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Appendix A to § 1910.119
Highly Hazardous Chemicals — The Complete List
All 137 chemicals listed in OSHA's PSM Appendix A with threshold quantities. Search by name or CAS number, filter by TQ range, and check whether your quantity triggers PSM coverage.
137Listed chemicals
100 lbsLowest TQ (many chemicals)
20,000 lbsHighest TQ on the list
Quick Coverage Check
Is My Quantity Above the Threshold?
Type a chemical name below, enter your on-site quantity, and see instantly whether you exceed the PSM threshold.
Showing 137 of 137 chemicals
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CAS Number
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Try a different name or CAS number. Remember: flammable liquids and gases at 10,000 lbs+ are also covered regardless of whether they appear in Appendix A.
Source:OSHA Appendix A to § 1910.119 (29 CFR Part 1910, Subpart H). Last amended 84 FR 15102, April 15, 2019. This table reproduces the official OSHA list verbatim. Always verify against the current e-CFR for compliance purposes. TQ = Threshold Quantity in pounds. Possessing a listed chemical at or above the TQ in a single 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.
Further reading: Understanding the potential consequences of a release at or above these threshold quantities requires quantitative analysis. The CCPS Guidelines for Chemical Process Quantitative Risk Analysis is the standard reference for consequence modeling, frequency analysis, and risk tolerance criteria.