• Risk and Exposure to Chemicals
  • Exposure
  • Dose
• Chemical Labels and Material Data Sheets
  • Chemical Safety
  • Materials in the Laboratory
  • Stocks and Storage
• Flamable Liquids
• Storage Limits
• Transfer of Chemicals
• Examples of Chemical Storage Groups
• Fume Hoods
• Spills
  • Clean-up of Chemical Spills

Risk and Exposure to Chemicals

There are hazards in the laboratory and chemicals figure prominently among them. In addition to the physical properties of reactive chemicals, traditionally the focus of life safety in the laboratory, their toxicity is of recent and growing concern. Although the toxic properties of certain chemicals has been known for thousands of years, the significance of risks associated with toxic chemicals in the laboratory on the health oflaboratory workers is only lately coming to light. While exposures to highly toxic or acutely toxic substances are, given their short-term effects, easy to identify, the long-term effect of exposure to certain chemicals is much more difficult to predict. However, the list of compounds for which there is sufficient evidence for carcinogenicity is growing (see appendix at the end of this section). Many of these chemicals are commonly found in laboratories. The OSHA Laboratory Standard cites five studies on the long-term effects of exposure to toxic substances in the laboratory. While the results are not conclusive, they suggest an increased incidence of pancreatic and possibly brain tumors and lymphohematopoietic malignancies among laboratory chemists.

Although it is simple to say that at some level all chemicals are toxic and direct contact should be avoided, special attention must be given to limiting exposure to those that are acutely toxic, present reproductive hazards and the selected chemicals listed in the appendix.

Unlike the regulation of radioactive materials or infectious agents for which precise standard laboratory guidelines exist, the regulation of chemicals has been made the responsibility of those in the laboratory. In essence the OSHA Laboratory Standard requires that laboratories develop a Chemical Hygiene Plan that is available to all laboratory workers. The plan includes standard operating protocols (SOPs) for the use, storage, and disposal of hazardous chemicals, using the best knowledge and techniques available. These Sops must include the use of engineering controls and personal protective equipment within the boundaries of "designated areas," which in many instances may mean the entire laboratory. This places much of the burden on laboratory supervisors and also on all laboratory workers, who must learn to familiarize themselves with the physical and health hazards associated with chemicals in their laboratory and to implement standard operating protocols which will minimize their exposure to them. A basic understanding of exposure, dose and toxicity is essential to this process.

Exposure

The nature and quantity of a chemical as well as the mode and duration of the exposure determine the risk inherent in contacting the chemical. ThresholdLimit Values (TLV) issued by the American Conference of GovernmentalIndustrial Hygienists (ACGIH) may be used as guides for assessing the severity of an exposure. Note that through the adoption of the TLVs by OSHA as Permissible Limit Values (PELs), these PELs now carry the weight of law for determining safe exposure as well as levels at which actions must be taken to reduce exposure. A list of these chemicals as well as those for which NIOSH has published Recommended Exposure Levels (RELs) appears in the appendix to this section.

Time Weighted Averages (TWA) refer to the average airborne concentration of substances to which it is believed nearly all workers may be repeatedly exposed during a normal 8-hour workday and 40-hour week, day after day without adverse effect. Because of wide variation in susceptibility, individuals may experience discomfort from some substance at concentrations at or below the threshold limit; a smaller percentage may be affected more seriously by aggravation of a preexisting condition or by development of an occupational illness.

Short Term Exposure Limit (STEL) is a 15 minute time-weighted average exposure which should not be exceeded at any time even if the eight-hour time-weighted average is within the TLV. If a STEL is not specified, short term exposures should exceed three times the TWA for no more than a total of 30 minutes per day. These levels are not necessarily conservative when applied to the research setting, where exposures to and synergistic effects from chemicals must also be considered. Likewise, individual experiences and sensitivities should be evaluated. For example, pregnant women and particularly their fetuses may be susceptible to levels lower than anticipated for most adults (see list of chemicals with reproductive hazards).

Although the repeated use of some hazardous chemicals may justify the use of specific monitors, if available, for the most part it is your vigilance upon which you must rely. This includes the appearance of vapors, moist surfaces, mixing patterns, color changes, skin, eye, or respiratory.

Do not ignore any of these signs and take steps to minimize your contact.

Some chemicals have characteristic odors. A list of odor thresholds has been compiled by the American Industrial Hygiene Association (AIHA; see GENERAL REFERENCES). While you should not use your nose to estimate chemical concentration because of the potential for overexposure, it can be of great practical value in identifying the source of an odor. Individual factory responses, fatigue, and acclimation are important factors. Remember that not all hazardous chemicals have odors and for some the level for olfactory detection may be too high to be of protective value. See the comparison of odor thresholds and TLVs for some hazardous chemicals in the Table 1.

Dose

Although all chemicals may be toxic at some level, the dose absorbed is the critical factor impacting the health of the individual. Since individuals may be more or less tolerant or susceptible to chemical exposures and the precise dose at which toxic effects will be manifested varies over a range. At certain dosages, some chemicals with known toxic properties elicit no response or may even have a beneficial effect. The ancient treatment of syphilis with mercury may not be the best example, because it was not realized that compounds such as metallic mercury are only partially excreted and can accumulate in fat and other tissues eventually causing a toxic effect. It is possible that the shorter life expectancies of the ancients precluded the manifestation for those chronic effects. A better example might be reproductive hormones which are essential to our health, yet at high concentrations, e.g., those initially used in oral contraceptives, may be carcinogenic. Symptoms related to chronic exposures are often distinct from the symptoms associated with acute exposures. Since most toxicological data is based upon data from work with other species, it is helpful to be able to compare dosage by weight and surface area in order to evaluate the data. Following a screening for mutagenicity using Salmonella (Ames test), the dosage of a chemical required to produce death in 50% of the treated animals (LD50) is usually the first determination of toxicity with a new chemical. Customarily this test is performed on rodents using oral or intraperitoneal routes of administration. When the dose received is not known, the lethal concentration of chemical in air or water that causes death to 50% of the subjects (LD50) is usually determined.

The dosages of different chemicals required to produce harmful health effects vary 10 billion-fold(Table 2). The acutely toxic chemicals, e.g., mold toxins of which aflatoxin is the most familiar ,are at the low end of this range where single doses of less than 10 mg/kg body weight can be lethal. For some chemicals, LD50s are included in the information that manufactures are required to provide to purchasers discussed below. The EPA and OSHA's Appendices A and B to the Hazard Communication Standard (29 CFR 1910.1200) consider the following "acutely toxic:"

• an oral LD50 (rat) of less than 50 mg/kg
• an inhalation LC50 (rat) of less than 2 mg/L
• dermal LD50 (rabbit) of less than 200 mg/kg

which "is otherwise capable of causing or significantly contributing to an increase in serious irreversible, or incapacitating reversible, illness." The accompanying table (Table 3) of relative hazard levels based on animal data provides a fuller perspective of the dose range.

Understanding the concepts of toxicity, exposure and dose can help effectively minimize the risk associated with working with hazardous chemicals. Check the chemicals in your laboratory against the PELs and the RELs. If you think that an exposure exceeding these values is likely,check with your laboratory supervisor for steps to minimize exposure, e.g., work in a fume hood, wear gloves. Arrange with those responsible for environmental health and safety to review the data and monitor your exposure, if they think it necessary. For quick identification of chemicals which may require special handling, in addition to the chemicals for which PELs and RELs exist,the EPA's Acutely Hazardous and Extremely Hazardous Substances, are included in the appendix along with a list of substances regulated by OSHA as carcinogens. The EPA's ExtremelyHazardous list is used with Title III of SARA (community right-to-know) and was developed using the above mentioned criteria for acutely toxic chemicals and their dispersal potential. A short list of selected chemicals with known reproductive hazards follows, but a more complete listis given by Shepard T.H. 1983. Catalog of Teratogenic Agents, 4th ed):

Some Common Chemicals With Known Reproductive Hazards

• Acrylonitrile
• Aniline
• Arsenic and its compounds
• Benzene
• Benzo(a)pyrene
• Beryllium
• Boric Acid (Boron)
• Cadmium and its Compounds
• Carbon Monoxide
• Carbon Tetrachloride
• Chlordecone (Kepone)
• Chloroform
• Chloroprene
• Dibromochloropropane (DBCP)
• Dichlorobenzene
• 1,1-Dichloroethane
• Dichloromethane
• Dioxane
• Epichlorohydrin
• Ethylene Dibromide (Dibromoethane)
• Ethylene Dichloride
• Ethylene Oxide
• Fluorocarbons
• Formaldehyde
• Formamides
• Lead (Organic)
• Manganese and Its Compounds
• Mercury and Its Compounds (Inorganic)
• Methyl n-Butyl Ketone
• Methyl Chloroform
• Methyl Ethyl Ketone (MEK)
• Nitrogen Dioxide
• Ozone
• Platinum and Its Compounds
• Polybrominated Biphenyls (PBB)
• Polychlorinated Biphenyls (PCB)
• Selenium and Its Compounds
• Styrene
• Tellurium and Its Compounds
• Tetrachloroethylene
• Thallium and Its Compounds
• Toluene
• Toluene-2,4-Diisocyanate
• o-Toluidine
• Trichloroethylene
• Vinyl Chloride
• Vinylidene Chloride
• Xylene

Where questions exist about the hazardous characteristics of a chemical, rapid access to several computerized databases at the National Library of Medicine is available through the Medical Literature Analysis & Retrieval System (MEDLARS). These include:

• CCRIS, Chemical Carcinogenesis Research Information System
• ChemID, Chemical Identification
• CHEMLINE, Chemical Dictionary Online
• DART, Developmental & Reproductive Toxicology
• EMIC, Environmental Mutagen Information Center
• HSDB, Hazardous Substances Data Bank
• IRIS, Integrated Risk Information System
• RTECS, Registry of Toxic Effects of Chemical Substances
• TOXLINE & TOXLIT, Toxicology Information Online and Toxicology Literature from Special Sources
• TRI, Toxic Release Inventory

Chemical Labels and Material Safety Data Sheets

Read the labels on reagent bottles so that you know beforehand what hazards are involved. If sufficient information is not given, as part of compliance with Right-to-Know laws, those responsible for environmental health can provide information about the various Material Safety Data Sheets(MSDS) for most common chemicals that are on hand. All containers of chemicals must be labeled clearly. Do not use any substance in an unlabeled or improperly labeled container. Chemicals with printed labels which have been partly obliterated, scratched over, or crudely labeled by hand should not be trusted and, together with unlabeled containers, should be disposed of promptly to avoid adverse reactions. If there must be a transfer to another container, careful attention must be paid to relabeling: the new label must contain all cautions from the original label; do not use initials or abbreviated names. Carefully read the label before removing a reagent from its container. Read it again as you promptly recap the container and return it to its proper location. Names of distinctly different substances are sometimes nearly alike and using the wrong substances can lead toaccidents. 

Chemical Safety

All of the precautions listed in the section on GENERAL SAFETY PRATICES should be followed.

