NIST Abstract

This is the second report in NIST’s response to the National Defense Authorization Act for Fiscal Year 2021, titled the “Guaranteeing Equipment Safety for Firefighters Act of 2020.”. The first report, NIST Technical Note 2248, provides a baseline that defines the type, concentration, and prevalence of per- and polyfluoroalkyl substances (PFAS) in textiles used in the construction of new/unused Firefighter’s jacket and pants. In this report, NIST Technical Note 2260, NIST is reporting the PFAS measured in the same jacket and pants textiles and using the same PFAS analyte list in TN 2248 after these new/unused fabrics are physically stressed.

Textiles used in the construction of structural firefighter turnout gear have been found to contain per- and polyfluoroalkyl substances (PFAS) as well as fluoropolymer membranes and durable water repellent treatments containing fluorinated polymers. Additionally, older and used turnout gear has been found to contain greater concentrations of PFAS compared with new gear, though the source of these elevated PFAS concentrations is still under investigation. To determine if the stresses that turnout gear textiles encounter during typical use could contribute to the observation of higher PFAS concentrations, this National Institute of Standards and Technology Technical Note reports the concentrations of 51 PFAS in 20 firefighter turnout gear textiles following exposure to abrasion, elevated temperature, laundering, or weathering, which is a combined exposure to ultraviolet radiation and elevated humidity. Compared with corresponding concentrations in unstressed textiles, individual and summed PFAS concentrations in all textile types were higher following abrasion but were similar or lower following laundering. Additionally, summed PFAS concentrations were higher in outer shell textiles following exposure to elevated temperature and weathering. For example, the median summed PFAS concentrations among durable water repellent treated outer shell textiles rose from 1430 µg/kg when new to 3500 µg/kg following abrasion, 4420 µg/kg following exposure to elevated temperatures, and 3540 µg/kg following weathering, while it fell to 963 µg/kg following laundering. These changes in summed PFAS concentrations with stressing largely reflected changes in the concentrations of PFAS that were present in the highest concentration in unstressed turnout gear textiles: 6:2 FTMAC and 6:2 FTOH. While physical stressing may contribute to altered PFAS concentrations in stressed compared with unstressed turnout gear textiles, the mechanisms responsible for these changes cannot be authoritatively identified by the targeted analytical approach employed here. For example, the analytical approach used in this report cannot distinguish between PFAS produced by the chemical transformation of PFAS that were excluded from the targeted analyte list and increased PFAS extraction due to degradation of firefighter gear textiles and associated fluorinated polymer treatments.