American Conference of Governmental Industrial Hygienists
is an organization of professional personnel in governmental
agencies or educational institutions engaged in occupational
safety and health programs. ACGIH establishes recommended
occupational exposure limits for chemical substances and
physical agents. See TLV©.
Any chemical that undergoes dissociation in water with the
formation of hydrogen ions. Acids have a sour taste and
may cause severe skin burns. Acid turns litmus paper red
and have pH values of 0 to 6.
- Acute Effect
Adverse effect on a human or animal that has severe symptoms
developing rapidly and coming quickly to a crisis.
- Acute Toxicity
Acute effects resulting from a single dose of, or exposure
to, a substance. Ordinarily used to denote effects in experimental
A tumor with glandular (secreting) elements.
Any disease of a gland
A union of two surfaces that are normally separate.
A fine aerial suspension of particles sufficiently small
in size to confer some degree of stability from sedimentation
(e.g., smoke or fog).
- Air-Line Respirator
A respirator that is connected to a compressed breathable
air source by a hose of small inside diameter. The air is
delivered continuously or intermittently in a sufficient
volume to meet the wearer's breathing requirements.
- Air-Purifying Respirator
A respirator that uses chemicals to remove specific gases
and vapors from the air or that uses a mechanical filter
to remove particulate matter. An air-purifying respirator
must only be used when there is sufficient oxygen to sustain
life and the air contaminant level is below the concentration
limits of the device.
Any chemical substance that forms soluble soaps with fatty
acids. Alkalis are also referred to as bases. They may cause
severe burns to the skin. Alkalis turn litmus paper blue
and have pH values from 8 to 14.
- Allergic Reaction
An abnormal physiological response to chemical or physical
Absence of menstruation
A chemical that causes a total or partial loss of sensation.
Overexposure to anesthetics can cause impaired judgment,
dizziness, drowsiness, headache, unconsciousness, and even
death. Examples include alcohol, paint remover, and degreasers.
American National Standards Institute is a privately funded,
voluntary membership organization that identifies industrial
and public needs for national consensus standards and coordinates
development of such standards.
A remedy to relieve, prevent, or counteract the effects
of a poison.
American Petroleum Institute is a organization of the petroleum
A description of a substance at normal room temperature
and normal atmospheric conditions. Appearance includes the
color, size, and consistence of a material.
- Aquatic Toxicity
The adverse effects to marine life that result from being
exposed to a toxic substance.
A vapor or gas that can cause unconsciousness or death by
suffocation (lack of oxygen). Most simple asphyxiants are
harmful to the body only when they become so concentrated
that they reduce oxygen in the air (normally about 21 percent)
to dangerous levels (18 percent or lower). Asphyxiation
is one of the principal potential hazards of working in
confined and enclosed spaces.
American Society for Testing and Materials is the world's
largest source of voluntary consensus standards for materials,
products, systems and services. ASTM is a resource for sampling
and testing methods, health and safety aspects of materials,
safe performance guidelines, effects of physical and biological
agents and chemicals.
Showing no symptoms.
Atmosphere, a unit of pressure equal to 760 mmHg (mercury)
at sea level.
A respirator that provides breathable air from a source
independent of the surrounding atmosphere. There are two
types: air-line and self-contained breathing apparatus.
- Auto-Ignition Temperature
The temperature to which a closed, or nearly closed container
must be heated in order that the flammable liquid, when
introduced into the container, will ignite spontaneously
British Anti-Lewisite - A name for the drug dimecaprol -
a treatment for toxic inhalations.
A substance that (1) liberates hydroxide (OH) ions when
dissolved in water, (2) receives hydrogen ions from a strong
acid to form a weaker acid, and (3) neutralizes an acid.
Bases react with acids to form salts and water. Bases have
a pH greater than 7 and turn litmus paper blue. See Alkali.
Blood-clotting mechanism effects.
Not recurrent or not tending to progress. Not cancerous.
Capable of being broken down into innocuous products by
the action of living things.
Removal and examination of tissue from the living body.
- Boiling Points - BP
The temperature at which a liquid changes to a vapor state
at a given pressure. The boiling point usually expressed
in degrees Fahrenheit at sea level pressure (760 mmHg, or
one atmosphere). For mixtures the initial boiling point
or the boiling range may be given.
materials with low boiling points generally present
special fire hazards. Some approximate boiling points:
BOM or BuMines
- Bureau of Mines, U.S. Department
The interconnecting of two objects by means of a clamp and
bare wire. Its purpose is to equalize the electrical potential
between the objects to prevent a static discharge when transferring
a flammable liquid from one container to another. The conductive
path is provided by clamps that make contact with the charged
object and a low resistance flexible cable which allows
the charge to equalize. See Grounding.
- Bulk Density
Mass of powdered or granulated solid material per unit of
- Centigrade, a unit of temperature.
- Ceiling Limit (PEL or TLV©)
The maximum allowable human exposure limit for an airborne
substance which is not to be exceeded even momentarily.
Also see PEL and TLV©.
Clean Air Act was enacted to regulate/reduce air pollution.
CAA is administered by the U.S. Environmental Protection
A substance or agent capable of causing or producing cancer
in mammals, including humans. A chemical is considered to
be a carcinogen if:
- It has been evaluated
by the International Agency for Research on Cancer (IARC)
and found to be a carcinogen or potential carcinogen;
- It is listed as a carcinogen
or potential carcinogen in the Annual Report on Carcinogens
published by the National Toxicology Program (NTP) (latest
- It is regulated by OSHA
as a carcinogen.
The ability to produce cancer.
A malignant tumor. A form of cancer.
Chemical Abstract Service is an organization under the American
Chemical Society. CAS abstracts and indexes chemical literature
from all over the world in "Chemical Abstracts". "CAS Numbers"
are used to identify specific chemicals or mixtures.
