What Is a Superfund Site?
How contaminated sites make the National Priorities List, what cleanup looks like, and what it means if you live near one.
Key Takeaway
Superfund is the EPA's program for cleaning up the nation's most contaminated sites. There are 1,839 sites on the National Priorities List (NPL), from former chemical plants to abandoned mines to landfills. Cleanup can take decades and cost hundreds of millions of dollars. PlainEnviro shows the location and status of every NPL 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 any other locations where hazardous substances were released into the environment. The most dangerous sites are placed on the National Priorities List (NPL), which prioritizes them for long-term cleanup action.
How Sites Get Listed
The path to the NPL follows a structured process:
- Discovery: Contamination is discovered through state reporting, citizen complaints, or facility inspections.
- Preliminary Assessment (PA): EPA evaluates available information to determine if further investigation is warranted.
- Site Inspection (SI): Physical sampling confirms the type and extent of contamination.
- 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.
- Proposed listing: The EPA publishes the proposal in the Federal Register and accepts public comment.
- 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.
Health Implications
Living near a Superfund site can pose health risks, depending on the type of contamination and exposure pathways. Common contaminants at Superfund sites include heavy metals (lead, mercury, arsenic), volatile organic compounds (TCE, benzene, PCBs), and pesticides. Health effects range from respiratory issues and skin irritation to increased cancer risk from long-term exposure.
Research published in environmental health journals has found associations between proximity to Superfund sites and adverse birth outcomes, childhood developmental issues, and cancer clusters, particularly at sites where groundwater contamination affects drinking water supplies. However, properly cleaned-up sites generally do not pose ongoing health risks.
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.
Worked example: a TCE-contaminated groundwater plume
Consider a generic site where trichloroethylene has migrated from a former degreasing operation into the shallow aquifer at concentrations of 250 micrograms per liter. Residential wells within the plume are sampled and the highest-concentration well shows TCE at 80 micrograms per liter. Using the EPA Region 9 tap water Regional Screening Level for TCE (0.49 micrograms per liter at a target hazard quotient of 1.0), the measured concentration corresponds to a hazard index approximately 16,300% above the screening threshold and 100% above the action threshold for tap-water supply, warranting immediate alternative water supply provision while remediation proceeds. Long-term remediation might combine pump-and-treat extraction at the source area, in-situ chemical oxidation in the plume core, and monitored natural attenuation of the dilute fringe.
Cleanup remedy comparison at a glance
| Remedy | Typical timeline | Relative cost | Best for |
|---|---|---|---|
| Excavation & off-site disposal | 1–3 years | Highest | Discrete soil hot spots |
| Pump-and-treat groundwater | 10–50+ years | High | Mobile contaminant plumes |
| In-situ chemical oxidation | 2–5 years | Medium | Source-zone DNAPL |
| Capping & institutional controls | Permanent | Low | Large landfills, mine waste |
| Monitored natural attenuation | 10–30 years | Lowest | Dilute fringes, biodegradable plumes |
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:
- Browse Superfund sites by state to see what's in your region.
- Check your county page for a combined view of TRI facilities, water violations, and Superfund sites.
- For water-related contamination, review your city's water quality data alongside nearby Superfund sites.
Frequently Asked Questions
How many Superfund sites are there in the US?
There are approximately 1,839 sites on the National Priorities List (NPL). About 450 have been cleaned up and delisted. The program has been active since 1980 and continues to add new sites. New Jersey, Pennsylvania, New York, and California have the most Superfund sites, in that order.
Is it safe to live near a Superfund site?
It depends on the site's status, the type of contamination, and the cleanup measures in place. Active cleanup sites may have institutional controls (groundwater use restrictions, fencing, soil caps) that protect nearby residents. However, research has found elevated health risks in communities near some Superfund sites, particularly before cleanup begins. Check PlainEnviro for your area's Superfund site status and contamination details.
Who pays for Superfund cleanup?
The EPA first tries to identify "potentially responsible parties" (PRPs) - companies or individuals who contributed to the contamination, and compels them to pay for cleanup. If no responsible party can be found or they cannot pay, the EPA uses the Superfund trust fund (funded by taxes on chemical and petroleum industries and general tax revenue) to finance the cleanup.
How long does Superfund cleanup take?
Average cleanup takes 12-15 years from listing to completion, though complex sites can take decades. Some sites have been on the NPL for over 30 years and are still being cleaned up. The cleanup process involves investigation, feasibility study, remedy selection, design, construction, and long-term monitoring.
Does Superfund status affect property values?
Research consistently shows that proximity to Superfund sites reduces property values, typically by 2-8% within a 3-mile radius. However, property values tend to recover after cleanup is completed and the site is delisted. The stigma effect can persist longer than the actual contamination risk.
What is the difference between Superfund and brownfield sites?
Superfund sites (NPL) are the most severely contaminated sites, requiring federal involvement and extensive cleanup. Brownfield sites are properties where expansion, redevelopment, or reuse may be complicated by the presence of contamination, but they are less severely contaminated. Brownfields are typically cleaned up through state programs or the EPA's Brownfields program, not Superfund.
Sources
- U.S. Environmental Protection Agency, Superfund National Priorities List (NPL)
- EPA, CERCLA / Superfund program overview
- EPA ArcGIS Feature Service, Superfund site locations and boundaries
This content is for informational purposes only. If you suspect contamination affecting your property or health, contact your state environmental agency or the EPA's Superfund hotline at 1-800-424-8802.
