Transitioning away from firefighter turnout gear with per- and polyfluoroalkyl substances could bring potential performance tradeoffs, according to new research.
The chemicals offer water- and oil-repelling properties on the outer shells of firefighter turnout gear.
The study showed that turnout gear without PFAS outer shell coatings were not oil-repellent, posing a potential flammability hazard to firefighters if exposed to oil and flame, says Bryan Ormond, assistant professor of textile engineering, chemistry, and science at North Carolina State University. Ormond is corresponding author of the study in the Journal of Industrial Textiles.
“All oil repellents can also repel water, but all water repellents don’t necessarily repel oil. Diesel fuel is really difficult to repel, as is hydraulic fluid; in our testing, PFAS-treated materials repel both,” he says. “In our tests, turnout gear without PFAS repelled water but not oil or hydraulic fluid. Further, oils seem to spread out even more on the PFAS-free gear, potentially increasing the hazard.”
PFAS chemicals—known as forever chemicals because of their environmental persistence—are used in food packaging, cookware, and cosmetics, among other uses, but have recently been implicated in higher risks of cancer, higher cholesterol levels, and compromised immune systems in humans.
In response, firefighters have sought alternative chemical compounds—like the hydrocarbon wax coating used in the study—on turnout gear to repel water and oils.
Besides testing the oil- and water-repelling properties of PFAS-treated and PFAS-free outer garments, the researchers also compared how the outer shells aged in job-related exposures like weathering, high heat, and repeated laundering, and whether the garments remained durable and withstood tears and rips.
The study showed that PFAS-treated and PFAS-free outer shells performed similarly after exposure to UV rays and various levels of heat and moisture, as well as passes through heating equipment—similar to a pizza oven—and through washing machines.
“Laundering the gear is actually very damaging to turnout gear because of the washing machine’s agitation and cleaning agents used,” Ormond says.
“We also performed chemical analyses to see what’s happening during the weathering process,” says lead author Nur Mazumder, a doctoral student in fiber and polymer science.
“Are we losing the PFAS chemistries, the PFAS-free chemistries, or both when we age the garments? It turns out that we lost significant amounts of both of these finishes after the aging tests.”
Both types of garments performed similarly when tested for strength against tearing the outer shell fabric. The researchers say the PFAS and PFAS-free coatings didn’t seem to affect this attribute.
Future work will explore how much oil repellency is needed by firefighters out in the field, Ormond says.
“Even with PFAS treatment, you see a difference between a splash of fluid and soaked-in fluid,” he says. “For all of its benefits, PFAS-treated gear, when soaked, is dangerous to firefighters.
“So we need to really ask ‘What do firefighters need?’ If you’re not experiencing this need for oil repellency, there’s no worry about switching to non-PFAS gear. But firefighters need to know the non-PFAS gear will absorb oil, regardless of what those oils are.”
Coauthor Andrew Hall, another doctoral student in fiber and polymer science, is also testing dermal absorption, or taking the aged outer shell materials and placing them on a skin surrogate for a day or two. Are outer shell chemicals absorbed in the skin surrogate after these admittedly extreme exposure durations?
“Firefighting as a job is classified as a carcinogen and it shouldn’t be,” Ormond says. “How do we make better gear for them? How do we come up with better finishes and strategies for them? These aren’t just fabrics. They are highly engineered pieces of material that aren’t easily replaced.”
The Federal Emergency Management Agency’s Assistance to Firefighters Grants Program funded the work.
Source: NC State
