What Is a Superfund Site?

The EPA says Congress established the Comprehensive Environmental Response, Compensation and Liability Act, or CERCLA, in 1980, and that CERCLA is informally called Superfund. It says the law allows the EPA to clean up contaminated sites, and forces the parties responsible for the contamination to either perform cleanups or reimburse the government for EPA-led cleanup work.

The EPA keeps a National Priorities List, which it defines as the list of sites of national priority among the known or threatened releases of hazardous substances, pollutants or contaminants throughout the United States and its territories, intended primarily to guide the EPA in deciding which sites warrant further investigation. It says the Hazard Ranking System is the principal mechanism it uses to place uncontrolled waste sites on the list, a numerically based scoring system that uses information from a preliminary assessment, a site inspection and, if necessary, an expanded site inspection to assess the relative potential of sites to threaten human health or the environment. The EPA says a total of 1,343 uncontrolled hazardous waste sites are listed, after it added one site in a rule published in the March 13, 2026 Federal Register, and it offers a search tool for sites proposed to, currently on and deleted from the list.

ATSDR says it conducts a Public Health Assessment for every site on or proposed for the National Priorities List, reviewing available information about hazardous substances at the site and evaluating whether exposure to them might cause any harm to people.

Two PFAS chemicals are now covered. The EPA designated PFOA and PFOS as CERCLA hazardous substances in a rule that became effective on July 8, 2024, and on September 17, 2025 it said the Justice Department had submitted a court filing on its behalf in litigation over the designation and that the agency is retaining the rule. On August 18, 2026, the US Court of Appeals for the District of Columbia Circuit denied the petitions for review, concluding that the EPA made a reasoned decision in designating PFOA and PFOS as hazardous substances even in the face of acknowledged uncertainties.