Consensus standards and exposure limits

ACGIH 2026 TLVs: six new adoptions

ACGIH's 2026 TLVs adopted values for six chemicals: 1,4-dichloro-2-butene, DEET, dimethyl carbamoyl chloride, ethyl butyl ketone, nitric acid and o-toluidine. No physical agent TLVs or BEIs were adopted. Carbon monoxide and five other chemicals are on the 2026 Notice of Intended Changes.

On your exam?

Not yet: the exam still tests the prior rule

Industrial hygiene questions test TLV concepts (TWA, STEL, ceiling, mixtures) and well-known agents. Values on the Notice of Intended Changes, like carbon monoxide, aren't adopted.

Judged against ASP11 and CSP11, the outlines in effect on October 16, 2026.

Status: New edition published
Exams: ASP, CSP
From: ACGIH
Last checked: October 16, 2026

2026 at a glance

Adopted chemical TLVs: 1,4-dichloro-2-butene, diethyltoluamide (DEET), dimethyl carbamoyl chloride, ethyl butyl ketone, nitric acid, o-toluidine.
Notice of Intended Changes (chemicals): aniline, n-butyl propionate, carbon monoxide, citronellol, geraniol and related compounds, propargyl alcohol.
Notice of Intended Changes (BEIs): methyl ethyl ketone.
Physical agents and BEIs adopted: none.

A substance on the Notice of Intended Changes keeps its current adopted value until ACGIH adopts a change.

For the exam

Know how TLVs differ from OSHA PELs (TLVs are guidelines; PELs are law), the TLV types, and how to calculate exposure to mixtures.

Practice what's tested now

Sources

Published October 16, 2026. Last checked against these sources October 16, 2026. Something out of date? Email hello@passcited.com.