Up to $14 billion in PFAS drinking-water settlements with 3M, DuPont and other manufacturers did not resolve claims tied to U.S. airport property. The federal government's authority to pursue cleanup of those sites then survived a major legal test on Aug. 18, 2026, when the U.S. Court of Appeals for the D.C. Circuit upheld the Environmental Protection Agency's 2024 designation of PFOA and PFOS as hazardous substances under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA).

The court rejected an industry challenge that targeted both EPA's authority and its analysis of the rule's economic effects. For airport operators, the ruling means the CERCLA pathway for PFAS enforcement and third-party claims is now firmly in place.

How AFFF use put airports in the firing line

AFFF containing PFAS was used for decades at U.S. airports under federal firefighting rules. At Part 139-certificated airports, the foam had to be discharged regularly for training and equipment testing, and many airfields — or the land beneath them — also hosted military operations where AFFF was released.

PFAS persist in soil, migrate into groundwater and move through stormwater systems. Contamination is most likely around ARFF stations, training areas, hangars, equipment-testing sites and emergency-response locations. The result is a legacy environmental liability that survives even when an airport has stopped using PFAS-containing foam.

What does the CERCLA ruling change?

The D.C. Circuit decision did not expand EPA's authority so much as confirm it. State regulators and private parties — including owners of nearby drinking-water wells — can now rely on CERCLA as a stable legal basis to pursue claims tied to airport properties.

Several state agencies had already ordered airports to begin site investigations before the CERCLA designation was finalized. The appellate ruling removes a major piece of uncertainty about whether those state actions would be preempted or unwound by a successful industry challenge.

The FAA's fluorine-free foam shift and its limits

The FAA now recognizes qualifying fluorine-free foams that meet the Department of Defense military specification as acceptable for satisfying Part 139 firefighting requirements. Airports are working through the operational consequences: decontaminating ARFF vehicles, disposing of old foam and rinsate, retraining personnel and verifying compatibility with new agents.

Switching foam prevents future releases. It does not remove PFAS already in soil, groundwater or stormwater systems. Airports that used AFFF for decades may still face investigation and remediation costs regardless of how quickly they transitioned.

What will the bill look like?

Cost categories that airport capital plans will need to absorb include:

• Environmental investigation and PFAS sampling
• Engineering and hydrogeological studies
• Cleaning or replacement of ARFF equipment
• Management and disposal of AFFF and PFAS-contaminated rinsate
• Soil or groundwater remediation
• Stormwater investigation and management
• Long-term monitoring
• Legal and regulatory expenses
• Response to off-site contamination, including neighboring wells

EPA continues to update its guidance on destruction and disposal of PFAS-containing materials. That ongoing revision creates a budgeting problem: airports must plan multiyear capital expenditures against a liability whose scope may not be clear for years.

Where can airports recover the money?

PFAS contamination is unusual among infrastructure liabilities because airports used the foam under federal mandate, without warning of long-term environmental risk. That opens a path to cost recovery from manufacturers through litigation, alongside traditional funding from operating revenue, airport bonds, state and federal grants and insurance.

Kenneth Sansone, senior partner at SL Environmental Law Group, is actively involved in representing more than 300 entities in the AFFF multi-district litigation against PFAS manufacturers. In separate contamination work, Sansone has obtained more than $155 million in recoveries for water systems to address TCP and a $30.2 million recovery for the city of Pomona, Calif., to cover perchlorate cleanup.

The drinking-water cases suggest timing matters. Public water systems that filed suit before the 3M and DuPont settlements were announced received enhanced allocations under the settlement formulas. Airports evaluating their legal options may need to weigh whether to act before any future airport-specific settlement terms are negotiated.

The next phase of airport PFAS exposure

PFOA and PFOS are now CERCLA hazardous substances, and that designation has cleared its first major appellate hurdle. The transition to fluorine-free foam is underway at Part 139 airports. EPA continues to refine remediation guidance, and drinking-water settlements have already pushed PFAS liabilities into the billions.

For airport executives, the question is shifting from whether AFFF was used to who pays for the contamination it left behind — and how those costs get sized, funded and litigated in the years ahead.