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Definitions
& Terms
- ACS, American Chemical
Society: Professional society that establishes standards of
purity for a number of reagents, e.g., the ACS Reagent Grade.
They publish Chemical Abstracts and a host of professional
journals and magazines dealing with various areas of chemistry,
chemical engineering, and allied sciences. (1155 Sixteenth St.,
N.W., Washington, DC 20036; [202] 872-4567.)
- Airline
Respirator: An atmosphere-supplying respirator
in which the respirable gas is not designed to be carried by the
wearer. Also known as a supplied-air respirator.
- ALARA: Acronym for "as
low as reasonably achievable."
- Alkali: A chemical that:
1) is usually corrosive to human tissue and must be handled with
care; 2) has a pH of more than 7.0; 3) neutralizes acids to form
salts; 4) dissociates in water yielding hydroxide ions; 5) turns
litmus paper blue; and 6) may also be called a base or
caustic. Common commercial alkalis are sodium carbonate
(soda ash), caustic soda and caustic potash, lime, lye, waterglass,
regular mortar, Portland cement, and bicarbonate of soda. See
Acid; Base; pH.
- Allergic Reaction:
An abnormal physiological response to a chemical or physical stimuli
by a sensitive person
- Anaerobic: Life or processes
that occur in the absence of molecular oxygen; growing in the
absence of molecular oxygen, such as anaerobic bacteria; occurring
in the absence of molecular oxygen, such as anaerobic decomposition.
- ANSI: American National Standards
Institute, 11 West 42nd Street, New York, NY 10036.
Their number is 212 642-4900 or visit their web page at http://www.ansi.org
- Asphyxiant: A material that
can cause suffocation.
- Asphyxiation: A condition
that causes asphyxia or suffocation. Asphyxiation is one of the
principal potential hazards of working in confined spaces.
- Aspiration: When a liquid
or solid from the mouth or throat is sucked into the lungs; in
some cases, this may be fatal (when stomach acids or solvents
are aspirated).
- Atmosphere-supplying Respirator:
A respirator that supplies the wearer with air or oxygen from
a source independent of the immediate ambient atmosphere. This
includes air-supplied respirators and self-contained breathing
apparatus (SCBA).
- Authorized Employee:
A person who locks out or tags out machines or equipment in order
to perform servicing or maintenance on those machines or equipment.
An affected employee becomes an authorized employee when that
employee's duties include performing servicing or maintenance
covered under this section. See Lock-out/Tag-out.
- Biohazard:
Biological hazard.
- Biohazardous: Substances
obtained from living tissues that create a risk of infection.
- Bloodborne Pathogens (BBP's):
Viruses, bacteria, or parasites carried in the blood or other
body fluids of infected persons and that, under certain conditions,
can be spread to others.
- Boiling Point, BP: The temperature
at which a liquid's vapor pressure equals the surrounding atmospheric
pressure so that the liquid rapidly vaporizes. Flammable materials
with low BPs generally present special fire hazards [e.g., butane,
BP = -0.5 degrees C (31 degrees F); gasoline, BP =38 degrees C
(100 degrees F)]. For mixtures, a range of temperature is given.
- Cancer, Carcinoma. A malignant
tumor or cancer; a new growth of cells that tends to grow rapidly,
infiltrate other tissue, and metastasize (spread). Each cancer
is believed to originate from a single "transformed"
cell that grows (splits) at a fast, abnormally regulated pace,
no matter where it occurs in the body. Cancer is the second most
common cause of death in the US. The National Toxicology Program
(NTP) reports that one- to two-thirds of cancers are associated
with our environment.
- C.A.S. Number: Chemical Abstracts
Service, a service provided by the American Chemical Society that
identifies a particular chemical with a number.
- CAR: Carcinogenic effects.
