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Permissible Exposure Limits (PELs)

OSHA sets enforceable permissible exposure limits (PELs) to protect workers against the health effects of exposure to hazardous substances. PELs are regulatory limits on the amount or concentration of a substance in the air. They may also contain a skin designation. OSHA PELs are based on an 8-hour time weighted average (TWA) exposure.

Permissible exposure limits (PELs) are addressed in specific standards for the general industry, shipyard employment, and the construction industry.

OSHA Standards

This section highlights OSHA standards, preambles to final rules (background to final rules), Federal Registers (rules, proposed rules, and notices), and standard interpretations (official letters of interpretation of the standards) related to PELs.

Note: Twenty-five states, Puerto Rico and the Virgin Islands have OSHA-approved State Plans and have adopted their own standards and enforcement policies. For the most part, these States adopt standards that are identical to Federal OSHA. However, some States have adopted different standards applicable to this topic or may have different enforcement policies.

General Industry (29 CFR 1910)

Shipyard Employment (29 CFR 1915)

Construction Industry (29 CFR 1926)

Preambles to Final Rules

Federal Registers

Standard Interpretations

Establishing PELs

Approximately 500 PELs have been established. Existing PELs are contained in 29 CFR 1910.1000, the air contaminants standard. Most PELs are listed in 29 CFR 1910.1000 Table Z-1. 29 CFR 1910.1000 Table Z-2 contains PELs for the following substances:

  • benzene

  • beryllium and beryllium compounds

  • cadmium – dust and fumes
    (see 29 CFR 1910.1027)

  • carbon disulfide

  • carbon tetrachloride

  • chromic acid and chromates (see 29 CFR 1910.26 and corrections)

  • ethylene dibromide

  • ethylene dichloride

  • fluoride as dust

  • formaldehyde (see 29 CFR 1910.1048)
  • hydrogen fluoride

  • hydrogen sulfide

  • methylene chloride
    (see 29 CFR 1910.1052)

  • mercury

  • organo(alkyl)mercury

  • styrene

  • tetrachloroethylene

  • toluene

  • trichloroethylene

PELs for exposure to mineral dusts can be found in 29 CFR 1910.1000 Table Z-3. Mineral dusts listed include silica (crystalline and amorphous), silicates, graphite, coal dusts and inert or nuisance dusts. The following references provide additional information regarding establishing PELs.

Exposure Evaluation and Control

How an airborne hazard is best controlled depends on the nature of the hazard and the process and possibility that workers will be exposed. Whenever possible, airborne hazards should be engineered out of a process. If it is not possible to reduce the hazard, appropriate personal protective equipment must be used.

Additional Information

Related Safety and Health Topics Pages

Other Resources


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