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Chapter VI: Handling Chemicals

Handling and use of chemicals should minimize the risk of worker exposure to the chemicals. Workers must be informed about the hazards of working with chemicals and hazardous substances. This training must be well documented and provided at all levels in the organization. Training should cover chemical handling techniques, individual chemical hazards, procedures to protect safety and health, and personal protective equipment. In no case should worker exposure exceed the permissible exposure levels (PEL), the threshold limit values (TLV) or other recognized health standards.

This chapter is divided into three main sections:

  1. Under Safe Handling Recommendations, the basic information that needs to be communicated to workers is described.
  2. Under Chemical Storage, general information on safe chemical storage is given followed by more detailed information on storage within hazard classes.
  3. Under Chemical Hazards, chemical hazards are described in more detail and general handling recommendations given to help in planning controls for chemical procedures.

A. SAFE HANDLING RECOMMENDATIONS

Before using any chemical, workers need to be familiar with the characteristics associated with the particular chemical. Safety Data Sheets (SDSs), available to workers, are a good source of information. Other sources of chemical information include container/manufacturer labels, reference books (see Bibliography), and EH&S.

    CHEMICAL CHARACTERISTICS
    Workers must be familiar with the following:

  1. Quantity of chemical that is toxic or hazardous:

    1. know the amount of exposure considered to be safe
    2. know the lethal dose of any toxic chemical

  2. Route of exposure of the chemical: (how the chemical can enter the body)

    1. absorption through the skin or eye
    2. ingestion
    3. inhalation
    4. injection

  3. Type of hazard (many chemicals are dangerous in more than one way):

    1. corrosive
    2. explosive
    3. flammable
    4. irritant
    5. reactive
    6. sensitizer
    7. toxic

  4. Mode of action: (how does the chemical act on the body)

    1. acute toxicity (symptoms occur soon after one large exposure)
    2. chronic toxicity (numerous smaller exposures cause damage)
    3. carcinogen (can cause cancer)
    4. mutagen (can cause permanent mutation)
    5. teratogen (can cause abnormalities during prenatal development)

  5. Symptoms and target organs of over-exposure:

    Each chemical or group of chemicals has identifiable physical symptoms of overexposure and can preferentially affect certain body parts.

  6. Physical properties of the chemical:

    1. aerosol (airborne dusts or mists)
    2. cryogen
    3. dusts or particles (can become airborne and inhaled)
    4. gas
    5. liquid
    6. solid
    7. vapor density (heavy vapors will collect near the floor, may stay in pockets and flow into other areas)
    8. vapor pressure (fast evaporation can increase exposure)
    9. flammability

  7. Chemical compatibility (mixing some chemicals can cause explosion, release of toxic gases, or cause a fire).

    TRAINING AND WORK PRACTICES
    Workers must be informed about the hazards of working with chemicals and hazardous substances. This training must be well documented and provided at all levels in the organization. A sample training form is provided in Appendix B.Workers should be trained on the following:

  8. Standard operating procedures should be developed before starting any work with hazardous chemicals. Work that involves particularly dangerous or large quantities of chemicals should have a written standard operating procedure (see Appendix A) that clearly describes steps to be taken to protect health and minimize risks. Plans should be developed to deal with emergencies, spills and incidents that could occur.

