The Foam That Never Leaves: Why PFAS Is Now an Airfield Master-Planning Problem

By Nathaniel Pyron

Tomorrow — October 1, 2026 — is the final deadline for the Department of Defense to stop using aqueous film-forming foam, or AFFF, at its installations. Congress set the phase-out in the FY2020 NDAA, with two allowable one-year waivers; the Pentagon invoked the second and final waiver on July 31, 2025, while converting roughly 1,000 facilities and more than 6,000 mobile assets to fluorine-free foam. But the foam itself is only half the story. The other half is still in the ground, and it is not leaving. I'm Nathaniel Pyron, a military urban planner with an airport and airfield focus — and I now treat PFAS the same way I treat explosives arcs and noise contours: as a constraint layer that belongs on every constraints map I draw.

That is why PFAS — per- and polyfluoroalkyl substances, the "forever chemicals" — have become a master-planning problem, not just an environmental compliance headache.

The source map is an airfield map

AFFF is, first and foremost, an airfield chemical. For decades, military fire protection sprayed it around fuel fires, in hangar suppression systems, at crash-rescue stations, and — most consequentially — at fire-training pits where firefighters practiced with it over and over. Those releases left source areas under and beside runways, taxiways, and fuel farms. When I lay out the constraints map for an airfield master plan — airfield criteria, explosives arcs, AICUZ noise contours, flood zones — the PFAS source map now belongs on the same sheet: parcels with coordinates, plumes with boundaries, and deed restrictions with legal force.

The remedy is land use

The Government Accountability Office reports DoD has already spent $2.6 billion investigating and addressing PFAS, with assessments underway at 723 installations. That money buys things that occupy space: pump-and-treat plants, treatment vessels, monitoring-well networks by the hundreds, bottled-water distribution. Every one of those is a land-use decision that has to be sited, powered, and maintained — while the runway keeps operating.

Then there is the schedule. On August 31, 2026, the Pentagon told Congress that cleanup timelines at 243 military sites were being pushed back by an average of five years — some by as much as nineteen, the third such delay in about a year. Joint Base San Antonio slipped thirteen years; Fairchild Air Force Base slipped twelve. The FY2026 NDAA (Section 322) now requires DoD to deliver an accelerated PFAS strategy with explicit prioritization criteria, CERCLA cleanup timelines for each facility, and measurable benchmarks. A new barracks complex, child development center, or hangar sited near an unresolved PFAS plume inherits the plume's timeline — and the land-use controls that come with it. Like explosive safety arcs, a PFAS land-use control draws a real line on the future land-use map; the difference is that this line migrates with the groundwater.

The drinking-water standard changed the math

In April 2024, EPA finalized the first national drinking-water standards for six PFAS — including 4.0 parts-per-trillion limits for PFOA and PFOS — and a month later designated both as CERCLA hazardous substances. Parts per trillion rewrites well-siting decisions: the question is no longer whether a supply well can go near the flight line, but whether the aquifer beneath it carries fifty years of foam residue. In the Pacific, that math is unforgiving — island installations draw from thin freshwater lenses, so a plume a mainland base could dilute becomes a base-wide planning constraint. And a study published this month in Environmental Health Perspectives found veterans under 40 carry PFAS blood levels 13 to 24 percent higher than their civilian peers. The people our plans house are the people living on top of this.

The planner's five moves

So what does the master planner actually do about PFAS? Five moves, in my experience:

1. Map source areas like any other constraint. Put AFFF-use history — ARFF stations, training pits, hangar foam-discharge zones, testing areas — on the constraints map alongside AICUZ, ESQD, and floodplains. Future land-use decisions start there.

2. Site remedy infrastructure deliberately. Treatment plants, treatment vessels, monitoring networks, and access roads for decades of monitoring are permanent land uses. Siting them after the fact, wedged between a runway protection zone and a new mission facility, is how you manufacture conflicts.

3. Screen every siting decision for PFAS. New housing, child care, dining, and mission facilities near source areas need PFAS screening early — coordinated with drinking-water well placement, not parallel to it.

4. Plan the foam transition as a facilities project. The phase-out is logistics: collecting legacy AFFF, storing it, and disposing of it now that DoD's incineration pause has been lifted, while converting vehicles and fixed systems to fluorine-free alternatives that behave differently in extreme temperatures. That work needs yard space, staging areas, and a schedule.

5. Treat cleanup timelines as program risk. With delays averaging five years at 243 sites, construction phasing, temporary facility siting, and MILCON sequencing have to carry PFAS uncertainty the way they carry funding uncertainty. The FY2026 NDAA's required CERCLA timelines give planners milestones to build around — once they are published, use them.

Military master planning has always been the art of drawing the future around things you cannot move: the runway, the munitions arcs, the noise contours. PFAS adds one more invisible layer — one that migrates, persists, and now has a drinking-water standard measured in parts per trillion. A good airfield master plan maps where the foam went, sites around where it is, and folds the cleanup into the schedule.

About the author

Nathaniel Pyron is a military urban planner specializing in military master planning with an airport/airfield focus. A U.S. Navy veteran who served in 1995, he later spent three years as a civilian community planner working with the U.S. Marine Corps at Camp Blaz and Darwin, Australia. He studied at the Arizona State University School of Urban Planning, class of 2007, and is an active LEED AP BD+C. Based in Honolulu, Hawaii, he writes about installation planning, airfield land use, and where military readiness meets community design. His LinkedIn title is Urban Planner (Land Use & Airspace).