NIST Evaluates PFAS Concentrations in Stressed Firefighting Gear

A study conducted by the National Institute of Standards and Technology (NIST) found that subjecting protective equipment for firefighting to physical stressors increased the concentrations of per- and polyfluoroalkyl substances (PFAS) in gear intended for structural firefighters but decreased them in gear intended for wildland firefighters, according to a recently released report from the agency.

As explained in a NIST press release accompanying the report, firefighting equipment is sometimes treated with PFAS due to their ability to repel water. Because PFAS have been linked to cancer, the 2021 National Defense Authorization Act directs NIST to measure PFAS in firefighting gear. An earlier NIST study measured PFAS levels in unstressed equipment.

The new study applied abrasion, high temperatures, or weathering to samples of textiles from gloves and hoods for structural firefighters, as well as coats, shirts, and pants for wildland firefighters. Only one stressor was applied to each sample. The report notes that the gloves worn by structural firefighters are multilayered. For purposes of the study, researchers cut layers from the gloves.

Following exposure of samples to high temperatures in a convection oven for at least 30 minutes, total PFAS concentrations increased 643 percent in glove layers and nearly 8,000 percent in hoods, the report explains. Hoods were also subjected to abrasion, which led to a 274 percent increase in total PFAS concentrations.

In contrast, the abrasion and weathering of wildland firefighter clothing resulted in decreases in total PFAS concentrations of 83 and 74 percent, respectively.

Researchers also quantified concentrations for 56 individual PFAS through extraction via solvents and analysis by gas and liquid chromatography-mass spectrometry. The results “largely reflected changes in concentrations of PFAS already dominant in unstressed gear [. . .] rather than the appearance of new PFAS types,” the report states.

For more information, refer to the NIST report (PDF) and press release. The earlier study on unstressed equipment is also available as a PDF.