CERCLA Hazardous Substances

CERCLA hazardous substances are defined in terms of those substances either specifically designated as hazardous under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), otherwise known as the Superfund law, or those substances identified under other laws. In all, the Superfund law includes references to four other laws (Legal Authorities Defining Hazardous Substances) to designate more than 800 substances as hazardous, and identify many more as potentially hazardous due to their characteristics and the circumstances of their release.

The Superfund law gives EPA's Superfund Emergency Response program the authority to respond to emergencies involving these substances and to pollutants or contaminants that pose "imminent and substantial danger to public health and welfare or the environment." The term "pollutant or contaminant" includes, but is not limited to, any element, substance, compound or mixture, including disease-causing agents, which after release in the environment and upon exposure, ingestion, inhalation, or assimilation into any organism, will likely cause death, disease, behavioral abnormalities, cancer, genetic mutations, physiological malfunctions (including reproductive), or physical deformations in such organisms or their offspring.

The terms "hazardous substance" and "pollutant or contaminant" do not include petroleum or natural gas. EPA conducts emergency responses to incidents involving petroleum and non-petroleum oils through its Oil Program, which functions under the Clean Water Act authorities. Throughout the Emergency Response Program, the term "hazardous substance" includes pollutants and contaminants.

In addition to the hazardous substances identified under the Superfund law, the Title III amendments to Superfund, also known as the Emergency Planning and Community Right-to-Know Act (EPCRA), identify several hundred hazardous substances for their extremely toxic properties. EPA designated them as "extremely hazardous substances" to help focus initial chemical emergency response planning efforts.