The National Priorities List is the Environmental Protection Agency’s roster of contaminated sites serious enough to warrant long-term federal cleanup under the Comprehensive Environmental Response, Compensation, and Liability Act, better known as Superfund. It currently holds roughly 1,340 active sites. Created in 1980, the list is how the EPA decides where to focus its cleanup authority and money, and appearing on it triggers a structured evaluation, public rulemaking, and a cleanup process that can span decades and cost tens of millions of dollars per site.
How a Site Gets on the List
Reaching the list is a two-stage screening followed by a scoring exercise and a federal rulemaking. The first stage is a Preliminary Assessment, a low-cost review of existing records and a reconnaissance of the property to gauge whether a release could threaten people or resources. Sites that look potentially dangerous move to a Site Inspection, where crews collect samples, confirm what contaminants are present, and establish how they move through the environment.1U.S. Environmental Protection Agency. Superfund Site Assessment Activities
The data feeds the Hazard Ranking System, the scoring method required by CERCLA Section 105. It assigns a numerical value based on how contamination could reach people through four pathways: groundwater, surface water, soil exposure, and air.2Office of the Law Revision Counsel. 42 USC 9605 – National Contingency Plan A composite score of 28.50 or higher generally qualifies a site. That threshold was chosen because it would produce an initial list of at least 400 sites, the minimum Congress envisioned when creating the program. The scoring rules themselves sit at 40 CFR Part 300, Appendix A.3U.S. Environmental Protection Agency. The Revised Hazard Ranking System: Qs and As
Two alternative routes exist for sites that don’t clear 28.50. Each state or territory can designate one top-priority site for the list without scoring, provided the state considers it the greatest danger to public health, welfare, or the environment.4Environmental Protection Agency. State/Territory-Designated Top-Priority National Priorities List (NPL) Sites Separately, if the Agency for Toxic Substances and Disease Registry issues a health advisory for a site and the EPA determines long-term remediation is more cost-effective than short-term removal, the site can be added on that basis alone.5U.S. Environmental Protection Agency. Agency for Toxic Substances and Disease Registry (ATSDR) National Priorities List (NPL) Sites
A qualifying site is not automatically listed. The EPA must publish a proposed rule in the Federal Register, open a 60-day public comment period, and respond to significant comments. Property owners sometimes submit data during that window that changes the picture, and communities can raise concerns about the listing’s local impact. Only after that process does a final rule officially place the site on the list.6U.S. Environmental Protection Agency. Public Comment Process7U.S. Environmental Protection Agency. Current NPL Updates
What Happens After a Site Is Listed
Listing is the starting gun. The actual cleanup runs through a sequence that can stretch over many years, sometimes decades. First comes the Remedial Investigation and Feasibility Study. The investigation characterizes the nature and extent of contamination; the feasibility study tests candidate treatment technologies and compares their cost and performance.8U.S. Environmental Protection Agency. About the Superfund Cleanup Process
The EPA then issues a Record of Decision, the formal document selecting the remedy. It lays out the site’s history, the contaminants present, the alternatives considered, and the option chosen. The public gets another comment opportunity before that decision is finalized.8U.S. Environmental Protection Agency. About the Superfund Cleanup Process
The Remedial Design and Remedial Action phase covers engineering plans and the physical work: excavating contaminated soil, building groundwater treatment systems, installing containment structures. Duration depends heavily on the contamination. Some sites finish in a few years. Deep groundwater plumes can take decades.
Who Pays for the Cleanup
The Superfund program runs on a “polluter pays” principle. Under CERCLA Section 107, four categories of parties can be held liable: current owners or operators of the facility, anyone who owned or operated it when disposal occurred, anyone who arranged for disposal or treatment of hazardous substances at the site, and anyone who transported hazardous substances there.9Office of the Law Revision Counsel. 42 USC 9607 – Liability
Courts have consistently applied strict, joint, and several liability, even though the statute doesn’t use those exact words. The EPA can pursue any one responsible party for the full cost of cleanup regardless of that party’s share of the contamination. A company that contributed 5 percent of the waste at a site can be on the hook for 100 percent of the bill if the other responsible parties are bankrupt or can’t be found.
A party that pays more than its fair share can seek relief. Under CERCLA Section 113, any liable party can file a contribution claim against other responsible parties, and courts allocate costs using equitable factors that often include the volume and toxicity of each party’s contribution. A party that settles its liability with the government is protected from contribution claims on the matters covered by the settlement, though the settlement amount reduces what remaining parties owe rather than discharging them entirely.10Office of the Law Revision Counsel. 42 USC 9613 – Civil Proceedings
Enforcement-Lead vs. Fund-Lead
When viable responsible parties exist, a site is classified as enforcement-lead. Those parties perform the cleanup under EPA supervision or reimburse the government for costs already incurred, and settlements typically take the form of consent decrees filed in federal court. When no responsible party can be found or the ones identified lack the money, the site becomes fund-lead and the cleanup draws from the Superfund trust fund.
