What Is a Superfund Site?

The Superfund Program

The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), commonly known as Superfund, was enacted in 1980 in response to environmental disasters like Love Canal in New York, where a neighborhood was built on a former chemical waste dump. The law gives the EPA authority and funding to clean up the most severely contaminated sites in the country.

Superfund sites include former industrial facilities, military bases, mining operations, landfills, and other locations where hazardous substances were released. Sites that score at or above the EPA Hazard Ranking System threshold are proposed for the National Priorities List (NPL), which prioritizes them for long-term federal cleanup action.

How Sites Get Listed

The path to the NPL follows a structured process:

1. Discovery: Contamination is discovered through state reporting, citizen complaints, or facility inspections.
2. Preliminary Assessment (PA): EPA evaluates available information to determine if further investigation is warranted.
3. Site Inspection (SI): Physical sampling confirms the type and extent of contamination.
4. Hazard Ranking System (HRS): Sites are scored based on contamination severity, exposure pathways, and population at risk. A score of 28.5 or higher qualifies for the NPL.
5. Proposed listing: The EPA publishes the proposal in the Federal Register and accepts public comment.
6. Final listing: After public comment, the site is added to the NPL.

The Cleanup Process

Once listed, cleanup follows a multi-phase process that can span decades:

• Remedial Investigation (RI): Comprehensive study of contamination, what's in the soil, groundwater, and air, and how far it has spread.
• Feasibility Study (FS): Evaluates cleanup options, from full excavation to containment to monitored natural recovery.
• Record of Decision (ROD): The EPA selects the cleanup remedy based on effectiveness, cost, and community input.
• Remedial Design/Action: The cleanup is engineered and executed, soil removal, groundwater treatment, capping contaminated areas.
• Long-term monitoring: Even after active cleanup, sites are monitored for years or decades to ensure the remedy remains effective.
• Delisting: When all cleanup goals are met and no further action is needed, the site is removed from the NPL.

What EPA records cover (and what they are not)

PlainEnviro republishes Superfund registry fields from the EPA Superfund Enterprise Management System: NPL status, HRS score when present, contaminant catalogs from remedial investigation records, construction-complete and deletion flags, and location. Those fields describe cleanup-program status. They are not a personal medical diagnosis or a substitute for site-specific EPA Regional Superfund profiles, ATSDR public-health assessments, or state environmental agency notices.

Common contaminant classes appearing in NPL investigation records include heavy metals, volatile organic compounds, and pesticides. Whether any pathway presents an exposure concern at a given address is decided in official site assessments, not by ranking or listing alone.

Exposure pathways the EPA evaluates

EPA's baseline human health risk assessment models five primary exposure routes: ingestion of contaminated drinking water, dermal contact with contaminated soil or sediment, inhalation of vapor intrusion or airborne dust, ingestion of contaminated subsistence-caught fish, and direct ingestion of contaminated soil (especially relevant for children). Each pathway is quantified using site-specific concentration data, default exposure parameters from the EPA Exposure Factors Handbook, and toxicity values from the Integrated Risk Information System (IRIS) database. Official assessments for a named site live on EPA Regional Superfund pages.

Worked example: how an HRS-style groundwater reading is framed

Consider a generic illustration (not a PlainEnviro page claim): trichloroethylene measured in a shallow aquifer at concentrations that exceed an EPA tap-water Regional Screening Level. In the Superfund process, that kind of exceedance triggers further investigation and remedy selection documented in a Record of Decision, pump-and-treat, in-situ oxidation, monitored natural attenuation, or other EPA-selected remedies. PlainEnviro surfaces the resulting NPL status and contaminant catalog when present in the public extract; it does not compute private-well risk scores.

Cleanup remedy comparison at a glance

Funding mechanics: Trust Fund vs Polluter-Pays

The original 1980 Superfund statute established a chemical and petroleum excise tax that funded the Hazardous Substance Superfund Trust Fund through 1995, after which Congress allowed the tax to lapse. From 1996 through 2021 cleanup at orphan sites without identifiable responsible parties was funded by general appropriations. The Infrastructure Investment and Jobs Act of 2021 reinstated the chemical excise tax (Internal Revenue Code section 4661) effective July 1, 2022, restoring polluter-pays funding for chemicals listed in IRC section 4662, with rates that increased 100% on certain commodities relative to pre-1996 levels.

Liability under CERCLA section 107

CERCLA imposes strict, joint and several, and retroactive liability on potentially responsible parties (PRPs) including current owners, past owners at time of disposal, transporters who selected the disposal site, and arrangers (generators). The liability scheme is unusual in U.S. environmental law for being retroactive, actions taken decades before CERCLA's 1980 enactment can still trigger liability. Bona fide prospective purchaser, contiguous property owner, and innocent landowner defenses created by the 2002 Brownfields Amendments offer carefully scoped protections for parties acquiring contaminated property under defined conditions including all-appropriate-inquiry due diligence.

How to Check Your Area

PlainEnviro maps all 1,839 NPL Superfund sites. To check your area:

1. Browse Superfund sites by state to see what's in your region.
2. Check your county page for a combined view of TRI facilities, water violations, and Superfund sites.
3. For water-related contamination, review your city's water quality data alongside nearby Superfund sites.