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Lab Safety Manual: Working with Hazardous Materials

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rev 11/2012

This section describes precautions that should be taken when conducting procedures involving chemically hazardous materials, including:

The faculty is responsible for the use of hazardous materials and must inform everyone involved in working with such materials of the associated hazards, and the appropriate emergency response measures to be taken. In addition, all participants should:

  • know the toxicity of the materials (e.g. by reviewing the MSDS for the material)
  • follow the recommended precautions 
  • use the appropriate safety and personal protective equipment to minimize all routes of potential exposure (e.g., inhalation, dermal contact, and ingestion)
  • identify and label all materials and work areas where hazardous materials are used
  • clean up immediately, appropriately decontaminating for the materials being used
  • be aware of necessary safety precautions and specific actions to be taken in the event of an emergency

Written Protocols and Notifications

Prior to purchasing or using any amount of an acute toxin (Section 5.6) or perchloric acid (Section 5.2.3), a written protocol is required. The safety committee may also request protocols for the use of other hazardous materials. Written protocols must be submitted to the chair of the safety committee at least three weeks prior to the anticipated purchase date (or use date for materials already at CSC) for approval by the safety committee, and include the following information.

  • faculty name
  • chemical name, CAS number, and hazard information
  • anticipated date of purchase and use
  • location of storage and use
  • quantity to be stored and used in each experiment
  • names of all users and description of user training
  • experimental procedure
  • emergency procedures (include fire, spill, and personal contamination)
  • waste disposal procedures
  • protective equipment to be used

The protocol must be reviewed with each user and a record of training submitted to the lab manager. The experiment cannot be conducted until approval is obtained from the safety committee. 

Prior to purchasing or using any amount of a select carcinogen (Section 5.8) or reproductive toxin (Section 5.7), a written notification is required, including the following information:

  • faculty name
  • chemical name, CAS number, and hazard information
  • anticipated date of purchase and use
  • location of storage and use

Each user must be informed of the hazard(s) of the chemicals and proper experimental and emergency procedures. Notification should be submitted to the laboratory manager at least one week prior to anticipated use. The lab manager may approve, request additional information, or refer to the safety committee needs for review. The safety committee may request a written protocol for use of the chemical. The experiment may proceed unless additional information is requested by the lab manager, or a protocol is requested by the safety committee.

5.1 FLAMMABLE CHEMICALS

In order for a flammable chemical fire to occur, three conditions must be met:

  • a flammable gas or vapor must be at a concentration between the lower and upper flammable limits
  • an oxidizing agent (e.g., the air in the room or a chemical oxidizer) must be available
  • there must be a source of ignition or the material is at its auto-ignition temperature

5.1.1 Definitions

Safe use and storage of flammable chemicals, and the evaluation of fire hazard, requires understanding the following important definitions. Information on the physical characteristics of flammable chemicals is listed on manufacturer's container labels and on the Material Safety Data Sheet.

  1. Auto-ignition Temperature: The minimum temperature that will initiate a self-sustained combustion of liquid, gas or solid in the absence of a spark or flame; the lower the auto-ignition temperature, the greater the fire hazard.
  2. Boiling Point: The temperature at which the vapor of the liquid is in equilibrium with atmospheric pressure; the lower the boiling point, the greater the fire hazard.
  3. Flammable or Explosion Limits: The minimum (lower) or maximum (upper) concentration of a gas or vapor in air, by volume percent, in which a fire or explosion can occur upon ignition in a confined area; the wider the range of the explosion limits and the lower the lower limit, the greater the fire/explosion hazard.
  4. Flammable Gas: Gases that form a flammable mixture in air at less than or equal to 13% by volume; or the flammable range (explosive range) in air is wider than 12 percent regardless of the lower limit (U.S. Department of Transportation definition).
  5. Flammable or Combustible Liquids are divided into several classes based on the degree of fire hazard as described in Table 5-1.

    Table 5-1 - CLASSES OF FLAMMABLE AND COMBUSTIBLE LIQUIDS
    CLASS 
    BOILING POINT
    oC(oF)
    FLASH POINT
    oC(oF)
    EXAMPLES 
    1A Flammable Liquid
    <37.8(100)
    <22.8(73)
    ethyl ether, pentane
    1B Flammable Liquid
    >37.8(100)
    <22.8(73)
    acetone, ethyl alcohol
    1C Flammable Liquid
    -
    >22.8(73) and
    <37.8(100)
    butanol, isoamyl acetate
    2 Combustible Liquid
    -
    >37.8(100) and
    <60(140)
    formalin, cyclohexanone
    3A Combustible Liquid
    -
    >60(140) and
    <93.3(200)
    phenol, dichlorobenzene
    3B Combustible Liquid
    -
    >93.3(200)
    ethylene glycol, mineral oil
    Source: National Fire Protection Association, 2003. Flammable and Combustible Liquids Code, NFPA 30.

  6. Flammable Solid: A nonexplosive material that is capable of producing fire as a result of: friction; water exposure; air exposure; heat retained from synthesis or processing; or, when ignited, burns so vigorously and persistently so as to create a hazard.
  7. Flash Point: The minimum temperature at which a liquid gives off vapor in sufficient concentration to form an ignitable mixture with air near the surface of the liquid: also applies to certain solids that evaporate or volatilize; the lower the flashpoint the greater the fire hazard.
  8. Vapor Density: The weight of a volume of pure vapor or gas compared to the weight of an equal volume of dry air at the same temperature and pressure; vapor densities greater than one indicate the vapor or gas is heavier than air.

5.1.2 Storage and Dispensing 

The quantity of flammable chemicals, liquids, solids, and gases stored in laboratories should be kept at an absolute minimum. Flammable chemicals should only be ordered in quantities that can be used in the course of a semester.

For those flammables that must be stored in the laboratory, the preferred storage methods are in flammable storage cabinets meeting NFPA standards for liquids or solvents or in UL- or FM-approved flammable safety cans. Total volume stored in a flammable storage cabinet should not exceed the rated capacity of the cabinet. Flammable chemicals should not be stored outside of the flammable cabinets without the express permission of the lab manager.

If refrigeration is required, the refrigerator or freezer must meet NFPA Standards for flammable storage. Flammable materials refrigerators and freezers have spark-free interiors. All units designed for flammable storage are clearly marked as "approved for flammable storage." All units not approved are clearly marked "not for flammable storage" or other similar wording.

5.1.3 Laboratory Use

All laboratory procedures using flammable chemicals should:

  • minimize the release of flammable vapors
  • prevent the travel or accumulation of vapors
  • eliminate sources of ignition
  • minimize the amount of flammable chemical or other combustible materials (e.g., paper) in the vicinity of the handling area

The following precautions should always be followed when working with flammable chemicals. These precautions do not apply to the use of natural gas as a fuel for combustion. Additional precautions may be necessary in certain situations.

  • Use fume hoods whenever possible, particularly when transferring or heating flammable liquids.
  • Always use flammable gases in a fume hood.
  • Never use open flames in the same area where flammables are being used, unless it is part of an experimental procedure approved by the faculty member.
  • Control other sources of ignition and heat in the laboratory such as electric motors and ovens in areas where flammable vapors are expected to exceed 10% of the lower flammability limit (refer to MSDS or other current references).
  • Use only electrical equipment (e.g., heating and stir plates) that is labeled as explosion proof (a.k.a. intrinsically safe).
  • When transferring flammable liquids from a metal container, ground the metal container.
  • Minimize the generation of dust when handling flammable solids.
  • Make sure you have the proper extinguishing media in the vicinity of the operation (e.g., Class D powder for combustible metals).
  • Never leave solvent distillation processes unattended.

