For the past several years, much of the national conversation surrounding PFAS has centered on drinking water. Billions of dollars in settlements with major PFAS manufacturers have provided public water systems with resources to address treatment and other costs associated with contamination. For airports, however, the PFAS story is far from over. 

Decades of required use of aqueous film-forming foam (AFFF) have left many airports confronting a difficult set of questions. PFAS may remain in soil and groundwater at areas where AFFF was historically stored, tested, released during training exercises or deployed during emergency responses. Even airports that have transitioned—or are transitioning—to fluorine-free firefighting foam may still have to manage the consequences of these past releases. 

At the same time, the regulatory environment surrounding PFAS continues to evolve. For airport leaders, the challenge comes down to understanding the airport's potential exposure, anticipating future costs and determining how those costs will be funded. 

The Drinking Water Settlements did not Resolve Airport Claims, Which are Still Pending 

The groundbreaking settlements involving 3M, DuPont and other manufacturers, which provided up to $14 billion total for public drinking water systems nationwide, represented a major development in PFAS litigation. But those settlements did not address airport property claims related to historical AFFF contamination. 

That distinction is important for airports owned by cities, counties and airport authorities. An airport may be connected to a municipality whose drinking water utility participated in a PFAS settlement, but that does not necessarily resolve claims associated with contamination at the airport itself. 

AFFF containing PFAS was used for decades at airports across the country. At federally certificated airports, firefighting requirements mandated that AFFF be discharged regularly for training exercises and as part of testing equipment, in addition to emergency situations. In the past, many airports, or the property where they now sit, may have also hosted military activities during which AFFF was discharged. 

Because PFAS are highly persistent, contamination associated with those historical activities may remain long after the original release. PFAS in contaminated soil can also migrate into groundwater or be carried through stormwater, potentially extending the impact beyond the immediate area where foam was originally used. 

The result is a legacy environmental issue that may continue creating costs even after an airport stops using PFAS-containing foam. 

CERCLA has Raised the Stakes 

One of the most consequential regulatory developments for airports and PFAS occurred when the U.S. Environmental Protection Agency (EPA) designated PFOA and PFOS—two PFAS commonly associated with AFFF as hazardous substances under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA), also known as Superfund. That designation took effect in 2024 and expanded the federal government's ability to investigate releases and pursue cleanup of PFOA and PFOS contamination. 

The designation also recently survived a significant legal challenge. On Aug. 18, 2026, the U.S. Court of Appeals for the D.C. Circuit upheld EPA's ruling after industry groups challenged the agency's authority and its consideration of the rule's economic impacts. 

For airports, the decision provides greater certainty that CERCLA will remain part of the PFAS regulatory landscap, and it exposes airports to the risk of claims by state regulators or third parties (such as the owners of private drinking water supply wells) based on PFAS contamination from airport properties. Indeed, even before the CERCLA designations were announced, regulators in several states had already ordered some airports to start expensive site investigations to determine potential off-site PFAS impacts from AFFF. 

Moving Away From AFFF Does not Eliminate Legacy Contamination 

The transition to fluorine-free foam is an important step toward preventing additional PFAS releases. The FAA now recognizes qualifying fluorine-free foam that meets the Department of Defense's military specification as acceptable for satisfying Part 139 firefighting requirements. Airports across the country have consequently been working through the operational challenges of replacing AFFF. 

The transition itself can involve extensive planning. Airports must consider existing foam inventories, decontamination of ARFF vehicles and equipment, safe disposal of old foam and contaminated rinsate, training personnel on the use of fluorine-free foam, testing and compatibility with replacement products. 

And replacing the foam does not remove PFAS already in the environment. An airport that used AFFF for decades may still have PFAS in soil, groundwater, stormwater systems, training areas, hangars or other locations associated with historical foam use or storage. Understanding those legacy conditions is becoming increasingly important as federal and state agencies expand their attention to PFAS soil contamination. 

