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 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 This website is no longer updated and links to external websites and some internal pages may not work.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 »

Clean Water Act (CWA) and CERCLA hazardous substance lists

What is the relationship between the hazardous substance lists under the Clean Water Act (CWA) and under CERCLA?

All CWA hazardous substances are CERCLA hazardous substances (only some CERCLA hazardous substances are CWA hazardous substances). Table 117.3 in 40 CFR 117.3, which is entitled "Reportable Quantities of Hazardous Substances," lists substances that were designated as hazardous under section 311(b)(4) of the CWA. Table 117.3 provides the CWA RQs for the substances. Substances designated under this section of the CWA are automatically CERCLA hazardous substances because CERCLA section 101(14) defines "hazardous substance" chiefly by reference to lists under other statutes, including CWA section 311(b)(4). Therefore, all of the hazardous substances in Table 117.3 are also in the list of CERCLA hazardous substances.