The lab manager and safety committee will assist in evaluating the hazards of particular operations or experiments upon request.
 
5.2 CORROSIVE CHEMICALS

Corrosives are one of the most commonly encountered hazards in the laboratory. The major classes of corrosive chemicals are:

  • strong acids and bases
  • dehydrating agents
  • oxidizing agents

Some chemicals, such as sulfuric acid, belong to more than one class. Corrosives are chemicals that can cause visible destruction of or irreversible alteration in living tissue, as well as destruction of other materials. In addition, many corrosives have other hazards such as reactivity (e.g., perchloric acid), flammability (e.g., organic acids), and toxicity (e.g., phenol).

The strength of acids and bases is defined as the degree of ionization of the acid or base in water. Inorganic, or mineral, acids (e.g., hydrochloric acid, a strong acid) generally ionize more than organic acids (e.g., acetic acid, a weak acid). Similarly, sodium hydroxide is highly ionized and classified as a strong base, whereas ammonium hydroxide is slightly ionized and characterized as a weak base.

The concentration of the acid or base, which is unrelated to its strength, refers to the percentage of the chemical dissolved in water. The corrosivity of acids and bases is dependent on their strength and concentration.

Dehydrating agents, such as sulfuric acid, sodium hydroxide, calcium oxide, and glacial acetic acid are corrosive because of their strong affinity for water. This reaction with water is extremely exothermic. Because of this exothermic reaction with water, concentrated acids should always be added slowly to water. If water is added to the concentrated acid, the rapid generation of heat can cause the water to vaporize, causing the hot concentrated acid solution to splash.

5.2.1 Hazards of Selected Corrosives

Corrosives, in their solid, liquid, and vapor state, can cause acute and chronic damage to human tissue. Acute hazards can be manifested as burns, ulceration, permanent tissue damage, or toxic effects. Acid burns are generally perceived as more painful than base burns, which is due to the formation of a protective protein layer that resists further penetration of the acid. In fact, tissue damage from bases is often more serious, as no protective layer is formed and the injury penetrates deeper. Many corrosives also have chronic hazards, repeated exposure to even dilute solutions or vapors can cause dermatitis, bronchitis, or eye damage. The destructive effect of corrosives is greatly increased when they are used at elevated temperatures.

Some corrosives also pose physical hazards. For example, when in contact with metal, many inorganic acids release hydrogen gas (flammable), posing a serious fire and explosion hazard.

The following are examples of some of the hazards of commonly used corrosives. The list is by no means exhaustive. The hazards of each corrosive should be thoroughly investigated prior to use.

  • Sulfuric acid is a strong acid, a dehydrating agent, and an oxidizing agent. As a dehydrating agent, it is highly water-reactive, generating tremendous amounts of heat on contact with water. It is very destructive to tissue and metals, and releases hydrogen gas (flammable) on contact with active metals (e.g., Na, Mg, Ca, Rb, K, Al, Mn, Zn, Fe, Ni). Fuming sulfuric acid is even more hazardous and produces extremely hazardous vapors.
  • Nitric acid is a strong acid and powerful oxidizing agent. Nitric acid is extremely corrosive and can release toxic vapors (hydrogen and nitrogen oxides) on contact with most metals. Nitrogen oxides can cause delayed respiratory distress, pulmonary edema (fluid in the lungs), and death. Fuming nitric acid is more dangerous than regular nitric acid, again due to the presence of nitrogen oxides. Fuming nitric acid is listed as an acute toxin in Section 5.6.
  • The halogen acids include hydrofluoric (HF), hydrochloric (HCl), hydrobromic (HBr), and hydriotic acid (HI). The corresponding acid gases--hydrogen fluoride, hydrogen chloride, hydrogen bromide, and hydrogen iodide--are very soluble in water; upon exposure to moisture on the body, formation of the acid occurs. All are strong acids and release hydrogen on contact with active metals.
  • Hydrofluoric acid is extremely corrosive and attacks glass as well as metal. It is extremely dangerous in all concentrations. It causes severe slow-healing burns to tissue that may not be noticed for several hours. It can also cause severe and permanent damage to the respiratory system, including fatal pulmonary edema, and blindness. In addition to these corrosive effects, it can cause delayed systemic poisoning including depletion of tissue calcium and magnesium. It is listed as an Acute Toxin in Section 5.6, and special handling instructions are included in Section 5.2.4.
  • Perchloric acid is a strong acid and at temperatures above 160oC a strong oxidizing and dehydrating agent. It may decompose explosively when heated; and if distilled, dried, or reacted with dehydrating agents or any oxidizable materials, the mixture may spontaneously explode. It forms flammable hydrogen gas on contact with many metals; and forms explosive metal perchlorates on contact with certain metals. Perchloric acid is especially hazardous at concentrations above 70%. Special handling instructions, including required safety committee protocol approval, are listed later in Section 5.2.3.
  • Acetic acid is a severe irritant to the skin and eyes. Severe irritation can occur at 25 ppm, but eye damage can occur at lower concentrations. Glacial (100%) acetic acid causes severe eye and tissue damage, is a dehydrating agent, reacts violently with oxidizing agents, and has a flash point of 110oF.
  • Phenol is a crystalline solid that adsorbs moisture from the air. In addition to being corrosive, it is highly toxic and readily absorbed through the skin as a liquid or vapor.
  • Sodium and potassium hydroxides are strong corrosives and often referred to as caustics, a term referring to hydroxides. They are both solids that readily absorb water, and can absorb enough water from the skin to cause severe injury if not washed off immediately. They are both dehydrating agents. They cause severe and permanent eye damage. At low concentrations, the sensation of irritation may not occur for several hours, and can result in severe ulceration. They are even more hazardous in heated solutions.

5.2.2 Laboratory Use of Corrosives

  1. Always investigate the additional hazards such as flammability and reactivity before using.
  2. Purchase only the amount needed; small quantities are recommended for easier handling and storage.
  3. Bottle carriers or some other means of containment should be used when moving chemicals between floors.
  4. Store separately from incompatible materials.
  5. Wear appropriate protective equipment, as described in Section 4.5.
  6. Always add chemicals slowly and always add concentrated acid to water.
  7. Keep ignition sources away from inorganic acid spills (that may produce flammable hydrogen gas on contact with metals), and from glacial acetic acid, which as an organic acid is a combustible material.
  8. When neutralizing corrosives, never add a concentrated acid to base or a concentrated base to acid.

5.2.3 Special Precautions for Perchloric Acid

  1. Use of perchloric acid requires a written protocol approved by the CSC safety committee.
  2. The number of people using the acid should be limited to the extent possible, and all users should be familiar with the chemistry of the acid, its hazards, proper handling procedures, and emergency procedures.
  3. Heating of perchloric acid is prohibited.
  4. Perchloric acid should never be used in areas where the material would be absorbed if spilled.
  5. Perchloric acid should be purchased on an as-needed basis in small containers and must be stored separately from incompatible materials.
  6. Prior to performing experiments using perchloric acid, disposal procedures should be defined.
  7. Spilled solutions must not be allowed to dry. They should be neutralized and then soaked up with rags or paper towels. The area should then be rinsed with a large quantity of water. The wet rags or paper towels should be placed in a container, and the container filled with water and tightly closed. The container should be disposed of as hazardous waste.
  8. Refer to Furr, A.K. (ed.), 2000 CRC Handbook of Laboratory Safety, 5th Edition, and Schilt, A.A., 1979, Perchloric Acid and Perchlorates, for additional precautions.