Cubic centimeter is a volume measurement in the metric system
that is equal in capacity to one milliliter (ml). One quart
is about 946 cubic centimeters.
- Central Nervous System
" The brain and spinal cord. These organs supervise
and coordinate the activity of the entire nervous system.
Sensory impulses are transmitted into the central nervous
system, and motor impulses are transmitted out.
Comprehensive Environmental Response, Compensation, and
Liability Act of 1980. The Act requires the Coast Guard
National Response Center be notified in the event of a hazardous
substance release. The Act also provides for a fund (the
Superfund) to be used for the cleanup of abandoned hazardous
waste disposal sites.
Code of Federal Regulations. A collection of the regulations
that have been promulgated under United States Law.
An element (e.g. chlorine) or a compound (e.g., sodium bicarbonate)
produced by chemical reaction.
- Chemical Cartridge
A respirator that uses various chemical substances to purify
inhaled air of certain gases and vapors. This type of respirator
is effective for concentrations no more than ten times the
TLV© of the contaminant, if the contaminant has warning
properties (odor or irritation) below the TLV©.
- Chemical Family
A group of single elements or compounds with a common general
name. Example: acetone, methyl ethyl ketone (MEK), and methyl
isobutyl ketone (MIBK) are of the "Ketone" family; acrolein,
furfural, and acetaldehyde are of the "aldehyde" family.
- Chemical Name
The name given to a chemical in the nomenclature system
developed by the International Union of Pure and Applied
Chemistry (IUPAC) or the Chemical Abstract Service (CAS).
The scientific designation of a chemical or a name that
will clearly identify the chemical for hazard evaluation
- Chemical Pneumonitis
Inflammation of the lungs caused by accumulation of fluids
due to chemical irritation.
Chemical Transportation Emergency Center is a national center
established by the Chemical Manufacturers Association (CMA),
to relay pertinent emergency information concerning specific
chemicals on request from individuals. CHEMTREC has a 24-hour
toll-free telephone number (800-424-9300) to help respond
to chemical transportation emergencies.
- Chronic Effect
An adverse effect on a human or animal body, with symptoms
that develop slowly over a long period of time or that recur
frequently. Also see Acute.
- Chronic Exposure
Long-term contact with a substance.
- Chronic Toxicity
Adverse (chronic) effects resulting from repeated doses
of or exposures to a substance over a relatively prolonged
period of time. Ordinarily used to denote effects in experimental
- Clean Air Act
- Clean Water Act
Federal law enacted to regulate/reduce water pollution.
CWA is administered by the EPA.
Chemical Manufacturers Association. See CHEMTREC.
Carbon monoxide is a colorless, odorless, flammable, and
very toxic gas produced by the incomplete combustion of
carbon. It is also a byproduct of many chemical processes.
A chemical asphyxiant; it reduces the blood's ability to
carry oxygen. Hemoglobin absorbs CO two hundred times more
readily than it does oxygen.
Carbon dioxide is a heavy, colorless gas that is produced
by the combustion and decomposition of organic substances
and as a byproduct of many chemical processes. CO2
will not burn and is relatively nontoxic (although high
concentrations, especially in confined spaces, can create
hazardous oxygen-deficient environments).
Cleveland Open Cup is a flash point test method.
A term used by NFPA, DOT, and others to classify certain
liquids that will burn, on the basis of flash points. Both
NFPA and DOT generally define "combustible liquids" as having
a flash point of 100°F (37.8°C) or higher but below 200°F
(93.3°C). Also see "flammable." Non-liquid substances such
as wood and paper are classified as "ordinary combustibles"
by the NFPA.
- Combustible Liquid
Any liquid having a flashpoint at or above 100°F (37.8°C),
but below 200°F (93.3°C), except any mixture having components
with flashpoints of 200°F (93.3°C) or higher, the total
volume of which makes up ninety-nine (99) percent or more
of the total volume of the mixture.
- Common Name
Any designation or identification such as code name, code
number, trade name, brand name or generic name used to identify
a chemical other than by its chemical name.
- Compressed Gas:
- A gas or mixture of gases
having, in a container, an absolute pressure exceeding
40 pounds per square inch (psi) at 70°F (21.1°C); or
- A gas or mixture of gases
having, in a container, an absolute pressure exceeding
104 psi at 130°F (54.4°C) regardless of the pressure
at 70°F (21.1°C); or
- A liquid having a vapor
pressure exceeding 40 psi at 100°F (37.8°C) as determined
by ASTM D-323-72.
The relative amount of a substance when combined or mixed
with other substances. Examples: 2 ppm hydrogen sulfide
in air, or a 50 percent caustic solution.
- Conditions to Avoid
Conditions encountered during handling or storage that could
cause a substance to become unstable.
- Confined Space
Any area that has limited openings for entry and exit that
would make escape difficult in an emergency, has a lack
of ventilation, contains known and potential hazards, and
is not intended nor designated for continuous human occupancy.
Inflammation of the conjunctiva, the delicate membrane that
lines the eyelids and covers the eyeballs.
- Any bag, barrel, bottle, box,
can, cylinder, drum, reaction vessel, storage tank, or the
like that contains a hazardous chemical. Pipes or piping
systems, and engines, fuel tanks, or other operating systems
in a vehicle, are not considered to be containers under
the Hazard Communication Standard.
A chemical that causes visible destruction of, or irreversible
alterations in, living tissue by chemical action at the
site of contact. For example, a chemical is considered to
be corrosive if, when tested on the intact skin of albino
rabbits by the method described by the DOT in Appendix A
to 49 CFR Part 173, it destroys or changes irreversibly
the structure of the tissue at the site of contact following
an exposure period of 4 hours. This term shall not refer
to action on inanimate surfaces.
Consumer Product Safety Commission has responsibility for
regulating hazardous materials when they appear in consumer
goods. For CPSC purposes, hazards are defined in the Hazardous
Substances Act and the Poison Prevention Packaging Act of
Cleansing of a diseased surface.
