Rinse, rebound, repeat: The challenge of decontaminating PFAS-impacted aircraft rescue and firefighting vehicles.

The transition from aqueous film-forming foam (AFFF) to fluorine-free foams (F3) requires effective decontamination of aircraft rescue and firefighting (ARFF) vehicles to prevent further PFAS releases. Comprehensive, publicly accessible field assessments of PFAS decontamination protocols for ARFF vehicles are sparse. Herein, PFAS decontamination methods were evaluated on AFFF-impacted ARFF vehicles. PFAS removal was assessed using target PFAS analysis and adsorbable organic fluorine (AOF). While initial samples collected and analyzed using target PFAS analysis demonstrated high removal in the initial rinses (up to 84% of the readily removable PFAS fraction in three rinses), subsequent efforts yielded diminishing returns. Notably, the introduction of cleaning solvents failed to meaningfully enhance decontamination efficiency. Post-cleanout assessments revealed significant PFAS rebound after two months, representing ∼40% of the total readily removable PFAS fraction removed during ARFF vehicle decontamination. Samples collected and analyzed for AOF revealed large quantities of fluorinated compounds not captured by target PFAS analytical methods with between 25 and 160 times greater AOF concentrations emanating from the two ARFF vehicles examined. The higher AOF values compared to target PFAS suggests the importance of non-target PFAS analytical techniques for more comprehensive performance evaluation. The findings of this field study demonstrate that the decontamination methods examined were insufficient to achieve complete PFAS removal from the interior surfaces of ARFF vehicles as evident by the significant PFAS rebound observed post-decontamination. Additional work is needed as inadequate ARFF vehicle decontamination may result in the accidental discharge of PFAS into the environment.