class of the most severe hazard should be used on a label.

Hazard Statements
Hazard statements are standardized and assigned phrases that describe the hazard(s) as determined by hazard classification. An appropriate statement for each GHS hazard should be included on the label for products possessing more than one hazard. The assigned label elements are provided in each hazard chapter of the Purple Book as well as in Annexes 1 & 2. Figure 4-11 illustrates the assignment of standardized GHS label elements for the acute oral toxicity categories.
 

Other GHS label elements include:

  • Precautionary Statements and Pictograms: Measures to minimize or prevent adverse effects.
  • Product Identifier (ingredient disclosure): Name or number used for a hazardous product on a label or in the SDS.
  • Supplier identification: The name, address and telephone number should be provided on the label.
  • Supplemental information: non-harmonized information.

Precautionary Statements and Pictograms
Precautionary information supplements the hazard information by briefly providing measures to be taken to minimize or prevent adverse effects from physical, health or environmental hazards. First aid is included in precautionary information. The GHS label should include appropriate precautionary information. Figure 4.9-4.11 includes precautionary statements and pictograms that can be used on labels.


Figure 4.9

GHS Pictograms and Hazard Classes

  • Oxidizers
  • Flammables
  • Self Reactives
  • Pyrophorics
  • Self-Heating
  • Emits Flammable Gas
  • Organic Peroxides
  • Explosives
  • Self Reactives
  • Organic Peroxides

  • Acute toxicity (severe)
  • Corrosives
  • Gases Under Pressure

  • Carcinogen
  • Respiratory Sensitizer
  • Reproductive Toxicity
  • Target Organ Toxicity
  • Mutagenicity
  • Aspiration Toxicity
  • Environmental Toxicity
  • Irritant
  • Dermal Sensitizer
  • Acute toxicity (harmful)
  • Narcotic Effects
  • Respiratory Tract
  • Irritation

Figure 4.10

Transport "Pictograms"

Flammable Liquid Flammable Gas Flammable Aerosol

Flammable solid Self-Reactive Substances

Pyrophorics (Spontaneously Combustible) Self-Heating Substances

Substances, which in contact with water, emit flammable gases (Dangerous When Wet)

Oxidizing Gases Oxidizing Liquids Oxidizing Solids

Explosive Divisions 1.1, 1.2, 1.3

Explosive Division 1.4

Explosive Division 1.5

Explosive Division 1.6

Compressed Gases

Acute Toxicity (Poison): Oral, Dermal, Inhalation

Corrosive

 

Marine Pollutant Organic Peroxides  

Figure 4.11

ACUTE ORAL TOXICITY - Annex 1

 

Category 1

Category 2

Category 3

Category 4

Category 5

LD50

£ 5 mg/kg

> 5 < 50 mg/kg

³ 50 < 300 mg/kg

³ 300 < 2000 mg/kg

³ 2000 < 5000 mg/kg

Pictogram

 

No symbol

Signal word

Danger

Danger

Danger

Warning

Warning

Hazard statement

Fatal if swallowed

Fatal if swallowed

Toxic if swallowed

Harmful if swallowed

May be harmful if swallowed



Product Identifier (Ingredient Disclosure)
A product identifier should be used on a GHS label and it should match the product identifier used on the SDS. Where a substance or mixture is covered by the UN Model Regulations on the Transport of Dangerous Goods, the UN proper shipping name should also be used on the package.

The GHS label for a substance should include the chemical identity of the substance (name as determined by IUPAC, ISO, CAS or technical name). For mixtures/alloys, the label should include the chemical identities of all ingredients that contribute to acute toxicity, skin corrosion or serious eye damage, germ cell mutagenicity, carcinogenicity, reproductive toxicity, skin or respiratory sensitization, or Target Organ Systemic Toxicity (TOST), when these hazards appear on the label. Where a product is supplied exclusively for workplace use, the Competent Authority may give suppliers discretion to include chemical identities on the SDS, in lieu of including them on labels. The Competent Authority rules for confidential business information (CBI) take priority over the rules for product identification.

Supplier Identification
The name, address and telephone number of the manufacturer or supplier of the product should be provided on the label.

Supplemental Information
Supplemental label information is non-harmonized information on the container of a hazardous product that is not required or specified under the GHS. In some cases this information may be required by a Competent Authority or it may be additional information provided at the discretion of the manufacturer/distributor. The GHS provides guidance to ensure that supplemental information does not lead to wide variation in information or undermine the GHS information. Supplemental information may be used to provide further detail that does not contradict or cast doubt on the validity of the standardized hazard information. It also may be used to provide information about hazards not yet incorporated into the GHS. The labeler should have the option of providing supplementary information related to the hazard, such as physical state or route of exposure, with the hazard statement.