- Carcinogen: A substance that
causes cancer. A cancer is characterized by the proliferation
of abnormal cells, often as a tumor. Asbestos, vinyl chloride
and benzene are carcinogens. OSHA 1910.1001 to 1910.1047 states
that: "A chemical is considered to be a carcinogen if: (a)
It has been evaluated by the International Agency for Research
on Cancer (IARC) and found to be a carcinogen or potential carcinogen;
or (b) It is listed as a carcinogen or a potential carcinogen
in the Annual Report on Carcinogens published by the National
Toxicology Program (NTP) (latest edition); or (c) It is regulated
by OSHA as a carcinogen."
- Cardiovascular: System of
the human body involving the heart and blood vessels.
- Classic Sign: A design that
follows the original OSHA design guidelines. The DANGER header
appears in white letters on a red oval. The oval, with a thin
white border is then placed onto a black rectangular field.
- CAS Number (CAS Registration
Number): An assigned number used to identify a chemical. CAS
stands for Chemical Abstracts Service, an organization that indexes
information published in Chemical Abstracts by the American
Chemical Society and that provides index guides by which information
about particular substances may be located in the abstracts. Sequentially
assigned CAS numbers identify specific chemicals, except
when followed by an asterisk (*) which signifies a compound (often
naturally occurring) of variable composition. The numbers have
no chemical significance. The CAS number is a concise, unique
means of material identification. (Chemical Abstracts Service,
Div. of American Chemical Society, Box 3012, Columbus, OH 43210;
[614] 447-3600.)
- Class 1 (explosive):
Any substance or article, including a device, that is designed
to function by explosion (i.e., an extremely rapid release of
gas and heat) or which, by chemical reaction within itself, is
able to function in a similar manner even if not designed to function
by explosion, unless the substance or article is otherwise classed
under the provisions of DOT regulations. Div. 1.1 (mass explosion
hazard); Div. 1.2 (projection hazard); Div. 1.3 (fire
hazard & minor blast hazard or minor projection hazard);
Div. 1.4 (minor explosion hazard); Div. 1.5 (very insensitive
explosives); Div. 1.6 (extremely insensitive explosives).
See 49 CFR 173.50 for detailed definitions of each division.
- Class 2: Div. 2.1
(flammable gas); Div. 2.2 (non-flammable, non-poisonous
compressed gas, including compressed gas, liquefied gas, pressurized
cryogenic gas and compressed gas in solution); or Div. 2.3 (gas
poisonous by inhalation). See 49 CFR 173.115 for detailed
definitions of each division.
- Class 3 (flammable
liquid): A liquid having a flash point of not more
than 60.5 degrees C (141 degrees F), or any material in a liquid
phase with a flash point at or above 37.8 degrees C (100 degrees
F) that is intentionally heated and offered for transportation
or transported at or above its flash point in a bulk packaging,
with the exceptions detailed in 49 CFR 173.120.
- Class 4: Div. 4.1
(flammable solid); Div. 4.2 (spontaneously combustible
material); or Div. 4.3 (dangerous when wet material).
See 49 CFR 173.124.
- Class 5: Div. 5.1
(oxidizing material) or Div. 5.2 (organic peroxide).
See 49 CFR 173.127.
- Class 6: Div. 6.1
(poisonous material), or Div. 6.2 (infectious substance).
See 49 CFR 173.132.
- Class 7 (radioactive
material): Any material having a specific activity
greater than 0.002 microcuries per gram (µCi/g). See definition
of Specific Activity and other technical definitions in 49 CFR
173.403.
- Class 8 (corrosive
material): A liquid or solid that causes visible destruction
or irreversible alterations in human skin tissue at the site of
contact, or a liquid that has a severe corrosion rate on steel
or aluminum, in accordance with the criteria given in 49 CFR 173.136(a).
- Class 9 (miscellaneous
hazardous material): A material that has an anesthetic,
noxious, or other similar property that could cause extreme annoyance
or discomfort to a person so as to prevent the correct performance
of assigned duties; and meets the definition in 49 CFR 171.8 for
a hazardous substance or a hazardous waste. See Hazardous Substance;
Hazardous Waste.
