By Bill Carey
GAITHERSBURG, Md. — The National Institute of Standards and Technology (NIST) has released findings from a follow-up study on turnout gear and per- and polyfluoroalkyl substances (PFAS), showing that wear and tear releases more PFAS in simulated testing.
The two studies identified the PFAS compounds present in selected turnout gear textiles, how much of each was present, and whether simulated wear and tear increased the amount of PFAS that the textiles released.
“The firefighter community has raised concerns about PFAS in turnout gear, but before these studies, there was very little data that address those concerns,” NIST chemist and study co-author Rick Davis said. “Based on these studies we can confidently say that more than 20 types of PFAS might be present in firefighter gear and that the amount and type of PFAS vary depending on the type of textile used and the amount of stress it has been subjected to.”
The earlier study reviewed 21 textiles that are typically used in the thermal layer, moisture barrier and outer shell. They tested those textiles for 53 different PFAS compounds and measured how much of each was present.
In a recent study, the researchers stressed those same textiles using four techniques: abrasion, heat, laundering and weathering. The weathering was simulated by exposing the textiles to UV radiation and high humidity. The researchers then measured the PFAS present after the textiles were stressed.
The results showed that abrasion can cause measured PFAS concentrations to increase across all textiles tested. Weathering and heat caused measured PFAS concentrations to increase in the outer shell materials.
Laundering had little effect, and in some cases reduced PFAS concentrations, presumably because PFAS were washed away.
Before and after stressing, PFAS concentrations were highest in outer shell fabrics that had been treated with a water-repellent coating. PFAS concentrations were lowest in the thermal layer.
Researchers concluded that it is unclear what caused PFAS concentrations to change during the stressing. The changes might have been caused by chemical transformations, but it is also possible that stressing loosened the PFAS from the textile fibers, allowing more of it to be extracted.