750 Introduction to Industrial Hygiene

Permissible Exposure Limits (PELs)

Permissible Exposure Limit (PEL) is a term used in occupational health and safety to refer to the maximum concentration of a hazardous substance to which workers can be exposed to during their workday without experiencing negative health effects.

By law, employers who use regulated chemicals must control employee exposures below the PELs. Permissible exposure limits usually represent the maximum amount (concentration) of a chemical that can be present in the air without presenting a health hazard. However, permissible exposure limits may not always be completely protective for the following reasons:

1. Although exposure limits are usually based on the best available information, this information, particularly for chronic (long-term) health effects, may be incomplete.
2. Exposure limits are set to protect most workers. However, there may be a few workers who will be affected by a chemical at levels below these limits.
3. Exposure limits do not take into account chemical interactions. When two or more chemicals in the workplace have the same health effects, IHs adjust the exposure limits for those substances in that workplace.
4. Exposure limits usually apply to the concentration of a chemical in the air, however, limiting the concentration in air may not prevent excessive exposure through skin contact or ingestion. Workers exposed to these chemicals must be provided with protective clothing to wear when overexposure through the skin is possible.

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