Remove persistent PFAS from surfaces
CDM Smith applied a heated solvent with surface agitation, generating minimal waste and site footprint, to dissolve PFAS assemblies that water alone cannot remove.
Addressing PFAS rebound risks in ARFF vehicles
Legacy aqueous film-forming foams (AFFFs) contain PFAS that pose environmental and health concerns. As U.S. airports transition to fluorine-free foams (F3), a key challenge is PFAS rebound. Standard draining and rinsing are ineffective because PFAS fluorosurfactants self-assemble into persistent layers on tanks and piping. To address this risk, SFO partnered with CDM Smith to deliver a first-of-its-kind ARFF vehicle decontamination program that reduced exposure while maintaining operational readiness.
Advanced testing to verify success
Surface swab sampling and the Total Oxidizable Precursor (TOP) Assay were used to quantify PFAS mass removal, rather than relying on ineffective rinse testing.
Maintain ARFF readiness during cleaning
Vehicles were cleaned on a staggered schedule, with two ARFF units processed at a time to meet Part 139 Index requirements and keep emergency response intact.
Estimate and manage PFAS rebound risk
Post-cleaning surface data enabled calculation of theoretical PFAS rebound into F3 foam, supporting informed risk management and compliance decisions.
SFO completed full decontamination of eight ARFF vehicles in early 2025, achieving an average 97% removal of PFAS mass from interior surfaces as measured by the TOP Assay. Estimated rebound concentrations into replacement F3 foam were below the DoW’s 1 ppb limit for all but one vehicle, which measured 1.1 ppb. The results indicate a negligible regulatory risk and demonstrate that effective cleaning is achievable when chemical dissolution, heat and physical attrition are combined with surface-based verification. As AFFF Discipline Leader Jill Greene noted, “One of SFO’s primary objectives was that we utilize the most current data on decontamination and analytical testing.” This project sets a practical benchmark for airports nationwide transitioning away from PFAS-based foams while protecting personnel, infrastructure, and the environment.