CERCLA/Superfund Process - How Federal Cleanup Sites Work

Overview

The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), commonly known as Superfund, is the federal law that governs the cleanup of the nation’s most contaminated sites. Enacted in 1980 and amended by the Superfund Amendments and Reauthorization Act (SARA) in 1986, CERCLA gives EPA the authority to investigate and clean up sites contaminated with hazardous substances, and to compel responsible parties to perform or pay for cleanup.

CERCLA is distinct from RCRA (which regulates active waste management) and from state voluntary cleanup programs (which are typically faster and less expensive). CERCLA applies to the worst sites - abandoned waste dumps, former industrial facilities with widespread contamination, and sites where responsible parties cannot or will not clean up voluntarily.

The National Priorities List

The National Priorities List (NPL) is the list of the nation’s most contaminated sites that are eligible for long-term cleanup under Superfund. Listing on the NPL is based on the Hazard Ranking System (HRS), a scoring methodology that evaluates the potential threat to human health and the environment based on contaminant toxicity, migration pathways, and nearby receptors.

Not all CERCLA sites are on the NPL. EPA can and does conduct removal actions and other response activities at sites that are not listed. However, NPL listing makes a site eligible for fund-financed remedial action (long-term cleanup).

The Superfund Process

Step 1: Site Discovery and Preliminary Assessment

Sites come to EPA’s attention through state referrals, citizen complaints, emergency reports, or federal agency notifications. EPA conducts a Preliminary Assessment (PA) - a desktop evaluation of existing information about the site, including historical records, regulatory databases, aerial photos, and available analytical data.

If the PA indicates potential contamination warranting further evaluation, EPA proceeds to a Site Inspection.

Step 2: Site Inspection (SI)

The Site Inspection involves collecting limited environmental samples to confirm the presence of contamination and evaluate potential threats. This is a screening-level investigation, not a comprehensive characterization. Typical SI activities include:

Collecting soil, groundwater, surface water, and sediment samples
Evaluating potential exposure pathways
Identifying nearby receptors (residents, drinking water wells, surface water bodies, ecosystems)

Based on the SI results, EPA scores the site using the Hazard Ranking System. If the HRS score is 28.50 or higher, the site is eligible for proposal to the NPL.

Step 3: NPL Listing

Proposed NPL sites go through a public comment period before final listing. Once listed, the site is eligible for fund-financed remedial action. EPA assigns a Remedial Project Manager (RPM) to oversee the cleanup.

Step 4: Remedial Investigation / Feasibility Study (RI/FS)

The RI/FS is the most intensive phase of the Superfund process. It is typically conducted by the responsible party under EPA oversight, or by EPA using Superfund money if no viable responsible party exists.

Remedial Investigation (RI):

Comprehensive characterization of the nature and extent of contamination
Evaluation of all environmental media (soil, groundwater, surface water, sediment, air)
Baseline risk assessment to determine the risks posed by the contamination to human health and the environment
Identification of applicable or relevant and appropriate requirements (ARARs) - the federal and state standards that the cleanup must meet

Feasibility Study (FS):

Development and screening of remedial alternatives
Detailed evaluation of the most promising alternatives against nine criteria:
1. Overall protection of human health and the environment
2. Compliance with ARARs
3. Long-term effectiveness and permanence
4. Reduction of toxicity, mobility, or volume through treatment
5. Short-term effectiveness
6. Implementability
7. Cost
8. State acceptance
9. Community acceptance

The RI/FS typically takes 2-4 years, sometimes longer for complex sites.

Step 5: Proposed Plan and Record of Decision (ROD)

Based on the FS, EPA publishes a Proposed Plan identifying the preferred remedial alternative and the rationale for the selection. The Proposed Plan is subject to a public comment period (minimum 30 days).

After considering public comments, EPA issues the Record of Decision (ROD) - the formal document selecting the remedy for the site. The ROD describes the selected remedy, the rationale for selection, the cleanup levels to be achieved, and the response to public comments.

The ROD is one of the most important documents in the Superfund process. It establishes the cleanup standards and the approach that will govern all subsequent remedial work at the site.

