Firefighters' exposure to per-and polyfluoroalkyl substances (PFAS) as an occupational hazard: A review.

The term "firefighter" and "cancer" have become so intertwined in the past decade that they are now nearly inseparable. Occupational exposure of firefighters to carcinogenic chemicals may increase their risk of developing different types of cancer. PFAS are one of the major classes of carcinogenic chemicals that firefighters are exposed to as occupational hazard. Elevated levels of PFAS have been observed in firefighters' blood serum in recent studies. Possible sources of occupational exposure to PFAS include turnout gear, aqueous film-forming foam, and air and dust at both the fire scene and fire station. Preliminary discussion on PFAS includes definition, classification, and chemical structure. The review is then followed by identifying the sources of PFAS that firefighters may encounter as an occupational hazard. The structural properties of the PFAS used in identified sources, their degradation, and exposure pathways are reviewed. The elevated level of PFAS in the blood serum and how this might associate with an increased risk of cancer is discussed. Our review shows a significant amount of PFAS on turnout gear and their migration to untreated layers, and how turnout gear itself might be a potential source of PFAS exposure. PFAS from aqueous film-forming foams (AFFF), air, and dust of fire stations have been already established as potential exposure sources. Studies on firefighters' cancer suggest that firefighters have a higher cancer risk compared to the general population. This review suggests that increased exposure to PFAS as an occupational hazard could be a potential cancer risk for firefighters.

Toward the future of firefighter gear: Assessing fluorinated and non-fluorinated outer shells following simulated on-the-job exposures.

In 2022, the occupation of firefighting was categorized as a "Group 1" carcinogen, meaning it is known to be carcinogenic to humans. The personal protective equipment that structural firefighters wear is designed to safeguard them from thermal, physical, and chemical hazards while maintaining thermo-physiological comfort. Typically, the outer layer of structural turnout gear is finished with a durable water and oil-repellent (DWR) based on per- and polyfluoroalkyl substances (PFAS) that helps limit exposure to water and hazardous liquids. The PFAS-based aqueous emulsion typically used in DWR finishes is highly persistent and can cause various health problems if absorbed into the body through ingestion, inhalation, and/or dermal absorption. In response, the U.S. Fire Service has begun using non-PFAS water repellants in firefighter turnout gear. This study aims to evaluate the performance of both traditional PFAS-based and alternative non-PFAS outer shell materials. The study involved exposing both PFAS-based and non-PFAS DWR outer shell materials in turnout composites to simulated job exposures (i.e., weathering, thermal exposure, and laundering) that artificially aged the materials. After exposures, samples were evaluated for repellency, durability, thermal protection, and surface chemistry analysis to determine any potential performance trade-offs that may exist. Non-PFAS outer shell fabrics were found not to be diesel/oil-repellent, posing a potential flammability hazard if exposed to diesel and subsequent flame on an emergency response. Both PFAS-based and non-PFAS sets of fabrics performed similarly in terms of thermal protective performance, tearing strength, and water repellency. The surface analysis suggests that both PFAS and non-PFAS chemistries can degrade and shed from fabrics during the aging process. The study indicates that firefighters should be educated and trained regarding the potential performance trade-offs, such as oil absorption and flammability concerns when transitioning to non-PFAS outer shell materials.

Rapid and Easy Enrichment Strategy for Naturally Acetylated N Termini Based on LysN Digestion and Amine-Reactive Resin Capture.

Protein N-terminal acetylation (Nα-acetylation) is one of the most common modifications in both eukaryotes and prokaryotes. Although studies have shown that Nα-acetylation plays important roles in protein assembly, stability, and location, the physiological role has not been fully elucidated. Therefore, a robust and large-scale analytical method is important for a better understanding of Nα-acetylation. Here, an enrichment strategy was presented based on LysN digestion and amine-reactive resin capture to study naturally acetylated protein N termini. Since LysN protease cleaves at the amino-terminus of the lysine residue, all resulting peptides except naturally acetylated N-terminal peptides contain free amino groups and can be removed by coupling with AminoLink Resin. Therefore, the naturally acetylated N-terminal peptides were left in solution and enriched for further liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. The method was very simple and fast, which contained no additional chemical derivatization except protein reduction and alkylation necessarily needed in bottom-up proteomics. It could be used to study acetylated N termini from complex biological samples without bias toward different peptides with various physicochemical properties. The enrichment specificity was above 99% when it was applied in HeLa cell lysates. Neo-N termini generated by endogenous degradation could be directly distinguished without the use of stable-isotope labeling because no chemical derivatization was introduced in this method. Furthermore, this method was highly complementary to the traditional analytical methods for protein N termini based on trypsin only with ArgC-like activity. Therefore, the described method was beneficial to naturally acetylated protein N termini profiling.