To avoid direct contact with chemicals, particular attention must be given to using a fume hood and selecting personal protective equipment appropriate for the chemicals handled. Select gloves that are not readily degraded and/or permeated by the specific chemicals used. A table in the appendix to the GENERAL SAFETY PRACTICES provides information on the resistance of different glove materials to some common chemicals.

Purchase of Chemicals:  "The decision to procure a specific quantity of a specific chemical is a commitment to handle it responsibly from receipt to ultimate disposal. Each operation in which it is handled and each period between operations presents opportunities for misadventure."

Materials in the Laboratory

When acquiring toxic or hazardous chemicals, obtain the smallest quantity sufficient for your work since their storage may constitute a hazard and disposal costs negate most volume discounts. In1990 disposal costs in the U.S. northeast for labpacked chemicals averaged $10.00 per pound of chemical waste. Purchase chemicals in shatter-proof containers when available.

Chemical Stocks and Storage

Although storing chemicals in alphabetical order may seem convenient, it increases the chances that incompatible materials will mix in the event of leaks, spills, breakage, floods or fires. Physical hazards can be reduced by purchasing the minimal amounts of chemicals required and requesting that they be supplied in shatter-proof containers. Storing heavier items on lower shelves, but not on the floor,will further reduce these hazards. While separating chemicals into mutually exclusive compatible groups for separate storage is ideal, it is difficult to reach a consensus of what those groups should be.

Moreover, for these groups to be truly exclusive, requires many sub-divisions with appropriate separate and well-maintained storage locations.

Unlike dedicated chemical storage rooms within which partitioned areas or separate storage cabinets or drums can be allocated to specific groups of chemicals, laboratory space must also accommodate personnel, fixtures and equipment. Inevitably this means there will be only a few possible distinct locations for storing chemicals. For convenience these locations are typically under sinks for corrosives, under fume hoods for flammable and volatile chemicals, and on shelves near a set of balances for general chemicals. An explosion-proof refrigerator may be needed to store flammable chemicals that tend to decompose at room temperature. Due to the reactivity of oxidizers, it is important to segregate them from other chemicals at all storage locations. Ordering the minimal amounts of the chemicals required is especially important for highly hazardous materials, e.g.explosives, carcinogens, acutely toxic chemicals. These materials should not be purchased in excess so that storing them will not be necessary. For this reason no storage category for explosives is listed below. Given that fewer separate storage locations will be available than ideal, secondary containers should be used to separate incompatible chemicals within storage groups. For example, chemically resistent plastic trays of adequate size should be used to both separate and contain corrosive liquids such as acids and bases. Also, containers may be useful for keeping track of small amounts of extremely toxic and controlled substances.

The use of a basic color code affixed upon receipt will greatly aid in identifying the correct chemical group and facilitate proper storage and inspection, especially by laboratory staff without backgrounds in chemistry. Chemicals, particularly those known to decompose with time, should also be marked with the date of receipt. In addition to checking the physical condition of primary and/or secondary containers, chemicals should be inspected regularly for signs of decomposition, such as discoloration, turbidity, caking, moisture in dry chemicals, particulates in liquids, and the build up of pressure in the vessel. Any of these conditions is adequate cause for disposing of the material as soon as possible. 

The storage scheme outlined in Table 4, although incomplete by many standards, is a practical starting approach for a working laboratory and should be further tuned to specific requirements.

When transporting chemicals from one area to another, place the chemical bottle into a plastic bucket as a secondary container in case of breakage.

Flammable Liquids

A flammable liquid is any liquid mixture, substance or compound with a flash point below 100F, when tested in a Tagliabue open cup tester. Liquids have vapor pressures below 40 psi absolute at 100F. The flash point is the lowest temperature at which a flammable liquid gives off vapor sufficient to form an ignitable mixture with air near the surface of the liquid or within the vessel used.

Flammable liquids and solids must be separated from oxidizing materials. Flammable solvents requiring refrigeration should only be stored in flammable storage refrigerators in which electrical contacts are isolated from solvent vapors. All domestic type refrigerators must have signs warning of the danger of storing volatile or flammable chemicals, such as alcohol, acetone, and ether.

Carcinogens and highly toxic chemicals should be stored inside of marked containers in a central laboratory location. (See appendix for list of selected chemicals.)

Storage Limits

It is recommended that laboratories have no more than 5 gallons of flammable liquid (15 for organic chemistry laboratories), 1 pound flammable solids, 5 pounds oxidizable materials, 1 pound unstable(reactive) materials, and no explosives except under special circumstances and then only with the explicit approval of environmental health.

Transfer of Chemicals

Do not pipet by mouth. Use an aspirator bulb, a pipetting device or a loose-fitting hose attached to a water aspirator. When pouring chemicals, hold the bottle with its label toward your palm to protect the label in case some reagent drains down the outside of the bottle. Do not pour towards yourself when adding liquids or powders. Use a funnel if the opening is small. Use a glass rod between the outside of the funnel and the neck of the receiving bottle so that air can be displaced. If a stopper or lid is stuck, use extreme caution in opening the bottle. Friction caused by removing tops can cause an explosion of sensitive substances. When a flammable liquid is withdrawn from a drum or whena drum is filled, the drum and the other equipment must be electrically grounded. Remove from the container only approximately what is needed, discarding any excess. Never return a chemical to its original container.

Always add a reagent slowly; never "dump" it in. Observe what takes place when the first small amount is added and wait a few moments before adding more; some reactions take time to start.With a gloved hand, feel the outside of the receiver vessel. If it is hot, cease the additions and seek advise on whether this is part of the reaction profile. If so, the receiver vessel should be placed on ice. If an expected reaction does not initiate, seek advice before adding more reagent.

To avoid violent reaction and splattering while diluting solutions, always pour concentrated solutions slowly into water or into less concentrated solutions while mixing,TABLE 4. Summary of Chemical Storage Arrangements

Examples of Chemical Storage Groups

Flammable/Non-Flammable Volatile Liquids

Placing these two groups of chemicals near a fume hood is convenient. Separating the flammable chemical group makes it easy to calculate the total volume of flammable chemicals stored per room.

Flammable: Alcohols, Amines, Amides, Imines, Imides, Hydrocarbons, Esters, Aldehydes Ethers, Ketones, Ethylene OxideVolatile: Chloroform, Methylene chloride, Carbon tetrachloride Ethers are peroxidizable.

Flammable and/or Water/Air Reactive Solids

These solids are usually stored under mineral oil.

Sulfur, Phosphorus, Phosphorus pentoxide, Hydrides Metals, e.g. Sodium, Potassium and Metal Dusts Corrosives [Acids and Bases] 

Store acids and bases below eye-level in a dedicated area, e.g., in separate plastic trays under sink. 

Store nitric acid separately.

Store organic bases with flammable chemicals.

Hydroxides, Phenol, Cresols, Halogens Acids, Peracids, Anhydrides Perchloric, Nitric and Chromic Acids areoxidizers.

Sulfuric and Acetic Acids are dehydrating agents.

Hydrofluoric Acid requires special precautions.

General Chemicals, e.g. buffers, salts, organics 

These chemicals may be stored alphabetically.

Selenides, Phosphides, Carbides, Nitrides

Halides, Sulfates, Sulfites, Thiosulfites

Phosphates, Acetates, Isocyanates, Amides

Silicates, Carbonates, Carbon, Glycols,

Borates Sulfides, Polysulfides, Sulfoxides, Nitriles

Oxidizers

Store separately from the rest. Store peroxidizing chemicals at minimum temperatures required to prevent decomposition. Avoid freezing or precipitation of peroxides; either process increases their heat- or shock-sensitivity. Avoid grinding or using metal spatulas with peroxides.

Chlorates, Perchlorates, Chlorites, Hypochlorites Peroxides, Hydrogenperoxide, Hydroperoxides

Borates, Chromates, Manganates, Permanganates

Amides, Nitrates, Nitrites

Chemicals Requiring Refrigeration

Flammable materials should be placed in an explosion-proof refrigerator. Oxidizers should be grouped in separate secondary containers.

Flammable Oxidizers Other Acetaldehyde Dibenzoyl peroxide

Methyliodide Dimethylether Hydrogenperoxide Methylbromide

Peroxyacetic acid

Carcinogens, Extremely Toxic Chemicals and Controlled Substances

These materials should be stored in a separate area or container to facilitate the required tracking of their use storage and disposal.

See lists of chemicals in Appendix.

When available, antidotes should be on hand for extremely toxic materials (see Table 5). preferable on a mechanical stirrer. The more concentrated solution is usually heavier and any heat evolved is better distributed. This procedure is particularly applicable in diluting acids. Always wear goggles and use the hood when diluting concentrated solutions.

Beakers should be supported by holding them around the side with one hand. If the beaker is 500ml or larger, support it from the bottom with the other hand and consider using heavy-duty beakers. 

When setting the beaker down, deposit slowly on the clean surface of the bench. If the beaker is hot ,use gloves and place the beaker on a protective pad. Flasks should be grasped by the neck, not by a side arm. Large flasks (3-liter) should be supported at the base when lifted. A round bottomed flask should rest on a properly sized cork ring when not assembled for reaction.

Never look down the opening of a vessel unless it is empty.

Fume Hoods

The fume hood is the most important piece of protective equipment in a laboratory. See GENERAL SAFETY PRACTICES for guidelines and discussion of their use and limitations.

Spills

Most spills in the laboratory involve comparatively small quantities of chemicals which can readily be neutralized and cleaned up by laboratory personnel. It is recommended that the laboratory supervisor be notified and that spill control procedures be performed under his/her supervision. 

Arrange for disposal of chemicals with environmental health or chemistry stores.

If a spill is of such size (> 1 liter) and/or potential hazard that additional assistance or equipment is required, contact environmental health at 243-2881; after hours, dial your emergency contact number, e.g., 243-4000. Give the following information: 

1. Name of person calling

2. Type of spill and approximate quantity

3. Location: building, floor, and room number

Measures to be taken while waiting for assistance:

1. If a flammable liquid spilled, shut down all electrical equipment and extinguish all flames.

2. If volatile chemicals are involved, open windows for ventilation (but close doors).

3. If an infectious or particulate agent is involved, close all windows and shut off ventilation.(Wait 30 minutes for aerosol to settle before reentering room.)

4. Clear laboratory of all personnel.

5. Close all doors to corridor or adjacent rooms. Hang an appropriate warning sign on the door.

Spills and accidents involving hazardous materials must be immediately reported to those responsible for environmental health and safety.

Clean-up of Chemical Spills

In all cases immediately alert neighbors, laboratory supervisor, and/or department head.

PERSONNEL DECONTAMINATION

If chemicals are spilled on the body, quickly remove all contaminated clothing while using the safety shower or sink. If a large area is affected or if chemical is highly toxic and skin permeable, call your emergency contact number, e.g., 1111, to summon medical assistance. Seconds count and no time should be wasted because of modesty. Immediately flood the affected body area in cold water for at least 15 minutes. Do not use neutralizing chemicals, unguents, creams, lotions or salves. Resume rinsing if pain returns. Report to those responsible for employee health and notify the head of the department or the environmental health and safety office as soon as possible. Delayed reactions, often the next day, may occur and should be reported.

