Regulatory Alert: EPA to Maintain Biden-era Designation of PFOA and PFOS as CERCLA Hazardous Substances
September 17, 2025
The U.S. Environmental Protection Agency (EPA) announced in the evening of September 17 that the agency will retain a Biden-era rule that designated two PFAS chemicals, PFOA and PFOS, as “hazardous substances” under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), known as the Superfund law. The designation provides EPA with the authority to respond to releases of PFOA or PFOS in the environment and address hazards caused by historical releases of these chemicals. The rule, which went into effect in July 2024, has been subject to an ongoing legal challenge by a number of organizations since it was issued. However, until today, it was unclear whether the Trump administration would defend the rule in the litigation.
One major question remains unanswered after the announcement. When the rule was released in 2024, EPA also issued an “enforcement discretion policy” that outlined how the agency will not pursue PFAS response actions or cost recovery under CERCLA from some entities, including publicly owned airports. EPA recognized that airports were innocent users and did not manufacture or profit from the use of PFOA or PFOS. In the statement released today, EPA Administrator Lee Zeldin indicated that the agency “intends to do what we can” to protect passive receivers and other users that did not manufacturer or generate these chemicals. However, the agency emphasized that “we will need new statutory language from Congress to fully address our concerns with passive receiver liability.” No update was provided on EPA’s current enforcement discretion policy.
For years, AAAE has raised concerns with EPA that such a designation could unfairly trigger costly litigation and cleanup efforts for airports to address PFOA/PFOS-related contamination because the Federal Aviation Administration (FAA) has required airports to use aqueous film forming foam (AFFF) for decades. While EPA retaining the enforcement discretion policy would be helpful and provide some level of protection, airport sponsors may still be subject to private party actions. As a result, AAAE has continued, and will continue, to advocate for Congress to provide airports with CERCLA liability protection based on the longstanding FAA mandate. We will also continue to monitor the ongoing legal challenge now that EPA has decided to defend the PFOA/PFOS CERCLA rule.
Please note that EPA’s announcement on the PFOA/PFOS CERCLA rule was distributed via email press release. As of the time of this Alert, the agency has not published the announcement on its website.
Background on CERCLA. Under CERCLA, EPA has the authority to respond directly to releases, or threatened releases, of any “hazardous substances” that may endanger public health and/or the environment. The statute gives EPA the authority to conduct or order two types of responses: short-term “removal” actions when there is a release or threatened release and long-term “remedial” actions to permanently and significantly reduce risks associated with releases of the substance. Most importantly, CERCLA imposes retroactive, joint and several, and strict liability on parties that are responsible, in whole or in part, for the release of any hazardous substance.
EPA’s PFOA/PFOS CERCLA Rule. In August 2022, EPA released a proposed rule that would designate PFOA and PFOS as CERCLA hazardous substances. This was the first time that EPA exercised its authority to designate any substances as hazardous under the statute. The agency based the proposed designation on the potential human health and environmental hazards associated with exposure to the chemicals. In our response, AAAE argued that such a designation would be a draconian measure that unfairly punishes airports for procuring and using AFFF in accordance with federal requirements and ignores the cost-related impacts on industry. We also strongly urged EPA to provide airports with protection from CERCLA liability.
In April 2024, EPA released a final rule with the hazardous substance designation for PFOA and PFOS. The agency emphasized that that it gave “serious consideration” to concerns over the possibility of some entities being exposed to liability even though they did not manufacture or generate PFOA or PFOS-containing materials. These considerations led to the issuance of the “PFAS Enforcement Discretion and Settlement Policy Under CERCLA,” which outlined how EPA will exercise its enforcement discretion under CERCLA in matters involving PFAS. Under the policy, EPA does not pursue enforcement against certain entities where equitable factors do not support seeking response actions or costs under CERCLA. Publicly owned airports and local fire departments are included in the list of these entities.
You can find additional information about EPA’s PFOA/PFOS CERCLA rule, along with the enforcement discretion policy, in our April 19, 2024 Regulatory Alert.
