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Hazard Communication FAQ

Hazard Communication FAQ

SDS Glossary


American Conference of Governmental Industrial Hygienists . A professional organization of government and university industrial hygienists.

Acute Health Effect

An adverse effect arising from a short (minutes to hours) period of exposure.


American Industrial Hygiene Association . A professional organization of industrial hygienists. 


Defined by OSHA as "any manufactured item other than a fluid or particle which is formed to a specific shape or design during manufacture, has end use function(s) dependent in whole or in part upon its shape or design during end use, and which under normal conditions of use does not release more than. minute or trace amounts of a hazardous chemical and does not pose a physical hazard or health risk to employees".

CAS Number

Chemical Abstracts Service number - a way in which chemicals are uniquely identified by a numbering system.

Ceiling Limit

A designated maximum airborne level to which people can be exposed.

Chronic Health Effect

An adverse effect arising after long periods (months to years) of exposure.

Hazardous chemical

Any chemical that is a physical hazard or a health hazard 

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.

Lethal Dose (LD50)

The dose producing death in 50% of a test animal population

Lower Explosive Limit (LEL)

The minimum concentration as a percentage, of flammable gas that can be ignited. Also referred to as the Lower Flammable Limit (LFL)

Lowest Lethal Concentration (LCLo)

The lowest concentration of a substance in air that has been known to kill animals

Lowest Toxic Dose (TDLo)

The lowest dose reported to cause toxic effects in humans or test animals. Permissible Exposure Limit - Permissible concentration in air of a substance to which nearly all workers may be repeatedly exposed 8 hours a day, 40 hours a week, for 30 years without adverse side effects. This value is legally enforceable by OSHA.


Concentration measurement in milligrams per cubic meter.


Material Safety Data Sheet


National Institute for Occupational Safety and Health


Occupational Exposure Limit - A health based workplace standard to protect workers from adverse exposure. For example, TLV or PEL.


Occupational Safety and Health Administration . Located within the US Department of Labor. The agency responsibilities include formulating occupational safety and health standards and inspecting workplaces to ensure compliance with these standards.


Permissible Exposure Limit - the maximum eight-hour time-weighted-average air concentration to which employees can be exposed. This level is enforced by OSHA.


Permissible Exposure Limit-Short Term Exposure Limit - 15 min Time Weighted Average exposure that shall not be exceeded at any time during a workday.

Physical Hazard

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


Personal Protective Equipment - Includes items such as gloves, safety goggles and respirator masks that are worn to reduce the potential for exposure to chemicals.


Concentration in parts per million (by volume).Label Any written, printed, or graphic material displayed on or affixed to containers of hazardous chemicals.


Short Term Exposure Limit - Maximum concentration for continuous 15 minute period, allowed four times a day with at least 60 minutes between exposures


Time Weighed Average - The average exposure for an individual over a given working period (normally 8 hours).


Threshold Limit Value - An exposure level under which most people can work consistently for 8 hours a day, without adverse effects. Can also be used with 15-minute Short Term Exposure Limits. This exposure level was developed by the ACGIH and is not a legally enforceable value.

(UEL) Upper Explosive Limit

Percentage by volume of a flammable gas or vapor that is the maximum level ignitable. Also referred to the Upper Flammable Limit (UFL).


Workplace Environmental Exposure Level - exposure guidelines developed by AIHA .