Alkali solutions spilled onto the skin may not be as painful as an acid burn; in fact, they may not be noticeable until some time later. The reason for this is that acids precipitate a protein barrier on contact with skin, and this both prevents the acid from penetrating further and also causes pain. Alkalisolutions do not precipitate a protein barrier; the tissue may become thoroughly soaked and deeply damaged with relatively little discomfort, resulting in an insidious wound. For this reason the skin that has been splashed with alkali should be continuously flushed to reach the alkali that has soaked into the tissue.

TABLE 5. Poisons and Antidotes

POISON

ANTIDOTE - Mechanism of Action

Alkaloids (Quinine, Physostigmine, Strychnine)

Potassium permanganate - 1:10,000 (gastric lavage)

Oxidation

Amphetamines

Gastric lavage; chlorpromazine (i.m.) - decreases cerebral effects

Arsenic

Dimercaprol, BAL (i.m.) - chelation

Bishydroxycoumarin

Phytonadione (vitamin K1) - reverses hypoprothrombenemia; stops hemorrhage due to overdose of anticoagulant therapy

Cardiac glycosides (Digitalis)

Potassium chloride versenateTM - chelates calcium

Carbon tetrachloride

Calcium glucanate (i.v.); vitamin B complex (i.m. or i.v.)

Cyanides

Sodium nitrate (i.v.) or amyl nitrate inhaled followed by sodium thiosulfate

Convulsive agents

Phenobarbital sodium; amytal sodium

DDT and chlorinated hydrocarbons

Symptomatic Rx only

Heavy metals

BAL, versenate, penicillamine - chelation

Hydrocarbon ingestion (e.g., gasoline)

Phosphate-buffered saline lavage; emesis; oxygen

Iron and iron salts

Emesis; sodium dihydrogen phosphate or sodium bicarbonate (gastric lavage); fluid replacement; desferrioxamine mesylate (i.v.) - chelation

Lye and other caustics

Symptomatic phosphate buffered saline (weak acid - 1% acetic acid). In severe cases, open airway and administer oxygen, arrange gastroscopy

Lead

Dimercaprol (BAL) versenateTM - chelation

Mercury

Dimercaprol (BAL) - chelation

Methanol

Sodium bicarbonate (i.v.); emesis; ethanol

Combat acidoses; to inhibit oxidation to toxic metabolites

Muscarine prostogmin

Atropine

Narcotics

Naloxone hydrochloride - antagonist

Phenothiazines

Early gastric lavage; saline cathartics; fluid replacement

Phosphorous

Copper sulfate 0.2% lavage; dexamethasone

Phosphate esters and

organophosphates

Atropine; pralidoxime chloride (ProtopamTM)

Propoxyphene

Activated charcoal; naloxone hydrochloride (i.v.); open airway and supply oxygen and IV fluids

Salicylates

Emesis if conscious; early gastric lavage; vigorous fluid

IV; replace potassium; supply oxygen

Hydration and acid minimization

Tricyclic antidepressants

Emesis and airway lavage if conscious; lavage for 24 hours or longer

Warfarin (commadin)

Phytonadione (vitamin K1)

A list of poisons and antidotes is provided in Table 5.

LABORATORY OR AREA DECONTAMINATION

If chemicals are spilled on the floor or work area, seek the advice of your supervisor orenvironmental health.

When cleaning up spills, wear safety glasses and gloves impermeable to the substance, consider the need for a respirator and apply an absorbent material which will neutralize the liquids. Work from the perimeter of the liquid spill inward and then use a dust pan to collect solid materials into a bag. If the spill is on the floor, some absorbent should be sprinkled on the spot to prevent slipping. Do not use vermiculite. If water or some other agent is used as a diluent, be sure it is compatible with the spilled material and other chemicals in the area (see listing of incompatible chemicals elsewhere in this section). The laboratory supervisor will be responsible for designating the proper clean up procedure. If a flammable or toxic chemical is spilled, call environmental health at 243-2881 for assistance. Warn everyone to extinguish flames and turn off spark-producing equipment such as brush-type motors and bunsen burners. Shut down all equipment, close the doors and windows, and vacate the room until it is decontaminated.

Wall-mounted spill control stations containing agents for absorbing and neutralizing such spills may be located in corridors readily accessible to the laboratories. Clean-up kits for mercury, cyanide, and hydrofluoric acid spills are available. Contact your purchasing agent or Chemistry Stores for replacement kits when necessary.

SPILL KIT USE

Acids

1. Tear open corner of bag of neutralizing agent and pull out spout.

2. Apply the agent to the spill from perimeter inward.

3. After foaming subsides, dilute with water until color changes from red/pink to blue/green.

4. Pick up neutralized waste with the scoop and transfer to plastic disposal bag.

5. Wipe up residual absorbent with a moistened sponge.

6. Place sponge, scoop, and gloves in disposal bag and seal; arrange for disposal as chemical waste.

Caustics (Bases, i.e., ammonium, potassium, and sodium hydroxides)

1. If concentrated, add equal volume of water or ice.

2. Tear open bag of neutralizing agent at corner and pull out spout.

3. Squeeze bag to break up lumps and apply agent to the spill from the perimeter inward

4. Thoroughly mix the agent and spill material with brush provided until material turns orange/yellow throughout, adding more if required.

5. Open bag of liquid absorbent and apply to treated spill to absorb liquid.

6. Pick up saturated absorbent with plastic scoops and transfer to plastic disposal bag.

7. Wipe up residual absorbent with moistened sponge

8. Place sponge, scoop, and gloves in disposal bag and seal. Arrange for disposal as chemical waste.

Flammable Solvents (For 500 ml of solvent or less)

1. Immediately remove all sources of ignition and provide maximum ventilation.

2. Open bag of absorbent by tearing top corner and pull out flap to form spout.

3. Apply sufficient quantity of materials to absorb all of the solvent (1 bag for 30 to 150 ml).

4. Thoroughly mix the absorbent and solvent with scoops provided. The absorbent should regain its appearance as a dry, free running, non-adhering powder. Clumping indicates flammable condition.

5. Pick up the absorbent with scoops and transfer to disposal bag along with gloves and scoops.

Seal and arrange for disposal as chemical waste.

Mercury

Mercury spills, commonly from broken thermometers, result in a large number of very small particles that are difficult to clean up. Small particles of mercury have an increased rate of vaporization, due to the higher ratio of surface area to volume, and this can cause greater contamination of the air than can be safely handled by normal ventilation. The safe exposure limit can be exceeded by a singlebroken thermometer if not cleaned up properly. This can be further aggravated by higher temperatures, such as a broken thermometer in an oven. As a precaution, place a container underneath all mercury sources, such as manometers and barometers, and use "unbreakable" (Teflon-coated) ornon-mercury thermometers.

To clean the spill, wear protective clothes and gloves. Sprinkle the contaminated area with material from the spill kit which will combine with the smaller mercury droplets to form a solid compound that will no longer vaporize as readily. Alternatively, use an aspirator bulb, scotch tape or place a small piece of dry ice on the surface of the mercury which very quickly freezes (m.p. -38 C) and can then be transferred with tweezers. Collect materials with a circular sweeping motion. All mercury and sweepings should then be disposed of through normal chemical waste procedures. Containers with liquid should be tightly sealed and unbreakable.

Alkali Metal

A spill of an alkali metal (e.g., sodium, potassium) should be smothered with powdered graphite, sand, or Class D extinguisher and removed to a safe location where it can be disposed of by reaction with a dry secondary alcohol. Particles of alkali metal splattered on the skin should be rapidly removed, and the skin flushed quickly with water. If any metal on the skin becomes ignited, deluge it with cold water immediately.

Reactive Chemicals

Reactive chemicals are substances which, under certain ambient or induced conditions, enter into violent reactions with spontaneous generation of large quantities of heat, light, gases (flammableandnon-flammable), or toxicants that can be destructive to lives and property. Types of reactive chemicals have been loosely categorized:

EXPLOSIVES

In general, protect explosive substances from shock, elevated temperatures, rapid temperature changes, and other reactive chemicals. Some examples: nitroglycerin, nitrocellulose, and organic peroxides. Many substances, when mixed, are potentially explosive (such as hydrazines and nitric acid).

Note that the following compounds readily form peroxides upon:

Storage (3 Months)

Isopropyl ether*

Divinyl acetylene

Vinylidene chloride

Potassium metal

Sodium amide

Concentration (12 Months)

Ethyl ether*

Tetrahydrofuran

Dioxane

Acetal

Methyl i-butyl ketone

Ethylene glycol

Methyl ether (glyme)

Vinyl ethers

Dicyclopentadie ne

Diacetylene

Initiation of P olymerization (12 Months)

Styrene

Butadiene

Tetrafluoroethy lene

Chlorotrifluoro ethylene

Vinyl acetylene

di-Vinyl acetat e

Vinyl chloride

Vinyl pyridine

Chlorobutadiene

(Chloroprene)

Methyl acetylen e

Cumene

Tetrahydronapht halene

Cyclohexene

Methylcyclopent ane

*Storage in metal containers slows peroxide formation.

OXIDIZING AND REDUCING SUBSTANCES

In many oxidizing and reducing reactions, both agents must be present. In some cases, one or the other substance may create a hazard by coming into contact with a normally innocuous substance. 

These reactions tend to generate heat and are often explosive, e.g., glycerol and potassium permanganate blended at room temperature for a few minutes react violently producing fire. The following examples of typical oxidizers may:

Increase Rate of Combustion

Aluminum nitrate

Ammonium persulfate

Barium chlorate

Barium peroxide

Calcium chlorate

Calcium nitrate

Calcium peroxide

Cupric nitrate

Hydrogen peroxide

Lead nitrate

Lithium hypochlorite

Lithium peroxide

Magnesium nitrate

Magnesium perchlorate

Magnesium peroxide

Nickel nitrate

Nitric acid 70% or less

Perchloric acid 60% or less

Potassium chlorate

Potassium dichromate

Potassium nitrate

Potassium persulfate

Silver nitrate

Silver nitrite

Sodium perborate

Sodium perchlorate

Sodium persulfate

Strontium chlorate

Strontium nitrate

Strontium nitrite

Thorium nitrite

Uranium nitrate

Zinc chlorate

Zinc peroxide

Cause Spontaneous Ignition

Calcium hypochlorite

Chromic acid

Hydrogen peroxide (27.5-52%)

Nitric acid

Potassium bromate

Potassium permanganate

Sodium chlorite (more than 40%)

Sodium peroxide

Sodium permanganate

Trichloroisocyanuric acid

Sodium dichloroisocyanurate

Decompose With Catalyst or Heat

Ammonium dichromate

Hydrogen peroxide (52-91%)

Calcium hypochlorite (over 50%)

Perchloric acid (60-72.5%)

Potassium dichloroisocyanurate

Sodium dichloroisocyanurate

Cause Explosive Reaction When Exposed to

Catalyst, Heat, Shock, or Friction

Ammonium perchlorate

Ammonium permanganate

Perchloric acid

Potassium superoxide

WATER SENSITIVE SUBSTANCES

These chemicals react with water, steam, and moisture in the air to evolve heat and/or flammable or explosive gases. Isolate water-sensitive substances fromother reactive compounds, and store in a cool, waterproof area. Some substances that liberate only heat are: strong acids and bases, acid anhydride sand sulfides. Some substances that liberate flammable gases when exposed to water are: alkali metals, hydrides, nitrites, carbides, and anhydrous metallic salts.