  9. Recommended work practices:

    1. Restrict the amount of chemicals ordered, kept on hand, and used - control inventory using the Chemical Inventory System (CIS). Chemicals should be ordered in quantities that can be used within a year of receipt.
    2. Substitute less hazardous chemicals whenever possible.
    3. Use a fume hood (or other containment device, like exhaust hood or snorkel) and always when using volatile, smelly or toxic liquids.
    4. Do not work alone when handling hazardous materials.
    5. Keep work area clean.
    6. Wear eye protection.
    7. Wear a clean laboratory coat and remove the coat before leaving the lab - don't take contamination home with you on your lab coat.
    8. Wear the proper type of gloves, remembering that latex gloves provide virtually no protection against solvents and strong corrosives. Glove compatibility charts are available from glove manufacturers.
    9. Wash hands frequently, after a splash to the skin and before eating, drinking, handling contact lenses, applying cosmetics or taking medications.
    10. Label all containers with chemical name, hazard warning, date, and name of preparer.
    11. Keep containers tightly closed except when in use.
    12. Segregate chemicals in storage to keep incompatibles separated. Do not store chemicals in alphabetical order.
    13. Do not taste chemicals.
    14. Do not mouth pipet.
    15. Avoid smelling chemicals.
    16. Know the locations of fire extinguishers, alarm pull stations, eyewashes, and emergency showers, and know how they operate.
    17. Do not smoke, eat, drink, apply cosmetics, take oral medications, chew gum, or tobacco while using chemicals.
  10. Chemical fume hoods are the primary defense against inhalation and release of hazardous materials in the laboratory and are an effective means of controlling exposure. The laboratory supervisor must provide training on fume hood operation and use, including the limitations of fume hoods. Operations should be performed as far into the hood as possible, at least six inches from the edge of the hood work surface. The air slots at the back of the hood must not be blocked. The sash on a vertical sash hood should be operated at the lowest possible position, but not more than 18 inches (work opening). Horizontal sash hoods must be operated with the sash(es) in place. Make sure the hood's work surface is uncluttered. Check the hood flow indicator to make sure that it is working properly by before starting work. All hoods are required to have flow indicators or devices. See Chapter IV for more details.

  11. Personal protective equipment (PPE), when used in conjunction with thorough knowledge of the chemical and good work practices, will make chemical work reasonably safe. Chapters V and X go into further detail on personal protective equipment.

    The following personal protection should be part of all chemical and laboratory work:

    1. Eye protection, if faithfully and properly worn, will eliminate nearly all eye injuries. Contact lens wearers should be particularly meticulous about eye protection.
    2. Glove type must be chosen for the specific task and chemical (refer to Chapter IV). Even with the correct gloves, protection may not be complete; therefore, gloves should be changed frequently and always after a chemical splash.
    3. Respirators should be used only for specific situations and for emergencies. All respirator use must have prior approval by EH&S. All individuals using a respirator must undergo a pulmonary function test, physical exam, be personally fit-tested, and trained in the proper use and care of a respirator before it can be used during work. Chapter X goes into further detail on respiratory protection.
    4. Foot protection must be used when the situation warrants. Safety shoes should be worn when handling drums or other heavy items. Laboratory workers and persons entering laboratories should wear closed-toed, closed-heel shoes.
    5. Aprons and laboratory coats should be worn to protect clothing and when using corrosive or toxic chemicals. Remove aprons and lab coats when leaving the lab.

B. CHEMICAL STORAGE

Many laboratory accidents are due to improper storage practices and both Cal/OSHA and State fire code regulations require certain minimum storage practices. Although instituting a sound storage protocol requires an investment of time, it pays off in the long run.For safe storage of laboratory chemicals, four major principles apply:

1. Maintain control of the inventory.
2. Label containers.
3. Segregate chemicals by compatibility.
4. Provide adequate storage space and appropriate containers.
  1. Maintain control of the inventory:

    • Keep the minimum amount on hand.
    • Purchase limited quantities - a good rule of thumb is to only order quantities that can be used within one year.
    • Inspect storage locations regularly.
    • Properly dispose outdated chemicals through the EH&S hazardous waste program (see Chapter VIII for details).
    • Control inventory by using the Chemical Inventory System (CIS).

  2. Label containers: Label transfer containers. Include:

    • Chemical name.
    • Hazard warning(s).
    • Storage class (this can be color-coded to make storage decisions easier)
    • Name of preparer.
    • Date prepared (this is especially important for peroxidizable chemicals).

  3. Segregate incompatible chemicals from one another:

    Segregation by broad class, alone, is complicated and largely impractical since many chemicals in laboratory use have more than one hazardous property. The practical solution is to adopt a manageable number of classes (defined mainly by flammability, explosivity, and toxic exposure hazard) and then to apply careful and consistent judgment to solve the inevitable problems associated with the limited number of classes.
  • DO NOT ALPHABETIZE STORED CHEMICALS.
  • Initially assign each chemical to broad hazard classes, for example: flammable, corrosive (acids and bases), toxic, reative oxidizer or reducer, special hazard (air/water reactive, peroxide forming chemical, store at reduced temperature (see section C) or under an inert atmosphere).
  • Chemicals that possess more than one hazard (i.e., oxidizer and corrosive) are assigned to the class that, in the judgment of the assigning person, represents the greater hazard for that laboratory.
  • If the assignment would result in a potential incompatibility with other chemicals in that class, then the multiple hazard chemical is further assigned to a special subclass within the originally assigned class. Physically separate subclasses in separate cabinets, if possible, or in bins, tubs or buckets.
  • Label the container with the assigned class (color-coded tape can make storage decisions easier).
  • Document final storage class on the inventory hard copy as a record. This helps ensure consistency.
  • Keep incompatibility lists on hand for reference. (See example list at the end of this chapter.)