5.2.4 Special Precautions for Hydrofluoric Acid

  1. Hydrofluoric acid is an acute toxin. A written protocol approved by the safety committee is required.
  2. The number of people using the acid should be limited to the extent possible, and all users should be familiar with the chemistry of the acid, its hazards, proper handling procedures, and emergency procedures.
  3. When possible, the acid should be purchased at the concentration to be used to avoid preparation of solutions.
  4. Hydrofluoric acid should be purchased on an as-needed basis in small containers.
  5. Always use in a functioning fume hood with the sash as low as possible and no higher than 15 inches.
  6. Keep ignition sources away from the area.
  7. Wear chemical splash goggles, a face shield providing face and neck protection, neoprene or polyvinyl chloride gloves, non-absorbent resistant clothing, and a rubber or neoprene apron.
  8. Dispose of protective clothing if contaminated per directions from lab manager.
  9. Wash hands thoroughly after each use.
  10. Use only resistant equipment (e.g., polyethylene, teflon).
  11. Emergency procedures in Appendix 5-A must be posted in all use areas. Calcium gluconate must be available in all use areas.
  12. Prior to performing experiments using hydrofluoric acid, disposal procedures should be defined.
  13. Spills should be neutralized with lime acid neutralizer or an appropriate equivalent, and the resulting solution collected for disposal as hazardous waste.

5.3 REACTIVE CHEMICALS

Reactive chemicals are chemicals that can, under certain conditions, release very large and potentially dangerous amounts of energy. This section deals with the physical hazards of reactive chemicals. Reactive chemicals may also have health hazards that must also be considered. Reactive chemicals can lead to reactions that differ from the routine mainly in the rate at which they progress. A chemical reaction can be considered routine if the reaction rate is relatively slow or can be easily controlled. It is the rate of reaction and ability to control it that marks certain chemicals as warranting special precautions and the label "reactive chemical".

There are a variety of conditions under which certain chemicals undergo an uncontrollable hazardous reaction. Some chemicals are unstable and can vigorously polymerize, decompose, condense, or become self-reactive. Other chemicals can react violently when exposed to common environmental chemicals or conditions, such as water or air. Many chemicals are stable except when combined with certain other chemicals. These hazardous combinations are listed in the table "Classes of Incompatible Chemicals” in Section 6.3.1.

There are some additional hazardous conditions that are not usually attributed to "reactive chemicals" but should be mentioned. Extreme differences in physical properties can cause an uncontrollable release of energy. For example, bringing a hot liquid such as oil into contact with a liquid with a lower boiling point such as water will cause instantaneous vaporization of the lower boiling point liquid and a violent release of energy. 

The following discussion highlights the most common groups of reactives and includes examples of chemicals in each group.

5.3.1 Examples of Reactive Chemicals

The following list of examples is compiled from several general references. Manufacturer's Material Safety Data Sheets or the references cited should be consulted to determine the specific reactive characteristics of a particular chemical.

1. OXIDIZERS

Oxidizers are chemicals that can readily provide reactive oxygen readily under certain conditions. When in contact with organic materials, (e.g., wood. paper, organic chemicals), or other easily oxidizable chemicals, (e.g., metal powders), oxidizers can form unstable and explosive compounds sensitive to shock. Examples of oxidizers include:

  • bromine and compounds
  • chlorine and compounds
  • chromium and dichromates
  • chromium trioxide
  • chromic acid
  • fluorine
  • iodine and compounds
  • manganese dioxide
  • nitrates
  • nitric acid
  • nitrites
  • nitrogen trioxide
  • permanganates
  • peroxides
  • persulfates
  • phosphomolybdic acid
  • picrates
  • sodium bismuthate
  • sulfuric acid

2. WATER EXPOSURE SENSITIVE

Water reactive chemicals can develop pressure, generate flammable, explosive, corrosive or toxic gases, or ignite or explode when exposed to water or moisture. Examples of water exposure sensitive chemicals include:

  • alkali and alkaline-earth metals (sodium, lithium, calcium, potassium, magnesium)
  • aluminum chloride
  • anhydrous metal halides (aluminum tribromide, germanium tetrachloride)
  • anhydrous metal oxides (calcium oxide)
  • benzoyl chloride
  • calcium carbide 
  • calcium oxide 
  • nonmetal halides (boron tribromide, phosphorous pentachloride)
  • nonmetal halide oxides (inorganic acid halides, phosphoryl chloride, sulfuryl chloride, chlorosulfonic acid)
  • nonmetal oxides (acid anhydrides, trioxides)

3. AIR EXPOSURE SENSITIVE

Air exposure-sensitive chemicals can develop pressure, generate flammable or explosive gases, ignite, or explode when exposed to air. Examples of air exposure sensitive chemicals include:

  • alkyl metal derivatives (ethoxydiethylaluminum and dimethylbismuth chloride)
  • analogous derivatives of nonmetals including diborane, dimethylphosphine, triethylarsine,
  • dichloro(methyl)silane
  • carbonyl metals (pentacarbonyliron and octacarbonyldicobalt)
  • finely divided metals (calcium, titanium)
  • metal hydrides (potassium hydride and germane)
  • partially or fully alkylated metal hydrides (diethylaluminum hydride, triethylbismuth)
  • sodium methoxide  
  • sec-butyl lithium 
  • triethylaluminum
  • white phosphorus 

4. TEMPERATURE SENSITIVE

Temperature sensitive chemicals may decompose when held above their maximum safe storage temperature, resulting in pressure buildup, flammable or explosive gas generation, ignition, or explosion. Examples of temperature sensitive chemicals include:

  • Certain oxidizers (perchlorates, chlorates, nitrates, bromates, chlorites, iodates)
  • Certain Azo compounds
  • Lithium nitrate
  • Organic peroxides
  • Phenylhydrazine hydrochloride

5. SPONTANEOUS DECOMPOSITION
 
Spontaneous Decomposition: Chemicals that change structure over time and with no apparent stimulation can develop pressure, generate flammable or explosive gases, ignite, or explode. Examples of chemicals that spontaneously decompose include:

  • benzoyl peroxide (dry)
  • nitroglycerine
  • contaminated concentrated  hydrogen peroxide

6. SHOCK, FRICTION, AND STATIC DISCHARGE SENSITIVE

Shock, friction, and static discharge sensitive chemicals can violently decompose when initiated by shock, friction, or static discharge. Examples of these chemicals include:

  • acetylides
  • azides
  • contaminated oxidizers
  • diazo compounds
  • explosives
  • fulminates
  • halamine
  • nitro compounds
  • nitroso compounds
  • organic nitrates
  • organic and inorganic peroxides
  • ozonide
  • picric acid (trinitrophenol)

7. PEROXIDES

Many common laboratory compounds can form peroxides when exposed to air over a period of time. A single opening of a container to remove some of the contents can introduce enough air for peroxide formation to occur. Peroxides are sensitive to heat, friction, impact, and light, and are among the most hazardous chemicals that are routinely encountered in laboratories. Their hazard potential is even greater because they may not be suspected or detected in commonly used solvents or reagents. Many explosions have occurred during distillation of peroxide-containing substances particularly when the distillation has been taken to or near to dryness.

Crystal formation or cloudy appearance inside a container is a possible sign of peroxide formation. Crystal formation is most likely (and most hazardous) around the cap. Friction caused just by turning the cap can cause an explosion that ignites flammable solvent in the container. 