AIR REACTIVE SUBSTANCES

These materials are capable of rapid release of energy by themselves, as by self-reaction or polymerization, for example white phosphorus. Also included in this category are substances that can be easily ignited by common sources ofheat when mixed with air; for example: alkali metals, ammonium nitrate, ammonium perchlorate, ammonium permanganate, benzoyl peroxide, boronhydrides, dinitrobenzene, lithium hydride, sulfur.

ACID REACTIVE SUBSTANCES

These chemicals react with acid to evolve heat, flammable and/or explosive gases, and toxicants. Some examples are: alkali metals, hydroxides, carbides, nitrites, arsenic and related elements, cyanides, sulfides, and structural alloys(most metals).

SPECIAL ORGANIC COMPOUNDS

These compounds are unstable and may decompose spontaneously or through contact with the immediate environment (air, water, and other reactants).Some examples: diazonium compounds, diazomethane, chlorination intermediates, butadiene, nitration intermediates, organic sulfates, polymerization reactions, and highly nitrated compounds.

PYROPHORIC AGENTS

Pyrophoric agents burn when exposed to air. In general, they require absolute protection against air. Examples: phosphorus and activated zinc. 

Incompatible Chemicals

ACETIC ACID with chromic acid, nitric acid, hydroxyl-containing compounds, ethylene glycol, perchloric acid, peroxides, and permanganates

ACETONE with concentrated sulfuric & nitric acid mixtures or chloroform & bases

ACETYLENE with copper(tubing), halides, silver mercury and their compounds

ALKALI METALS: aluminum, calcium, lithium, magnesium, potassium and sodium with water or chlorinated hydrocarbon, carbon dioxide, halogens

AMMONIA, Anhydrous with mercury, halogens, calcium hypochlorite, hydrogen fluoride

AMMONIUM NITRATE with acids, metal powders, flammable fluids,chlorates, sulfur nitrate

ANILINE with nitric acid and hydrogen peroxide

AZIDES with acids

BROMINE with ammonia, acetylene, butadiene, butane, hydrogen, sodiumcarbide, turpentine

CHLORATES with ammonium salts, acids, metal powders, sulfur, finely divided organic and combustible materials

CHROMIC ACID with acetic acid, alcohol, camphor, flammable liquids,glycerol, naphthalene

CHLORINE with ammonia, acetylene, butadiene, benzene and other petroleum fractions, hydrogen, sodium carbides, powdered metals

COPPER SALTS with acetylene, hydrogen peroxide

CYANIDES with acids

ETHYLENEDIAMINE greater than 3 percent with methylene chloride(explosive)

FLAMMABLE LIQUIDS with ammonium nitrate, chromic acid, hydrogenperoxide, halogens, nitric acid, sodium peroxide

HYDROCARBONS (butane, propane, benzene) with halogens, chromic acid, peroxides

HYDROGEN PEROXIDE with copper chromium, iron, most metals and their salts, flammable fluids, aniline, and nitromethane

HYDROGEN SULFIDE with nitric acid and oxidizing gases

IODINE with acetylene, ammonia

MERCURY with acetylene, hydrogen

METHYLENE CHLORIDE with greater than 3 percent ethylenediamine(explosive)

NITRIC ACID with acetic, chromic and hydrochloric acids, aniline, carbon, hydrogen sulfide, flammable fluids, or gases which are readily nitrated

OXYGEN with oils, grease, hydrogen, flammable liquids, solids, and gases

OXALIC ACID with mercury, silver

PERCHLORIC ACID with acetic anhydride, alcohol, organic materials, e.g.,wood, paper, grease, and oils

PHOSPHORUS with air, alkalis, oxygen, reducing agents

PHOSPHORUS PENTOXIDE with water

SODIUM with carbon dioxide, carbon tetrachloride, water

SODIUM PEROXIDE with any oxidizable substances; acetic acid, acetic anhydride, benzaldehyde, carbon disulfide, glycerol, ethylene glycol, ethylacetate, methanol

SULFURIC ACID with potassium chlorate, potassium perchlorate, potassium permanganate

An annotated list of hazardous chemical reactions is available from the NFPA; a much longer compendium is provided by Bretherick.

Hazards of Some Common Hazardous Chemicals

Some hazards one may face when working with reactive chemicals are illustrated below; for specific information on distillation and extraction see GENERAL SAFETY PRACTICES. Threshold Limit Values (TLV) are included for some agents as an indication of the upper limits of exposure that are considered "safe." Values are either 8-hour time-weighted averages (TWA)or short term (usually 15 minutes) exposure limits (STEL). (See "Exposure" above for further information.) Note that some of these compounds are also regulated as carcinogens. This list is far from complete. Gloves, goggles, anda fume hood may be appropriate. If there are any questions, consult the department head, laboratory supervisor or those responsible for environmental health and safety.

ACETONITRILE

The effect of exposure to CH3CN is due partially to the intact molecule and also to the cyanide ions released by metabolism. Acetonitrile is skin permeable. Ingestion, acute inhalation or contact exposures should be treated as for hydrogen cyanide exposure. The vapors are irritating to the eyes and skin.

Acetonitrile has a "etherish" odor detectable at 40 ppm but olfactory fatigue occurs within 2 hours. A TWA of 40 ppm and a STEL of 60 ppm are recommended to protect against organic cyanide poisoning and injury to therespiratory tract.

ACRYLAMIDE

Acrylamide is a potent neurotoxin. No data are available to evaluate the reproductive effects or prenatal toxicity of acrylamide to humans. The TLV is0.03 mg/m3. There is sufficient evidence for carcinogenicity of acrylamide to experimental animals (IARC 2B). Purchase acrylamide in concentrated stocksolution. If dry acrylamide is absolutely necessary, wear gloves and weigh in a still area of the lab away from traffic, fume hoods and drafts.

BENZENE

Benzene is readily absorbed through intact skin, as well as through the respiratory tract. Do not handle carelessly. Poisoning can occur by inhalation of relatively small amounts causing white cell aberrations and possibly aplasticanemia. The TLV is 10 ppm (TWA) and 32 ppm (STEL). Benzene is a knownhuman carcinogen.7 Whenever possible toluene should be substituted for benzene as a reagent.

CHLOROFORM

Exposure to high concentrations and/or chronic exposure can result in disorientation, conjunctivitis, liver and kidney damage, and possible sensitization of the heart to adrenaline, resulting in cardiac arrhythmias. There is sufficient evidence of carcinogenicity in experimental animals (IARC 2B). 

Exposure of chloroform to heat or flame can results in generation of phosgenegas. In a few minutes phosgene may cause eye irritation and coughing at 5ppm, severe lung injury at 20 ppm, and death at 50 ppm. The odor detection threshold of chloroform is 200-300 ppm while the TLV without regard to its potential carcinogenicity is 10 ppm (TWA).

CHROMIC ACID

Dichromate cleaning solution is an extremely corrosive agent. The TLV for chromium III is 0.5 mg/m3(TWA) and the TLV for chromium VI is 0.05mg/m3(TWA). Use alternatives for glassware cleaning such as MICROTM and rinse glassware with straight mineral acids if necessary to remove inorganicmetals. Alternatively, use 3:1 H2SO4:HNO3 in a fume hood. 

CYANOGEN BROMIDE

This chemical is explosive in the solid state unless it is absolutely white. Keep bottles tightly stoppered. Vapors are highly irritating and very poisonous. Aqueous solutions of alkalies decompose cyanogen bromide to alkali cyanide and alkali bromide. The ceiling TLV is 0.3 ppm for cyanogen chloride.

DIISOPROPYL FLUOROPHOSPHATE

This compound reacts with acetylcholinesterase and inactivates this enzyme, leading to the accumulation of acetylcholine. DFP can be absorbed byinhalation, ingestion or topical contact and can cause pinpoint pupils, lacrimation, rhinitis, weakness, wheezing, tachycardia. Severe intoxication is evidenced by ataxia, confusion, convulsions, and respiratory paralysis.

Sufficient 2 N NaOH should be on hand whenever DFP is being used in order to neutralize the entire amount of DFP. If exposed to DFP call for medical assistance immediately. Treatment consists of administration of atropine followed by pyridine-2-aldoxime.

DIETHYL ETHER

Repeated exposure via inhalation has caused loss of appetite, exhaustion, and headache. At a concentration of 3.6-6.5% in air general anesthesia occurs. Acute overexposure produces vomiting, irregular respiration, and low pulserates and body temperatures. The lethal oral dose is about 420 mg/kg. TheTLV is 400 ppm (TWA) and 500 ppm (STEL). No open flame is permitted in the same room where ether is being used. Open bottles of ether should be stored in a fume hood or in a flammable storage refrigerator. Even vessels of ether containing an oxidation inhibitor, should not be kept more than a few months to avoid the hazard of explosive peroxide formation. Do not dispose of ether by allowing it to evaporate in a fume hood or by pouring it down the drain; arrange for proper chemical disposal.

DIMETHYLFORMAMIDE

DMF readily penetrates the skin and causes stomach pain, nausea, vomiting, epigastric cramps, and liver damage. The TLV is 10 ppm(TWA).

DIMETHYL SULFATE

An extremely reactive material, especially when it comes in contact with the skin or mucous membranes, dimethyl sulfate was used as a war gas. A very short time of contact with the mucous membranes will result in painful burns. If it comes in contact with the eye, sight will be impaired if it is not removed immediately; wash out the eye with a stream of water from an eyewash station.

In addition to the local effect, the inhalation of vapors will cause a very severe toxic effect which may be delayed up to 10 hours. The TLV is 0.1 ppm (TWA)and there is sufficient evidence of carcinogenicity in experimental animals(IARC 2A). In case of contact, wash the surface liberally with soap and wateror alcohol containing a little ammonia; then, cover the area with bicarbonate paste. Seek medical assistance.

DIMETHYL SULFOXIDE

This substance decomposes violently on contact with a wide variety of active halogen compounds. Its toxicity is still unknown, but it is an excellent solvent for many compounds and does carry dissolved substances through the skin. Thick latex gloves should be worn when handling this substance.