General Storage of Chemicals by Class (Examples):

  • Flammable and Combustible Chemicals
    Flammables are chemicals that have a flash point less than 100oF. Combustible chemicals have flash points that are 100-200oF. If stored or used improperly, flammables and combustibles can be a fire hazard.

    Examples:

    • benzene
    • alcohols
    • hydrogen sulfide
    • acetone
    • ethers
    • organic acids (i.e., glacial acetic acid)

    Up to 10 gallons of flammable liquids, in glass containers of one gallon or less, may be stored in the laboratory. Over 10 gallons must be stored in an approved flammable storage cabinet in the lab. Flammable liquids may be stored in glass containers less than one-gallon capacity. Up to two gallons of flammable liquids may be stored in safety cans - safety cans must be less than two-gallon capacity. Safety cans have spring release caps and spark arresters. Flammable liquids, stored in flammable storage cabinets, must be limited to 60 gallons per fire area. A fire area is a space surrounded by fire-rated walls and doors (typical campus laboratory). Contact the UC Davis Fire Department for advice in assessing your storage area.

Segregate flammables from oxidizers and corrosives.

Keep flammables away from ignition sources.

  • Corrosives: Acids

    Acids are corrosive and react violently with bases. There are two main groups of acids: organic acids, and inorganic (mineral) acids. Some inorganic (mineral) acids are oxidizers and will react with organics, increase burning rate of combustibles and contribute an oxygen source to a combustion reaction. Therefore, inorganic (mineral) acids should be stored separately from organic acids.

    Examples of inorganic acids:
    • Oxidizing acids
      • perchloric acid (particularly dangerous at elevated temperature)
      • chromic acid
      • nitric acid
      • sulfuric acid (particularly dangerous at elevated temperature)
    • Mineral acids
      • hydrochloric acid
      • hydrofluoric acid
      • phosphoric acid

    Examples of organic acids:
    • acetic acid
    • formic acid
    • butyric acid
    • propionic acid
    • picric acid
    • acrylic acid

Segregate acids from bases and active metals such as potassium and magnesium.

Segregate acids from chemicals that could generate toxic gases upon contact, such as sodium cyanide.

Segregate acids from solvents such as toluene and xylene.

All acids should be stored in secondary containers that are large enough to contain 110% of the volume of the largest container.

Segregate oxidizing inorganic acids from organic acids, flammable and combustible materials. Most mineral acids can be stored together except perchloric acid (see below).

Organic
acids (e.g. glacial acetic acid) are combustible and should be stored separately or with flammables rather than with inorganic acids. Several inorganic acids are oxidizers and therefore, incompatible with organics.

Perchloric acid and picric acid require special handling.

Picric acid is reactive with metals or metal salts and is potentially explosive when dry. Contaminated picric acid is particularly dangerous, as picrate metal salts are potentially explosive compounds. Picric acid must be stored wet with at least 10% water. Store picric acid in a cool, dry, non-ventilated area away from incompatibles or ignition sources.

Perchloric acid at elevated temperature is a very strong oxidizer. It can react with metals, wood and other combustibles to form potentially explosive compounds. For information on the handling, storage and use of perchloric acid, contact EH&S.

  • Corrosives: Bases

    Bases are corrosive and react violently with acids.

    Examples:
    • ammonium hydroxide
    • sodium hydroxide
    • calcium hydroxide
    • organic amines

    Segregate bases from acids. Bases are also corrosive to skin and tissue. Pay meticulous attention to personal protective equipment when using bases.
  • Highly Toxic Chemicals

    Highly toxic chemicals should be stored according to the hazards of the chemical. Poison gases should be stored in a chemical fume hood or ventilated cabinet with alarm. Contact the Fire Department for advice on storage requirements for poison/highly toxic gases.