The Next PFAS Challenge may be Financial 

For airport executives, PFAS is not simply an environmental compliance issue. It is also a long-term capital planning issue. The precise costs will vary significantly from airport to airport depending on the degree of AFFF use, hydrogeology, the extent of contamination, regulatory requirements and the remediation strategy ultimately selected. Regardless of the unique factors influencing each airport’s situation, potential expenses will likely extend well beyond purchasing replacement firefighting foam. 

An airport's PFAS costs could 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 or management 

• Long-term monitoring 

• Legal and regulatory expenses 

• Response to contamination affecting neighboring properties or water supplies. 

Treatment and disposal create another layer of uncertainty. The EPA continues to update its guidance on destruction and disposal methods for PFAS-containing materials as the science and available technologies evolve. For airports trying to build multiyear capital plans, this ambiguity creates a difficult problem: How do you budget today for an environmental liability whose ultimate scope may not become clear for years? 

Start By Understanding the Airport's Historical Exposure 

Not every airport will face the same PFAS risk. A useful first step is therefore to investigate where PFAS may exist on the property and what historical operations may have contributed to AFFF releases. 

Airport leaders can begin by identifying locations where AFFF may have been stored, discharged or handled. These could include ARFF stations, training areas, hangars, equipment-testing locations and sites of documented emergency responses or spills. 

Historical records may also be important. Training logs, purchasing records, incident reports, maps, photographs and information from current and former ARFF personnel can help reconstruct how and where foam was used. Taking these steps before a regulatory requirement or legal claim arises can help airport leaders stay ahead of the process. It also provides the information needed to estimate future costs and identify potential funding sources. 

PFAS Planning Should Include a Litigation Strategy 

Traditionally, public infrastructure and environmental projects have been financed through some combination of operating revenues, municipal or airport bonds, state and federal grants and other public funding programs. Those tools remain important, but PFAS presents an unusual opportunity: the contamination stems from products that airports were required to use without any warning as to their environmental risks, and as a result, airports may now face substantial costs through no fault of their own. That makes it important to evaluate a litigation strategy alongside an environmental strategy. 

One potential funding source is litigation against the companies that manufactured and sold PFAS and AFFF. The drinking water settlements demonstrated that litigation can shift costs away from public entities and toward manufacturers. Airport claims are distinct from the public water system settlements and litigation involving AFFF and other PFAS contamination is ongoing. Airports across the country have pursued claims seeking recovery of costs associated with investigating and addressing contamination on their properties. 

Cost recovery does not have to replace traditional sources of infrastructure funding. Instead, it can be evaluated as another component of a broader financial strategy—alongside grants, capital reserves, insurance where applicable, and other funding mechanisms. 

When considering litigation options, timing can be crucial. In the drinking water litigation, for example, systems that filed lawsuits before the 3M and DuPont settlements were announced received enhanced allocations under the settlement formulas. While there is no guarantee that anticipated airport settlements will follow the same structure, the experience of the drinking water cases illustrates why potentially affected entities may want to understand their legal options before settlement terms have already been negotiated. 

From PFAS Response to PFAS Risk Management 

PFAS regulations and legal developments are likely to continue evolving over the next decade, continuing the trend established over the past few years. PFOA and PFOS are now CERCLA hazardous substances, and that designation has survived a major court challenge. The transition away from PFAS-containing firefighting foam is underway. EPA continues to refine its approach to PFAS disposal and remediation, and drinking water settlements have demonstrated that PFAS liabilities can reach into the billions of dollars. 

Together, these developments point toward a new phase of the PFAS issue for airports. The question is no longer simply whether an airport used AFFF. For many airport executives, it is now time to determine what costs they may incur to address contamination--and who should ultimately pay for those costs. Airports that begin tackling PFAS issues now will be better positioned to respond as requirements continue to change while giving their governing bodies more options for managing what could otherwise become an unexpected—and potentially significant—future liability.