Chemical Hygiene Plan Glossary

Revised January 2023

Action Level

The airborne chemical concentration that triggers air monitoring and the implementation of additional control measures. The action level is always lower than the corresponding exposure limit and is designed to protect personnel from overexposure. At the University, the more conservative of either the OSHA-defined action level (generally one-half the PEL) or one-half the ACGIH TLV is used as the action level.

Carcinogen

Any substance which meets one of the following criteria: (i) it is regulated by OSHA as a carcinogen, (ii) it is listed under the category, “known to be carcinogens,” (Type 1 carcinogen) in the Annual Report on Carcinogens published by the National Toxicology Program (NTP), or (iii) it is listed under Group 1 (“carcinogenic to humans”) by the International Agency for Research on Cancer Monographs (IARC).

Combustible Liquid

Any liquid having a flashpoint at or above 100 °F (38 °C), but below 200 °F (93 °C), except any mixture having components with flashpoints of 200 °F (93 °C), or higher, the total volume of which make up 99 percent or more of the total volume of the mixture. Combustible liquids are divided into the following classes:

• Class II – Liquids having a flashpoint at or above 100 °F (38 °C), but below 140 °F (60 °C).
• Class IIIA – Liquids having a flashpoint at or above 140 °F (60 °C), but below 200 °F (93 °C).

Compressed Gas

(i) A gas or mixture of gases having, in a container, an absolute pressure exceeding 40 psi at 70 °F (21 °C); or (ii) A gas or mixture of gases having, in a container, an absolute pressure exceeding 104 psi at 130 °F (54 °C) regardless of the pressure at 70 °F (21 °C); or (iii) A liquid having a vapor pressure exceeding 40 psi at 100 °F (38 °C).

Corrosive

A chemical that causes visible destruction of, or irreversible alteration in, living tissue by chemical action at the site of contact.

Cryogenic Liquid

A liquefied gas at atmospheric pressure and subzero temperatures (less than –100 °F (-73 °C)).

Designated Area

An administrative area established for work with particularly hazardous substances (carcinogens, reproductive toxins, and chemicals with a high degree of acute toxicity). A designated area may be the entire laboratory, an area within the laboratory, or a device such as a lab hood.

Explosive

A chemical that causes a sudden, almost instantaneous release of pressure, gas, and heat when subjected to sudden shock, pressure, or high temperature.

Exposure Limit

The air concentration of a specific chemical below which it is believed that most workers will not experience adverse health conditions as a result of the exposure. Exposure limits are defined for specific time periods. See “permissible exposure level” and “threshold limit value.”

Flammable

A chemical which falls into one of the following categories:

• Flammable Aerosol – An aerosol that yields a flame projection exceeding 18 inches at full valve opening, or a flashback at any degree of valve opening.
• Flammable Gas – 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 that forms a range of flammable mixtures with air wider than 12 percent by volume, regardless of the lower limit.
• Flammable Liquid – Any liquid having a flashpoint below 100 °F, except any mixture having components with flashpoints of 100 °F (38 °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, 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.

Flammable Liquid

OSHA Flammable Liquid Categories:
Category 1 - Flash point < 23°C (73.4°F) and initial boiling point ≤ 35°C (95°F)
Category 2 - Flash point < 23°C (73.4°F) and initial boiling point > 35°C (95°F)
Category 3 - Flash point ≥ 23°C (73.4°F) and ≤ 60°C (140°F)
Category 4 - Flash point > 60°C (140°F) and ≤ 93°C (199.4°F)

International Fire Code Flammable Liquid Classes:
Class IA – Liquids having a flashpoint below 73 °F (23 °C), and having a boiling point below 100 °F (38 °C).
Class IB – Liquids having a flashpoint below 73 °F (23 °C), and having a boiling point at or above 100 °F (38 °C).
Class IC – Liquids having a flashpoint at or above 73 °F (23 °C), and below 100 °F (38 °C).

Flashpoint

The minimum temperature at which a liquid gives off a vapor in sufficient concentration to ignite in the presence of an ignition source.

Hazardous Chemical

Any chemical that is a physical hazard or a health hazard.

Hazard 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 hazards of the chemical in the container.