    Examples:
    • phosgene
    • arsine
    • phosphine
    • osmium tetroxide
    • dimethyl sulfate
    • toluene-2,4-diisocyanate
    • sodium azide
    • 37% formaldehyde

    Store highly toxic solid and liquid chemicals in secondary containers and in a well-ventilated area. Containers should be closed with tape or sealant. Make sure highly toxic chemicals and the areas they are stored are scrupulously labeled.

  • Reactive: Oxidizers

    Oxidizers react vigorously with reducing materials. The reaction can lead to fires or explosions. Oxidizers will increase the burning rate of combustible materials and contribute oxygen to a combustion reaction.

    Examples:
    • halogens
    • ammonium persulfate
    • hydrogen peroxide
    • sodium dichromate
    • potassium permanganate
    • perchloric acid, at elevated temperature
    • ammonium nitrate (and other nitrate salts)

    Keep oxidizers away from flammables, combustibles (such as paper, wood) and other reducing agents.

  • Reactive: Reducers

    Reducing materials react vigorously with oxidizers. The reaction can lead to fires or explosions.

    Examples:
    • ammonia
    • carbon
    • metals
    • metal hydrides
    • phosphorus
    • silicon
    • sulfur

    Store reducing materials away from oxidizers.

  • Water-reactive Chemicals

    Water reactive materials react with water, water solutions, moisture, or humidity in the air to produce heat and/or flammable gases, which can ignite.

    Examples:
    • sodium (elemental)
    • potassium (elemental)
    • calcium carbide
    • phosphorous pentachloride

    Store water reactives away from any sources of water or moisture. Review manufacturer's recommendations for special storage conditions, such as under an inert atmosphere or, as in the case of elemental sodium, under mineral oil.

  • Peroxide Forming Chemicals

    Potentially explosive peroxides are formed by a free-radical reaction of hydrocarbons with molecular oxygen. Distillation, evaporation or other concentration of the peroxide can cause an explosion in contaminated hydrocarbons.

    Examples:
    • diethyl ether
    • tetrahydrofuran
    • acetaldehyde
    • isopropyl ether

    Store peroxide-forming chemicals away from light and heat. Carefully label all containers with the date received and the date opened. Monitor container dates and avoid keeping peroxide-forming chemicals on hand for more than a year after receipt and 6 months after opening. Consult SafetyNet #23 for further details on safe handling and storage of peroxide forming chemicals.

C. REFRIGERATORS AND FREEZERS

Ordinary household refrigerators and freezers constitute a hazard when used to store flammable or unstable chemicals. These units produce conditions that can lead to explosions. Domestic (household-type) refrigerators must not be used for flammable chemical storage. "Lab-safe" refrigerators and freezers (designed for storage of flammable liquids) must be used for flammable chemicals.

When searching for an item in a refrigerator used for chemical storage, be careful not to inhale vapors that may have built up in the cabinet.

All chemicals, including those stored in refrigerators and freezers, should be sealed and labeled with the name of the material, the date it was placed in storage, and the name of the person storing it. Refrigerators and freezers should be cleaned on a regular schedule, and old chemicals must be disposed through the EH&S hazardous waste program.

DO NOT store food in any refrigerator used to store chemicals. DO NOT store flammable liquids at reduced temperature in refrigerators and freezers unless recommended by the manufacturer.

D. FLAMMABLE STORAGE

The following minimum restrictions apply in all laboratories on campus as part of the university's compliance with state fire regulations. Some laboratories and buildings have more stringent regulatory requirements.

  • Up to 10 gallons of flammable liquids, including hazardous waste, may be stored in the laboratory at any one time.
  • Up to 20 gallons may be stored in the laboratory if the quantity in excess of 10 gallons is stored in two-gallon safety cans.
  • Quantities in excess of 10 gallons but less than 60 gallons must be stored in approved flammable storage cabinets.
  • Amounts in excess of 60 gallons (stored in a flammable liquid storage cabinet) per laboratory must be stored in an approved chemical storage room.