- Clearview: SmartSigns Clearview®
is a new font specifically developed and tested for the warnings
and is exclusively offered with this software. It is based on
the new highway font, Clearview. As a highway font, Clearview
has been tested to give motorists an extra 30 feet of reading
distance, when traveling at highway speeds. SmartSign Clearview® is protected by U.S.
copyrights and several pending patent applications. This font
cannot be used to print signs or labels for resale.
- Combustible: A material that
will burn under most conditions and may ignite easily depending
on its flash point. The DOT defines combustible liquids
as a liquid with a flash point above 141 degrees F (60.5 degrees
C) and below 200 degrees F (93 degrees C). Both NFPA and OSHA
generally define a combustible liquid as a liquid with
a flash point at or above 100 degrees F (38 degrees C) but below
200 degrees F (93.3 degrees C). See Flammable
- Combustible Liquid: Any liquid
having a flash point at or above 100 F (37.8 degrees C), but below
200 degrees F (93.3 degrees C), except any mixture
having components with flash points of 200 degrees F (93.3 degrees
C) or higher, the total volume of which make up 99% or more of
the total volume of the mixture.
- Common Name: A designation
for a material other than its chemical name, such as code name
or code number or trade, brand, or generic name. May be used as
the "product identifier" in Canadian law [Workplace
Hazardous Materials Information System (WHMIS) regulations].
- Confined Space: A space that:
1) is large enough and so configured that an employee can bodily
enter and perform assigned work; 2) has limited or restricted
means for entry or exit (for example, tanks, vessels, silos, storage
bins, hoppers, vaults, and pits are spaces that have limited or
restricted means of entry); 3) a space with little ventilation
where an oxygen-deficient environment may develop or where chemicals
may reach high concentrations; and 4) is not designed for continuous
human occupancy.
- Conjunctivitis: Inflammation
of the conjunctiva, the delicate membrane that lines the eyelid
and covers the eyeball.
- Corrosive: 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 U.S.
Department of Transportation 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 four hours.
This term shall not refer to action on inanimate surfaces.
- Corrosivity: Characteristic
that defines a waste that can extract and make soluble toxic contaminants
from other waste. Must have a pH less than 2 or greater than 12.5
or corrode steel (SAE 1020) at a rate greater than 1/4-inch/year.
- Dangerous When Wet: A
label required for certain materials being shipped under U.S.
DOT, ICAO, and IMO regulations. Any of this labeled material that
is in contact with water or moisture may produce flammable gases.
In some cases, these gases are spontaneously combustible.
- Dangerously Reactive Material:
A material that can react by itself (e.g., polymerize) or
with air or water to produce a hazardous condition. Preventive
measures can be taken if you know what conditions may cause the
dangerous reaction.
- Defatting: Natural oils are
removed from the skin by a fat dissolving agent.
- Demand Respirator: A
mode of operation for atmosphere-supplying respirators in which
air flows into the respirator only when inhalation creates a lower
pressure within the facepiece than the ambient atmospheric pressure.
- Dermatitis: Skin rash; inflammation
of the skin.
- Disposable Respirator: A
respiratory protective device which cannot be resupplied with
an unused filter or cartridge and which is to be discarded in
its entirety after its useful service life has been reached.
- DOT Identification Numbers: Four-digit
numbers [preceded by UN (United Nations) or NA (North America)]
used to identify particular materials for regulation of their
transportation. See DOT publications that describe the regulations
(49 CFR 172.102). These numbers are called product identification
numbers (PINs) under the Canadian Transportation of Dangerous
Goods Regulation. Those numbers used internationally may carry
a "UN" prefix (e.g., UN 1170, ethyl alcohol), but those
used only North America have an "NA" prefix (e.g., NA
9121, ferric sulphate).
- Effluent: Solid, liquid,
or gas wastes which enter the environment as a by-product of man-oriented
processes; the discharge or outflow of water from ground or subsurface
storage.
