• When a determination is made to regulate a substance under the CAA, CWA, RCRA, or TSCA, it automatically becomes a CERCLA hazardous substance.

Hazardous substance is defined in the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) 101(14) to include a compilation of substances listed in accordance with the Clean Air Act (CAA), Clean Water Act (CWA), Resource Conservation and Recovery Act (RCRA), and Toxic Substances Control Act (TSCA).

When a determination is made to regulate a substance under the CAA, CWA, RCRA, or TSCA, it automatically becomes a CERCLA hazardous substance and will be added to the Table 302.4 found at 40 CFR 302.4. When a substance is delisted from the CAA, CWA, RCRA, or TSCA lists, the substance remains on the hazardous substance list unless the Environmental Protection Agency (EPA) determines that there is no independent basis for retaining the hazardous substance listing. CERCLA grants EPA the authority to automatically add new substances to the list of hazardous substances codified in Table 302.4 found at 40 CFR 302.4. In a nutshell, 40 CFR 302.4 offers a list of covered hazardous substances.

In addition, according to 302.4, the release of a material that exhibits one or more characteristics (identified at 40 CFR 261.20 through 261.24) of hazardous waste, but is not specifically listed on Table 302.4, is reportable provided the material becomes a waste upon release and the amount released meets the reportable quantity (RQ).