The trust was originally funded by excise taxes on petroleum and chemical manufacturers. Those taxes expired in 1995 and weren’t collected for more than 25 years. Congress reinstated them in two waves: the Infrastructure Investment and Jobs Act brought back chemical excise taxes effective July 1, 2022, through December 31, 2031, and the Inflation Reduction Act reinstated oil and petroleum taxes beginning January 1, 2023, with no expiration date.11U.S. Environmental Protection Agency. 2024 Superfund Tax Final
Penalties for Ignoring an EPA Order
Under CERCLA Section 106, the EPA can issue unilateral administrative orders compelling responsible parties to clean up a site. Willful violation or refusal to comply carries a civil penalty of up to $25,000 per day under the original statutory text, adjusted upward annually for inflation. On top of daily fines, the EPA can seek punitive damages of up to three times the cleanup costs the government incurred because of the party’s refusal to act.
Buying Property On or Near a Listed Site
CERCLA’s liability net catches current owners of contaminated property even when they had nothing to do with the contamination. Two defenses added by Congress in 2002 make it possible to buy formerly industrial property without inheriting cleanup liability, and both hinge on doing the environmental homework before closing.
Bona Fide Prospective Purchaser
If you buy property after January 11, 2002, knowing contamination exists, you can still avoid Superfund liability by qualifying as a Bona Fide Prospective Purchaser. You must conduct “all appropriate inquiries” into the property’s history before closing and then meet continuing obligations afterward: exercising appropriate care regarding hazardous substances on the property and taking reasonable steps to stop ongoing releases and prevent future ones. Under the 2018 BUILD Act, lessees can also qualify if the property owner is a Bona Fide Prospective Purchaser or if the lessee independently meets the same criteria.12U.S. Environmental Protection Agency. Bona Fide Prospective Purchasers
Innocent Landowner Defense
This defense applies to buyers who genuinely didn’t know about contamination at the time of purchase. You must show that you performed all appropriate inquiries before acquiring the property and had no reason to suspect contamination. The defense also covers governments that acquired property involuntarily through condemnation or similar processes and people who inherited contaminated land.13U.S. Environmental Protection Agency. Third Party Defenses/Innocent Landowners
Both defenses turn on “all appropriate inquiries,” which in practice means a Phase I Environmental Site Assessment. The EPA recognizes assessments performed under ASTM E1527-21 as satisfying the requirement. The assessment must be completed or updated within one year before the purchase date, and certain components — interviews with past owners, government records review, on-site visual inspection, and environmental lien searches — must be current within 180 days of closing.14U.S. Environmental Protection Agency. Brownfields All Appropriate Inquiries Skip the Phase I on property with any industrial history and neither defense is available.
Institutional Controls That Survive the Cleanup
Many cleaned-up sites don’t return to a condition where you could build a school or dig a residential well. Where contamination remains at levels that limit how the property can be used, the EPA relies on institutional controls: legal and administrative tools that keep people from being exposed to what’s left behind.15Environmental Protection Agency. Institutional Controls: A Citizen’s Guide
They come in four broad forms. Governmental controls use existing authority, such as local zoning restrictions, building permits, or well-drilling bans. Proprietary controls, including easements and restrictive covenants, are recorded in the property’s chain of title and bind future owners. Enforcement tools like consent decrees, administrative orders, and permits require or prohibit specific activities at the site. Informational devices such as deed notices and public advisories alert people to remaining contamination without legally restricting use.
Proprietary controls are the most durable for real estate purposes because they travel with the deed. A title search on property near or on a former Superfund site should surface any restrictive covenants. Deletion of a site from the National Priorities List does not lift institutional controls, many of which remain in effect indefinitely.
Getting a Site Off the List
A site comes off the National Priorities List only when the EPA and the relevant state agree that no further cleanup action is needed. The removal process mirrors listing: the EPA publishes a proposed deletion notice, opens a 30-day public comment period, and, if satisfied that the cleanup met its goals, publishes a final deletion in the Federal Register.16Federal Register. Proposed Deletion From the National Priorities List
Because full cleanup can take many years, the EPA can also delete specific portions of a site while the rest stays listed. A portion can be a defined geographic area or a specific medium like surface soil. That allows cleaned-up parcels at sprawling industrial complexes to return to productive use without waiting for the entire site to finish.17Environmental Protection Agency. Superfund: NPL Deletion Guidance and Policy
Deletion isn’t always the end of the story. When hazardous substances remain on-site above levels that would permit unrestricted use, the lead agency must review the remedy at least every five years to confirm it still works. Those reviews catch situations where containment systems degrade, land use changes unexpectedly, or new information emerges about the toxicity of remaining contaminants.18Environmental Protection Agency. Superfund Five-Year Reviews
PFAS and the Expanding Reach of the Program
Effective July 2024, the EPA designated two widely known “forever chemicals,” PFOA and PFOS, as hazardous substances under CERCLA. The designation matters less for scoring, since both were already counted as pollutants in Hazard Ranking System evaluations, than for enforcement. It unlocks the full range of CERCLA tools at sites where those chemicals drive contamination, including the ability to recover cleanup costs from responsible parties rather than paying from the trust fund.19Federal Register. Designation of PFOA and PFOS as CERCLA Hazardous Substances
The EPA has said it doesn’t expect the annual rate of new NPL listings to rise because of the designation. The practical shift is financial: sites contaminated primarily by PFOA or PFOS can now be treated as enforcement-lead rather than fund-lead, which can free trust fund money to address more sites or move faster at existing ones.