Why Firefighters Have Higher PFAS Levels
Firefighters have elevated PFAS levels primarily due to occupational exposure from aqueous film-forming foam (AFFF) used in firefighting, PFAS-treated turnout gear, and contaminated air and dust at fire scenes and stations 1.
Primary Exposure Sources
Aqueous Film-Forming Foam (AFFF)
The most significant occupational source is AFFF, which contains high concentrations of PFAS compounds, particularly perfluorooctane sulfonate (PFOS) and perfluorohexane sulfonic acid (PFHxS) 1. Aircraft rescue and firefighting (ARFF) personnel show particularly elevated serum levels of PFHxS, PFOS branched isomers, and perfluoroundecanoic acid (PFUnDA) compared to the general population 2. Firefighters who reported recent changes in workplace AFFF behavior or practices had lower summed PFAS concentrations, demonstrating the direct link between foam use and body burden 2.
Turnout Gear and Personal Protective Equipment
Firefighter turnout gear treated with PFAS for water and stain resistance serves as a continuous exposure source 3. Studies demonstrate significant PFAS migration from treated outer layers to untreated inner layers of gear 3. Four PFAS compounds (8:2 FTS, FOSA, PFBS, and PFPeS) were detected exclusively in firefighter serum and not in the general population, with three of these commonly found in turnout gear 4.
Fire Scene and Station Environment
Exposure occurs through inhalation and dermal contact with contaminated air and dust at both fire scenes and fire stations 3. Novel phosphate-containing PFAS were significantly elevated in firefighter serum within 35 hours post-fire, likely from exposure to fluorinated aryl phosphate flame retardants or their combustion transformation products 5.
Specific Elevated Compounds
UK firefighters showed geometric mean serum levels of:
- PFHxS: 4.1 times higher than general population
- PFOS: 1.5 times higher
- PFHPS: 1.6 times higher 4
These compounds have been historically associated with AFFF use 4.
Occupational Risk Factors
PFAS concentrations increase with age and years of service, reflecting the cumulative and persistent nature of these chemicals in the body 4, 6. The strong carbon-fluorine bonds in PFAS result in delayed degradation rates and resistance to physicochemical and biological mineralization, causing bioaccumulation over firefighting careers 1.
Exposure Pathways Include:
- Direct contact during foam application
- Inhalation of contaminated air during fire suppression
- Dermal absorption from contaminated gear
- Ingestion through hand-to-mouth contact
- Contaminated drinking water at some fire stations 2
Important Caveats
Background environmental contamination can confound occupational exposure assessment. The UK general population comparison group from a region with high environmental PFAS contamination showed relatively elevated baseline levels, making it harder to distinguish purely occupational exposure 4. Three fire departments had detectable PFAS in tap water, with one showing correlation between water and serum levels 2.
Clinical Implications
The persistence and bioaccumulation of PFAS means firefighters experience latent and cumulative effects throughout their careers 7. PFAS exposure has been linked to increased cancer risk (thyroid, kidney, bladder, testicular, prostate, colon), cardiovascular disease, thyroid dysfunction, and reproductive effects 1, 7. Given that carcinogens have additive effects and firefighters face multiple carcinogenic exposures, PFAS contamination represents a significant occupational health concern requiring ongoing monitoring and exposure reduction strategies 7.