Threshold limit value

Strictly speaking, TLV is a reserved term of the American Conference of Governmental Industrial Hygienists (ACGIH), who determines and publishes TLVs annually.

The TLV is an estimate based on the known toxicity in humans or animals of a given chemical substance, and the reliability and accuracy of the latest sampling and analytical methods.

[2] It is also not a static value, since new research can often modify the risk assessment of substances, and new laboratory or instrumental analysis methods can improve analytical detection limits.

As such, it should not be confused with exposure limits having a regulatory status, like those published and enforced by the Occupational Safety and Health Administration(OSHA).

[3] Many people accredit the idea of government responsibility for the protection of its workers in the workplace to Franklin D. Roosevelt in the Great Depression era.

"[7] This fund ensures that TLVs and BEIs will continue to have the necessary financial support to be created and revised in order to provide up-to-date standards.

The TLV and most other occupational exposure limits are based on available toxicology and epidemiology data to protect nearly all workers over a working lifetime.