Only flammable materials should be kept in flammable storage cabinets. Corrosives are incompatible with flammable liquids and must NOT be stored in flammable storage cabinets. Flammable storage cabinets are designed to protect the contents from external fires. For this reason, the door(s) must be kept closed except when removing or replacing containers. Additionally, flammable storage cabinets are designed to contain a two-inch depth of a spilled liquid. For questions concerning flammable/combustible liquid storage, contact the Fire Department or EH&S.

E. CHEMICAL HAZARDS

This section contains descriptions of the general categories of chemical hazards and the safety principles associated with each. This section does not contain advice for handling specific chemicals. Safe work in a chemical laboratory requires very detailed knowledge of the nature, potential, and compatibility of each substance used. Anyone planning an experiment or procedure should review the Safety Data Sheet (SDS) and other references, such as those listed in the Bibliography, for each chemical used.

The following sections provide information for thinking about and planning controls and protection against common chemical hazards. In actual practice, such hazards do not group themselves in neat categories, but usually occur in combination or sequence. The categories and concepts are provided as an aid to awareness, and as encouragement for consistent safe planning and practice.

  1. Fire Hazard
    Flammability is one of the most common chemical hazards. To handle a flammable material safely, you must know its flammability characteristics: flash point, upper and lower limits of flammability, and ignition temperatures. This information appears on each SDS.

    1. Flash Point
      For a liquid, the flash point is the lowest temperature at which the liquid gives off enough vapors to form an ignitable mixture with air and produce a flame when a source of ignition is present. Many common laboratory solvents have flashpoints lower than room temperature.
    2. Autoignition Temperature
      The autoignition (or ignition) temperature is the temperature at which a flammable chemical ignites spontaneously in the air under controlled conditions.
    3. Spontaneous Combustion
      Spontaneous combustion occurs when a substance reaches its ignition temperature without the application of external heat. This characteristic is particularly important to keep in mind in the storage and disposal of chemicals.
    4. Limits of Flammability
      Each flammable gas and liquid (as a vapor) has a limited range of flammable concentration in mixtures with air. The lower flammable limit (or lower explosive limit) is the minimum concentration below which a flame is not propagated when an ignition source is present - such a mixture would be too "lean" to burn. The upper flammable limit (or upper explosive limit) is the maximum concentration of vapor in air above that a flame is not propagated -- such a mixture is too "rich." The flammable range (or explosive range) lies in between the two limits.
    5. Precautions with Flammable Liquids
      Flammable liquids do not burn; their vapors do. For a fire to occur, there must be 1) a concentration of vapor between the lower and upper flammable limits, 2) a source of oxygen, usually air, and 3) an ignition source. To avoid high vapor levels, use careful handling and fume hoods. Do not use open flames where flammable vapors are present. Ventilation is very important. A fume hood must be used when flammable liquids are used.

      Ignition sources include electrical equipment, open flames, static electricity, and hot surfaces. Others working in the laboratory should be informed of the presence of flammable vapors so that the ignition sources can be eliminated. Remember that most flammable vapors are heavier than air, and can spread out horizontally for considerable distances until reaching an ignition source.

      Handle flammable liquids only in areas free of ignition sources. Heating should be limited to water and oil baths, heating mantles, heating tapes, and sand baths.

      Static-generated sparks can be sudden and unpredictable ignition sources. When transferring flammable liquids in metal equipment, take care that metal vessels are bonded together and grounded to a common ground.
    6. Precautions with Flammable Gases
      Leakage of compressed or liquefied gases can quickly produce a flammable or explosive atmosphere in the laboratory.

  2. Explosion Hazard
    There are substances that are explosive in response to heat, light, friction, static discharge, mechanical shock, or contact with a catalyst. With some substances, very tiny amounts of impurity are sufficient to begin a reaction that can quickly transition to detonation.

    1. Precautions - Acquire a Safety Data Sheet (SDS) for each chemical being used. It is crucial to know a chemical’s potential, including compatibility with other substances. Be alert to any unusual change in the appearance of a reaction mixture. Rapid unexpected temperature rise or fuming are signals of imminent decomposition and emergency measures need to be taken immediately, such as removing the heat source, quickly applying a cooling bath, or leaving the room.