ETHIDIUM BROMIDE

Ethidium bromide is a potent mutagen and should be handled carefully; its carcinogenicity has not been sufficiently studied. Treatment with bleach mayproduce oxidation products that are also mutagenic. Dispose of ethidium solutions as chemical waste. Exposure to ultraviolet light (UV) from transilluminators used to examine ethidium bromide stained gels may cause serious eye and skin burns, the latter may make an individual more susceptible to skin cancer. Equipment shields, UV-rated face shields, a lab coat, and opaque gloves all increase protection.

FORMALDEHYDE

Inhalation of vapors, 2-10 ppm, may result in severe irritation and edema of the upper respiratory tract, burning and stinging of the eyes, headache, and has been known to cause death. It is a skin sensitizer and severe eye irritant, causing delayed effects that are not appreciably eased by eye washing. The 1982 TLV is 1 ppm (TWA) and 2 ppm (STEL). There is evidence of carcinogenicity in animals (IARC 2A). Laboratory operations with formalin in open vessels should be carried out in a hood. In addition, splash-proof goggles and neoprene, butyl rubber, or polyvinyl gloves should be worn.

HYDRAZINE AND ITS SALTS

Acute exposure to vapors can cause respiratory tract irritation, convulsions, cyanosis and a decrease in blood pressure. Hydrazine can cause fatty degeneration of the liver, nephritis, and hemolysis and there is sufficient evidence of carcinogenicity in experimental animals (IARC 2B). In addition, hydrazine poses a significant fire hazard. Hydrazine has an ammonia-like odor detectible at 3 ppm. The TLV for hydrazine is 0.1 ppm (TWA). Hydrazine is volatile and readily absorbed through the skin. Nitrile rubber gloves are recommended. Prompt washing with water effectively removes hydrazine from skin.

HYDROFLUORIC ACID

Hydrogen fluoride (HF) is a very serious hazard since both its gaseous and liquid forms are toxic and it is rapidly absorbed through the skin and deep into the body tissues causing long term excruciating pain and burns which are slow to heal. It is difficult to contain because it attacks glass, concrete and some metals, especially iron. It also attacks organic materials such as leather, natural rubber, and wood. Because aqueous HF can cause formation of hydrogen in metallic containers and piping, which presents a fire and explosion hazard, potential sources of ignition should be excluded from an area in which it is stored. It is crucial that this substance be used only in a fume hood to ensure that the level considered safe (3 ppm) is not exceeded. All contact with the vapor or liquid must be avoided by using protective equipment such as face shields and neoprene or PVC gloves. This equipment should be washed after each use to remove any HF. Although immediate pain is felt from the concentrated acid, action of the acid may be insidious and contact with a less concentrated solution may go unnoticed for hours. In concentrations greater than 50%, the burn is felt immediately and tissue destruction is apparent; in the 20 to 50% range, it may take eight hours for a burn to become apparent; below 20% pain and erythema can be latent for as long as 24 hours after exposure, sometimes delaying proper treatment. After any contact, even if there is no immediate pain, obtain medical aid. Prompt removal of contaminated clothing while the injured person is being flushed with water under a safety shower is essential. Continuous flushing with cool water is vital until any whitening of the tissue has disappeared. Simple flushing with water does not remove HF deep in the tissues. Soak in ice water or solution of benzalkonium chloride. Alternatively, apply 2.5% calcium gluconate gel to the exposed area after a five minute shower or swab the area with cotton moistened with 10% solution of 28% aqueous ammonia and immerse area in a bath of water for a prolonged period. If HF is ingested, drink a large quantity of water as quickly as possible, then drink milk or milk of magnesia to sooth burning. Do not induce vomiting. Commercial containers of this acid are labeled with a blue color code which turns yellow when contaminated with the acid. The container then requires continuous flushing with water until the blue color is restored. Spills should be contained and diluted with water and the resulting solution neutralized with lime before disposal.

HF Cleavage Operation

Commercially available HF systems utilizing a vacuum rather than positive pressure to transfer reagents are preferred as the potential for escape of HF is significantly less under negative pressure. All HF system operators will receive formal and/or hands-on training on the hazards presented by HF and the safe operating procedures for the unit. Detailed written operating protocols will be prepared and approved by those responsible for environmental health and safety prior to the inauguration of HF system use. Protocols to be posted at the HF fume hood, containing, at the minimum:

- Guidelines for personal protective equipment (22 mil thick heavy-grade neoprene gloves, chemically resistant sleeves and apron, and splash-proof goggles)

- Response to malfunctions such as occlusion of tubing, ports or control valve associated with the reaction vessel, e.g., freezing with a Dry-Ice alcohol bath and transferring vessel to an unused position on the apparatus

- Availability of HF specific spill absorbent pillows

- Emergency response and notification procedures

- First Aid procedures:

- 25% magnesium gluconate for skin exposure

- 1% calcium gluconate in a nebulizer and an eye dropper or squeeze bottle for inhalation or eye exposure to HF

HYDROGEN CYANIDE

Hydrogen Cyanide (HCN) should always be used under a hood. Liquid hydrogen cyanide is best kept over anhydrous calcium chloride. Formation of a yellow color in the liquid indicates the lot should be destroyed. Hydrogen cyanide and other cyanides are dangerous poisons which cause muscle paralysis. The TLV has a ceiling of 10 ppm and an exposure to 200-500 ppm can be fatal after 30 minutes. Aside from its high toxicity, HCN has a low flash point and forms an explosive mixture with air over a wide range of concentrations. When exposed to traces of base, detonation may result.

HYDROGEN PEROXIDE

A solution is considered dangerous in concentrations over 3%. In contact with the skin, it may cause severe burns. The TLV is 1 ppm (TWA). At a concentration of 30% it may decompose violently if contaminated with iron, copper, chromium, or other metals and their salts.

MERCURY

Mercuric compounds can be absorbed into the body by inhalation, ingestion, or contact with the skin. The effects of mercury poisoning are cumulative and not readily reversible. Chronic inhalation produces emotional disturbances, inflammation of mouth and gums, memory loss, headaches, general fatigue, and possible kidney damage. The TLV for exposure to vapor is 0.05 ppm (TWA). Containers of mercury must be kept tightly closed and in well-ventilated areas.Thick, high-density polyethylene bottles are useful for this purpose.

METHYLENE CHLORIDE

In the 1940s, CH2Cl2 was considered the safest of the chlorinated hydrocarbons and a high exposure limit was thought to be adequate protection against narcosis and liver injury. Subsequently the metabolism of methylene chloride to carbon monoxide and production of carboxyhemoglobin was reported. While the exposure limit was lowered to 50 ppm (TWA), the same as the TLV for carbon monoxide, the exposure duration, peak concentration, and slow metabolism make prediction of actual carboxyhemoglobin levels difficult. Exposures to carboxyhemoglobin through processes generating carbon monoxide, e.g., automotive exhausts, smoking should be considered additive. The sweet odor, while distinctive, is a poor indicator of exposure since most people can not detect less than 300 ppm. There is sufficient evidence of carcinogenicity in experimental animals (IARC 2B). The carcinogenicity of this compound is under extensive investigation and the literature as well as the environmental health and safety office should be consulted for current information.

METHYLMERCURIC HYDROXIDE

A fairly volatile and highly toxic agent useful to molecular biologists primarily because it is a reversible denaturant of nucleic acids. Alkyl mercury compounds pass through the blood brain barrier and the placenta very rapidly, in contrast to inorganic mercury compounds. Major target organs are the central and peripheral nervous systems and the kidneys. Work with methyl mercury is very hazardous because of the difficulty of eliminating it from the body. The human threshold for dangerous exposure levels is a urinary concentration of between 10-15 g/L. Studies have shown that while 35% of the compound is excreted in a few days, months are required to approach complete excretion, and some organic mercury becomes incorporated into body tissues. If the air concentration is greater than 0.03 mg/m3, one is considered overexposed; over an 8-hour day one should not be exposed to an air concentration greater than 0.01 mg/m3.

To guard against the major dangers posed by this compound, namely inhalation, absorption through the skin, or ingestion, the following guidelines are suggested:

The stock solution of methyl mercuric hydroxide (1M) will be kept under a fume hood at all times. All work involving use of the stock solution, including dilutions, will be done in the hood.

All gels (methylmercury at 5-10 mM) will be diluted, poured and run in the hood. After completion, any gels which require extensive handling, e.g., cutting out and eluting bands, will first be treated with 7 mM 2-mercapto-ethanol, which converts the mercurial to a metallic, non-volatile form. Only gels which must be autoradiographed may be removed from the hood without being treated with 2-mercaptoethanol.

Disposable pipettes will be used to draw from any methylmercury-containing solution and a solid waste container will be maintained for used pipettes and gels to be discarded. This waste will be disposed of along with other chemical waste; arrange for disposal as chemical waste.

All workers using methylmercury will wear gloves and lab coats.

Buffer solutions used in gel electrophoresis have been found to leach approximately 0.6 g/ml of methylmercury out of gels. This is, of course, a fairly low concentration, and could probably be washed down the drain. To insure against unintentional accumulation in the plumbing system, however, liquid waste should be accumulated and disposed of through the chemical disposal service.

OSMIUM TETROXIDE

Osmium tetroxide is a volatile chemical with a disagreeable chlorine-like odor. The toxic vapors cause lacrimation, eye and respiratory irritation and coughing, blurred vision and headache, following acute exposure. It should be used only in a functioning fume hood and stored in tightly sealed containers. The TLV is 0.0002 ppm (TWA) and 0.0006 ppm (STEL).

PERACETIC ACID

Explodes at 100C and decomposes at lower temperatures with the generation of oxygen. It reacts vigorously with organic materials. In addition, it is an irritant affecting skin, eyes, and upper respiratory tract. Rubber gloves and apron should be worn and, in the absence of a fume hood, an appropriate respirator.

PERCHLORIC ACID

Cold perchloric acid, 70% or weaker, is not considered to have significant oxidizing power. The oxidizing power, however, increases rapidly as the concentration increases above 70%. Temperature rises will also increase the oxidizing power of perchloric acid solutions. Aqueous perchloric acid can cause violent explosions if misused or used in concentrations greater than 72%.

Anhydrous perchloric acid is unstable even at room temperature and ultimately decomposes spontaneously with violent explosion. Therefore, perchloric acid should be segregated from dehydrating agents such as concentrated sulfuric acid, phosphorus pentoxide, or acetic anhydride. Should only be used in laboratories with specially designed perchloric acid hoods. These hoods feature duct work of stainless steel and a wash-down facility to prevent the collection of explosive perchlorate compounds in the duct system. Dried spills on wooden or asphalt surfaces can ignite spontaneously with friction or impact. Perchlorate esters have the same shattering effect as nitroglycerine. Do not use magnesium perchlorate as a desiccant, except in the standard procedure for the determination of carbon and hydrogen.

PHENOL

Phenol is highly corrosive. Inhalation or skin contact can result in serious or fatal poisoning. When phenol is dissolved in organic solvents it is readily absorbed into the blood stream. If phenol is accidentally spilled, flush all contaminated parts with water. Phenol vapors are toxic, and the TLV is 5 ppm (TWA) and 10 ppm (STEL). Purchase ultrapure phenol; if phenol must be redistilled, see warnings under "Distillation" in GENERAL SAFETY PRACTICES.