How are multiple hazards handled on labels?
Where a substance or mixture presents more than one GHS hazard, there is a GHS precedence scheme for pictograms and signal words. For substances and mixtures covered by the UN Recommendations on the Transport of Dangerous Goods, Model Regulations, the precedence of symbols for physical hazards should follow the rules of the UN Model Regulations. For health hazards the following principles of precedence apply for symbols:

(a) if the skull and crossbones applies, the exclamation mark should not appear;
(b) if the corrosive symbol applies, the exclamation mark should not appear where it is used for skin or eye irritation;
(c) if the health hazard symbol appears for respiratory sensitization, the exclamation mark should not appear where it is used for skin sensitization or for skin or eye irritation.

If the signal word 'Danger' applies, the signal word 'Warning' should not appear. All assigned hazard statements should appear on the label. The Competent Authority may choose to specify the order in which they appear.

Is there a specific GHS label format / layout?
The GHS hazard pictograms, signal word and hazard statements should be located together on the label. The actual label format or layout is not specified in the GHS. National authorities may choose to specify where information should appear on the label or allow supplier discretion.

Figure 4.12 shows an example of a GHS label for the fictional product 'ToxiFlam'. The core GHS label elements are expected to replace the need for the array of different labels shown earlier for ToxiFlam. 

Figure 4.12  Example GHS Inner Container Label (e.g., bottle inside a shipping box) Toxiflam (Contains: XYZ)

flammable

   
Danger! Toxic If Swallowed, Flammable Liquid and Vapor



acute toxic

Do not eat, drink or use tobacco when using this product. Wash hands thoroughly after handling. Keep container tightly closed. Keep away from heat/sparks/open flame. - No smoking. Wear protective gloves and eye/face protection. Ground container and receiving equipment. Use explosion-proof electrical equipment. Take precautionary measures against static discharge.
Use only non-sparking tools. Store in cool/well-ventilated place.


IF SWALLOWED: Immediately call a POISON CONTROL CENTER or doctor/physician. Rinse mouth.
In case of fire, use water fog, dry chemical, CO2, or "alcohol" foam.

See Material Safety Data Sheet for further details regarding safe use of this product.
MyCompany, MyStreet, MyTown NJ 00000, Tel: 444 999 9999

There has been discussion about the size of GHS pictograms and that a GHS pictogram might be confused with a transport pictogram or "diamond". Transport pictograms (Table 4.10) are different in appearance than the GHS pictograms (Table 4.9). Generally the GHS pictograms would be smaller than the transport pictograms.

Figure 4.13 Combination packaging (Outer box with inner bottles)

combopack

Figure 4.13 shows an arrangement for a combination packaging with an outer shipping box and inner bottles. The shipping box has a transportation pictogram. The inner bottles have a GHS label with a GHS pictogram.

Figure 4.14 Single packaging (GHS label and required transport regulations pictograms.)

combopackdrum

For a container such as a 55 gallon drum, the transport required markings and pictograms may be combined with the GHS label elements or presented separately. In Figure 4.14 a label arrangement for a single packaging such as a 55 gallon drum is shown. Pictograms and markings required by the transport regulations as well as GHS label and non-duplicative GHS pictogram are shown on the drum.

A label merging the transportation requirements and the GHS requirements into one label for the fictional product "ToxiFlam" is shown in Figure 4.15. This combined type label could also be used on a 55 gallon drum.

Figure 4.15 Example GHS Outer Container Label (55gallon/200 liter drum)

ToxiFlam 

Flammable liquids, toxic, n.o.s.




Danger! Toxic If Swallowed
 Flammable Liquid and Vapor

(contains XYZ)
UN 1992

Do not eat, drink or use tobacco when using this product. Wash hands thoroughly after handling. Keep container tightly closed. Keep away from heat/sparks/open flame. - No smoking. Wear protective gloves and eye/face protection. Ground container and receiving equipment. Use explosion-proof electrical equipment. Take precautionary measures against static discharge. Use only non-sparking tools. Store in cool/well-ventilated place

IF SWALLOWED: Immediately call a POISON CONTROL CENTER or doctor/physician. Rinse mouth.

In case of fire, use water fog, dry chemical, CO2, or "alcohol" foam.

See Material Safety Data Sheet for further details regarding safe use of this product.


MyCompany, MyStreet, MyTown NJ 00000, Tel: 444 999 9999