Peroxide formation can also occur in many polymerizable, unsaturated compounds. These peroxides can initiate a runaway, and sometimes explosive, polymerization reaction. 

Structural groups of chemicals that can form peroxides, listed in approximate order of decreasing hazard, include:

  • Organic Structures:
    • ethers and acetals with alpha hydrogen atoms
    • olefins with allylic hydrogen atoms
    • chloroolefins and fluoroolefins
    • vinyl halides, esters, and ethers
    • dienes
    • vinylacetylenes with alpha hydrogen atoms
    • alkylacetylenes with alpha hydrogen atoms
    • alkylarenes that contain tertiary hydrogen atoms
    • alkanes and cycloalkanes that contain tertiary hydrogen atoms
    • acrylates and methacrylates
    • secondary alcohols
    • ketones that contain alpha hydrogen atoms
    • aldehydes
    • ureas, amides, and lactams that have a hydrogen atom on a carbon atom attached to nitrogen

 

  • Inorganic Substances:
    • alkali metals, especially potassium, rubidium, and cesium
    • metal amides
    • organometallic compounds with a metal atom bonded to carbon
    • metal alkoxides

 

5.3.2 General Safety Procedures for Working with Reactive Chemicals

  1. Find out as much as possible about the reagents and procedures before the experiment.
  2. Investigate the purity of the reactive chemical. Determine whether impurities or spontaneous decomposition products (such as peroxides) will make the experiment more hazardous. 
  3. Conduct small-scale preliminary experiments to assess the thermodynamic and physical properties of the reaction.
  4. Use as little of the reactive chemical or as dilute a solution as possible.
  5. Consider all methods of controlling reaction variables. The rate of addition can be controlled as well as the rate at which the energy of activation is supplied. Cool exothermic reactions adequately to control the reaction rate. Remember to provide cooling arrangements for both liquid and vapor stages if appropriate. Pressure relief valves should be include in pressurized systems and checked before adding chemicals to the system.
  6. Determine the proper degree of agitation and mixing rate. Add oxidants slowly with appropriate cooling or mixing.
  7. Use a face shield in addition to goggles when appropriate.
  8. Work in a fume hood using the sash as a protective shield.
  9. Have emergency equipment in the immediate area. 
  10. Notify people in the laboratory of any new or unique hazards that could potentially be created by use of a reactive chemical. 

5.3.3 Special Procedures for Peroxide Forming Chemicals

It is important that information on the age of peroxide forming chemicals be maintained and that these chemicals are tested or disposed of on a regular basis.

5.3.3.1 Labeling Peroxide Formers

All peroxidizable compounds should be labeled with preprinted labels that read:

PEROXIDIZABLE COMPOUND
May Become Explosive With Time or Exposure to Air or Light
Date Opened:                     Discard Date:

The date and discard period should be filled in the first time the container is opened, along with test dates and associated results. 

5.3.3.2 Testing Peroxide Formers

The level of peroxides can be tested using peroxide test strips. Peroxidizable compounds must be tested for safety every 6 months and the bottled dated with the most recent test date. Do not use these materials if more than six months have passed since the most recent date indicated on the bottle. The lab manager should be made aware of any peroxide forming substances in Cole Science Center.

Table 5-2 lists recommendations for testing or disposal of potential peroxide forming chemicals.

Table 5-2  POTENTIAL PEROXIDE-FORMING CHEMICALS
A: Chemicals posing severe peroxide hazard on storage after exposure to air.
DISCARD WITHIN 3 MONTHS
diisopropyl ether (isopropyl ether) [108-20-3]
divinylacetylene (DVA)*
potassium metal [7440-09-7]
potassium amide
sodium amide (sodamide) [7782-92-5]
vinylidene chloride (1,1-dichloroethylene)* [75-35-4]
 
B: Chemicals posing peroxide hazard on concentration; do not distill or evaporate without first testing for the presence of peroxides.
DISCARD OR TEST FOR PEROXIDES AFTER 6 MONTHS
acetaldehyde diethyl acetal (acetal) [75-07-0] 
cumene (isopropylbenzene) [98-82-8] 
cyclohexene [110-83-8] 
cyclopentene [142-29-0] 
decalin (decahydronaphthalene) [91-17-8] 
diacetylene [106-99-0] 
dicyclopentadiene [77-73-6] 
diethyl ether (ether, ethyl ether) [60-29-7] 
diethylene glycol dimethyl ether (diglyme) [11-96-6] 
dioxane [123-91-1] 
ethylene glycol dimethyl ether (glyme) [110-71-4] 
ethylene glycol ether acetates 
ethylene glycol monoether (cellosolves) 
furan [110-00-9] 
methylacetylene [74-99-7] 
methylcyclopentane [96-37-7] 
methyl isobutyl ketone [108-10-1] 
tetrahydrofuran (THF) [109-99-9] 
tetralin (tetrahydronaphthalene) [119-64-2] 
vinyl ethers 
 
C: Chemicals posing a hazard of rapid polymerization initiated by internally formed peroxides.
Normal Liquids DISCARD OR TEST FOR PEROXIDES AFTER 6 MONTHS  
chloroprene (2-chloro-1,3-butadiene)+ [126-99-8]
styrene [100-42-5]
vinyl acetate [108-05-4]
vinylpyridine
Normal Gases DISCARD AFTER 12 MONTHS 
butadiene+ [106-14-3]
tetrafluoroethylene (TFE) [116-14-3]
vinylacetylene (MVA)+
vinyl chloride [75-10-4]
*Polymerizable monomers should be stored with a polymerization inhibitor from which the monomer can be separated by distillation just
before use. 

**Although common acrylic monomers such as acrylonitrile, acrylic acid, ethyl acrylate, and methyl methacrylate can form peroxides, they have not been reported to develop hazardous levels in normal use and storage.

+The hazard from peroxides in these compounds is substantially greater when they are stored in the liquid phase, and if stored without an inhibitor they should be considered as in group A.


5.4 COMPRESSED GASES

Compressed gas cylinders are defined by the U. S. Department of Transportation (DOT) as any materials or mixtures in containers having an absolute pressure in excess of 40 psi at 20oC (70oF) or in excess of 104 psi at 54.5oC (130oF). 

Compressed gas cylinders should be considered high-energy sources regardless of the type of gas and all should be treated as potential explosives. Compressed gases have many properties that make them a unique hazard, such as their pressure, diffusivity, low flash points for flammable gases, low boiling points, and, for some, no visual and/or odor warnings. 

5.4.1 Cylinder Purchase, Labeling, and Storage

Purchase

Gas cylinders and lecture bottles should be ordered through the lab manager. Lecture bottles (small cylinders of compressed gases or liquids) are leased in returnable cylinders whenever possible. 

Labeling

Gas cylinders as received from the manufacturer are labeled with the product name, Department of Transportation hazard class, date of the last hydrostatic test, and identity of the manufacturer. If cylinders do not contain this information they should not be accepted. Cylinders should be inspected periodically to ensure that the product name is still legible.

Storage Area

  1. Cylinders must be stored in designated storage areas away from ignition sources, corrosives, electrical supply sources and heat. 
  2. Store oxidizers away from flammable gases. Oxygen and fuel gases must be separated by a distance of at least 25 feet or by a firewall meeting the standards established by the Compressed Gas Association’s CGA P-1. As an alternative, oxygen can be moved directly to the area of use.
  3. The valve protection cap must be kept on at all times, except when a cylinder is in use.
  4. Cylinders must be chained or strapped, or otherwise mounted, securely in place to prevent them from falling over. Cylinders must be individually mounted or strapped.
  5. Corrosive gases should be stored for the shortest possible time period: under three months is preferable. 
  6. Cylinders may not be stored in areas not protected from the weather.
  7. Cylinders must be clearly labeled with the contents, by the vendor’s identification label. If labels are coming off, notify the lab manager immediately. Unlabeled cylinders cannot be returned to the vendor.

