Occupational Exposure Limit

Many of the OSHA PELs are outdated and inadequate for ensuring protection of worker health. Most PELs were issued shortly after adoption of the OSH Act in 1970 and have not been updated since that time.

Occupational Exposure Limits (OELs) have been established by a number of organizations to supplement OSHA PELs. Many of these OELs have been adopted by OSHA. To provide employers and employees with an alternate list of OELs, OSHA created the annotated Z-Tables that provide additional OELs. The table includes Cal/OSHA PELs, the National Institute for Recommended Safety and Health (NIOSH) Recommended Exposure Limits (RELs), and the ACGIH^© TLVs^®. The Z-Tables list air concentration limits but do not include notations for skin absorption or sensitization.

Cal/OSHA has established an extensive list of PELs, more than any other OSHA-approved state plan. These levels are not enforceable outside of the Cal/OSHA jurisdiction; however, they provide information on acceptable levels of chemicals in the workplace.

NIOSH developed the Recommended Exposure Limit (REL). These levels have been recommended by NIOSH to OSHA. NIOSH states that these levels will protect a worker's health and safety over a working lifetime if used in combination with engineering and work practice controls. The RELs are published in the NIOSH Pocket Guide to Chemical Hazards.

The American Conference of Governmental Industrial Hygienists (ACGIH) is a private, not-for-profit corporation that develops recommendations for occupational health hazards. They annually review exposure limits for chemical substances and publish their findings in the Threshold Limit Values (TLVs) of Airborne Contaminants. TLVs are not intended to be used as legal standards.

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