ACGIH

ACGIH is a scientific association of industrial hygienists and occupational health professionals. Each year, its committees review the research and update guidelines for airborne chemical exposure and for biological monitoring.

The best known products are the TLVs, which set levels to which it is believed nearly all workers may be repeatedly exposed, day after day, without adverse health effects, usually expressed as a time-weighted average, with some chemicals also given a short-term limit or ceiling. ACGIH also publishes BEIs, which relate to measurements in blood, urine, or breath.

ACGIH values are not legally binding on their own. In the United States, enforceable limits come from OSHA. Many of OSHA's older PELs were drawn from early ACGIH lists, so they can lag behind the current TLVs. In some cases the TLV is lower, and many companies and safety professionals use the TLV as a better guide to protection.

Some other jurisdictions and state programs do adopt TLVs, and a few regulations refer to them directly. Check the rule that applies to your site.

TLVs are updated regularly and are meant for use by trained professionals, not as a sharp line between safe and unsafe.