5.4.2 Moving Cylinders 

  1. Faculty or staff will move all large cylinders from the storage area to the laboratory.
  2. Always consider cylinders full and handle them accordingly; the same hazards exist even if the cylinder is only partially full.
  3. Use a hand truck to transport cylinders that cannot be easily carried. Do not drag, roll, or slide cylinders. Cylinders must be secured to the hand truck.
  4. The valve protection cap should remain on until the cylinder has been secured in its final position and is ready for use. 
  5. Never drop a cylinder or permit cylinders to strike each other.
  6. Protect cylinders from any object that will produce a cut or abrasion in the surface of the metal. 
  7. Mount cylinders so that the valve is easily accessible and the label is readable.
  8. Always chain or strap cylinders immediately. Do not leave a cylinder in a laboratory if equipment is not available to secure it. Cylinders in the laboratory must be secured individually.

5.4.3 Laboratory Use

  1. Handling and use of gas cylinders and lecture bottles (e.g., attaching regulators) must comply with manufacturers' recommendations.  
  2. Do not use flammable gases near exit paths.
  3. Wear safety glasses or goggles when installing or removing regulators on gas cylinders.
  4. Attach the proper regulator designed for the particular gas that is being used. Cylinder valves have been standardized for specific families of gases to prevent the interchange of regulator equipment between gases that are not compatible. Never modify, tamper with, or force a cylinder valve or regulator. Be sure that all components of a distribution system are compatible with the gas in use. Corrosive gases require special attention to the resistance of materials in the distribution system.
  5. After connecting the regulator, secure all hose connections with clamps, secure any loose hoses to prevent sudden movement when pressure is supplied, and, when appropriate, place a trap between the regulator and the reaction vessel to prevent backflow. 
  6. Verify that the regulator is securely in place after installation or changing it by checking for leaks.
  7. Start the gas flow with the following procedure. 
    1.  Do not stand in front of the delivery valve.
    2. With the regulator secured to the cylinder valve outlet, turn the delivery pressure adjusting the screw until it turns freely.
    3. Next slowly open the cylinder valve until the cylinder pressure gauge on the regulator reads the cylinder pressure. The cylinder valve should be opened by hand; never use a wrench or other tool unless the vendor supplies a special tool for that purpose.
    4. With the cylinder valve open and the flow control valve (the outlet from the regulator) in closed position, set the desired delivery pressure by turning the delivery-pressure adjusting screw (clockwise increases) until the desired pressure is reached.
    5. Begin gas flow by opening the flow control valve at the outlet of the regulator. 
  8. All gas lines leading from a compressed gas supply should be clearly labeled. Signs should be conspicuously posted in areas in which flammable compressed gases are present.
  9. Never mix gases in a cylinder; unless the cylinder is designed for that purpose and labeled appropriately.
  10. Never completely empty a cylinder. Leave a slight pressure (about 25 pounds) to keep out contaminates that may react with the contents or corrode the cylinder. 

Empty cylinders should have the regulator removed and the protector cap in place, the cylinder should be labeled EMPTY or "MT", and the lab manager notified.

5.4.4 Special Precautions

Acetylene

  1. Gaseous acetylene under pressure may also decompose with explosive force, and should not be used at pressures in excess of 15 psig (30 psi absolute pressure). Acetylene pressure gauges should have a warning red line at this point.
  2. Acetylene in cylinders is dissolved in a liquid (e.g., acetone) and should always be used in an upright position. Do not use a cylinder that has been stored or handled in a non-upright position until it has remained in an upright position for at least 30 minutes. 
  3. The outlet line of an acetylene cylinder must have a flash arrester. 
  4. Use the correct kind of tubing to transport the gaseous acetylene. Some tubing materials, such as copper, form explosive acetylides.

Oxidizers

Oxidizers under pressure (oxygen, chlorine, etc.) will rapidly oxidize organic material, such as oil or grease, resulting in an explosion. Never use oil or grease on valves or gauges intended for cylinders containing oxidizers. 

5.5 CRYOGENIC SYSTEMS

Cryogenics is the science of very low temperatures. An accepted temperature used to distinguish between refrigeration and cryogenics is -73.3oC (-100oF). Low temperatures in the cryogenic range are generally obtained by the liquidification or solidification of gases. The most commonly used cryogens and their properties are listed in Table 5-3.

The primary hazard of cryogenic materials is their extreme coldness, which can result in frostbite and severe tissue damage. Accumulated vapors may also act as asphyxiants. Liquefied inert gases, such as nitrogen, in contact with cold metal surfaces can cause condensation of oxygen from the room air resulting in an oxygen-enriched atmosphere and, consequently, an increased fire hazard. The low temperatures involved also affect the properties of other materials; for example, rubber may become brittle and disintegrate, some metal alloys may become brittle, and plastic and glass can shatter.

Table 5-3  PROPERTIES OF CRYOGENS
Gas
Normal Boiling
Point (°C)
Volume Expansion
to Gas
Flammable
Toxic
Odor

carbon dioxide

-78.5

553:1

No

Yes

Slightly Pungent

hydrogen

-252.7

861:1

Yes

No

No

nitrogen

-195.8

696:1

No

No

No

helium-3 isotope

-269.9

757:1

No

No

No

argon

-185.7

847:1

No

No

No

fluorine

-187.0

888:1

No

Yes

Sharp

oxygen

-183.0

860:1

No

No

No

methane

-161.4

578:1

Yes

No

No

Source: Furr, A.K. (ed.), 2000. CRC Handbook of Laboratory Safety, 5th Edition.


Cryogens have very high liquid:vapor expansion ratios. For example, liquid nitrogen expands to approximately 700 times its initial volume when it vaporizes (e.g., 22 cf expands to 15,400 cf). This rapid expansion can cause a displacement of oxygen and, consequently, a life-threatening asphyxiant atmosphere.

5.5.1 Storage and Handling Precautions for Cryogens

These are general precautions; the faculty or supervising staff member responsible for the cryogenic operation should establish more specific safety guidelines.

  1. Store and use only in containers and equipment recommended for cryogenic service.
  2. Avoid confined areas where vaporization occurs, (e.g., do not put your head down into the dry ice freezer).
  3. Ensure that all apparatus is properly vented to prevent accumulation of pressure and be cognizant of ice blocks that could block vent lines.
  4. Wear chemical splash goggles when there is a risk of pressure buildup or splash or particle hazard. Wear a face shield in cases where there is a high likelihood of contact.
  5. Always wear long sleeves and/or a lab coat.
  6. Watches, rings, or other jewelry that could trap the material next to the skin should not be worn.
  7. If gloves are necessary to handle containers or cold metal parts, they should be impervious and loose enough to be thrown off in the case of contamination.
  8. Neither liquid nitrogen, liquid air, nor any other cryogen with a normal boiling point < 188 °C should be used to cool a flammable mixture in the presence of air, as oxygen can condense from the air leading to an explosive mixture.
  9. Equipment must be kept clean to avoid contamination of organics with a cryogenic oxidant (e.g., liquid oxygen) or oxidants with a cryogenic fuel (e.g., liquefied natural gas).
  10. When flammable gases are being used, eliminate potential ignition sources.
  11. Flammable and toxic gases should only be used in a fume hood.
  12. If liquid nitrogen has a blue tint, it has been contaminated with oxygen and should be replaced. The contaminated material is dangerous and potentially explosive.
  13. When spilled, liquid oxygen soaks into materials it comes into contact with, and the resulting mixture may be explosive.