- Cutaneous Toxicity
See "Dermal Toxicity".
Clean Water Act was enacted to regulate/reduce water pollution.
It is administered by the EPA.
A sac containing a liquid. Most cysts are harmless.
The scientific study of cells.
Breakdown of a material or substance (by heat, chemical
reaction, electrolysis, decay, or other processes) into
parts or elements or simpler compounds.
The mass (weight) per unit volume of a substance. For example,
lead is more dense than aluminum.
A substance that reduces a bodily functional activity or
an instinctive desire, such as appetite.
Relating to the skin.
- Dermal Toxicity
Adverse effects resulting from skin exposure to a substance.
Ordinarily used to denote effects in experimental animals.
U.S. Department of Health and Human Services (replaced U.S.
Department of Health, Education and Welfare). NIOSH and
the Public Health Service (PHS) are parts of DHHS.
A barrier constructed to control or confine hazardous substances
and prevent them from entering sewers, ditches, streams,
or other flowing waters.
- Dilution Ventilation
Air flow designed to dilute contaminants to acceptable levels.
Also see general ventilation or exhaust.
U.S. Department of Labor. OSHA and MSHA are part of DOL.
U.S. Department of Transportation regulates transportation
of chemicals and other substances.
- Dry Chemical
A powdered fire-extinguishing agent usually composed of
sodium bicarbonate, potassium bicarbonate, etc.
An abnormality of development.
A sense of difficulty in breathing; shortness of breath.
- Ectopic pregnancy
The fertilized ovum becomes implanted outside the uterus.
An abnormal accumulation of clear watery fluid in the tissues.
- Endocrine glands
Glands that regulate body activity by secreting hormones.
The mucous membrane lining the uterus.
- Environmental Toxicity
Information obtained as a result of conducting environmental
testing designed to study the effects on aquatic and plant
U.S. Environmental Protection Agency.
Science concerned with the study of disease in a general
population. Determination of the incidence (rate of occurrence)
and distribution of a particular disease (as by age, sex,
or occupation) which may provide information about the cause
of the disease.
The covering of internal and external surfaces of the body.
Principal female sex hormone.
- Evaporation Rate
The rate at which a material will vaporize (evaporate) when
compared to the known rate of vaporization of a standard
material. The evaporation rate can be useful in evaluating
the health and fire hazards of a material. The designated
standard material is usually normal butyl acetate (NBUAC
or n-BuAc), with a vaporization rate designated as 1.0.
Vaporization rates of other solvents or materials are then
- evaporating if greater than 3.0 Examples: Methyl Ethyl
Ketone = 3.8; Acetone = 5.6, Hexane = 8.3
- evaporating if 0.8 to 3.0. Examples: 190 proof (95%)
Ethyl Alcohol = 1.4, VM&P Naphtha = 1.4, MIBK = 1.6.
- evaporating if less than 0.8. Examples: Xylene = 0.6,
Isobutyl Alcohol = 0.6, Normal Butyl Alcohol = 0.4,
Water = 0.3, Mineral Spirits = 0.1.
A chemical that causes a sudden, almost instantaneous release
of pressure, gas, and heat when subjected to sudden shock,
pressure, or high temperature.
- Exposure or Exposed
An employee is subjected in the course of employment to
a chemical that is a physical or health hazard, and includes
potential (e.g. accidental or possible) exposure. "Subjected"
in terms of health hazards includes any route of entry (e.g.
inhalation, ingestion, skin contact or absorption.)
- Extinguishing Media
The firefighting substances to be used to control a material
in the event of a fire. It is usually identified by its
generic name, such as fog, foam, water, etc.
- Eye Protection
Recommended safety glasses, chemical splash goggles, face
shields, etc., to be utilized when handling a hazardous
Fahrenheit is a scale for measuring temperature. On the
Fahrenheit scale, water boils at 212°F and freezes at 32°F.
Fibers per cubic centimeter of air.
U.S. Food and Drug Administration
Pertaining to the fetus.
An abnormal thickening of fibrous connective tissue, usually
in the lungs.
Federal Insecticide, Fungicide, and Rodenticide Act requires
that certain useful poisons, such as chemical pesticides,
sold to the public contain labels that carry health hazard
warnings to protect users. It is administered by EPA.
- First Aid
Emergency measures to be taken when a person is suffering
from overexposure to a hazardous material, before regular
medical help can be obtained.
A chemical that includes one of the following categories:
- "Aerosol, flammable."
An aerosol that, when tested by the method described
in 16 CFR 1500.45, yields a flame projection exceeding
18 inches at full valve opening, or a flashback (a flame
extending back to the valve) at any degree of valve
- "Gas, flammable."
(1) A gas that, at ambient temperature and pressure,
forms a flammable mixture with air at a concentration
of 13 percent by volume or less; or (2) A gas that,
at ambient temperature and pressure, forms a range of
flammable mixtures with air wider than 12 percent by
volume, regardless of the lower limit;
- "Liquid, flammable."
Any liquid having a flashpoint below 100°F (37.8°C),
except any mixture having components with flashpoints
of 100°F (37.8°C) or higher, the total of which makes
up 99 percent or more of the total volume of mixture.
- "Solid, flammable."
A solid, other than a blasting agent or explosive as
defined in 1910.109(a), that is liable to cause fire
through friction, absorption of moisture, spontaneous
chemical change, or retained heat from manufacturing
or processing, or which can be ignited readily and when
ignited burns so vigorously and persistently as to create
a serious hazard. A solid is a flammable solid if, when
tested by the method described in 16 CFR 1500.44, it
ignites and burns with a self-sustained flame at a rate
greater than one tenth of an inch per second along its
Occurs when flame from a torch burns back into the tip,
the torch, or the hose. It is often accompanied by a hissing
or squealing sound with a smoky or sharp-pointed flame.
