Appendix A to § 1910.119

OSHA PSM Chemical List —
Complete Appendix A

All 137 chemicals listed in OSHA's PSM Appendix A — with hazard classification, physical state, EPA RMP cross-reference, and an inventory scanner to check your coverage at a glance.

137Listed chemicals

100 lbsLowest PSM threshold

66Also on EPA RMP list

4Hazard / state filters

T Toxic

R Reactive

T+R Toxic & Reactive

Gas

Liq

Sol

■

EPA RMP TQ same as PSM

■ EPA RMP stricter

■ EPA RMP less strict / not listed

Chemical Name	CAS	PSM TQ (lbs)	Hazard per Appendix A	State at ambient	EPA RMP TQ 40 CFR Part 68

Source: OSHA Appendix A to § 1910.119 (29 CFR Part 1910, Subpart H). Last amended 84 FR 15102, April 15, 2019. TQ = Threshold Quantity in pounds. Possessing a listed chemical at or above the TQ in a single process location triggers PSM coverage for that process.

Important: Appendix A covers toxic and reactive chemicals only. Flammable liquids and gases (as defined in § 1910.106(a)) at 10,000 lbs or more in one location are covered separately under § 1910.119(a)(1)(ii), regardless of whether they appear in this list.

EPA RMP column: Threshold quantities from EPA's Risk Management Program (40 CFR Part 68). Many PSM chemicals also trigger RMP requirements; TQs differ because the programs use different consequence models and receptor definitions. Cross-listed TQs are matched by CAS number to the toxic and flammable substance tables in 40 CFR 68.130 (checked October 2026). EPA concentration limits can differ from OSHA's; for example, RMP covers nitric acid at 80% or greater and ammonia solutions at 20% or greater. Verify against the current eCFR for compliance. Chemicals not appearing on the EPA RMP list show "—".

Further reading: Guidelines for Chemical Process Quantitative Risk Analysis (CCPS) — the standard reference for consequence modeling and risk tolerance criteria.

OSHA PSM Chemical List —Complete Appendix A

OSHA PSM Chemical List —
Complete Appendix A