PFAS and AFFF: How Firefighting Foam Contamination Affects Hangar Value

Many aircraft hangars, particularly those built for jet operations, were fitted with high-expansion foam fire-suppression systems. The foam of choice was aqueous film-forming foam, or AFFF, which contains per- and polyfluoroalkyl substances, known as PFAS. Every discharge, every scheduled system test, and every accidental release put PFAS into hangar floors, drains, soil, and groundwater. PFAS does not break down on any practical timescale, so a hangar that last tested its foam system twenty years ago can still sit above a contaminated plume today.

See which airports carry documented or presumed PFAS exposure in our U.S. Airport PFAS / AFFF Exposure Map, a searchable screening tool for buyers and lenders.

Why hangars carry the exposure

Three features make hangars a recurring source of PFAS liability. Foam deluge systems were standard in maintenance and storage hangars for turbine aircraft. Testing and maintenance discharged foam directly onto floors that often drained to soil rather than to a treatment system. And many hangars sit on airport land where firefighting training and equipment washdown compounded the loading. The result is that contamination is frequently present even where there was never a reported fire.

What it does to value

PFAS affects a hangar in four separate ways, and an analysis that captures only one of them will overstate value.

• Remediation cost. Soil and groundwater treatment for PFAS is expensive and the standards are still tightening. A cost-to-cure that looked adequate two years ago may be low today.
• Regulatory liability. Federal and state programs are moving PFAS toward hazardous-substance treatment, which raises the prospect of joint and several liability for current and past owners. Lenders read this as balance-sheet risk, not just property risk.
• Marketability and stigma. Even after cleanup, a documented PFAS history narrows the buyer pool and lengthens marketing time. That shows up as a higher capitalization rate, not only as a one-time deduction.
• Insurance and financing friction. Carriers exclude PFAS more often each renewal, and lenders increasingly require an environmental review before they will size a loan against the improvements.

How the analysis should treat it

A defensible valuation starts with the environmental record, not with the replacement-cost estimate. If a Phase I assessment flags historical foam use, the value work should proceed on an as-is basis with a supportable cost-to-cure, and it should test whether contamination changes the highest and best use of the site. A remediated value and an as-is value can differ by more than the cleanup cost alone once stigma and holding period are priced in. Where the record is silent, the absence of testing is itself a finding to disclose rather than a clean bill of health.

What buyers and lenders should ask for

Before underwriting a hangar, confirm whether a foam suppression system was ever installed, obtain any discharge or testing logs, review prior environmental assessments, and establish whether the site drains to soil. On leased airport land, determine who bears remediation responsibility under the ground lease, because the answer often sits with the tenant even when the sponsor owns the dirt.

This article is general information for professionals evaluating aviation real estate. It is not appraisal, legal, or tax advice, and it does not create an engagement.