The minimum temperature at which a liquid gives off a vapor
in sufficient concentration to ignite when tested by the
- Tabliabue Closed
Tester (See American National Standard Method
of Test for Flash Point by Tag Closed Tester, Z11.24
1979 [ASTM D56-79]).
Closed Tester (See American National Standard
Method of Test for Flash Point by Pensky-Martens Closed
Tester, Z11.7-1979 [ASTM D93-79]).
- Setaflash Closed
Tester (See American National Standard Method
of Test for Flash Point by Setaflash Closed Tester [ASTM
- Foreseeable Emergency
Any potential occurrence such as, but not limited to, equipment
failure, rupture of containers, or failure of control equipment
which could result in an uncontrolled release of a hazardous
chemical into the workplace.
The scientific expression of the chemical composition of
a material (e.g., Water is H2O, sulfuric acid is H2SO4,
sulfur dioxide is SO2).
A solid condensation particle of extremely small diameter,
commonly generated from molten metal as metal fume.
Gram is a metric unit of weight. One ounce U.S. (avoirdupois)
is about 28.4 grams.
- General Exhaust
A system for exhausting air containing contaminants from
a general work area. Also see Local Exhaust.
- Generic Name
A designation or identification used to identify a chemical
by other than its chemical name (e.g., code name, code number,
trade name, and brand name).
Pertaining to or carried by genes. Hereditary.
The development of the fetus in the uterus from conception
to birth; pregnancy.
Grams per kilogram is an expression of dose used in oral
and dermal toxicological testing to denote grams of a substance
dosed per kilogram of animal body weight. Also see "kg"
The procedure used to carry an electrical charge to ground
through a conductive path. A typical ground may be connected
directly to a conductive water pipe or to a grounding bus
and ground rod. See Bonding.
The study of the reproductive organs in women.
- Hand Protection
Specific types of gloves or other hand protection required
to prevent harmful exposure to hazardous materials.
- Hazardous Chemical
Hazardous chemical means any chemical which is classified
as a physical hazard or a health hazard, a simple asphyxiant,
combustible dust, pyrophoric gas, or hazard not otherwise
- Hazardous Warning
Any words, pictures, symbols, or combination thereof appearing
on a label or other appropriate form of warning which convey
the specific physical and health hazard(s), including target
organ effects, of the chemical(s) in the container(s).
Hazard Communication Standard is an OSHA regulation issued
under 29 CFR Part 1910.1200.
- Health Hazard
Health hazard means a chemical which is classified as posing
one of the following hazardous effects: acute toxicity (any
route of exposure); skin corrosion or irritation; serious
eye damage or eye irritation; respiratory or skin sensitization;
germ cell mutagenicity; carcinogenicity; reproductive toxicity;
specific target organ toxicity (single or repeated exposure);
or aspiration hazard. The criteria for determining whether
a chemical is classified as a health hazard are detailed
in Appendix A to §1910.1200 -- Health Hazard Criteria.
An iron-containing conjugated protein or respiratory pigment
occurring in the red blood cells of vertebrates.
A blood clot under the surface of the skin.
- Hematopoietic System
The blood-forming mechanism of the human body.
The presence of blood in the urine.
A substance that causes injury to the liver.
- Highly toxic
A chemical in any of the following categories:
- A chemical with a median
lethal dose (LD50) of 50 milligrams or less per kilogram
of body weight when administered orally to albino rats
weighing between 200 and 300 grams each.
- A chemical with a median
lethal dose (LD50) of 200 milligrams or less per kilogram
of body weight when administered by continuous contact
for 24 hours (or less if death occurs within 24 hours)
with the bare skin of albino rabbits weighing between
2 and 3 kilograms each.
- A chemical that has a
median lethal concentration (LD50) in air of 200 parts
per million by volume or less of gas or vapor, or 2
milligrams per liter or less of mist, fume, or dust,
when administered by continuous inhalation for 1 hour
(or less if death occurs within 1 hour) to albino rats
weighing between 200 and 300 grams each.
Act as chemical messengers to body organs.
Increase in volume of a tissue or organ caused by the growth
of new cells.
- International Agency for Research
Capable of being set afire.
A material that does not allow another substance to pass
through or penetrate it.
Materials that could cause dangerous reactions by direct
contact with one another.
Taking in by the mouth.
Breathing in of a substance in the form of a gas, vapor,
fume, mist, or dust.
A chemical added to another substance to prevent an unwanted
Incapable of being dissolved in a liquid.
Within the uterus.
A chemical, which is not corrosive, that causes a reversible
inflammatory effect on living tissue by chemical action
at the site of contact. A chemical is a skin irritant if,
when tested on the intact skin of albino rabbits by methods
of 16 CFR 1500 41 for 4 hours exposure or by other appropriate
techniques, it results in an empirical score of 5 or more.
A chemical is an eye irritant if so determined under the
procedure listed in 16 CFR 1500.42 or other appropriate
As defined by DOT, a property of a liquid or solid substance
which, upon contact with fire or when exposed to air, gives
off dangerous or intensely irritating fumes (not including
poisonous materials). See Poison, Class A and Poison, Class
Kilogram is a metric unit of weight, about 2.2 U.S. pounds.
Also see "g/kg", "g", and "mg."
Liter is a metric unit of capacity. A U.S. quart is about
9/10 of a liter.
Secretion and discharge of tears.
Label means an appropriate group of written, printed or
graphic information elements concerning a hazardous chemical
that is affixed to, printed on, or attached to the immediate
container of a hazardous chemical, or to the outside packaging.
The secretion of milk by the breasts.
Lethal concentration is the concentration of a substance
being tested that will kill.
Lethal concentration, low, lowest concentration of a gas
or vapor capable of killing a specified species over a specified
The concentration of a material in air that will kill 50
percent of a group of test animals with a single exposure
(usually 1 to 4 hours). The LC50 is expressed
as parts of material per million parts of air, by volume
(ppm) for gases and vapors, or as micrograms of materials
per liter of air (g/l) or milligrams of material per cubic
meter of air (mg/m3) for dusts and mists, as
well as for gases and vapors.