PICRIC ACID

Classified as a high explosive, it is particularly dangerous when in a dry or crystallized state (containing less than 20% water); do not store for more than two years. Weigh bottle before and after each use and record use. Picric acid that is old or dried out is shock sensitive; careless handling or removing the cap can cause detonation. Arrange for chemical disposal. Picric acid dust, solutions, and fumes are potent skin and eye irritants. The STEL is 0.3 mg/m3.

PYRIDINE

Acute exposure can produce dizziness, eye and nasal irritation, nausea, and anorexia. Chronic exposure has produced serious liver, kidney, and bone marrow damage and possible central nervous system effects. Transient symptoms of overexposure are nausea, headache, insomnia and nervousness, and low back or abdominal discomfort with urinary frequency. Exposure to heat or flame with pyridine vapors can be explosive. It reacts violently with sulfuric acid, nitric acid, maleic anhydride, chromic acid; cyanides can be liberated on decomposition. The TLV is 5 ppm (TWA) and 10 ppm (STEL). The odor threshold is below 1 ppm.

TRICHLOROETHYLENE

Acute exposure primarily affects the central nervous system, but the mildness of the irritation which produces headache, fatigue, and irritability does not provide sufficient warning to protect against overexposure, and coma and death have been reported following severe intoxication. The TLV is 50 ppm (TWA) and 200 ppm (STEL). The odor recognition level is 20 ppm.

XYLENE

In addition to the hazards of flammability, xylene can present a broad range of neurological and gastrointestinal symptoms and possible injury to heart, liver, and kidneys. The TLV is 100 ppm (TWA) and 150 ppm (STEL).

NON-HAZARDOUS WASTES

The following can be disposed of as trash or into the sanitary sewer system without special handling:

Organic chemicals

Acetates: Ca, Na, NH4, and K

Amino acids and their salts

Citric acid and salts of Na, K, Mg, Ca, and NH4

Lactic acid and salts of Na, K, Mg, Ca, and NH4

Sugars

Inorganic chemicals

Bicarbonates: Na, K

Borates: Na, K, Mg, Ca

Bromides: Na, K

Carbonates: Na, K, Mg, Ca

Chlorides: Na, K, Mg, Ca

Fluorides: Ca

Iodides: Na, K

Oxides: B, Mg, Ca, Al, Si, Fe

Phosphates: Na, K, Mg, Ca, NH4

Silicates: Na, K, Mg, Ca

Sulfates: Na, K, Mg, Ca, NH4

When in doubt about the disposal of chemicals, consult your supervisor or environmental health.

CHEMICAL WASTE PREPARATION AND LABELING

Chemical wastes should be treated as follows:

Collect, identify, and label the containers of all chemical waste. "Unknowns" are unacceptable. Make sure that the label contains the full chemical name(s) and percentages of mixtures, the waste volume, and its location.

Do not pour any flammable, water immiscible, water reactive, or highly toxic chemicals down the drain. Small amounts (e.g., <100 ml) of neutralized acids, alkalies, and water miscible alcohols may be disposed of by slowly flushing them down the laboratory drain with large amounts of water.

Caution: Acids and alkalies react vigorously and exothermically with water. Always add acid or alkali to water, not the reverse.

Use a waste container with a volume as close to that of the waste as possible. If plastic containers are used, make sure that they are compatible with the chemical to be stored.

Generally, wastes should not be combined. Each container of waste should have only one component unless mixtures are a necessary part of the process that produces the waste, e.g., solid state peptide synthesis. Machine- or process-generated wastes should be segregated and labeled according to the type of machine. For example, Peptide Synthesis ABI 430A waste should be labeled as such and kept separate from DNA Synthesis ABI 380A waste. A detailed description of the composition of machine-generated waste should be obtained from the manufacturer and given to those responsible for waste disposal.

Combining waste solvents is permissible ONLY if the quantities of individual components are small, i.e., < 2 L/week, and if the solvents are from the same categories, e.g., all halogenated solvents. This eliminates the need to have dozens of waste containers in a synthesis lab. If solvents are combined, a record of the approximate composition of each waste must be kept. If the quantity of combined solvent waste exceeds 2 L per week, other arrangements must first be made with those responsible for chemical waste disposal.

Contaminated labware should be placed in the clear plastic bags provided.

No more than 1 kg of waste and NO liquid should be put into the bag.

Do not dispose of volatile chemical waste by allowing it to evaporate in a fume hood.

NOTE: The presence of any radioactivity must be indicated on the hazardous waste labels. These materials must be treated as radioactive waste (see waste handling procedures in The Radiation Safety Manual.)

COMPRESSED GASES

When ordering hazardous gases, consider factors such as handling and storage, compatibility of gas regulators, eye and skin absorption, and chemical properties. Remember that some gases are corrosive, e.g., ammonia, chlorine, hydrogen chloride, hydrogen fluoride; flammable, e.g., acetylene, butane, hydrogen, methane, propane; oxidizers, e.g., oxygen, chlorine; or toxic, e.g., carbon monoxide, ethylene oxide; and cryogenic, e.g., nitrogen, carbon dioxide, oxygen.

General Precautions

Cylinders of compressed gases should be handled as high energy sources and therefore as potential explosives. The following rules apply:

When storing or moving a cylinder, have the cap securely in place to protect the valve stem.

When moving large cylinders, they should be strapped to a properly designed wheeled cart to ensure stability.

Cylinders of all sizes must be restrained by straps, chains, or a suitable stand to prevent them from falling.

Cylinders of toxic, flammable, or reactive gases should be used in fume hoods and, when possible, stored in fume hoods.

Do not expose cylinders to temperatures higher than 50C. Some rupture devices on cylinders will release at about 65C. Some small cylinders including lecture bottles are not fitted with rupture devices and may explode if exposed to high temperatures.

Never use a cylinder that cannot be positively identified. Do not rely on the color of the cylinder to identify its contents.

Use the appropriate regulator on each gas cylinder. Adaptors or homemade modifications can be dangerous.

Use only, correct, pressure-rated tubing.

Never lubricate, modify, force or tamper with a cylinder valve. Do not loosen or remove the safety plug or rupture disc.

Leaks can be monitored by pressurizing the system, turning off the cylinder stem valve and looking for a drop in the discharge pressure. The location of leaks can be identified by painting all fittings and joints with soapy water and watching for bubble formation. When using toxic gases, it is advisable to use a toxic gas detector or indicator for detection and warning. Wrapping the thread with Teflon tape may be necessary to stop the leaks.

When corrosive gases are being used, the cylinder stem valve should be worked frequently to prevent its freezing.

Keep cylinders containing liquified gases upright. Note that it is often difficult to determine the contents of a cylinder containing liquified gas, except by weighing. As long as a liquid is present, the cylinder or vapor pressure will remain constant. The cylinder pressure for liquified carbon dioxide does provide an indication of cylinder content.

Oil or grease on the high pressure side of an oxygen cylinder can lead to an explosion.

Care should be exercised when compressed air or gas is used to blow away dust or dirt, since the resultant flying particles are dangerous.

Rapid release of a compressed gas will cause an unsecured gas hose to whip dangerously and also may build up a static charge which could ignite a combustible gas.

Do not extinguish a flame involving a highly combustible gas until the source of gas has been shut off as it can re-ignite causing an explosion.

Never bleed a cylinder completely empty. Leave a slight pressure to keep contaminants out. In case of nitrogen cylinders, leave approximately 10 psi. This prevents contamination of the cylinder.

When not in use, cylinder and bench valves should be closed tightly.

Remove the regulators from empty cylinders and replace the protective caps.

Mark the cylinder "Empty" or "MT" and return to the distributer.

Do not keep cylinders filled with corrosive, explosive, or highly toxic gases more than 6 months; do not keep cylinders with oxygen or liquids or flammable gases more than 3 years.

If a cylinder begins to leak move it outdoors and contact the supplier.

Damaged or corroded cylinders and cylinders with a test date more than 5 years old stamped on the shoulder should be returned to the vendor.

Do not order a surplus of cylinders. Besides presenting a safety hazard, there usually is a daily rental fee.

Precautions for Cryogenic Gases

Avoid contact, both the liquid and the gases can cause frostbite. Do not touch uninsulated piping.

Wear loose-fitting thermal gloves, goggles and/or face shield, closed shoes.

Work in a well ventilated area. Liquified gas can rapidly expand, e.g., nitrogen expands almost 700-fold.

Never attempt to prevent vapors from escaping from cylinders of liquified, cryogenic gases. Since they are not at thermal equilibrium, vapor is produced as the liquid boils and, if not vented to the atmosphere, could produce excessive pressures.

Use only the special (usually metal) tubing designed for use with these gases. Do not improvise with plastic or rubber tubing.

Be aware that oxygen enrichment and a fire hazard can result from the condensation of oxygen (boiling point -183C) from the air onto piping cooled by liquid nitrogen (boiling point -196C).

If skin contacts liquified cryogenic gases, thaw burned area slowly in cold water. Do not rub.

Cylinder Features

The valve outlet connection connects to pressure and/or flow-regulating equipment. Specific connections are provided to prevent interchange of equipment for incompatible gases. They are identified by a CGA number; for example, CGA 350 is used for hydrogen, carbon monoxide, methane and some other flammable gases. For information on valve and regulator fittings, consult the manufacturer or those responsible for environmental health and safety.

A pressure relief device prevents a fully charged cylinder from bursting in case of exposure to high heat. The cylinder collar holds the cylinder cap which protects the cylinder valve from mechanical or weather damage. It should be removed from the cylinder only when the cylinder is supported and ready to be attached to pressure-reducing and/or flow control equipment for use.

The DOT number signifies that the cylinder conforms to DOT specifications and that the service pressure for which the cylinder is designed is 2265 psi at 21C with an exception indicated by the + sign following the last test date, which allows a 10% overfilling.

The cylinder serial number is registered with the DOT, and can be used to verify the contents of the cylinder by querying the manufacturer.

The cylinder test date indicates the month and year of initial hydrostatic test.

Thereafter, hydrostatic tests are performed on a cylinder at intervals specified by the DOT (usually every 5 years), or when the supplier feels they are necessary, to determine whether the cylinder is fit for further use. For each hydrostatic test, the new test date is stamped into the cylinder shoulder.

The encircled insignia is that of the original inspector.

Cylinder size is important to consider when purchasing compressed gas, especially flammable gases. The National Fire Protection Association has recommended that laboratories using flammable gas contain no more than a single tank of 0.59 cu. ft. water volume as long as the presence of other combustible items in the room is minimal. For example, a tank of 0.59 cu. ft. water volume is a Matheson Company size 2 cylinder (8" diameter x 27" length) or Ohio size 30.