- Electrocution: Receiving
a lethal dose of electricity that causes the heart to beat convulsively,
and possibly stop beating.
- Electrolyte: A substance
(as an acid, base, salt) that dissociates into ions when in aqueous
solution and that provides ionic conductivity. Electrolytes are
lost from the body through perspiration as salts, causing impairment
of CNS functions if not adequately replaced.
- Embryo: An organism in the
early stages of development before birth. In humans, the developing
child is considered an embryo from conception to the end of the
second month of pregnancy.
- Embryotoxin: A material harmful
to a developing embryo at a concentration that has no adverse
effect on the pregnant female.
- Engulfment: The surrounding
and effective capture of a person by a liquid or finely divided
(flowable) solid substance that can be aspirated to cause death
by filling or plugging the respiratory system or that can exert
enough force on the body to cause death by strangulation, constriction,
or crushing.
- EPA Hazardous Waste: The
designation that the U.S. Environmental Protection Agency (EPA)
has assigned to certain hazardous wastes.
- EPA Number: The EPA has their
own numbering scheme for hazardous waste.
- First Aid: Immediate
measures that can be taken by the victim or others before qualified
medical help arrives in order to reduce or eliminate the potential
effects of a chemical exposure or other injury.
- Flammable: Describes any
solid, liquid, vapor, or gas that ignites easily and burns rapidly.
See Combustible.
- Flammable Aerosol: An aerosol
that 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 opening.
- Flammable Gas: A gas that,
(a) at ambient temperature and pressure, forms a flammable mixture
with air at a concentration of thirteen (13) percent by volume
or less; or (b) at ambient temperature and pressure, forms a range
of flammable mixtures with air wider than 12% of volume, regardless
of the lower limit.
- Flammable Liquid: Any liquid
having a flash point below 100 degrees F (37.8 degrees C), except
any mixture having components with flash points of 100 degrees
F (37.8 degrees C) or higher, the total of which make up 99 percent
or more of the total volume of the mixture.
- Flammable Solid: A solid,
other than a blasting agent or explosive as defined in section
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 chemical shall be considered to be a flammable
solid if, when tested by the method described in 16 CFR 500.44,
it ignites and burns with a self-sustained flame at a rate greater
than one-tenth of an inch per second along its major axis.
- Flash Point, FP: Lowest temperature
at which a flammable liquid gives off sufficient vapor to form
an ignitable mixture with air near its surface or within a vessel.
FP is determined by laboratory tests in cups.
- Gingivitis: Inflammation
of the gums.
- Hazard and Operability
Study (HAZOP): A formally structured method of systematically
investigating each element of a system for all of the ways in
which important parameters can deviate from the intended design
conditions to create hazards and operability problems. The hazard
and operability problems are typically determined by a study of
the piping and instrument diagrams (or plant model) by a team
of personnel who critically analyze effects of potential problems
arising in each pipeline and each vessel of the operation.
- Hazard Class: The
category of hazard assigned to a hazardous material under the
criteria of 49 CFR Part 173 and the provisions of the 49 CFR 172.101
Table. A material may meet the defining criteria for more than
one hazard class, but it is assigned to only one hazard class.
See Class.
- Hazard Communication
Rule: Requires chemical manufacturers and importers to
assess the hazards associated with the materials in their workplace
(29 CFR 1910.1200). Material safety data sheets, labeling, and
training are all results of this law. You are urged to acquire
and become familiar with these regulations. Contact your local
OSHA office.
- Hazard Warning: Defined
by OSHA as "any words, pictures, symbols, or combination
thereof appearing on a label or other appropriate form of warning
which convey the hazard(s) of the chemical(s) in the container(s)".