Lethal dose is the quantity of a substance being tested
that will kill.
Lethal dose low, lowest administered dose of a material
capable of killing a specified test species.
A single dose of a material expected to kill 50 percent
of a group of test animals. The LD50 dose is
usually expressed as milligrams or grams of material per
kilogram of animal body weight (mg/kg or g/kg). The material
may be administered by mouth or applied to the skin.
- LEL, or LFL
Lower explosive limit, or lower flammable limit, of a vapor
or gas; the lowest concentration (lowest percentage of the
substance in air) that will produce a flash of fire when
an ignition source (heat, arc, or flame) is present. At
concentrations lower than the LEL, the mixture is too "lean"
to burn. Also see "UEL".
Any damage to a tissue.
Linear feet per minute, a unit of air velocity.
- Local Exhaust
A system for capturing and exhausting contaminants from
the air at the point where the contaminants are produced
(welding, grinding, sanding, other processes or operations).
Also see General Exhaust.
Meter is a unit of length in the metric system. One meter
is about 39 inches.
Cubic meter is a metric measure of volume, approximately
35.3 cubic feet or 1.3 cubic yards.
A feeling of general discomfort, distress, or uneasiness,
an out-of-sorts feeling.
Tending to become progressively worse and to result in death.
Pertaining to the breast.
- Mechanical Exhaust
A powered device, such as a motor-driven fan or air steam
venturi tube, for exhausting contaminants from a workplace,
vessel, or enclosure.
- Mechanical Filter
A respirator used to protect against airborne particulate
matter like dusts, mists, metal fume, and smoke. Mechanical
filter respirators do not provide protection against gases,
vapors, or oxygen deficient atmospheres.
- Melting Point
The temperature at which a solid substance changes to a
Periodic discharge of blood from the vagina of a nonpregnant
Physical and chemical processes taking place among the ions,
atoms, and molecules of the body.
The transfer of disease from one organ or part to another
not directly connected with it.
A unit of length; equivalent to 39.37 inches.
Milligram is a metric unit of weight that is one-thousandth
of a gram.
Milligrams of substance per kilogram of body weight is an
expression of toxicological dose.
Milligrams per cubic meter is a unit for expressing concentrations
of dusts, gases, or mists in air.
- Micron (Micrometer)
A unit of length equal to one-millionth of a meter; approximately
0.000039 of an inch.
Suspended liquid droplets generated by condensation from
the gaseous to the liquid state, or by breaking up a liquid
into a dispersed state, such as splashing, foaming or atomizing.
Mist is formed when a finely divided liquid is suspended
Mixture means a combination or a solution composed of two
or more substances in which they do not react.
Milliliter is a metric unit of capacity, equal in volume
to 1 cubic centimeter (cc), or approximately one-sixteenth
of a cubic inch. One-thousandth of a liter.
Millimeters (mm) of mercury (Hg) is a unit of measurement
for low pressures or partial vacuums.
- Molecular Weight
Weight (mass) of a molecule based on the sum of the atomic
weights of the atoms that make up the molecule.
Million particles per cubic foot is a unit for expressing
concentration of particles of a substance suspended in air.
Exposure limits for mineral dusts (silica, graphite, Portland
cement, nuisance dusts, and others), formerly expressed
as mppcf, are now more commonly expressed in mg/m3.
Mine Safety and Health Administration, U.S. Department of
A substance or agent capable of altering the genetic material
in a living cell.
See molecular weight.
Nitrogen is a colorless, odorless, and tasteless gas that
will not burn and will not support combustion. The earth's
atmosphere (air) is about 78 percent nitrogen. At higher
concentrations, nitrogen can displace oxygen and become
a lethal asphyxiant. See asphyxiant.
A state of stupor, unconsciousness, or arrested activity
produced by the influence of narcotics or other chemicals.
Tendency to vomit, feeling of sickness at the stomach.
National Cancer Institute is that part of the National Institutes
of Health that studies cancer causes and prevention as well
as diagnosis, treatment, and rehabilitation of cancer patients.
National Fire Protection Association is an international
membership organization which promotes/improves fire protection
and prevention and establishes safeguards against loss of
life and property by fire. Best known on the industrial
scene for the National Fire Codes - 16 volumes of codes,
standards, recommended practices and manuals developed (and
periodically updated) by NFPA technical committees. Among
these is NFPA 704M, the code for showing hazards of materials
as they might be encountered under fire or related emergency
conditions, using the familiar diamond-shaped label or placard
with appropriate numbers or symbols.
The first 4 weeks after birth.
A condition characterized by the presence of new growths
A substance that causes injury to the kidneys.
A material that affects the nerve cells and may produce
emotional or behavioral abnormalities.
To eliminate potential hazards by inactivating strong acids,
caustics, and oxidizers. For example, acids can be neutralized
by adding an appropriate amount of caustic substance to
Nanogram, one-billionth of a gram.
National Institute for Occupational Safety and Health, U.S.
Public Health Service, U.S. Department of Health and Human
Services (DHHS), among other activities, tests and certifies
respiratory protective devices and air sampling detector
tubes, recommends occupational exposure limits for various
substances, and assists OSHA and MSHA in occupational safety
and health investigations and research.
Not easily ignited, or if ignited, not burning rapidly.
- Non-Sparking Tools
Tools made from beryllium-copper or aluminum-bronze greatly
reduce the possibility of igniting dusts, gases, or flammable
vapors. Although these tools may emit some sparks when striking
metal, the sparks have a low heat content and are not likely
to ignite most flammable liquids.
Oxides of nitrogen which are undesirable air pollutants.
NO emissions are regulated by EPA under the Clean Air Act.