5.6 ACUTE TOXINS

As defined by the Laboratory Standard, acute toxins, one of OSHA's three categories of Particularly Hazardous Substances (Acute Toxins, Select Carcinogens, and Reproductive Toxins), are chemicals which may be fatal as a result of a single exposure or exposure of short duration. The OSHA Hazard Communication Standard defines a similar category, highly toxic chemicals, based on animal (rat) toxicity data using the following criteria. 
 
LD50 - ingestion:  < 50 mg/kg
LD50 - contact (24hrs):  < 200 mg/kg
LD50 - inhalation:  < 200 ppm/hr

LD50, also known as LC50, is defined as the amount of chemical which when ingested, inhaled or applied to the skin of a group of test animals under controlled conditions will kill 50% of the test animals. 

 A review of Material Safety Data Sheets reveals, however, that these toxicity data are not readily available for many laboratory chemicals. As there is no definitive list of acute toxins, they will be defined here as a chemical that meets one or more of the following three criteria.

  1. Animal toxicity data is available and meets the LD50 criteria listed above.
  2. The container label or Material Safety Data Sheet identifies the substance as "acutely toxic," "highly toxic," "may be fatal if inhaled," "may be fatal if enters the bloodstream," or similar warning of acute toxicity.
  3. It is on the following list of examples (Table 5-4), which was compiled from several sources as referenced and includes all Department of Transportation Poison A chemicals, and chemicals with a National Fire Protection Association "Health" rating of 4 for highly toxic. (See Appendix 4-B for a description of NFPA ratings.)
  4. The faculty member has knowledge that the chemical is an acute toxin.

5.6.1 Written Protocols

Each faculty member using or supervising the use of an acute toxin must develop a written protocol for that chemical. The protocol must include a description of the quantity to be used, experimental procedure, the location of the experiment, who will be handling the acute toxin, protective equipment to be worn, emergency procedures, and waste disposal procedures. The protocol must be submitted to the chair of the safety committee at least 3 weeks prior to the anticipated purchase date (or use date for materials already in CSC),  for approval by the safety committee. If an acute toxin is to be stored after completion of its approved usage, it should be given to the lab manager for proper storage. 

Table 5-4  EXAMPLES OF ACUTE TOXINS (1)
Chemical
Target Organ
abamectrin * systemic
acrolein * systemic, pulmonary
acrylonitrile * systemic
adiponitrile systemic, blood
aminopyridine, 4- * systemic
ammonia (gas) pulmonary
aniline and cmpds * blood
arsenic acid and salts * systemic
arsenic pentafluoride systemic
arsenic pentoxide systemic
arsenic trichloride systemic
arsenic trioxide systemic
arsenious acid and salts systemic
arsine systemic
arsonic acid and salts systemic
atropine * CNS
bischloroethylnitrosourea systemic
boron tribromide pulmonary
boron trifluoride pulmonary
bromine pulmonary, skin
bromine pentafluoride pulmonary
bromoacetone pulmonary
chlorine pulmonary
chlorine trifluoride pulmonary
chloropicrin pulmonary
colchicine pulmonary, systemic
cyanamide * systemic
cyanides and cmpds * blood
cyanogen and cmpds blood
decaborane * CNS
diazomethane pulmonary
diborane pulmonary
dichloroacetylene pulmonary
diclorvos * systemic
digitoxin * systemic
dimethyl mercury * CNS, systemic
dimethyl sulfate * pulmonary, skin, eyes
dinitrophenol, 2,4 - * systemic
endosulfan * CNS
endrin * CNS
ethylene chlorohydrin * systemic
fluorine pulmonary, skin
germane pulmonary, blood
heptachlor * systemic
heptachlor epoxide * systemic
hydrogen cyanide * systemic
hydrogen fluoride * pulmonary, skin, systemic
hydrogen selenide * pulmonary
hydrogen sulfide systemic
methyl bromide * pulmonary
manganese tricarbonyl methylcyclopentadienyl * CNS
methylaziridine, 2-* systemic
methyldichloroarsine systemic
methylfluorosulfonate systemic
methyl bromide * pulmonary
methyl hydrazine * pulmonary, CNS, blood
methyl isocyanate * systemic
methyl mercury compounds * CNS
mitomycin C systemic
mustard gas * pulmonary
nickel carbonyl pulmonary, CNS
nicotine * CNS
nitric acid, fuming * pulmonary, skin
nitric oxide systemic
nitrogen dioxide systemic
nitrogen mustard and compounds * systemic
nitrogen tetroxide systemic
nitrosomethylvinylamine systemic
ochratoxin A systemic
osmium tetroxide systemic
ozone pulmonary
parathion * CNS
pentaborane CNS
pentachlorophenol * systemic
phosgene pulmonary
phosphine systemic
phosphorus (yellow) pulmonary
propargyl bromide systemic
propionic nitrile * systemic
propylene oxide * pulmonary
selenium hexafluoride pulmonary
sodium azide * (1) systemic
sodium fluoroacetate * systemic
stibine systemic, blood
strychnine systemic, CNS
TCCD * systemic
tetraethyl lead * CNS
tetraethylpyrophosphate * systemic
tetramethyl succinonitrile * CNS
thiophenol * CNS, systemic
thiotepa systemic
toluidine, ortho- * blood
tubocurarine chloride hydrate, (+)- * systemic
vanadium pentoxide systemic
venom, snake, crotalus adamateus systemic
venom, snake, crotalus atrox systemic
xylidine * blood
* = readily absorbed through the skin

(1) Requirements of this section do not apply to chemicals in which sodium azide is used in small amounts as a preservative. Sodium azide and solutions containing sodium azide should not be put into the sewer system. They should be collected as hazardous waste.

 

5.6.2 Employee/Student Notification and Use

The supervising faculty member is responsible for informing all employees or students that the chemical they are working with is an acute toxin and providing them with a copy of the written protocol. These materials should be used only under direct supervision and in the approved designated area. 

5.6.3 Personal Protective Equipment

Protective Clothing

Laboratory coats must be worn when acute toxins are being used. Laboratory coats used for this purpose must not be worn outside of the laboratory. Contaminated clothing must be removed immediately, placed in a sealed plastic bag, and given to the lab manager for proper disposal.

If hand contact is possible, gloves appropriate for the task and with resistance to the acute toxin involved must be worn. Disposable gloves must be collected for proper disposal after every use, and immediately after known or suspected contact with an acute toxin. Non-disposable gloves must be designated for use only with the acute toxin and must be decontaminated or disposed of after every use.

Eye Protection

Appropriate eye protection must be worn as described in Section 4.5.1. Splash goggles are required when using any quantity of an acute toxin in liquid or powder form.

5.6.4 Personal Hygiene

Hands must be washed with soap and water immediately after known or suspected contact, at the completion of any procedure, and prior to leaving the laboratory. If eyes or other parts of the body are contaminated, they must be immediately washed or flushed as described in Section 2.3.1.