- Hazardous Atmosphere: An
atmosphere that may expose employees to the risk of death, incapacitation,
impairment of ability to self-rescue (i.e. escape unaided from
a permit space), injury, or acute illness from one or more of
the following causes: 1) flammable gas, vapor, or mist in excess
of 10% of its lower flammable limit (LFL); 2) airborne combustible
dust at a concentration that meets or exceeds its LFL; 3) atmospheric
oxygen concentration below 19.5% or above 23.5%; 4) atmospheric
concentration of any substance for which a dose or a permissible
exposure limit is published in subpart G, Occupational Health
and Environmental Control or subpart Z, toxic and hazardous substances
of this part and which could result in employee exposure in excess
of its dose or permissible exposure limit; and 5) any atmospheric
condition that is immediately dangerous to life and health.
- Hazardous Material:
A substance or material, which has been determined by the Secretary
of Transportation to be capable of posing an unreasonable risk
to health, safety, and property when transported in commerce,
and has been so designated. The term includes hazardous substances,
hazardous wastes, marine pollutants, elevated temperature materials,
materials designated as hazardous under the provisions of 49 CFR
§172.101 and §172.102, and materials that meet the defining criteria
for hazard classes and divisions in 49 CFR Part 173.
- Header: The colored band
on the top of a sign or tag that contains the signal word.
- Health Hazard: A chemical
for which there is significant evidence based on at least one
study conducted in accordance with established scientific principles,
that acute or chronic health effects may occur in exposed employees.
The term health hazard includes chemicals which are carcinogens,
toxic or highly toxic agents, reproductive toxins, irritants,
corrosives, sensitizers, heptatoxins, nephrotoxins, neurotoxins,
agents which act on the hematopoietic system, and agents which
damage the lungs, skin, eyes, or mucous membranes.
- HEPA: High-Efficiency Particulate
Air Filter. A specialized filter that is capable of removing 99.97%
of particles 0.3 microns or greater in diameter. Filters may be
used in ventilation systems to remove particles from air or in
personal respirators to filter air before it is inhaled by the
person wearing the respirator. The use of HEPA filters in ventilation
systems requires expertise in installation and maintenance.
- Highly Toxic: A chemical
falling within any of the following categories: (a) A chemical
that has 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. (b) A chemical that
has 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 two and three kilograms
each. (c) A chemical that has a median lethal concentration (LC50)
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 one hour (or less if
death occurs within one hour) to albino rats weighing between
200 and 300 grams each.
- Hot Work Permit: The employer's
written authorization to perform operations which could provide
a source of ignition, such as riveting, welding, cutting, burning,
or heating.
- Hydrophilic: Describing materials
having large molecules that tend to absorb and retain water, causing
them to swell and frequently to gel.
- IATA: International Air Transport
Association.
- ICAO: International Civil
Aviation Organization.
- Ignitability: Identifies
a waste that may cause a fire during routine disposal and storage
conditions. A characteristic, which identifies a waste as hazardous,
when the waste has a flashpoint of less than 60 degrees C (140
degrees F).
- Infectious Waste: Waste that
contains pathogens. May consist of tissues, organs, body parts,
blood, and body fluids that are removed during surgery.
- Inflammable: Capable of being
easily set on fire and continue burning, especially violently.
Do not confuse with nonflammable. See Combustible and Flammable.
- Ingestion: Swallowing a chemical
or biological substance; may inadvertently result from eating,
drinking, or smoking in the workplace or with contaminated hands.
- Inhalation: Entry of a chemical
substance to the lungs by breathing.
- Irritant: A chemical, which
is not corrosive, but which 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 the methods of 16 CFR 1500.41 for four hours
exposure or by other appropriate techniques, it results in an
empirical score of five or more. A chemical is an eye irritant
if so determined under the procedure listed in 16 CFR 1500.42
or other appropriate techniques.
- Lock-out/Tag-out: OSHA standard
29 CFR 1910.147 "Control of Hazardous Energy (lock-out/tag-out)."
Designed to protect employees, when involved in service and maintenance
activities, against the unexpected start-up of machines or equipment
or the release of stored energy that could cause injuries.
- LOTO: Lock-Out/Tag-Out. Also
see OSHA 1910.147 and OSHA 1910.296.