The U.S. Environmental Protection Agency (EPA) announced in the evening of September 17 that the agency will retain a Biden-era rule that designated two PFAS chemicals, PFOA and PFOS, as “hazardous substances” under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), known as the Superfund law. The designation provides EPA with the authority to respond to releases of PFOA or PFOS in the environment and address hazards caused by historical releases of these chemicals. The rule, which went into effect in July 2024, has been subject to an ongoing legal challenge by a number of organizations since it was issued. However, until today, it was unclear whether the Trump administration would defend the rule in the litigation.
One major question remains unanswered after the announcement. When the rule was released in 2024, EPA also issued an “enforcement discretion policy” that outlined how the agency will not pursue PFAS response actions or cost recovery under CERCLA from some entities, including publicly owned airports. EPA recognized that airports were innocent users and did not manufacture or profit from the use of PFOA or PFOS. In the statement released today, EPA Administrator Lee Zeldin indicated that the agency “intends to do what we can” to protect passive receivers and other users that did not manufacturer or generate these chemicals. However, the agency emphasized that “we will need new statutory language from Congress to fully address our concerns with passive receiver liability.” No update was provided on EPA’s current enforcement discretion policy.
For years, AAAE has raised concerns with EPA that such a designation could unfairly trigger costly litigation and cleanup efforts for airports to address PFOA/PFOS-related contamination because the Federal Aviation Administration (FAA) has required airports to use aqueous film forming foam (AFFF) for decades. While EPA retaining the enforcement discretion policy would be helpful and provide some level of protection, airport sponsors may still be subject to private party actions. As a result, AAAE has continued, and will continue, to advocate for Congress to provide airports with CERCLA liability protection based on the longstanding FAA mandate. We will also continue to monitor the ongoing legal challenge now that EPA has decided to defend the PFOA/PFOS CERCLA rule.
Please note that EPA’s announcement on the PFOA/PFOS CERCLA rule was distributed via email press release. As of the time of this Alert, the agency has not published the announcement on its website.
Background on CERCLA. Under CERCLA, EPA has the authority to respond directly to releases, or threatened releases, of any “hazardous substances” that may endanger public health and/or the environment. The statute gives EPA the authority to conduct or order two types of responses: short-term “removal” actions when there is a release or threatened release and long-term “remedial” actions to permanently and significantly reduce risks associated with releases of the substance. Most importantly, CERCLA imposes retroactive, joint and several, and strict liability on parties that are responsible, in whole or in part, for the release of any hazardous substance.
EPA’s PFOA/PFOS CERCLA Rule. In August 2022, EPA released a proposed rule that would designate PFOA and PFOS as CERCLA hazardous substances. This was the first time that EPA exercised its authority to designate any substances as hazardous under the statute. The agency based the proposed designation on the potential human health and environmental hazards associated with exposure to the chemicals. In our response, AAAE argued that such a designation would be a draconian measure that unfairly punishes airports for procuring and using AFFF in accordance with federal requirements and ignores the cost-related impacts on industry. We also strongly urged EPA to provide airports with protection from CERCLA liability.
In April 2024, EPA released a final rule with the hazardous substance designation for PFOA and PFOS. The agency emphasized that that it gave “serious consideration” to concerns over the possibility of some entities being exposed to liability even though they did not manufacture or generate PFOA or PFOS-containing materials. These considerations led to the issuance of the “PFAS Enforcement Discretion and Settlement Policy Under CERCLA,” which outlined how EPA will exercise its enforcement discretion under CERCLA in matters involving PFAS. Under the policy, EPA does not pursue enforcement against certain entities where equitable factors do not support seeking response actions or costs under CERCLA. Publicly owned airports and local fire departments are included in the list of these entities.
You can find additional information about EPA’s PFOA/PFOS CERCLA rule, along with the enforcement discretion policy, in our April 19, 2024 Regulatory Alert.