5.6.5 Work Area Identification and Access

Each designated work area where acute toxins are being used must be clearly labeled with a sign with the following or similar warning:

CAUTION
DESIGNATED WORK AREA
SELECT CARCINOGENS, REPRODUCTIVE HAZARDS, OR SUBSTANCES
OF HIGH ACUTE TOXICITY MAY BE PRESENT.
AUTHORIZED USERS ONLY

5.6.6 Handling and Storage Procedures

Work Surfaces

All work surfaces on which acute toxins are used should be a smooth nonporous material or covered with stainless steel or plastic trays. The work surface or trays must be decontaminated after the procedure is complete.

Containment Equipment

Procedures using volatile acute toxins and those involving solid or liquid acute toxins that may result in the generation of aerosols or airborne particles should be conducted in a fume hood, glove box, or other containment device. Examples of aerosol generation procedures include: transfer operations, blending, and open vessel centrifugation.

Vacuum Lines

Vacuum lines should be protected (e.g., with an absorbent or liquid trap or filter) to prevent entry of any acute toxin into the system.

Decontamination

Equipment and contaminated materials should be decontaminated using procedures that deactivate the acute toxin, if such procedures are available. If deactivation procedures are not available, the equipment should be rinsed in an appropriate solvent and the solvent collected as hazardous waste. All glassware must be decontaminated or rinsed before it is sent for washing. Decontamination of the work area must be done whenever there has been known or suspected contamination and at the end of each experiment. The work area should be decontaminated daily.

Container Labeling

All non-original containers in which acute toxins are stored must be labeled with the chemical name; student and faculty name; date; and a warning indicating it is a acute toxin. Do not use abbreviations.

5.6.7 Waste Disposal

Collection for Off-Site Disposal

All contaminated materials must be collected for off-site disposal. The procedures outlined in Section 6.5 for hazardous waste disposal should be followed.
 
5.7 REPRODUCTIVE TOXINS

Reproductive toxins, one of OSHA's three categories of Particularly Hazardous Substances, are substances that affect reproductive capability and include four general categories.

  • Mutagens: Substances that may cause a change (mutation) in the genetic material of a cell.
  • Teratogens: Substances that may affect the viability or cause physical or metabolic defects in the developing embryo or fetus when a pregnant female is exposed to that substance.
  • Sterility/Infertility: Substances that may affect female or male fertility.
  • Lactation: Substances that may be transferred from the mother to the child through breast milk and cause adverse health effects in the child.

Reproductive toxins include physical agents (e.g. radiation), biological agents (e.g. viruses), maternal metabolic imbalances, and chemical agents. This section will focus on chemical reproductive toxins. There are numerous references on reproductive toxicology but, unfortunately, no scientific or government agency has established a definitive method for classifying potential human chemical reproductive toxins as they have done for carcinogens. It is, therefore, impossible to give a complete list of all chemicals that should be considered reproductive toxins. Appendix 5-D gives examples of chemicals known or suspected to be human reproductive toxins. The list does not take into account the chemical form, concentration, toxicity, or length of exposure.

A large number of chemicals have been reported to be animal reproductive toxins in various species, but since there is no established method for defining when animal evidence is sufficient to relate to human reproductive toxicity potential, it cannot be meaningfully organized here. Container labels and Material Safety Data Sheets should be consulted for the manufacturer's assessment of animal reproductive toxicity, and precautions should be taken to minimize exposure to those chemicals particularly during pregnancy or childbearing years.

As there is no definitive list of human reproductive toxins, they will be defined here as a chemical which meets one of the following criteria.

  1. It is listed on Appendix 5-D as an "Example of Known or Suspected Human Reproductive Toxin".
  2. The container label or Material Safety Data Sheet reports positive findings of human reproductive toxicity.
  3. The faculty member has knowledge that the chemical is a human reproductive toxin.

5.7.1 Notification of Use and Protocols

Each faculty member using or supervising the use of any human reproductive toxin must notify the lab manager using the form included in Appendix 5-B. Review procedures are detailed in the introduction to Section 5. If the toxin is to be stored after completion of its approved used, it should be given to the lab manager for proper storage.

Upon request, the safety committee will evaluate specific experimental procedures to determine if additional handling requirements are advisable or if certain requirements of this section may be waived. The committee may also request protocols for use of reproductive toxins.

5.7.2 Employee/Student Notification

The supervising faculty member is responsible for informing all employees and students that the chemical they are working with is considered a human reproductive toxin.

5.7.3 Personal Protective Equipment

Protective Clothing

Laboratory coats must be worn when greater than 10 milliliter or 10 milligrams of a human reproductive toxin is being used. Laboratory coats used for this purpose must not be worn outside of the laboratory. Contaminated clothing must be removed immediately, sealed in a plastic bag and given to the lab manager for proper disposal.

If hand contact is possible, gloves appropriate for the task and with resistance to the reproductive toxin involved must be worn. Disposable gloves must be properly discarded after every use and immediately after known or suspected contact with a human reproductive toxin. Non-disposable gloves must designated for use only with the human reproductive toxin and must be decontaminated or discarded after every use.

Eye Protection

Appropriate eye protection must be worn as described in 4.5.1.

5.7.4 Personal Hygiene

Hands must be washed with soap and water immediately after known or suspected contact, at the completion of any procedure, and prior to leaving the laboratory. If other parts of the body are contaminated they must be immediately washed or flushed, in the case of eye contamination, described in Section 2.3.1.

5.7.5 Work Area Identification and Access

Designated work areas where human reproductive toxins are being used must be clearly labeled with a sign with the following, or similar, warning:

CAUTION
DESIGNATED WORK AREA

SELECT CARCINOGENS, REPRODUCTIVE HAZARDS, OR SUBSTANCES OF
HIGH ACUTE TOXICITY MAY BE PRESENT.
AUTHORIZED USERS ONLY.

5.7.6 Handling and Storage Procedures

Work Surfaces

All work surfaces on which human reproductive toxins are used should be smooth and nonporous or covered with stainless steel or plastic trays. The work surface or trays should be decontaminated after the procedure is complete.

Containment Equipment

Procedures using volatile human reproductive toxins and those involving solid or liquid human reproductive toxins that may result in the generation of aerosols or airborne particles should be conducted in a fume hood, glove box, or other containment device. Examples of aerosol generation procedures include: transfer operations, blending, and open vessel centrifugation.

Vacuum Lines

Vacuum lines should be protected (e.g. with an absorbent or liquid trap or filter) to prevent entry of any human reproductive toxin into the system.

Decontamination

Equipment and contaminated materials should be decontaminated by procedures that deactivate the human reproductive toxin if such procedures are available. 

If deactivation procedures are not available, the equipment should be rinsed with an appropriate solvent and the solvent collected as hazardous waste. All glassware must be decontaminated and rinsed before it is sent for washing. Decontamination of the work area must be done whenever there has been known or suspected contamination and at the end of each experiment. The work area must be decontaminated daily. 

Container Labeling

All non-original containers in which a human reproductive toxin is stored must be labeled with the chemical name; student and faculty name; date; and a warning indicating it is a reproductive toxin.

5.7.7 Waste Disposal

Waste Minimization

One goal of experimental design should be the minimization of waste produced. Using the least amount of the reproductive toxin possible and limiting the use of disposable equipment are effective methods.
 
Deactivation

When possible, wastes should be deactivated to form non-toxic degradation products. Deactivation procedures for some human reproductive toxins that are also carcinogens may be available from the manufacturer.

Collection for Off-Site Disposal

If deactivation methods are not available or the deactivation product remains hazardous (e.g., flammable) all contaminated materials must be collected for off-site disposal. The procedures outlined in Section 6.5 for Hazardous Waste Disposal should be followed.

