A Superfund site is any land in the United States that has been contaminated by hazardous waste and identified by the Environmental Protection Agency (EPA) as a candidate for cleanup because it poses a risk to human health and/or the environment. These sites are placed on the National Priorities List (NPL) .

The NPL is the list of national priorities among the known releases or threatened releases of hazardous substances, pollutants, or contaminants throughout the United States and its territories. The NPL is intended primarily to guide the EPA in determining which sites warrant further investigation. The site's NPL "status" can provide more information about the site in relationship to the NPL:

• Proposed: Site proposed (by the EPA, the state, or concerned citizens) for addition to the NPL due to contamination by hazardous waste and identified by the Environmental Protection Agency (EPA) as a candidate for cleanup because it poses a risk to human health and/or the environment
• Withdrawn: Site removed from the National Priorities List (NPL) because the EPA has determined that it poses no real or potential threat to human health and the environment
• Final: Site determined to pose a real or potential threat to human health and the environment after completion of Hazard Ranking System (HRS) screening and public solicitation of comments about the proposed site
• Deleted: Site deleted from the National Priorities List (NPL) by the EPA (with state concurrence) because site cleanup goals have been met and no further response is necessary at the site.