Federal Court Upholds EPA PFAS Hazardous Substance Designation: What You Should Know

Per- and polyfluoroalkyl substances (PFAS) regulations have changed significantly in recent years, and a new federal court decision has reinforced one of the Environmental Protection Agency’s (EPA’s) most consequential actions involving these “forever chemicals.”

On August 18, 2026, the U.S. Court of Appeals for the D.C. Circuit upheld the EPA’s designation of two PFAS chemicals [perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS)] as hazardous substances under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), commonly known as the federal Superfund law.

The decision leaves EPA’s 2024 rule in place and has important implications for businesses that may have manufactured, used, released, transported, or disposed of materials containing PFAS.

What Are PFAS?

If you follow our blogs, you’re probably well-versed in PFAS terminology and regulations by now. If not, here’s a quick refresher.

PFAS are a large group of synthetic chemicals that have been used since the 1940s because of their durability and longevity. They have been used in a wide range of industrial processes and consumer products, including certain fire extinguishing agents, coatings, textiles, food packaging, construction materials, and more.

PFAS are sometimes referred to as “forever chemicals” because many of them break down very slowly and can persist in the environment for decades.

PFOA and PFOS are two specific chemicals within the much larger PFAS family that are at the center of the recent federal court decision.

What Did EPA Do?

In 2024, EPA designated PFOA and PFOS, including their salts and structural isomers, as hazardous substances under CERCLA.

CERCLA is the federal environmental law that provides EPA with the authority to respond to releases of hazardous substances and address contaminated sites. It also provides a framework for determining which parties may be responsible for cleanup costs.

By adding PFOA and PFOS to the list of CERCLA hazardous substances, EPA significantly expanded the regulatory consequences associated with releases of these chemicals.

For example, the release of one pound or more of PFOA or PFOS within a 24-hour period generally triggers federal release reporting requirements. The designation may also affect the investigation and cleanup of contaminated properties and the potential liability of parties associated with PFAS contamination.

Several industry organizations challenged EPA’s rule, including the U.S. Chamber of Commerce and the National Waste and Recycling Association. Among their arguments, the challengers questioned EPA’s interpretation of its authority under CERCLA and raised concerns about the costs and potential liability associated with designating PFOA and PFOS as hazardous substances.

The D.C. Circuit rejected the challenges and upheld EPA’s rule. As a result, the CERCLA hazardous substance designation for PFOA and PFOS remains in effect.

For businesses with current or historical PFOA or PFOS use, the designation may have implications for release reporting, environmental investigations, contaminated property transactions, remediation projects, waste management, and potential cleanup liability.

PFAS Compliance Goes Beyond CERCLA

The immediate impact will vary considerably depending on a company’s operations and its historical use of PFAS. However, CERCLA is only one part of the federal PFAS regulatory landscape.

Businesses should also be aware of a separate PFAS reporting requirement under the Toxic Substances Control Act (TSCA).

Although the CERCLA hazardous substance designation and the TSCA PFAS reporting rule both involve PFAS, they are separate requirements created under different federal laws and for different purposes.

• CERCLA primarily addresses environmental releases, contamination, cleanup, and liability.
• The TSCA PFAS reporting rule requires certain companies to provide EPA with historical information about PFAS they manufactured or imported during any year from 2011 through 2022.

Companies that have been following the TSCA PFAS reporting rule may remember an October 13, 2026 reporting deadline. That timeline has changed.

In April 2026, EPA delayed the beginning of the TSCA reporting period while the agency completes revisions to the PFAS reporting rule. The reporting period is now scheduled to begin 60 days after the effective date of EPA’s forthcoming revisions to the PFAS reporting rule, or January 31, 2027, whichever occurs first. Once the submission period begins, covered manufacturers and importers will generally have six months to submit the required information.

EPA is also considering changes to the scope of the rule, including proposed exemptions for certain imported articles, low-concentration PFAS, byproducts, impurities, research and development chemicals, and non-isolated intermediates.

What Should Businesses Be Doing Now?

The recent court decision is another reminder that PFAS should remain on the compliance radar, even as individual requirements and deadlines continue to evolve.

Companies do not necessarily need to have manufactured PFAS themselves to have potential PFAS considerations. Depending on their operations, PFAS may have entered a facility through raw materials, coatings, processing aids, finished products, imported articles, or other materials.

Businesses should consider:

• Reviewing current and historical operations for potential PFAS use,
• Identifying products, raw materials, or processes that may contain PFOA, PFOS, or other PFAS,
• Evaluating historical manufacturing and importing activities from 2011 through 2022 for potential TSCA reporting obligations,
• Communicating with suppliers when PFAS content is unknown,
• Maintaining documentation of PFAS evaluations and supplier information,
• Evaluating potential environmental releases or historical contamination where appropriate, and
• Continuing to monitor EPA’s ongoing changes to PFAS requirements.

How Walden Can Help

PFAS requirements continue to evolve, and determining which requirements apply to a facility can require reviewing current operations, historical records, chemical inventories, supplier information, and environmental conditions.

Walden can assist with evaluating potential PFAS regulatory obligations, reviewing historical manufacturing and importing activities, assessing PFAS use and potential releases, and preparing for applicable reporting requirements. Contact us today at 860-846-4069.

Need more information about the TSCA PFAS reporting requirements? Click here for additional information about applicability, reporting requirements, and steps businesses can take to prepare.