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News|Articles|April 3, 2026

LC-MS/MS Profiling Links PFAS Exposure to Reduced Cognitive Processing Speed in Firefighters

Author(s)John Chasse
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Key Takeaways

  • Whole-blood LC‑MS/MS enabled individual-analyte and mixture modeling of 24 PFAS, linked to domain-specific cognition using NIH Toolbox measures of global cognition and processing speed.
  • Firefighting-relevant PFAS sources include turnout gear and AFFF/Class B foams; mechanistic plausibility is supported by BBB penetration and neurotransmitter perturbations with potential neurotoxicity.
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A pilot study conducted by researchers from Texas State University and Yale utilized liquid chromatography-tandem mass spectrometry (LC-MS/MS) to analyze whole blood samples from active-duty firefighters for 24 distinct per- and polyfluoroalkyl substances (PFAS). The analysis successfully quantified key analytes, revealing a direct negative association between PFOS concentrations and cognitive processing speed. This research highlights the essential role of advanced LC-MS/MS techniques in uncovering the hidden occupational hazards and neurotoxicological impacts of "forever chemicals" on first responders.

Influenced by the fact that evidence on cognitive function in relation to per- and polyfluoroalkyl substances (PFAS) exposure in firefighters is scarce, a pilot study conducted by researchers at Texas State University (San Marcos, Texas) and the Yale School of Public Health (New Haven, Connecticut) explored the associations of individual PFAS analyte and PFAS mixture with domain-specific cognitive performance in firefighters. Whole blood samples were collected from firefighters participating in the study and analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) for 24 PFAS analytes. A paper based on this research was published in the Journal of Exposure Science & Environmental Epidemiology.1

Exposure to PFAS might be especially relevant to the firefighting profession due to these compounds being used in turnout gear, training activities in airports and military bases, and are found in some firefighting foams, including aqueous film-forming foams (AFFF) or Class B foam.2,3 PFAS can cross the blood-brain barrier (BBB) and alter neurotransmitter concentrations, which can result the activation of neurons and signal transmission among neurons; an increase or decrease in neurotransmitters may lead to neuron cell death.4,5

The researchers assessed 65 firefighters who were actively serving four central Texas cities in 2003-2025 for global cognition and processing speed measured by the NIH Toolbox Cognition Battery. Once their blood samples were analyzed using LC-MS/MS, linear regression models were used for evaluating associations between cognitive performance and individual PFAS analytes, as well as the overall 24-PFAS mixture. Quantile g-computation and Bayesian Kernel Machine Regression (BKMR) were also applied for investigating associations between 6-PFAS mixture and cognitive performance, with adjustments made for potential covariates.1

The data collected revealed PFAS analytes, including potassium perfluoro-1-octanesulfonate (PFOS), perfluoro-n-octanoic acid (PFOA), perfluoro-n-heptanoic acid (PFHpA), perfluoro-n-nonanoic acid (PFNA), perfluoro-n-decanoic acid (PFDA), and potassium perfluoro-1-hexanesulfonate (PFHxS), found in the least 70% of participants. PFOS was negatively associated with scores of processing speed (ß = -0.58 p < 0.001). Neither the 6-PFAS mixture nor the 24-PFAS mixture was associated with either cognitive domain.1

The researchers believe the preliminary findings from this study may shape future research seeking a clarification of the biological pathways linking PFAS exposure to cognitive outcomes, as well as the exploration of possible modifiable factors related to cognitive health in firefighters. In addition, they may also underscore the potential value of continued effort to minimize workplace PFAS exposure for this occupational group.1

The study, write the authors of the paper,1 “provides the first data on PFAS exposure and cognitive performance for firefighters. Our analysis revealed that PFOS was the primary contributor among the PFAS mixture (consisting of PFOS, PFOA, PFHxS, PFHpA, PFNA, and PFDA) linked to reduced processing speed scores in firefighters. Our findings pave the way for future, larger studies that observe firefighters for longer duration to develop confident estimates of cognitive health in relation to PFAS exposure. These data could inform analyses in support of workplace exposure reduction efforts and revision of preventive health care for first responders.”

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References

  1. Pan, X.; Pollitt, K. J. G.; Liu, S. et al. Association of Per- and Polyfluoroalkyl Substances (PFAS) Exposure with Cognitive Function in Firefighters. J Expo Sci Environ Epidemiol. 2026. DOI: 10.1038/s41370-026-00861-y
  2. Laitinen, J. A.; Koponen, J.; Koikkalainen, J. et al. Firefighters' Exposure to Perfluoroalkyl Acids and 2-butoxyethanol Present in Firefighting Foams. Toxicol Lett. 2014, 231 (2), 227-232. DOI: 10.1016/j.toxlet.2014.09.007
  3. Jin, C.; Sun, Y.; Islam, A. et al. Perfluoroalkyl Acids Including Perfluorooctane Sulfonate and Perfluorohexane Sulfonate in Firefighters. J Occup Environ Med. 2011, 53 (3), 324-328. DOI: 10.1097/JOM.0b013e31820d1314
  4. Foguth, R. M.; Flynn, R. W.; de Perre, C. et al. Developmental Exposure to Perfluorooctane Sulfonate (PFOS) and Perfluorooctanoic Acid (PFOA) Selectively Decreases Brain Dopamine Levels in Northern Leopard Frogs. Toxicol Appl Pharmacol. 2019, 377, 114623. DOI: 10.1016/j.taap.2019.114623
  5. Cao, Y.; Ng, C. Absorption, Distribution, and Toxicity of Per- and Polyfluoroalkyl Substances (PFAS) in the Brain: A Review. Environ Sci Process Impacts 2021, 23 (11), 1623-1640. DOI: 10.1039/d1em00228g

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