      Known explosive compounds must be protected from heat, light, friction, static discharge, mechanical shock, contact with a catalyst, or other conditions to which the compounds are sensitive. Check the SDS and other references to see what those conditions are. Such substances should be used only as required, and only in the smallest quantities absolutely necessary. Reactions involving or producing explosives should be designed on as small a scale as possible. Such reactions should be protected behind a blast shield secured to an immovable object or in a room specially designed to contain a detonation.

      Special care should be taken that equipment is maintained (for example, that oil is routinely changed in vacuum pumps) and that heating methods used do not cause, or increase the potential for ignition.

      Other laboratory workers must be notified when an explosion hazard is present, through direct announcement and conspicuous warning signs. Highly exothermic, potentially explosive reactions, or sudden polymerization reactions must never be left unattended.

    2. Personal Protection - In addition to protection otherwise required in the laboratory, wear face shields, and grounding straps (to dissipate static electric charge) at all times when handling known explosive substances. Laboratory coats of a flame-resistant and static-discharging material may help reduce minor injuries from flying glass or flash and reduce the risk of producing a static spark. When a serious explosion hazard is anticipated, shields and barricades secured to an immovable object will be necessary, along with devices for manipulating equipment at a safer distance - long-handled tongs, stopcock turners, mechanical arms, etc.

  3. Toxicity
    Toxicity is the potential of a chemical to cause injury to the body. Whether the effect is acute or chronic, the only way to avoid such injury is to prevent or greatly minimize ingestion, inhalation, absorption, or injection of toxic chemicals into the body.

    1. Exposure Limits - The dose, or amount of chemical, and how the body is exposed, determines the body's response. In the workplace, there are certain guidelines or regulations that limit your exposure to hazardous substances. These guidelines, which are set by various regulatory or professional organizations, are referred to as "workplace exposure limits." EH&S recommends that chemical exposure via all routes of entry be kept as low as reasonably achievable.

      1. A workplace exposure limit is the airborne concentration of a material below which most persons can be exposed without adverse effect. These limits are based on an 8-hour time-weighted average (TWA) over a working lifetime. Workplace exposure limits may be expressed as Threshold Limit Values (TLV) or Permissible Exposure Limits (PEL). A Permissible Exposure Limit is a legal limit and a TLV is a guideline.
      2. Time-Weighted Average (TWA) is the average concentration of a substance integrated over a period of time, typically, a normal 8-hour workday.
      3. A Short-Term Exposure Limit (STEL) is the maximum concentration limit for a continuous exposure period (usually no more than 15 minutes), provided that the daily TWA is not exceeded. Because workplace exposure limits are generally expressed as average concentrations, excursions above these values are permitted. The exposure levels during such excursions must be below the STEL. However, there are certain levels, which must never be exceeded, even instantaneously. These are known as the ceiling levels for a TLV or TLV-C.

      All these levels, though often based on data from animal research, refer to the exposure and resistance of a healthy adult. These levels do not necessarily apply to pregnant women, their unborn fetuses, or adults who are ill or under special stress. In such situations, the individual and his or her supervisor or instructor must carefully consider all pertinent information. Consult EH&S for further information.

    2. Acute Toxicity - Acute toxic effects are produced by a single large dose received in a short period of time. Damage is immediate, and may be partially or totally reversible. Acute toxic effects include:

      • Simple asphyxiation: the body does not receive enough oxygen (for example, when nitrogen has displaced the air in a room).
      • Chemical asphyxiation: the body is prevented from using oxygen (for example, when carbon monoxide instead of oxygen is absorbed in the blood).
      • Anesthetic: causes dizziness, drowsiness, headaches, and coma (for example, by the vapors of many organic solvents).
      • Neurotoxic: the brain's control of the nervous system is slowed down or changed (for example, by concentrations of lead and mercury).
      • Corrosive: body tissue is directly damaged by reaction with chemicals (for example, by strong acids or bases).
      • Allergic: repeated exposure to a chemical produces sensitizing, until there is an allergic reaction at the contact site (usually skin).
      • Irritant: a chemical that causes a reversible inflammatory effect by chemical action at the site of contact.

