On April 19, 2024, the US Environmental Protection Agency (EPA) released a pre-publication copy of its much-anticipated final rule adding two per- and polyfluoroalkyl substances (PFAS) to the list of “hazardous substances” under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA or Superfund). The rule will be effective 60 days after publication in the Federal Register.

EPA’s action is precedent-setting. PFOA and PFOS have been the leading candidates for regulation for some time, and subjecting them to regulation under CERCLA will have sweeping impacts on many industries. Not only will facilities be subject to new reporting obligations for spills and other releases, but designation of PFOA and PFOS will likely lead to a significant rise in expensive and disruptive Superfund litigation, EPA-driven enforcement actions, and compliance costs related to site investigation and cleanup that EPA admitted cannot be known at this time with reasonable certainty. Additionally, EPA’s action represents the first time the agency has exercised its discretion to designate any substance as a hazardous substance under CERCLA section 102(a) since Congress codified this authority over forty years ago.


EPA’s rule amends Part 302 of the CERCLA regulations to add PFOA and PFOS, including their salts and structural isomers, to the list of hazardous substances. Potentially affected industries include: PFOA/PFOS manufacturers, importers, and processors; manufacturers of products containing PFOA/PFOS; importers of articles containing PFOA/PFOS; downstream product makers and users of PFOA/PFOS products; waste management and wastewater treatment facilities; and owners of property that is presently contaminated with PFOA/PFOS that were passively received from other originating sources.

The Final Rule attempts to justify the action by pointing to two different analyses that EPA conducted regarding whether to designate PFOA and PFOS as “hazardous substances” under CERCLA: (1) assessing whether designation was warranted because they “may present a substantial danger to the public health or welfare or the environment,” and (2) assessing whether the “totality of the circumstances” confirms that designation was warranted under the first analysis.


CERCLA section 102(a) requires that, before listing a “hazardous substance,” EPA must determine that “when released into the environment [it] may present a substantial danger to the public health or welfare or the environment.” The final rule points to information regarding PFOA and/or PFOS that EPA has determined links human exposures to certain adverse health effects such as carcinogenic and non-carcinogenic effects in humans and animals. Based on this linkage alone, EPA concluded that designation of PFOA and PFOS as hazardous substances is warranted.


EPA then conducted an additional “totality of the circumstances” analysis to confirm its conclusion that designation was warranted. This analysis purports to weigh the advantages and disadvantages of designation, including quantitative and qualitative evaluation of benefits and costs. EPA points to a number of benefits of the rule, including:

  • An increase in its authority under CERCLA to address more sites, take earlier action, and expedite eventual cleanup. Designation will also empower EPA, other federal agencies, tribes, states, and private parties to pursue “cost recovery.” These entities may conduct cleanup themselves and then sue to seek reimbursement of eligible response costs from potentially responsible parties (PRPs), a term of art under the CERCLA regime.
  • Using PFOA and PFOS as a “gateway” contaminant, meaning that if either are found at a site, the exhaustive and expensive cleanup efforts needed to decontaminate the site from PFOA and PFOS would simultaneously remove other contaminants of concern, including those which may not be CERCLA “hazardous substances.”
  • Overcoming the limitations in its existing authority to address PFOA/PFOS as “pollutants or contaminants,” which did not authorize EPA to compel PRPs to conduct or pay for response work for mere pollutants or contaminants, and required the agency to provide a burdensome demonstration that a given release at a particular site may present an imminent and substantial danger for EPA to use government monies to conduct the response work.

EPA’s “totality of the circumstances” analysis provides some analysis of what the agency deemed to be “direct” and “indirect” costs associated with designating PFOA/PFOS as hazardous substances. The only significant “direct” cost that EPA quantified was the requirement that facilities and vessels must notify the National Response Center (NRC) and other authorities within 24 hours of learning of the release of a pound or more of PFOA or PFOS in a 24-hour period. EPA estimates that this notification requirement will cost less than $3,000 per release, with the total annual cost of the notification requirement expected to not exceed $1,630,000. Other “direct” effects of the rule include duties to give notice when selling or transferring federally owned real property where PFOA/PFOS may be present.

Regarding “indirect” costs, EPA estimated spending $10.3 million to $51.7 million annually (2% discount rate) on removal actions at sites on the National Priorities List (NPL)—which could be recovered from PRPs—and an additional $327,000 to $18.1 million annually (2% discount rate) at non-NPL sites. EPA then concluded that its previous conclusion that designation is warranted because PFOA/PFOS “may present a substantial danger” is confirmed by its “totality of the circumstances” analysis because, according to EPA, the advantages of designation outweigh the disadvantages.