Regulators

The proper choice of a regulator depends on the delivery-pressure range required, the degree of accuracy of delivery pressure to be maintained, and the flow rate required. There are two basic types of pressure regulators, single-stage and two-stage. The single-stage type will show a slight variation in delivery pressure as the cylinder pressure drops. It will also show a greater drop in delivery pressure than a two-stage regulator as the flow rate is increased. In addition, it will show a higher "lock-up" pressure (pressure increase above the delivery set-point necessary to stop flow) than the two-stage regulator. In general, the two-stage regulator will deliver a more constant pressure under more stringent operating conditions than will the single-stage regulator.

A regulator should be attached to a cylinder without forcing the threads. If the inlet of a regulator does not fit the cylinder outlet, no effort should be made to try to force the fitting. A poor fit may indicate that the regulator is not intended for use on the gas chosen. The following steps should be taken for delivery of gas:

1. After the regulator has been attached to the cylinder valve outlet, turn the delivery pressure-adjusting screw counterclockwise until it turns freely.

2. Open the cylinder valve slowly until the tank gauge on the regulator registers the cylinder pressure. At this point, the cylinder pressure should be checked to see if it is at the expected value. A large error may indicate that the cylinder valve is leaking.

3. With the flow-control valve at the regulator outlet closed, turn the delivery pressure-adjusting screw clockwise until the required delivery pressure is reached. Control of flow can be regulated by means of a valve supplied in the regulator outlet or by a supplementary valve installed in a pipeline downstream from the regulator. The regulator itself should not be used as a flow control by adjusting the pressure to obtain different flow rates. This defeats the purpose of the pressure regulator and in some cases where higher flows are obtained in this manner, the pressure setting may be in excess of the design pressure of the system.

ACETYLENE

Acetylene is the most thermodynamically unstable common gas, has a very wide explosive range (from 2% to 80% in air), and under pressure and certain conditions can decompose with explosive force. To allow safe handling of acetylene in cylinders, suppliers use a porous packing material saturated with a solvent in which the acetylene dissolves. The combination of porous filling and solvent markedly enhances the stability of acetylene. Acetylene is authorized for shipment only as a dissolved gas in cylinders marked DOT-8 or -8AL, and cylinders so designated may be used only for acetylene.

ARGON, CARBON DIOXIDE, HELIUM AND NITROGEN

These gases are inert, colorless, odorless, and tasteless but can cause asphyxiation and death in confined, poorly ventilated areas. Do not lean into or place your head into a freezer. In addition these gases can cause severe frostbite to the eyes or skin. Some carbon dioxide cylinders contain an eductor tube and are intended for liquid withdrawal. These cylinders are specially marked; be sure you are using equipment appropriate to the application. Air will condense on exposed helium liquid or cold-gas surfaces, such as vaporizers and piping. Nitrogen, having a lower boiling point than oxygen, will evaporate first, leaving an oxygen-enriched condensation on the surface. To prevent possible ignition of grease, oil, or other combustible materials, care must be taken that equipment is free of these materials.

HYDROGEN

Hydrogen is a flammable gas. A mixture of hydrogen and oxygen or air in a confined area will explode if ignited by a spark, flame or other similar source. Escaping hydrogen cannot be detected by sight, smell or taste and, because of its lightness, it has a tendency to accumulate in the upper portions of confined areas.

OXYGEN

Oxygen supports and can greatly accelerate combustion; keep combustibles away from oxygen and eliminate ignition sources. Oxygen is colorless, odorless, and tasteless and as a liquid or cold gas may cause severe frostbite to the eyes or skin. Many materials, especially some non-metallic gaskets and seals, constitute a combustion hazard when in oxygen service, although they may be acceptable for use with other gases. Before attaching regulator to cylinder, be certain that the regulator and inlet filter are free of oil, grease, or other contaminants, and crack the cylinder valve momentarily to blow out any dust or dirt that might have accumulated in the cylinder valve outlet. When using an oxygen torch remember to turn on the natural gas (in sufficient quantity) first and off last and wear UV absorbing eye protection.

Gas Cylinder Disposal

When compressed gas tanks are empty, label the cylinders with the letters

"MT."

When compressed gas tanks are empty or no longer needed, contact those responsible for chemical waste disposal to return the cylinders to the distributor. Never dispose of gas cylinders, even small propane canisters, lecture bottles, or chemical aerosol cans, in the general trash.

REFERENCES

GENERAL REFERENCES

American Chemical Society, Committee on Chemical Safety. 1989. Chemical

Safety Manual for Small Businesses. Washington DC: American Chemical

Society.

American Chemical Society, Committee on Chemical Safety. 1990. Safety in

Academic Chemistry Laboratories. Washington, DC: American Chemical

Society.

American Industrial Hygiene Association. 1989. Odor Thresholds for

Chemicals with Established Occupational Health Standards. Akron, OH:

AIHA.

Braker, W., and A.L. Mossman. 1980. Matheson Gas Data Book, 6th ed.

Lyndhurst, NJ: Matheson.

Bretherick, L. 1990. Handbook of Reactive Chemical Hazards, 4th ed.

London, England: Butterworths. ISBN

0-7506-0103-5.

Bretherick, L. (ed.). 1986. Hazards in the Chemical Laboratory, 4th ed. Port

Washington, NY: Royal Soc. Chem.

Compressed Gas Association. 1990. Handbook of Compressed Gases, 3rd ed.

New York, NY: Van Nostrand

Reinhold. ISBN 0-442-25419-9.

Fawcett, H.H., and W.S. Wood. 1982. Safety and Accident Prevention in

Chemical Operations, 2nd ed.

New York, NY: Wiley and Sons. ISBN 0-471-02435-X.

Foa, V. 1987. Occupational and Environmental Chemical Hazards: Cellular

and Biochemical Indices for

Monitoring Toxicity. New York, NY: Wiley and Sons.

Ho, M.H., and H.D. Dillon (eds.). 1987. Biological Monitoring of Exposure

to Chemicals: Organic Compounds. New York, NY: Wiley and Sons.

International Agency for Research on Cancer. 1979. Handling Chemical

Carcinogens in the Laboratory: Problems of Safety. IARC Scientific

Publications No. 33. Geneva,

Switzerland: WHO Publications

Center.

International Agency for Research on Cancer. 1972-. Monographs on The

Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva,

Switzerland: WHO Publications

Center. ISBN 92-832-1417-X.

Klaasen, C.D., Amdur, M.O., and J. Doull. 1986. Casarett and Doull's

Toxicology, 3rd ed. New York, NY:

Macmillan Publishing Co. ISBN 0-02-364650-0.

Manufacturing Chemists Association. 1973. Guide for Safety in the Chemical

Laboratory, 2nd ed. New York, NY: Van Nostrand Reinhold. ISBN 0-442-

05667-2

National Fire Protection Association. Quincy, MA: NFPA.

1991. NFPA 49: Hazardous Chemicals Data

1991. NFPA 321: Basic Classification of Flammable and Combustible

Liquids

1991. NFPA 325M: Fire Hazard Properties of Flammable Liquids, Gases

and Volatile Solids

1991. NFPA 491M: Hazardous Chemical Reactions

1986. NFPA 704: Fire Protection Guide on Hazardous Materials

National Institute of Occupational Safety and Health (NIOSH). 1985-86.

Registry of Toxic Effects, 14th ed. Washington, DC: U.S. Govt. Printing

Office.

National Research Council. 1981. Prudent Practices for Handling Hazardous

Chemicals in Laboratories.

Washington, DC: National Academy Press. ISBN 0-309-03390-X.

National Toxicology Program. Most recent. Annual Report on Carcinogens.

Research Triangle Park, NC: NIEHS.

Office of Science and Technology Policy. 1985. Chemical Carcinogens: A

Review of the Science and Its Associated Principles. Federal Register

50:10372-10442.

Pipitone, D.A. (ed.). 1991. Safe Storage of Laboratory Chemicals, 2nd ed.

New York, NY: Wiley and Sons.

Searle, C.E. 1984. Chemical Carcinogens, 2nd ed. Washington, DC: American

Chemical Soc. ISBN 0-8412-0869-7.

Shepard, T.H. 1983. Catalog of Teratogenic Agents, 4th ed. Baltimore, MD:

Johns Hopkins University Press. ISBN 0-8018-3027-3.

Sittig, M. 1985. Handbook of Toxic and Hazardous Chemicals and

Carcinogens, 2nd ed. Park Ridge, NJ: Noyes Publications. ISBN 0-8155-

1009-8.

United States Coast Guard. 1974. A Condensed Guide to Chemical Hazards.

Washington, DC: U.S. Dept. of Transportation. CG-4461-1.

Walters, D.B. (ed.). 1980. Safe Handling of Chemical Carcinogens, Mutagens,

Teratogens and Highly Toxic Substances. Ann Arbor, MI: Ann Arbor

Science. ISBN 0-250-40303-X.

Windholz, M. (ed.). 1989. The Merck Index, 11th ed. Rahway, NJ: Merck &

Co.

APPENDIX

SUBSTANCES SPECIFICALLY REGULATED BY OSHA UNDER THE

LABORATORY STANDARD

This list includes compounds regulated by OSHA under 1910.Subpart Z,1 compounds considered to be "Known Carcinogens" by the NTP,2 and the IARC designated carcinogens and suspect carcinogens.3 Those compounds included in the IARC lists are shown with their IARC Group; those from Subpart Z and the NTP lists are shown with the appropriate footnote.

Substance IARC

Group4

A--C(2-Amino-9H-pyrido[2,3,b]indole)

2B

Acetaldehyde 2B

Acetamide 2B

2-Acetylaminofluorene1 --

Acrylamide 2B

Acrylonitrile1 2A

Adriamycin 2A

AF-2[2-(2-Furyl)-3-(5-nitro-2-furyl)acrylamide] 2B

Aflatoxins 1

Aluminum production 1

para-Aminoazobenzene 2B

ortho-Aminoazotoluene 2B

4-Aminobiphenyl1,2 1

2-Amino-5-(5-nitro-2-furyl)-1,3,4-thiadiazole

2B

Amitrole 2B

Analgesic mixtures containing phenacetin2

1

Androgenic steroids 2A

ortho-Anisidine 2B

AramiteTM 2B

Arsenic and arsenic compounds1,2

1

Asbestos1,2 1

Auramine, technical-grade

2B

Auramine, manufacture of 1

Azaserine 2B

Azathioprine2 1

Benzene1,2 1

Benzidine1,2 1

Benzidine-based dyes 2A

Benzo[a]pyrene 2A

Benzo[b]fluoranthene 2B

Benzo[f]fluoranthene 2B

Benzo[k]fluoranthene 2B

Benzyl violet 4B 2B

Beryllium compounds 2A

Betel quid with tobacco 1

Bis(chloroethylnaphthyl)amine

1

Bischloroethyl nitrosourea (BCNU) 2A

Bis(chloromethyl) ether1,2 1

Bitumens, extracts of steam-refined & air-refined

2B

Substance IARC

Group4

Bleomycins 2B

Boot and shoe manufacture and repair

1

Bracken fern 2B

1,3-Butadiene 2B

1,4-Butanediol dimethanesulfonate ("Myleran")2 1

Butylated hydroxyanisole (BHA) 2B

-Butyrolactone 2B

Cadmium compounds 2A

Carbon-black extracts 2B

Carbon tetrachloride 2B

Carpentry and joinery 2B

Carrageenan, degraded 2B

Chlorambucil2 1

Chloramphenicol 2B

Chlordecone ("Kepone") 2B

-Chlorinated toluenes 2B

1-(2-Chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU)