National Pesticide Information Retrieval System is an automated
data base operated by Purdue University containing information
on EPA registered pesticides, including reference file SDSs.
National Response Center is a notification center that must
be called when significant oil or chemical spills or other
environment-related accidents occur. The toll free number
National Toxicology Program. The NTP publishes an Annual
Report on Carcinogens.
A description of the smell of the substance.
- Odor Threshold
The lowest concentration of a substance's vapor, in air,
that can be smelled.
Relating to the sense of smell.
Used in or taken into the body through the mouth.
- Oral Toxicity
Adverse effects resulting from taking a substance into the
body by mouth. Ordinarily used to denote effects in experimental
- Organic Peroxide
An organic compound that contains the bivalent -O-O structure
and may be considered a structural derivative of hydrogen
peroxide where one or both of the hydrogen atoms has been
replaced by an organic radical.
The formation of organs during development.
Occupational Safety and Health Administration, U.S. Department
The female sex gland in which ova are formed.
Exposure to a hazardous material beyond the allowable exposure
In a literal sense, oxidation is a reaction in which a substance
combines with oxygen provided by an oxidizer or oxidizing
agent. See Oxidizing Agent.
A chemical other than a blasting agent or explosive as defined
in 1910.109(a), that initiates or promotes combustion in
other materials, thereby causing fire either of itself or
through the release of oxygen or other gases.
- Oxidizing Agent
A chemical or substance that brings about an oxidation reaction.
The agent may (1) provide the oxygen to the substance being
oxidized (in which case the agent has to be oxygen or contain
oxygen), or (2) it may receive electrons being transferred
from the substance undergoing oxidation (chlorine is a good
oxidizing agent for electron-transfer purposes, even though
it contains no oxygen).
Pertaining to or caused by disease.
Scientific study of alterations produced by disease.
Permissible Exposure Limit is an occupational exposure limit
established by OSHA's regulatory authority. It may be a
time-weighted average (TWA) limit or a maximum concentration
- Percent Volatile
Percent volatile by volume is the percentage of a liquid
or solid (by volume) that will evaporate at an ambient temperature
of 70°F (unless some other temperature is specified). Examples:
butane, gasoline, and paint thinner (mineral spirits) are
100 percent volatile; their individual evaporation rates
vary, but in time, each will evaporate completely.
The symbol relating the hydrogen ion (H+) concentration
to that of a given standard solution. A pH of 7 is neutral.
Numbers increasing from 7 to 14 indicate greater alkalinity.
Numbers decreasing from 7 to 0 indicate greater acidity.
- Physical Hazard
Physical hazard means a chemical that is classified as posing
one of the following hazardous effects: explosive; flammable
(gases, aerosols, liquids, or solids); oxidizer (liquid,
solid or gas); self-reactive; pyrophoric (liquid or solid);
self-heating; organic peroxide; corrosive to metal; gas
under pressure; or in contact with water emits flammable
A structure that grows on the wall of the uterus during
pregnancy, through which the fetus is nourished.
Pensky-Martens Closed Cup. See Flashpoint.
A condition of the lung in which there is permanent deposition
of particulate matter and the tissue reaction to its presence.
It may range from relatively harmless forms of iron oxide
deposition to destructive forms of silicosis.
- Poison, Class A
A DOT term for extremely dangerous poisons -- poisonous
gases or liquids that, in very small amounts, either as
gas or as vapor of the liquid, mixed with air, are dangerous
to life. Examples: phosgene, cyanogen, hydrocyanic acid,
- Poison, Class B
A DOT term for liquid, solid, paste, or semisolid substances
-- other than Class A poisons or irritating materials --
that are known (or presumed on the basis of animal tests)
to be so toxic to humans that they are a hazard to health
A chemical reaction in which one or more small molecules
combine to form larger molecules. A hazardous polymerization
is such a reaction that takes place at a rate that releases
large amounts of energy. If hazardous polymerization can
occur with a given material, the SDS usually will list conditions
that could start the reaction and -- since the material
usually contains a polymerization inhibitor-- the length
of time during which the inhibitor will be effective.
Parts per billion is the concentration of a gas or vapor
in air -- parts (by volume) of the gas or vapor in a billion
parts of air. Usually used to express extremely low concentrations
of unusually toxic gases or vapors; also the concentration
of a particular substance in a liquid or solid.
Parts per million is the concentration of a gas or vapor
in air-parts (by volume) of the gas or vapor in a million
parts of air; also the concentration of a particulate in
a liquid or solid.
Pounds per square inch (for SDS purposes) is the pressure
a material exerts on the walls of a confining vessel or
enclosure. For technical accuracy, pressure must be expressed
in psig (pounds per square inch gauge) or psia (pounds per
square inch absolute; that is, gauge pressure plus sea level
atmospheric pressure, or pisg plus approximately 14.7 ponds
per square inch). Also see mmHg.
Relating to, or associated with, the lungs.
- Pulmonary Edema
Fluid in the lungs.
A chemical that will ignite spontaneously in air at a temperature
of 13°F (54.4°C) or below.
A chemical transformation or change. The interaction of
two or more substances to form new substances.
Chemical reaction with the release of energy. Undesirable
effects - such as pressure buildup, temperature increase,
formation of noxious toxic or corrosive byproducts - may
occur because of the reactivity of a substance to heating,
burning, direct contact with other materials, or other conditions
in use or in storage.
- Reducing agent
In a reduction reaction (which always occurs simultaneously
with an oxidation reaction) the reducing agent is the chemical
or substance which (1) combines with oxygen or (2) loses
electrons to the reaction. See Oxidation.
The NIOSH REL (Recommended Exposure Limit) is the highest
allowable airborne concentration which is not expected to
insure the workers. It may be expressed as a ceiling limit
or as a time-weighted average (TWA).
- Reproductive Toxin
Substances that affect either male or female reproductive
systems and may impair the ability to have children.