This final rule will activate the full panoply of powerful CERCLA enforcement authorities for actual or potential PFOA and PFOS releases. As previously reported, the significant implications of a hazardous substance designation for PFOA and PFOS designation could include the following:

  • The likely addition of more sites to the National Priorities List. EPA stated that it did not expect an uptick of sites placed on the NPL, based on the average number of sites added to the NPL between FY 2003 and FY 2022 and an assessment of non-federal NPL sites where PFOA/PFOS had been detected. As EPA and the regulated community have experienced, however, PFAS chemicals continue to be detected at a variety of sites, including sites with no history of PFAS use or disposal. EPA’s recent finalization of Method 1633 for detecting PFOA, PFOS, and 38 other PFAS in aqueous samples (groundwater, surface water, and wastewater), solids (soil, biosolids, and sediment), and animal and fish tissues at very low levels will likely result in even more sites with PFOA/PFOS detections. EPA’s enforcement-first approach to Superfund sites will likely continue at sites with PFOA or PFOS if there are potentially responsible parties, who do not meet the criteria of EPA’s enforcement discretion policy.
  • The potential disruption to ongoing remediation activities at thousands of sites that currently are, or may become, Superfund sites, as well as added complexity and costs if parties are required to utilize different treatment technologies to address PFOA and PFOS impacts.
  • The possible reopening of existing Superfund sites as an outcome of EPA’s statutory obligation under CERCLA to conduct a five-year review of its chosen remedial action for each site. Because EPA is expected to require PFOA/PFOS site testing in all five-year reviews, any detection of PFOA/PFOS could allow EPA to conclude that previously undertaken remedial actions are no longer protective under revised risk assessments that account for the presence of PFOA/PFOS, a finding that could support EPA’s decision to put sites back into the CERCLA cleanup process.
  • The significant rise in expensive and disruptive Superfund litigation that would result from any associated section 107 cost recovery actions, section 113 contribution actions, or enforcement of EPA section 106 cleanup orders. Given the draconian nature of CERCLA’s strict, and joint and several, liability scheme, even entities and industries that might have contributed minimally to PFOA or PFOS contamination at a particular site would be affected.


Cost estimates for this rulemaking provided by stakeholders ranged from $11 billion to $22 billion for private party compliance costs, and corresponding annualized private party PFOA/PFOS cleanup costs at non-federal sites between $700 and $900 million. In response to these comments, EPA argued that the analysis was based on several unfounded or inaccurate assumptions that lead to the overestimation of costs. EPA also believes it conducted a more thorough and robust Regulatory Impact Analysis (RIA) that characterizes the uncertainties to better describe potential direct and indirect costs and benefits. The RIA has not yet been released to the public by EPA.


Concurrent with release of the pre-publication of the final rule, EPA’s Office of Enforcement and Compliance Assurance (OECA) issued a memorandum on “PFAS Enforcement Discretion and Settlement Policy Under CERCLA.” In this memo, Assistant Administrator David Uhlmann describes the central role that CERCLA and the designation of PFOA and PFOS as hazardous substances will play in EPA’s initiative to address PFAS exposure, which was first described on August 17, 2023, in EPA’s National Enforcement and Compliance Initiatives (NECIs) for Fiscal Years 2024‒2027. The memo is consistent with EPA’s plans, described in the PFAS NECI, to focus on significant contributors of PFAS in the environment (e.g., manufacturers of PFAS, federal facilities, and “other industrial parties”). However, the memo provides detailed guidance regarding when it would be appropriate for EPA to exercise its discretion and not pursue entities with limited equitable responsibility (e.g., farmers that apply biosolids to agricultural fields, water utilities, publicly-owned airports, or local fire departments). The guidance is clear that it is “intended solely for the guidance of [EPA] employees” and therefore does not apply to other public or private parties who may now pursue powerful CERCLA legal claims that are costly and burdensome to defend against.

Regarding settlements to resolve CERCLA liability, the memo generally reiterates EPA’s long-standing policies for settling with parties that qualify for CERCLA’S de minimis or de micromis settlement protections. However, EPA describes a new policy that could result in EPA providing protections to certain non-settling parties when the agency enters settlement agreements with major PRPs. As an example, EPA states that if it were to settle with a PFAS manufacturer, EPA may require the PFAS manufacturer to agree to waive its right to seek contribution for litigation and cleanup costs against certain non-settling parties that EPA does not intend to pursue for the matters addressed by the settlement.

For more information on EPA’s designation of PFOA and PFOS as “hazardous substances” under CERCLA and how it might impact you, please contact Hunton’s PFAS Interdisciplinary Team.