An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to www.epa.gov. This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

What are extremely hazardous substances (EHSs)?

Emergency Planning and Community Right-to-Know Act (EPCRA) section 304 release reporting requirements apply to CERCLA hazardous substances and EPCRA extremely hazardous substances (EHSs). What are EHSs?

The EHS list was first compiled by EPA, and subsequently incorporated into EPCRA, to identify chemicals that could cause serious irreversible health effects from accidental releases. EHSs are listed in 40 CFR Part 355.