American Conference of Governmental Industrial Hygienists - TLVs and BEIs

TLVs and BEIs

ACGIH establishes the Threshold Limit Values (TLVs) for chemical substances and physical agents and Biological Exposure Indices (BEIs).

Undoubtedly the best known of ACGIH's activities, the Threshold Limit Values for Chemical Substances (TLV-CS) Committee was established in 1941. This group was charged with investigating, recommending, and annually reviewing exposure limits for chemical substances. It became a standing committee in 1944. Two years later, the organization adopted its first list of 148 exposure limits, then referred to as Maximum Allowable Concentrations. The term "Threshold Limit Values (TLV)" was introduced in 1956. The first Documentation of the Threshold Limit Values was published in 1962. A new edition is now published every year. Today's list of TLVs includes over 600 chemical substances and physical agents, as well as over 30 Biological Exposure Indices for selected chemicals.

The TLVs and BEI are developed as guidelines to assist in the control of health hazards. These recommendations or guidelines are intended for use in the practice of industrial hygiene, to be interpreted and applied only by a person trained in this discipline.

In certain circumstances, individuals or organizations may wish to make use of these recommendations or guidelines if the use of TLVs and BEIs contributes to the overall improvement in worker protection.