Health Hazard

A chemical for which there is statistically 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 personnel. The term “health hazard” includes chemicals which are carcinogens, toxic or highly toxic agents, reproductive toxins, irritants, corrosives, sensitizers, hepatotoxins, nephrotoxins, neurotoxins, agents which act on the hematopoietic system, and agents which damage the lungs, skin, eyes, or mucous membranes.

HEPA Filter

High Efficiency Particulate Air (HEPA) filter. A filter material which removes 99.7% or more of particles of 0.3 micrometers or larger under test conditions. Used in applications where toxic dusts must be carefully controlled.

Highly Toxic

A chemical falling within any of the following categories:

• 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.
• 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.
• A chemical that has a median lethal concentration (LC50) in air of 200 parts per million by volume or less of gas of 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.

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.

Laboratory

A facility where the “laboratory use of chemicals” occurs. A facility where relatively small quantities of chemicals are used on a non-production basis.

Laboratory Use of Hazardous Chemicals

Handling or use of such chemicals in which all of the following conditions are met: (i) chemical manipulations are carried out on a “laboratory scale,” (ii) multiple chemical procedures or chemicals are used, (iii) the procedures involved are not part of a production process, and (iv) protective laboratory practices and equipment are available and in common use to minimize the potential for personnel exposure to hazardous chemicals.

LC50

Lethal Concentration 50. The concentration of a substance in air that on the basis of laboratory tests (inhalation exposure) is expected to kill 50% of a group of test animals when administered as a single exposure in a specific time period (usually one hour).

LD50

Lethal Dose 50. The single dose of a substance that results in the death of 50% of an animal population from exposure to the substance by any route other than inhalation.

Safety Data Sheet (SDS)

Formerly known as a material safety data sheet (MSDS). Written or printed material concerning a hazardous chemical which is prepared in accordance with OSHA specifications.

Organic Peroxide

An organic compound that contains the bivalent –O-O- structure and which may be considered to be a structural derivative of hydrogen peroxide where one or both of the hydrogen atoms has been replaced by an organic radical.

Oxidizer

A chemical other than a blasting agent or explosive that initiates or promotes combustion in other materials, thereby causing fire either of itself or through release of oxygen or other gases.

Particularly Hazardous Substance

Includes carcinogens, reproductive toxins, and substances with high acute toxicity (defined as “highly toxic”).

Permissible Exposure Level (PEL)

An exposure limit promulgated by OSHA and enforceable by law.

Physical Hazard

A chemical for which there is scientifically valid evidence that it is a combustible liquid, a compressed gas, explosive, flammable, organic peroxide, an oxidizer, pyrophoric, unstable (reactive) or water-reactive.

Pyrophoric

A chemical that will ignite spontaneously in air at a temperature of 130 °F (54 °C) or below.

Reactive Chemical

A chemical with the ability to react vigorously, decompose or condense under conditions of shock, pressure or temperature.

Reproductive Toxin

A chemical that affects the reproductive capabilities including chromosomal damage (mutations) and effects on fetuses (teratogenesis). Chemicals identified in the SDS or other accepted hazard information as producing reproductive effects or teratogenesis are considered reproductive toxins.

Suspect Carcinogen

Any substance which meets one of the following criteria:

• it is listed under the category, “reasonably anticipated to be carcinogens,” (Type 2 carcinogen) in the Annual Report on Carcinogens published by the National Toxicology Program (NTP), or
• it is listed under Group 2A or 2B (“probably carcinogenic to humans” and “possibly carcinogenic to humans”, respectively) by the International Agency for Research on Cancer Monographs (IARC).

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.

Threshold Limit Value (TLV)

A recommended exposure limit set by the American Conference of Governmental Industrial Hygienists (ACGIH). A TLV is not enforceable by law.

Toxic

A chemical falling within any of the following categories:

• 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.
• 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 of vapor, or more than 2 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.

Unstable (reactive)

A chemical which in the pure state, or as produced or transported, will vigorously polymerize, decompose, condense, or will become self-reactive under conditions of shocks, pressure or temperature.

Water Reactive

A chemical that reacts with water to release a gas that is either flammable or presents a health hazard.

Laboratory Specific Training Documentation