- Manifest: A form used to
identify the quantity, composition, and origin, routing, and destination
of hazardous waste during transportation from the point of generation
to the point of disposal, treatment, or storage.
- Material Safety Data Sheet: A
fact sheet summarizing information about material identification;
hazardous ingredients; health, physical, and fire hazards; first
aid; chemical reactivities and incompatibilities; spill, leak,
and disposal procedures; and protective measures required for
safe handling and storage. OSHA has established guidelines for
the descriptive data that should be concisely provided on a data
sheet to serve as the basis for written hazard communication programs.
The thrust of the law is to have those who make, distribute, and
use hazardous materials responsible for effective communication.
See the Hazard Communication Rule, 29 CFR, 1910.1200, as amended,
Sec. g. The Chemical Manufacturers Association (CMA) has developed
a set of guidelines for developing a consistent MSDS format that
has been accepted by ANSI. Also see Schedule I, Sec. 12, of the
Canadian Hazardous Products Act.
- MSDS: Material Safety
Data Sheet. Generally, an MSDS is arranged into
16 parts, each addressing a separate issue regarding the hazardous
chemical. Also see ANSI 400.
- Mutagen: A chemical or physical
effects that can alter genetic material in a living cell or organism
and result in physical or functional changes in all subsequent
generations.
- National Institute of Occupational
Safety and Health (NIOSH): A Federal agency, part of the Centers
for Disease Control (CDC), responsible for conducting research
and making recommendations for the prevention of work-related
illness and injuries. (NIOSH, [800] 356-4674)
- NFPA: National Fire Protection
Association. An international voluntary membership organization
formed to promote/improve fire protection and prevention and establish
safeguards against loss of life and property by fire. Best known
for the National Fire Codes, 16 volumes of standards, recommended
practices, and manuals developed (and periodically updated) by
NFPA committees. NFPA 704M publication is the code for showing
hazards of materials using the familiar diamond-shaped label with
appropriate numbers or symbols (NFPA hazard rating). (1 Batterymarch
Park, PO Box 9101, Quincy, MA 02269-9101; [800] 344-3555, [617]
770-3000.)
- Non Permit Confined Space: A
confined space that does not contain or, with respect to atmospheric
hazards, have potential to contain, any hazard capable of causing
death or serious physical harm.
- Nonflammable: Incapable of
easy ignition. Does not burn, or burns very slowly. Also, a DOT
hazard class for any compressed gas other than a flammable one.
- Nonflammable Gas: Any material,
or mixture, in a cylinder or tank, other than poison gas, or flammable
gas having in a container an absolute pressure exceeding 40 psi
at 70 degrees F, or having an absolute pressure exceeding 104
psi at 130 degrees F (Title 49 CFR and CGA).
- N.O.S.: Not otherwise specified
(a generic shipping name; see 172.600).
- N.O.S. Description:
A shipping description from the 49 CFR 172.101 HMT that includes
the abbreviation "n.o.s.", and is listed in 49 CFR 172.203(k)(3),
regarding additional description requirements.
- Organic Peroxide: A
compound containing the bivalent -O-O- structure and which is
a structural derivative of hydrogen peroxide (H2O2) where one
or both hydrogen atoms are replaced by an organic radical. These
compounds tend to be reactive and unstable.
As used in the transportation of hazardous materials, organic
peroxide means any organic compound containing oxygen (O) in the
bivalent -O-O- structure and that may be considered a derivative
of hydrogen peroxide, where one or more of the hydrogen atoms
have been replaced by organic radicals; unless any of the exceptions
listed in 49 CFR 173.128(a) apply.
- Organic Solvents: Liquid
chemicals (hydrocarbons) that can dissolve oil and grease.
- OSHA 1910.145: OSHA regulations
covering safety signs and tags.
- Oxidizer: A chemical other
than a blasting agent or explosive as defined in section 1910.109(a),
that initates 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)
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.)
- Oxygen Deficient Atmosphere:
An atmosphere containing less than 19.5% oxygen by volume.