    3. Chronic Toxicity - Chronic toxicity refers to adverse or injurious effects that usually result from prolonged exposure to a substance, often at low dose levels. Damage may not appear for many years, and is often irreversible. As a result, this class of hazard is both very difficult and very important to guard against. Types of chronic toxic effects include:

      • Carcinogenicity: produces cancer (for example, acrylonitrile, asbestos, benzene, and vinyl chloride are known to produce cancer in humans).
      • Mutagenicity: altars cell genes; subsequent generations show genetic damage.
      • Teratogenicity: harms developing fetus.
      • Reproductive toxicity: interferes with the reproductive system in men or women.
      • Specific organ toxicity: damages specific organs (for example, carbon tetrachloride can cause liver damage).

    4. Precautions

      The precautions to take against contact with toxic substances are repeated many times throughout this manual. With chemicals of low acute toxicity, it may be tempting to be less rigorous; yet it is precisely those chemicals that most require continual caution - safety must become a habit.

      Each worker must protect his or her body against all forms of chemical contact - absorption, inhalation, ingestion, and injection. Never eat, drink, use tobacco products, apply cosmetics, handle contact lenses, or take medication in the laboratory; wear the appropriate protective gear (PPE), and always remove PPE before leaving the laboratory. Remember that the chemicals taken home on your clothes will have a more powerful effect on growing children and elderly people than on most adults.

      In order to know what level of personal protection will be adequate, keep up to date on current information for chemicals you are using. SDSs are updated regularly. It is important to consult the most recent data each time you begin a new procedure. The best precaution is to treat all chemicals as potentially toxic.
  4. Corrosivity
    Corrosiveness is a form of acute toxicity unique and hazardous enough to merit separate discussion. Corrosive chemicals include strong acids and bases, as well as oxidizing and dehydrating agents. When these chemicals come in contact with the skin, eyes, or respiratory tract they react with those tissues and cause local injury.

    1. Liquid Corrosives
      A liquid corrosive will act on the skin either rapidly or slowly, depending on concentration and length of contact. These chemicals react directly with the skin - dissolving or abstracting from it some essential components, denaturing the proteins of the skin, or disrupting/degrading the skin cells. Inorganic acids, organic acids, and bases are among typical liquid corrosives.

      When handling liquid corrosives, contact must be scrupulously prevented. Wear goggles, rubber or suitable synthetic gloves, and a face shield. A rubber or synthetic apron and rubber boots may also be necessary. Since many liquid corrosives also release irritating fumes or vapors, procedures using these materials may need to be performed in a fume hood.

    2. Solid Corrosives
      Solid corrosives interact with the skin when dissolved by moisture on the skin surface. Damage then occurs both from the corrosive action and from the heat of solution. Because they are solid, these chemicals are relatively easy to remove; but because they may not react immediately and may not be painful at first (as with the caustic alkalis), they could cause substantial damage before being detected.

      Solid corrosives are most commonly dangerous in a finely divided state. Dust control and good exhaust ventilation are essential. The use of goggles, gloves, and other protective clothing is critical. In case of chemical contact, care must be taken during the emergency shower irrigation to remove all particles of solid matter that might be lodged in the skin or clothes.

    3. Gaseous Corrosives
      Gaseous corrosives pose the most serious health hazard because of possible damage to the lungs, including spasm, edema, pneumonia, and even death. Different corrosive gases affect different parts of the lung. For example, ammonia affects the upper respiratory tract, while phosgene affects the lung, causing pulmonary edema. Do not inhale corrosive gases. These substances must be used in a chemical fume hood or other approved capture device. Skin and eyes must also be protected, as gases contact all exposed parts of the body.

  5. Impurities and Combinations
    SDSs contain information on pure chemicals, known mixtures, and proprietary materials -- unfortunately there are no such sheets for other materials found in the laboratory, including solutions, mixtures of unknown or uncertain composition, and byproducts of reactions, all common in the laboratory. Impurities, synergistic effects, formation of unexpected products and byproducts, insufficiently clean equipment, and the combination of vapors from your experiment with that of your neighbor's can all produce sudden and unanticipated hazards.

    There is no absolute protection against all contingencies, but it helps to wear protective gear, to clean equipment scrupulously, to be aware of experiments in progress in nearby areas, and to be completely familiar with emergency procedures.

F. TRANSPORTATION OF HAZARDOUS CHEMICALS

  1. Hazardous chemicals should not be transported in passenger vehicles. Federal, state, and campus policy (PPM 290-65) strictly regulate transport of hazardous materials and hazardous waste. Contact EH&S for further information.