2A

1-(2-Chloroethyl)-3-(methylcyclohexyl)-1-nitrosourea (Methyl-CCNU)

1

Chloroform 2B

Chlorophenols 2B

Chlorophenoxy herbicides 2B

4-Chloro-ortho-phenylenediamine 2B

para-Chloro-ortho-toluidine

2B

Chromium VI compounds2 1

Cisplatin 2A

Citrus Red No. 2 2B

Coal gasification operations 1

Coal tar pitches1 1

Coal tars1 1

Coke production1 1

Cotton dusts1 --

Creosotes 2A

para-Cresidine 2B

Cycasin 2B

Cyclophosphamide2 1

Dacarbazine 2B

Daunomycin 2B

DDT 2B

N,N'-Diacetylbenzidine 2B

2,4-Diaminoanisole 2B

4,4'-Diaminodiphenyl ether

2B

2,4-Diaminotoluene 2B

Dibenz[a,h]acridine 2B

Dibenz[a,f]acridine 2B

7H-Dibenzo[c,g]carbazole 2B

Dibenz[a,h]anthracene 2A

Dibenzo[a,e]pyrene 2B

Dibenzo[a,h]pyrene 2B

Dibenzo[a,i]pyrene 2B

Substance IARC

Group4

Dibenzo[a,l]pyrene 2B

1,2-Dibromo-3-chloropropane1

2B

para-Dichlorobenzene 2B

3,3'-Dichlorobenzidine1 2B

3,3'-Dichloro-4,4'-diaminodiphenyl ether

2B

1,2-Dichloroethane 2B

Dichloromethane 2B

1,3-Dichloropropene (technical-grade)

2B

Diepoxybutane 2B

Di(2-ethylhexyl)phthalate 2B

1,2-Diethylhydrazine 2B

Diethylstilboestral2 1

Diethyl sulfate 2A

Diglycidyl resorcinol ether 2B

Dihydrosafrole 2B

3,3'-Dimethoxybenzidine (ortho-Dianisidine)

2B

para-Dimethylaminoazobenzene1 2B

trans-2[(Dimethylamino)methylimino]-5-(2-(5-nitro-2-furyl)vinyl-

1,3,4-oxadiazole 2B

3,3'-Dimethylbenzidine (ortho-Tolidine)

2B

1,1'-Dimethylhydrazine

2B

1,2-Dimethylhydrazine 2B

Dimethylcarbamoyl chloride

2A

Dimethyl sulphate 2A

1,4-Dioxane 2B

Epichlorohydrin 2A

Erionite 1

Ethyl acrylate 2B

Ethylene dibromide 2A

Ethyleneimine1 --

Ethylene oxide1 2A

Ethylene thiourea

2B

Ethyl methanesulfonate 2B

N-Ethyl-N-nitrosourea 2A

Formaldehyde1 2A

2-(2-Formylhydrazino)-4-(5-nitro-2-furyl)thiazole

2B

Furniture and cabinet making 1

Glu-P-1 (2-Amino-6-methyldipyrido[1,2-:3',2'-d]imidazole)

2B

Glu-P-2 (2-Aminodipyrido[1,2-:3',2'-d]imidazole)

2B

Glycidaldehyde 2B

Griseofulvin 2B

Hematite mining, underground, with exposure to radon

1

Hexachlorobenzene 2B

Hexachlorocyclohexanes 2B

Hexamethylphosphoramide 2B

Hydrazine 2B

Indeno[1,2,3-cd]pyrene 2B

IQ (2-Amino-3-methylimidazo[4,5-f]quinoline) 2B

Iron-dextran complex 2B

Substance IARC

Group4

Iron and steel founding

1

Isopropyl alcohol manufacture, strong-acid process

1

Lasiocarpine 2B

Lead compounds (inorganic)1 2B

Magenta, manufacture of

1

MeA--C(2-Amino-3-methyl-9H-pyrido[2,3-b]indole)

2B

Medroxyprogesterone acetate

2B

Melphalan2 1

Merphalan 2B

5-Methoxypsoralen 2A

8-Methoxypsoralen & UV light2

1

2-Methylaziridine 2B

Methylazoxymethanol and its acetate

2B

Methyl chloromethyl ether1 1

5-Methylchrysene 2B

4,4'-Methylene bis(2-chloroaniline) (MOCA)

2A

4,4'-Methylene bis(2-methylaniline)

2B

4,4'-Methylenedianiline 2B

Methyl methanesulphonate 2B

2-Methyl-1-nitroanthraquinone

2B

N-Methyl-N-nitrosourethane

2B

N-Methyl-N'-nitro-N-nitrosoguanidine (MNNG) 2A

N-Methyl-N-nitrosourea 2A

Methylthiouracil 2B

Metronidazole 2B

Mineral oils 1

Mirex 2B

Mitomycin C 2B

Monocrotaline 2B

MOPP and combined chemotherapy preparations

1

5-(Morpholinomethyl)-3-[(5-nitrofurfurylidene)amino]-2-oxazolinone

2B

Mustard gas2 1

Nafenopin 2B

1-Naphthylamine1

3

2-Naphthylamine1,2 1

Nickel compounds 1

Niridazole 2B

5-Nitroacenaphthene 2B

4-Nitrobiphenyl1

3

Nitrofen (technical-grade) 2B

1-[(5-Nitrofurfurylidene)amino]-2-imidazolidonone

2B

N-[4-(5-Nitro-2-furyl)-2-thiazolyl]acetamide

2B

Nitrogen mustard 2A

Nitrogen mustard N-oxide 2B

2-Nitropropane 2B

N-Nitrosodiethylamine 2A

N-Nitrosodimethylamine1 2A

N-Nitrosodi-n-butylamine 2B

N-Nitrosodi-ethanolamine 2B

Substance IARC

Group4

N-Nitrosodi-n-propylamine 2B

3-(N-Nitrosomethylamino)propionitrile

2B

4-(N-Nitrosomethylamino)-1-(3-pyridyl)-1-butanone (NNK)

2B

N-Nitrosomethylethylamine

2B

N-Nitrosomethylvinylamine

2B

N-Nitrosomorpholine 2B

N-Nitrosonornicotine 2B

N-Nitrosopiperidine 2B

N-Nitrosopyrrolidine 2B

N-Nitrososarcosine 2B

Oestrogen replacement therapy

1

Oestrogens, non-steroidal 1

Oestrogens, steroidal 1

Oil Orange SS 2B

Oral contraceptives, combined

1

Oral contraceptives, sequential

1

Panfuran S (containing dihydroxymethylfuratrizine) 2B

Phenacetin & analgesics 2A

Phenazopyridine hydrochloride

2B

Phenobarbital 2B

Phenoxybenzamine hydrochloride 2B

Phenytoin 2B

Polybrominated biphenyls 2B

Polychlorinated biphenyls 2A

Ponceau MX 2B

Ponceau 3R 2B

Potassium bromate 2B

Procarbazine hydrochloride 2A

Progestins 2B

1,3-Propane sultone 2B

-Propiolactone1 2B

Propylene oxide 2A

Propylthiouracil 2B

The rubber industry 1

Saccharin 2B

Safrole 2B

Shale oils 1

Silica, crystalline 2A

Sodium ortho-phenylphenate

2B

Soots 1

Sterigmatocystin 2B

Streptozotocin 2B

Styrene 2B

Styrene oxide 2A

Sulfallate 2B

Talc containing asbestiform fibers 1

2,3,7,8-Tetrachlorodibenzo-para-dioxin (TCDD)

2B

Tetrachloroethylene 2B

Thioacetamide 2B

Substance IARC

Group4

4,4'-Thiodianiline 2B

Thiourea 2B

Thorium dioxide2 --

Tobacco products, smokeless

1

Tobacco smoke 1

Toluene diisocyanates 2B

ortho-Toluidine 2B

Toxaphene (polychlorinated camphenes)

2B

Treosulphan 1

Tris(1-aziridinyl)phosphine sulphide (Thiotepa) 2A

Tris(2,3-dibromopropyl) phosphate 2A

Trp-P-1 (3-Amino-1,4-dimethyl-5H-pyrido[4,3-b]indole)

2B

Trp-P-2 (3-Amino-1-methyl-5H-pyrido[4,3-b]indole)

2B

Trypan blue 2B

Uracil mustard 2B

Urethane 2B

Vinyl bromide 2A

Vinyl chloride1,2 1

1 OSHA Standard, Subpart Z - Toxic and Hazardous Substances (29 CFR

1910 Subpart Z) as of 19 January 1989.

2 National Toxicology Program (NTP), Substances "Known to be

Carcinogenic". NTP. 1989. Fifth Annual Report on Carcinogens. Report

NTP 89-239.

3 International Agency for Research on Cancer (IARC).1987. IARC

Monographs on the Evaluation of Carcinogenic Risks to Humans: Overall

Evaluations of Carcinogenicity. Supplement 7. Lyons, France.

4 IARC Carcinogen Groups: 1 = known carcinogenicity; 2A = probable; 2B =

possible; 3 = not classifiable due to insufficient or conflicting data.

TABLE 3. Relative Hazard Levelsa

METHOD

Relative Hazard 1

Relative Hazard 2

Relative Hazard 3

Relative Hazard

4

Relative Hazard 5

Eye Contactb

0.5 ml causes no

severe injury

0.005 ml causes

no severe injury

0.0005 ml or > 40%

solution causes severe

injury

> 5% solution

causes severe

injury

> 1% solution

causes severe

injury

Inhalationc

8 hrs fatal < 50%

2-4 hrs fatal < 66%

1/4-1 hrs fatal < 66%

2-5 min fatal <

66%

2 min fatal < 83%

Skin

Penetrationb

LD50 > 20 ml/kg body

weight

LD50 2-20 ml/kg

body weight

LD50 0.2-1.99 ml/kg

body weight

LD50 0.02-0.19

ml/kg body weight

LD50 < 0.02

ml/kg body

weight

Skin

Irritationb

Undiluted solution

causes capillary

injection

Undiluted solution

causes slight

erythema

Undiluted solution causes

erythema & slight edema

Undiluted solution

causes necrosis

10% solution

causes necrosis

Ingestionc

LD50 > 10 g/kg body

weight

LD50 1-10 g/kg

body weight

LD50 100-999 mg/kg

body weight

LD50 10-99 mg/kg

body weight

LD50 < 10 mg/kg

body weight

aHandbook of Laboratory Safety, 2nd Ed, 1984, ed. Norman V. Steere. Boca Raton, FA: CRCPress, Inc., 680-682.

Total pages 854.

bStudies performed on male albino rabbits

cStudies performed on male albino rats