- PCB: Polychlorinated biphenyl.
A family of compounds used as a heat-transfer medium. PCBs accumulate
in tissue, are environmentally hazardous, and are believed harmful
to human health. Their handling is regulated by law (40 CFR Part
761).
- PEL: Permissible exposure
limit. Established by OSHA. This may be expressed as a time-weighted
average (TWA) limit, a short-term exposure limit (STEL), or as
a ceiling exposure limit. A ceiling limit must never be exceeded
instantaneously even if the TWA exposure limit is not violated.
OSHA PELs have the force of law. OSHA has established an Action
Level for many substances, which is usually one-half of the PEL
set for that compound. Exposure at or above the Action Level triggers
additional employee protection measures, such as air analysis
of the workplace, additional employee training, medical surveillance
of affected employees, and record keeping. Note that ACGIH TLVs
and NIOSH RELs are recommended exposure limits that OSHA may or
may not enact into law.
- Physical Hazard: A substance
for which there is valid evidence that it is a combustible liquid,
compressed gas, explosive, flammable, an organic peroxide, an
oxidizer, pyrophoric, unstable (reactive), or water reactive.
In the general safety sense, a hazard of physical origin, such
as a fall, a heat burn, etc, and not a chemical or infective disease
hazard.
- Polymerization: A chemical
reaction in which one or more small molecules combine to form
larger molecules. Hazardous polymerization takes place
at a rate that releases large amounts of energy that can cause
fires or explosions or burst containers. Materials that can polymerize
usually contain inhibitors that can delay reactions. If hazardous
polymerization can occur with a given material, the MSDS will
usually 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.
- PPE: Personal Protective
Equipment (for example, "Gloves").
- psi: Pounds per square inch
(for MSDS purposes). The pressure a material exerts on the walls
of a confining vessel or enclosure. For technical accuracy, pressure
must be expressed as psig (pounds per square inch gauge) or psia
(pounds per square inch absolute) - gauge pressure plus sea level
atmospheric pressure, or psig plus approximately 14.7 pounds psi.
- PSM: The Process Safety Management
standard, 29 CFR 1910.119, promulgated by OSHA, effective May
26, 1992.
- Pyrophoric:
A chemical or mixture that will ignite spontaneously in dry or
moist air at or below 54.4 degrees C or 130 degrees F.
- Pyrophoric Liquid:
A liquid or solid that, even in small quantities and without an
external ignition source, can ignite within five (5) minutes after
coming in contact with air when tested according to paragraph
3.a.(1) or 3.a.(2), as appropriate, of 49 CFR 173 Appendix E.
- Radioactive: A property of
a material which emits ionizing radiation.
- RCRA: Resource Conservation
and Recovery Act, PL 94-580. Found at 40 CFR 240-271. EPA has
jurisdiction. Enacted November 21, 1976, and amended since. RCRA's
major emphasis is the control of hazardous waste disposal. It
controls all solid-waste disposal and encourages recycling and
alternative energy sources.
- RCRA Hazardous Waste: A material
designated by RCRA as a hazardous waste and assigned a number
to be used in record keeping and reporting compliance (e.g., D003,
F001, U169).
- Reactivity: A substance's
tendency to undergo chemical reaction either by itself or with
other materials with the release of energy. Undesirable effects
such as pressure buildup; temperature increase; or formation of
noxious, toxic, or corrosive by-products may occur because of
the substance's reactivity to heating, burning, direct contact
with other materials, or other conditions in use or in storage.
A solid waste that exhibits a "characteristic of reactivity,"
as defined by RCRA, may be regulated (by the EPA) as a hazardous
waste and assigned the number D003.
- Renal: Relating to
the kidneys.
- Reproductive Health Hazard/Toxin:
Any agent with a harmful effect on the adult male or female
reproductive systems or on the developing fetus or child. Such
hazards affect people in many ways, including loss of sexual drive,
impotence, infertility, sterility, mutagenic effects on germ cells,
teratogenic effects on the fetus, and transplacental carcinogenesis.