Step 6: Remedial Design / Remedial Action (RD/RA)

Remedial Design (RD): The engineering design phase where the selected remedy is translated into detailed construction plans and specifications. This includes all drawings, specifications, and technical documents needed to implement the remedy.

Remedial Action (RA): The actual construction and implementation of the remedy. This may include:

Soil excavation and off-site disposal or on-site treatment
Groundwater extraction and treatment systems
In situ treatment technologies (chemical oxidation, bioremediation, thermal treatment)
Containment systems (caps, slurry walls, reactive barriers)
Institutional controls (deed restrictions, land use limitations)
Engineering controls (vapor mitigation systems, alternative water supplies)

Construction can take years depending on the complexity of the remedy.

Step 7: Operation and Maintenance (O&M)

After construction is complete, most remedies require ongoing operation and maintenance. Groundwater pump-and-treat systems need to be operated, monitored, and maintained. Caps need periodic inspection. Institutional controls need enforcement.

O&M continues until cleanup goals are met or the remedy is modified.

Step 8: Five-Year Reviews

For sites where hazardous substances remain on-site above levels that permit unlimited use and unrestricted exposure, EPA conducts Five-Year Reviews to assess whether the remedy remains protective of human health and the environment. The review evaluates:

Whether the remedy is functioning as intended
Whether there are any changes in site conditions
Whether new information (updated toxicity values, changed land use) affects the protectiveness determination

Five-Year Reviews continue as long as hazardous substances remain at the site. A finding that the remedy is not protective triggers further evaluation and potential modification of the remedy.

Step 9: Site Completion

A site can be deleted from the NPL when all response actions are complete and EPA determines that no further action is needed to protect human health and the environment. In practice, many NPL sites remain listed for decades due to ongoing groundwater treatment or long-term monitoring requirements.

Removal Actions

In addition to the long-term remedial process described above, CERCLA authorizes EPA to conduct removal actions for situations requiring a more immediate response. Removal actions address:

Imminent threats to public health (contaminated drinking water, explosive hazards, acute exposure risks)
Time-critical situations where a delay would increase the threat
Situations where a limited action can prevent a larger problem

Removal actions are faster and more flexible than remedial actions. They are typically limited to $2 million and 12 months, though these limits can be extended with EPA approval. Removal actions do not require an RI/FS or ROD.

Potentially Responsible Parties

CERCLA liability is broad, strict, joint and several, and retroactive. This means:

Strict: Liability applies regardless of fault or negligence. You don’t have to have done anything wrong.
Joint and several: Any single responsible party can be held liable for the entire cost of cleanup, even if others contributed to the contamination.
Retroactive: Liability applies even if the disposal activity was legal at the time it occurred.

Four categories of potentially responsible parties (PRPs):

Current owners and operators of the facility
Past owners and operators at the time of disposal
Generators who arranged for disposal of hazardous substances at the facility
Transporters who selected the disposal facility

There are limited defenses, including the innocent landowner defense (expanded by the Brownfields Amendments of 2002), the bona fide prospective purchaser defense, and the contiguous property owner defense. These defenses require specific due diligence actions, including conducting an all appropriate inquiries (Phase I ESA) before acquisition.

CERCLA vs. State Voluntary Programs

Most contaminated sites in the United States are not on the NPL and will never go through the federal Superfund process. State voluntary cleanup programs (like Ohio’s VAP) handle the majority of contaminated property cleanups. Key differences:

Authority: CERCLA is federal (EPA). Voluntary programs are state-run.
Cost: Superfund cleanups are expensive and slow. Voluntary programs are typically faster and less expensive.
Liability: CERCLA imposes strict, joint and several liability. State programs often provide liability releases (e.g., Ohio’s Covenant Not to Sue).
Standards: CERCLA uses ARARs (which incorporate state standards). State programs use their own cleanup standards.
Oversight: Superfund has continuous EPA oversight. Many state programs (like Ohio’s VAP) use private-sector professionals with limited agency involvement.

For property transactions, understanding whether a site has CERCLA involvement (past, present, or potential) is critical. CERCLA liability can survive property transfers and affect parties who had nothing to do with the original contamination.

Source

CERCLA (42 U.S.C. 9601-9675). SARA (P.L. 99-499). EPA OSWER Directive 9355.7-04. EPA Superfund Process website.