Summary:

To investigate the extent to which physical stressors could change PFAS concentrations in firefighter gear, this NIST TN quantified the concentrations of 51 PFAS across 20 firefighter gear textiles following exposure to abrasion, elevated temperature, laundering, or weathering. Changes in PFAS concentration with stressing were determined by comparison with PFAS concentrations determined previously in corresponding unstressed textiles in NIST TN 2248.

Abrasion was found to increase summed PFAS concentrations for all textile types while weathering consistently increased summed PFAS concentrations in outer shell textiles. Laundering produced relatively small changes in summed PFAS concentrations across all textiles and exposure to elevated temperature increased summed PFAS in outer shell textiles but resulted in smaller changes in the remaining textile types. The largest absolute changes in PFAS concentration were observed in outer shell textiles with weathering, where the median summed PFAS concentration increased from 964 µg/kg to 3520 µg/kg. Where stressing increased summed PFAS concentrations, these changes were primarily due to increases in the concentrations of 6:2 FTMAC and 6:2 FTOH, which were also the highest concentration PFAS in unstressed turnout gear textiles, rather than the appearance of previously unobserved PFAS. As in unstressed textiles, summed PFAS concentrations tended to be highest in stressed DWR-treated outer shell textiles and lowest in stressed thermal liner textiles. While the targeted analytical approached used in this NIST TN cannot distinguish between the many processes that could contribute to altered textile PFAS concentrations with stressing, the observed changes with abrasion and weathering are consistent with changes in the fraction of PFAS that are extractable by the analytical method used in this report.

The findings of this NIST TN agree with those previously reported for PFAS in stressed DWR treated textiles, which also observed that stressing can increase PFAS concentrations in textiles. Therefore, accurately estimating firefighter PFAS exposure from gear requires considering how PFAS concentrations may change as the gear is used.

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