- Reproductive Toxin: Reproductive_Toxin
Chemicals which affect the reproductive capabilities including
chromosomal damage (mutations) and effects on fetuses (teratogenesis)
- Respirator:
A variety of devices that limit inhalation of toxic
materials. They range from disposable dust masks to self-contained
breathing apparatus (SCBA). All have specific uses and limitations.
Their use is covered by OSHA, 29 CFR 1910.134.
- Respiratory: Relating to
the lungs, airways, nose, mouth, or throat.
- Room-Air HEPA Recirculation Systems
and Units. Devices (either fixed or portable) that remove
airborne contaminants by recirculating air through a HEPA filter.
- RQ. Reportable Quantity.
The amount of a material that, when spilled, must be reported
to the DOT (Section 311 of the Clean Water Act).
- RTK: Right-to-Know.
Also see OSHA 1910.1200.
- Sensitizer: 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.
- Signal Word: That portion
of a tag's inscription that contains the word or words that are
intended to capture the employee's immediate attention.
- Target Organs: The organ
system or parts of the body that may be affected by overexposure
to a chemical.
- Teratogen, TER: A chemical
that has been demonstrated to cause malformations or physical
defects in the developing fetus or embryo.
- TLV: Threshold limit value.
A term ACGIH uses to express the maximum airborne concentration
of a material to which most workers can be exposed during
a normal daily and weekly work schedule without adverse effects.
"Workers" means healthy individuals; "healthy"
is defined as a 150 lb. male, age 25 to 44. The young, old, ill,
or naturally susceptible have lower tolerances and need to take
additional precautions. ACGIH expresses TLVs in three ways: TLV-TWA,
allowable time-weighted average concentration for a normal 8-hr
workday or 40-hr week; TLV-STEL, short-term exposure limit
or maximum concentration for a continuous exposure period of 15
min (with a maximum of four such periods per day, with at least
60 min between exposure periods, and provided that the daily TLV-TWA
is not exceeded); and Ceiling (C), concentration not to
exceed at any time.
- Toxic: A chemical falling
within any of the following categories: (a) A chemical that has
a median lethal dose (LD50) of 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. (b) 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 (c) 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 one hour)
to albino rats weighing between 200 and 300 grams each.
- Trifoil: Radiation symbol.
- UN Number: This number is
assigned according to recent UN listings. It defines the precise
chemical that is included in the container. For example, DICHLOROETHYLENE
is UN number 1150. It is Class 3 and uses Type II packaging. Consult
with your safety distributor and the Federal Register for the
latest UN numbers.
- Unstable: Tending toward
decomposition or other unwanted chemical change during normal
handling or storage. An unstable chemical in its pure state, or
as commonly produced or transported, polymerizes vigorously, decomposes,
condenses, or becomes self-reactive under conditions of shock,
pressure, or temperature.
- Vapor: The gaseous state
of a material normally encountered as liquid or solid at room
temperature. Vapors of organic liquids are loosely called fumes;
however, it is not technically appropriate to use the term fume
for vapors of organic liquids.
- Vascular: Relating to the
blood vessels (arteries, veins, or capillaries).
- Ventilation: Ventilation
Circulation of air within an environment.
- VOC: Volatile organic compounds.
Used in coatings and paint because they evaporate very rapidly.
Regulated by the EPA per the Clean Water Act.
- Water Reactive: Describes
a substance or mixture that reacts with water to release heat
or a flammable, toxic gas, or to otherwise present a health hazard.
- Water Reactive Material:
A material that, by contact with water, is liable to become spontaneously
flammable or to give off flammable or toxic gas at a rate greater
than 1 liter per kilogram of the material, per hour, when tested
in accordance with paragraph 4 of Appendix E in 49 CFR 173.
- WHMIS:Workplace Hazardous
Materials Information System. A regulation
of the Canadian government for chemicals.
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