  2. Federal and state law strictly regulates shipping of hazardous materials on common carriers. Contact Central Storehouse for further information on shipping requirements.
EXAMPLE INCOMPATIBLE CHEMICALS*
CHEMICAL: INCOMPATIBLE WITH:
Acetic acid Chromic acid, nitric acid, hydroxyl compounds, ethylene glycol, perchloric acid, peroxides,permanganates
Acetone Concentrated nitric and sulfuric acid mixtures
Acetylene Chlorine, bromine, copper, fluorine, silver, mercury
Alkali and alkaline earth metals (such as powdered aluminum or magnesium, calcium, lithium, sodium, potassium) Water, carbon tetrachloride or other chlorinated hydrocarbons, carbon dioxide, halogens
Ammonia (anhydrous) Mercury (e.g., in manometers), chlorine, calcium hypochlorite, iodine, bromine, hydrofluoric acid (anhydrous)
Ammonium nitrate Acids, powdered metals, flammable liquids, chlorates, nitrites, sulfur, finely divided organic combustible materials
Aniline Nitric acid, hydrogen peroxide
Arsenical materials Any reducing agent
Azides Acids
Bromine See chlorine
Calcium oxide Water
Carbon (activated) Calcium hypochlorite, all oxidizing agents
Chlorates Ammonium salts, acids, powdered metals, sulfur, finely divided organic or combustible materials
Chromic acid and chromium trioxide Acetic acid, naphthalene, camphor, glycerol, alcohol, flammable liquids in general
Chlorine Ammonia, acetylene, butadiene, butane, methane, propane (or other petroleum gases), hydrogen, sodium carbide, benzene, finely divided metals, turpentine
Chlorine dioxide Ammonia, methane, phosphine, hydrogen sulfide
Copper Acetylene, hydrogen peroxide
Cumene hydroperoxide Acids (organic or inorganic)
Cyanides Acids
Flammable liquids Ammonium nitrate, chromic acid, hydrogen peroxide, nitric acid, sodium peroxide, halogens
Fluorine All other chemicals
Hydrocarbons (such as butane, propane, benzene) Fluorine, chlorine, bromine, chromic acid, sodium peroxide
Hydrocyanic acid Nitric acid, alkali
Hydrofluoric acid (anhydrous) Ammonia (aqueous or anhydrous)
Hydrogen sulfide Fuming nitric acid, oxidizing gases
Hypochlorites Acids, activated carbon
Iodine Acetylene, ammonia (aqueous or anhydrous), hydrogen
Mercury Acetylene, fulminic acid, ammonia
Nitrates Acids
Nitric acid (concentrated) Acetic acid, aniline, chromic acid, hydrocyanic acid, hydrogen sulfide, flammable liquids and gases, copper, brass, any heavy metals
Nitrites Acids
Nitroparaffins Inorganic bases, amines
Oxalic acid Silver, mercury
Oxygen Oils, grease, hydrogen; flammable liquids, solids or gases
Perchloric acid Acetic anhydride, bismuth and its alloys, alcohols, paper, wood, grease, oils
Peroxides, organic Acids (organic or inorganic), avoid friction, store cold
Phosphorous (white) Air, oxygen, alkalies, reducing agents
Potassium Carbon tetrachloride, carbon dioxide, water
Potassium chlorate Sulfuric and other acids
Potassium perchlorate - see also chlorates Sulfuric and other acids
Potassium permanganate Glycerol, ethylene glycol, benzaldehyde, sulfuric acid
Selenides Reducing agents
Silver Acetylene, oxalic acid, tartaric acid, ammonium compounds, fulminic acid
Sodium Carbon tetrachloride, carbon dioxide, water
Sodium nitrite Ammonium nitrate and other ammonium salts
Sodium peroxide Ethyl or methyl alcohol, glacial acetic acid, acetic anhydride, benzaldehyde, carbon disulfide, glycerin, ethylene glycol, ethyl acetate, methyl acetate, furfural
Sulfides Acids
Sulfuric acid Potassium chlorate, potassium perchlorate, potassium permanganate, (similar compounds of light metals, such as sodium, lithium)
Tellurides Reducing agents

* Table from "Safety in Academic Chemistry Laboratories," A Publication of the American Chemical Society. 1995.