5.8 SELECT CARCINOGENS

These guidelines for the laboratory use of chemical carcinogens establish procedures and safeguards for minimizing exposure of laboratory personnel to chemicals that pose a carcinogenic risk. They apply to all chemicals defined as "select carcinogens," one of OSHA's three categories of Particularly Hazardous Substances, which include:

  • all OSHA regulated carcinogens (29 CFR Subpart Z),
  • all substances the National Toxicology Program (NTP) lists as "known to be  carcinogens", or "reasonably anticipated to be carcinogens",
  • all substances  that the International Agency for Research on Cancer (IARC) defines as Group 1,"carcinogenic to humans", or as Group 2A, "probably carcinogenic to humans" or Group 2B, "possibly carcinogenic to humans".

Appendix 5-E is a compilation of lists from the sources referenced above. It is taken directly from those sources and does not take into account relative hazards attributable to chemical form, concentration, toxicity, or length of exposure. These guidelines are adapted from the National Institute of Health 1981 "NIH Guidelines for the Laboratory Use of Chemical Carcinogens".

5.8.1 Notification of Use and Protocols

Each faculty member using or supervising the use of any select carcinogen must notify the lab manager using the form included in Appendix 5-B.  Review procedures are detailed in the introduction to Section 5. If the toxin is to be stored after completion of its approved used, it should be given to the lab manager for proper storage.

Upon request, the safety committee will evaluate specific experimental procedures to determine if additional handling requirements are advisable or if certain requirements of this section may be waived. The committee may also request protocols for use of select carcinogens.

5.8.2 Employee/Student Notification

The supervising faculty member is responsible for informing all employees and students that the chemical they are working with is a select carcinogen.

5.8.3 Personal Protective Equipment

Protective Clothing

Laboratory coats must be worn when greater than 10 milliliters or 10 milligrams of a select carcinogen is being used. Laboratory coats used for this purpose must not be worn outside of the laboratory. Contaminated clothing must be removed immediately, sealed in a plastic bag and given to the lab manager for proper disposal.

If hand contact is possible, gloves appropriate for the task and with resistance to the carcinogen involved must be worn. Disposable gloves must be properly discarded after every use and immediately after known or suspected contact with a select carcinogen. Non-disposable gloves must be designated for use only with select carcinogens and must be decontaminated after every use.

Eye Protection

Appropriate eye protection must be worn as described in 4.5.1.

5.8.4 Personal Hygiene

Hands must be washed with soap and water immediately after known or suspected contact, at the completion of any procedure, and prior to leaving the laboratory. If other parts of the body are contaminated, they must be immediately washed or flushed, in the case of eye contamination, described in Section 2.3.1.

5.8.5 Work Area Identification and Access

Designated work areas where select carcinogens are being used must be labeled with a sign with the following warning: 

CAUTION
DESIGNATED WORK AREA
SELECT CARCINOGENS, REPRODUCTIVE HAZARDS, OR SUBSTANCES
OF HIGH ACUTE TOXICITY MAY BE PRESENT. 
AUTHORIZED USERS ONLY.

5.8.6 Handling and Storage Procedures

Work Surfaces

All work surfaces on which select carcinogens are used should be smooth and nonporous or covered with stainless steel or plastic trays. The work surface or trays should be decontaminated after the procedure is complete.

Containment Equipment

Procedures using volatile select carcinogens and those involving solid or liquid select carcinogens that may result in the generation of aerosols or airborne particles should be conducted in a fume hood, glove box, or other containment device. Examples of aerosol generation procedures include: transfer operations, blending, and open vessel centrifugation.

Vacuum Lines

Vacuum lines should be protected (e.g. with an absorbent or liquid trap or filter) to prevent entry of any human reproductive toxin into the system.

Decontamination

Equipment and contaminated materials should be decontaminated by procedures that deactivate the select carcinogen if such procedures are available. 

If deactivation procedures are not available, the equipment should be rinsed with an appropriate solvent and the solvent collected as hazardous waste. All glassware must be decontaminated or rinsed before it is sent for washing. Decontamination of the work area must be done whenever there has been known or suspected contamination and at the end of each experiment. The work area should be decontaminated daily. 

Container Labeling

All non-original containers in which a select carcinogen is stored must be labeled with the chemical name; student and faculty name; date; and a warning indicating it is a select carcinogen.

5.8.7 Waste Disposal

Waste Minimization

One goal of experimental design should be the minimization of waste produced. Using the least amount of the select carcinogen possible and limiting the use of disposable equipment are effective methods.
 
Deactivation

When possible, wastes should be deactivated to form non-toxic degradation products. Deactivation procedures may be available from the manufacturer.

Collection for Off-Site Disposal

If deactivation methods are not available or the deactivation product remains hazardous (e.g., flammable) all contaminated materials must be collected for off-site disposal. The procedures outlined in Section 6.5 for Hazardous Waste Disposal should be followed.

5.8.8 Special Requirements for Formaldehyde

OSHA has established a separate standard for formaldehyde, 29 CFR 1910.1048, which applies to laboratories as well as other users of formaldehyde. Under that standard employee exposure monitoring is required to determine if a particular experiment may result in overexposure to formaldehyde. To accomplish the required monitoring, faculty members must notify the lab manager before any experiment where formaldehyde is used in concentrations greater than 1 percent (reagent concentration or final solution concentration), using the form in Appendix 5-B.

If previous monitoring has been conducted for that experiment and acceptable levels consistently achieved, notification is not required unless the lab manager has informed the faculty member that additional monitoring is required. Additional requirements of the standard may apply based on the results of monitoring. These requirements will be discussed with individual faculty as needed.

The Formaldehyde Standard also established hazard communication requirements (labeling, MSDS, and training) which apply to the use of solutions containing greater than 0.1 percent or capable of releasing formaldehyde in excess of 0.1 ppm.

Labeling

For products capable of releasing 0.1 to 0.5 ppm, labels must include a warning that the product contains formaldehyde and that more information is available on the MSDS. For products capable of releasing greater than 0.5 ppm, the label must also address health hazards and include the words "Potential Cancer Hazard." Products must be labeled with the appropriate warning.

MSDS

Material Safety Data Sheets must be readily accessible for all formaldehyde-containing products.

Training

Annual training is required for the users of formaldehyde product containing greater than 0.1 percent formaldehyde or capable of releasing in excess of 0.1 ppm. That training will be accomplished by distribution by the faculty member of the Formaldehyde Fact Sheet (Appendix 5-C) to all users of formaldehyde products.

5.9 SUMMARY OF PARTICULARLY HAZARDOUS SUBSTANCES

The OSHA Laboratory Standard classifies Acute Toxins (5.6), Select Carcinogens (5.8), and Reproductive Toxins (5.7) as Particularly Hazardous Substances. Each of those sections contains lists of chemicals that meet the criteria defining those three hazard categories. Appendix 5-F is a compilation of those lists. Please remember that the acute toxins and reproductive toxins lists are only examples and that other chemicals not listed can meet the definitions for those hazards. This list is taken directly from the sources referenced in those sections and does not take into account relative hazards attributable to chemical form, concentration, toxicity, or length of exposure.

Appendix 5-A: First Aid Treatment for Hydrofluoric Acid Exposure

Appendix 5-B: Notification of Use Form

Appendix 5-C: Formaldehyde Fact Sheet

Appendix 5-D: Examples of Known or Suspected Human Reproductive Toxins

Appendix 5-E: Select Carcinogens

Appendix 5-F: Summary of Particularly Hazardous Substances

 

 

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