- Respiratory Protection
Devices that will protect the wearer's respiratory system
from overexposure by inhalation to airborne contaminants.
Respiratory protection is used when a worker must work in
an area where he/she might be exposed to concentration in
excess of the allowable exposure limit.
- Respiratory System
The breathing system that includes the lungs and the air
passages (trachea or "windpipe", larynx, mouth, and nose)
to the air outside the body, plus the associated nervous
and circulatory supply.
- Routes of Entry
The means by which material may gain access to the body,
for example, inhalation, ingestion, and skin contact.
Resource Conservation and Recovery Act is environmental
legislation aimed at controlling the generation, treating,
storage, transportation and disposal of hazardous wastes.
It is administered by EPA.
A tumor that is often malignant.
- Safety Date Sheet (SDS)
Safety data sheet (SDS) means written or printed material
concerning a hazardous chemical
- Signal Word
- Signal word means a word
used to indicate the relative level of severity of hazard
and alert the reader to a potential hazard on the label.
The signal words used in this section are "danger"
and "warning." "Danger" is used for
the more severe hazards, while "warning" is used
for the less severe.
A respiratory protection device that consists of a supply
or a means of respirable air, oxygen, or oxygen-generating
material, carried by the wearer.
A chemical that causes a substantial proportion of exposed
people or animals to develop an allergic reaction in normal
tissue after repeated exposure to the chemical.
Setaflash Closed Tester. See Flashpoint.
A disease of the lungs (fibrosis) caused by the inhalation
of silica dust.
A notation (sometimes used with PEL or TLV© exposure
data) that indicates that the stated substance may be absorbed
by the skin, mucous membranes, and eyes -- either airborne
or by direct contact -- and that this additional exposure
must be considered part of the total exposure to avoid exceeding
the PEL or TLV© for that substance.
- Skin Absorption
Ability of some hazardous chemicals to pass directly through
the skin and enter the bloodstream.
- Skin Sensitizer
- Skin Toxicity
See Dermal Toxicity.
- Solubility in Water
A term expressing the percentage of a material (by weight)
that will dissolve in water at ambient temperature. Solubility
information can be useful in determining spill cleanup methods
and fire extinguishing agents and methods for a material.
A substance, usually a liquid, in which other substances
are dissolved. The most common solvent is water.
Oxides of sulfur.
On the SDSs, species refers to the test animals-usually
rats, mice, or rabbits - used to obtain the toxicity test
- Specific Chemical Identity
The chemical name, Chemical Abstracts Service (CAS) Registry
Number, or any precise chemical designation of a substance.
- Specific Gravity
The weight of a material compared to the weight of an equal
volume of water is an expression of the density (or heaviness)
of a material. Insoluble materials with specific gravity
of less than 1.0 will float in (or on) water. Insoluble
materials will specific gravity greater than 1.0 will sink
in water. Most (but not all) flammable liquids have specific
gravity less than 1.0 and, if not soluble, will float on
water - an important consideration for fire suppression.
- Spill or Leak Procedures
The methods, equipment, and precautions that should be used
to control or clean up a leak or spill.
- Splash-Proof Goggles
Eye protection made of a noncorrosive material that fits
snugly against the face, and has indirect ventilation ports.
A material that ignites as a result of retained heat from
processing, or that will oxidize to generate heat and ignite,
or that absorbs moisture to generate heat and ignite.
Scaly or platelike.
The ability of a material to remain unchanged. For SDS purposes,
a material is stable if it remains in the same form under
expected and reasonable conditions of storage or use. Conditions
that may cause instability (dangerous change) are stated:
for example, temperatures above 150°F; shock from dropping.
Short-Term Exposure Limit (ACGIH terminology). See TLV©.
Narrowing of a body passage or opening.
A complex molecule among which are the male and female sex
Beneath the layers of the skin.
- Supplied-Air Respirators
Air line respirators of self-contained breathing apparatus.
System or systemic.
- Systemic Poison
A poison that spreads throughout the body, affecting all
body systems and organs. Its adverse effect is not localized
in one spot or area.
- Systemic Toxicity
Adverse effects caused by a substance that affects the body
in a general rather than local manner.
Another name or names by which a material is known. Methyl
alcohol, for example, is known as methanol or wood alcohol
- Target Organ Effects
The following is a target organ categorization of effects
that may occur, including examples of signs and symptoms
and chemicals that have been found to cause such effects.
These examples are presented to illustrate the range and
diversity of effects and hazards found in the workplace,
and the broad scope employers must consider in this area,
but they are not intended to be all inclusive.
Chemicals which produce liver damage
Signs & Symptoms: Jaundice; liver enlargement
Chemicals: Carbon tetrachloride; nitrosamines
Chemicals which produce kidney damage
Signs & Symptoms: Edema; proteinuria
Chemicals: Halogenated hydrocarbons; uranium
Chemicals which produce their primary toxic effects
on the nervous system
Signs & Symptoms: Narcosis; behavioral
changes; decrease in motor functions
Chemicals: Mercury; carbon disulfide
- Agents which act
on the blood or hemato-poietic system: Decrease
hemoglobin function; deprive the body tissues of oxygen
Signs & Symptoms: Cyanosis; loss of consciousness
Chemicals: Carbon monoxide; cyanides
- Agents which damage
the lung: Chemicals which irritate or damage
Signs & Symptoms: Cough; tightness in chest;
shortness of breath
Chemicals: Silica; asbestos
- Reproductive toxins:
Chemicals which affect the reproductive capabilities
including chromosomal damage (mutations) and effects
on fetuses (teratogenesis)
Signs & Symptoms: Birth defects; sterility
Chemicals: Lead; DBCP
- Cutaneous hazards:
Chemicals which affect the dermal layer of the body
Signs & Symptoms: Defatting of the skin;
Chemicals: Ketones; chlorinated compounds
- Eye hazards:
Chemicals which affect the eye or visual capacity
Signs & Symptoms: Conjunctivitis; corneal
Chemicals: Organic solvents; acids
- Target Organ Toxin
A toxic substance that attacks a specific organ of the body.
