Risk-based Nature of CERCLA

CERCLA was passed in 1980 to provide a federally supervised system for the mitigation of chronic environmental damage, particularly the cleanup of sites contaminated with hazardous waste. In 1986, CERCLA was amended by the Superfund Amendments and Reauthorization Act (SARA). Each Superfund site has been assessed, characterized, and prioritized based on risk. Potential sites are first screened using a preliminary assessment (PA) sites deemed a significant threat are then evaluated using a hazard ranking system (HRS) to measure the risk of the site relative to that of other potential sites. The most hazardous sites are then placed on the NPL in the order of their potential risk. 

Hundreds of chemicals are regulated under CERCLA they are classified as (i) hazardous substances and (ii) pollutants or contaminants. The definition of a hazardous substance under CERCLA is broad and is based on other environmental regulations. A CERCLA hazardous substance does not need to be a waste or waste material. It can be a commercial chemical, formulation, or product. A CERCLA hazardous substance is defined as any chemical regulated under the Clean Water Act, the Clean Air Act, the Toxic Substances Control Act (TSCA), or the Resource Conservation and Recovery Act (RCRA). However, two materials that are excluded from the hazardous substances list are petroleum and natural gas. A CERCLA pollutant or contaminant is defined as any other chemical or substance that will or may reasonably be anticipated to cause harmful effects to human or 

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