For example, overexposure to carbon tetrachloride can cause
Tag (Tabliabue) Closed Cup. See Flashpoint.
Toxic concentration low, the lowest concentration of a gas
or vapor capable of producing a defined toxic effect in
a specified test species over a specified time.
Toxic dose low, lowest administered dose of a material capable
of producing a defined toxic effect in a specified test
A substance or agent, exposure to which by a pregnant female
can result in malformations in the fetus.
Threshold Limit Value is a term used by ACGIH to express
the airborne concentration of material to which nearly all
persons can be exposed day after day without adverse effects.
ACGIH expresses TLVs in three ways;
The allowable Time-Weighted Average concentration for
a normal 8-hour workday or 80-hour workweek.
The Short-Term Exposure Limit, or maximum concentration
for a continuous 15-minute exposure period (maximum
of four such periods per day, with at least 60 minutes
between exposure periods, and provided the daily TLV-TWA
is not exceeded).
The ceiling exposure limit - the concentration that
should not be exceeded even instantaneously.
Tag Open Cup. See Flashpoint.
A unit of pressure, equal to 1/760 atmosphere.
A chemical falling within any of the following categories:
- A chemical that has a
median lethal dose (LD50) or more than 50 milligrams
per kilogram but not more than 500 milligrams per kilogram
of body weight when administered orally to albino rats
weighing between 200 and 300 grams each.
- A chemical that has a
median lethal dose (LD50) of more than 200 milligrams
per kilogram but not more than 1,000 milligrams per
kilogram of body weight when administered by continuous
contact for 24 hours (or less if death occurs within
24 hours) with the bare skin of albino rabbits weighing
between two and three kilograms each.
- A chemical that has a
median lethal concentration (LC50) in air of more than
200 parts per million but not more than 2,000 parts
per million by volume of gas or vapor, or more than
two milligrams per liter but not more than 20 milligrams
per liter of mist, fume, or dust, when administered
by continuous inhalation for one hour (or less if death
occurs within 1 hour) to albino rats weighing between
200 and 300 grams each.
- Toxic Substance
Any substance that can cause acute or chronic injury to
the human body, or which is suspected of being able to cause
diseases or injury under some conditions.
The sum of adverse effects resulting from exposure to a
material, generally, by the mouth, skin, or respiratory
- Trade Name
The trademark name or commercial trade name for a material
An agent that causes physical defects in the developing
Toxic Substances Control Act (Federal Environmental Legislation
administered by EPA) regulates the manufacture, handling,
and use of materials classified as "toxic substances."
Time-Weighted Average exposure is the airborne concentration
of a material to which a person is exposed, averaged over
the total exposure time - generally the total workday (8
to 12 hours). Also see TLV©.
- UEL, or UFL
Upper explosive limit or upper flammable limit of a vapor
or gas; the highest concentration (highest percentage of
the substance in air) that will produce a flash of fire
when an ignition source (heat, arc, or flame) is present.
At higher concentrations, the mixture is too "rich" to burn.
Also see LEL.
- ug (µg)
Microgram, one-millionth of a gram.
Tending toward decomposition or other unwanted chemical
change during normal handling or storage.
- Unstable Reactive
A chemical that, in the pure state, or as produced or transported,
will vigorously polymerize, decompose, condense, or become
self-reactive under conditions of shocks, pressure, or temperature.
U.S. Department of Agriculture.
The gaseous form of a solid or liquid substance as it evaporates.
- Vapor Density
The weight of a vapor or gas compared to the weight of an
equal volume of air is an expression of the density of the
vapor or gas. Materials lighter than air have vapor densities
less than 1.0 (examples: acetylene, methane, hydrogen).
Materials heavier than air (examples: propane, hydrogen
sulfide, ethane, butane, chlorine, sulfur dioxide) have
vapor densities greater than 1.0. All vapors and gases will
mix with air, but the lighter materials will tend to rise
and dissipate (unless confined). Heavier vapors and gases
are likely to concentrate in low places - along or under
floors, in sumps, sewers, and manholes, in trenches and
ditches - where they may create fire or health hazards.
- Vapor Pressure
The pressure exerted by a saturated vapor above its own
liquid in a closed container. When quality control tests
are performed on products, the test temperature is usually
100°F, and the vapor pressure is expressed as pounds per
square inch (psig or psia), but vapor pressures reported
in SDSs are in millimeters of mercury (mmHg) at 68°F (20°C),
unless stated otherwise. Three factors are important to
- Vapor pressure of a substance
at 100°F will always be higher than the vapor pressure
of the substance at 68°F (20°C).
- Vapor pressures reported
on SDSs in mmHg are usually very low pressures; 760
mmHg is equivalent to 14.7 pounds per square inch.
- The lower the boiling
point of a substance, the higher its vapor pressure.
See General Exhaust, Local Exhaust, and Mechanical Ventilation.
An expanded mica (hydrated magnesium-aluminum-iron silicate)
used as sorbent for spill control and clean-up.
The tendency of a fluid to resist internal flow without
regard to its density.
A measure of how quickly a substance forms a vapor at ordinary
- Water Disposal Methods
Proper disposal methods for contaminated material, recovered
liquids or solids, and their containers.
A chemical that reacts with water to release a gas that
is either flammable or presents a health hazard.
- Work Area
A room or defined space in a workplace where hazardous chemicals
are produced or used, and where employees are present.
An establishment at one geographical location containing
one or more work areas.
- Zinc Fume Fever
A condition brought on by inhalation of zinc oxide fume
characterized by flu-like symptoms with a metallic taste
in the mouth, coughing, weakness, fatigue, muscular pain,
and nausea, followed by fevers and chills. The onset of
symptoms occurs for to twelve hours after exposure.