The following is in response to a FireRescue Magazine article
and is written by a consultant to LION
By Paul Chrostowski, Ph.D., QEP
Paul Chrostowski, Ph.D., QEP is an environmental health scientist with more than 40 years of experience in assessing health risks from exposure to chemicals in the workplace and environment. He is an expert who has examined hundreds of scientific studies on PFAS and their associated health effects. He is a consultant to Lion, a leading manufacturer of firefighter personal protective equipment.
Public concerns about PFAS chemicals in the environment have grown exponentially in the past few years. While those concerns remain valid, too often uninformed critics and environmental activists have inaccurately used them to raise alarms about the protective turnout gear used by firefighters throughout the United States. One recent example was Larissa Conroy’s recent article in FireRescue Magazine “What if I told you that your Turnout Gear was Causing Cancer,” an attention-grabbing title for sure, but one that is misleading and unsupported.
At the center of the issue are some 5,000 chemical compounds known as PFAS, or perfluoroalkyl and polyfluoroalkyl substances. One of those compounds is PFOA, which in the past was linked to health effects in people through drinking water. It had been used as a processing agent in the manufacture of water-repellent films and finishes for a variety of textiles, and the concern was that PFOA could be released into the environment at the textile manufacturer’s facility, ultimately finding its way into the local soil or drinking water. These textiles were used to make many garments, including turnout gear resistant to dangerous chemicals, viruses, flame, heat and water. But PFOA was never part of the gear itself and frequent independent testing has found only trace amounts of it in any of the gear — not nearly enough to cause concern, and in amounts similar to consumer products. And it is no longer even used in processing, as textile companies have phased it out due to concerns with on-site environmental release and found alternative ways to make water-repellent films and finishes.
Given the disconnect between the concern with PFOA in the environment and turnout gear, why do some persist in confusing the issue?
An isolated study by Professor Graham Peaslee conducted two years ago at the University of Notre Dame claimed that some of these chemicals leaching from other PFAS in the protective gear may transform into PFOA “with exposure and wear.”
But Peaslee has never published his work for scientific scrutiny despite repeated calls for him to do so, and no one has been able to replicate his findings. Peaslee himself has cautioned that more research into the issue must be done before any conclusions are reached or changes made to firefighter turnout gear.
Despite those facts, some observers cite Peaslee’s work as the foundation of their unsupported assertions that turnout gear worn by firefighters may cause cancer. Those assertions gain headlines and win attention for causes supported by environmental activists, but they also create unnecessary fear and misunderstanding.
The fact is that one may find trace amounts of “short-chain” PFAS such as PFBS and PFHxA in firefighting textiles, but the scientific research shows that these materials are far less toxic than even PFOA and at the tiny trace levels the risks are extremely low based on numerous credible published scientific research papers.[1] And when I say “tiny trace levels,” I mean less than 1 part per billion of PFOA on samples tested by one manufacturer, LION. Just to put this in the proper context, one part per billion is the equivalent of one drop in 500,000 barrels of water, or a square foot of floor tile on a floor the size of Indiana.
Firefighters are exposed to PFAS from many environmental sources at a rate consistent with the general population. Almost every individual in the United States has PFAS in their bodies, mostly from food, water and/or consumer products. There have been four epidemiologic studies performed that evaluated PFAS in the blood of firefighters compared to different control groups.[2]
The evidence from these studies shows that firefighters are not exposed to PFAS at levels greater than control groups including the general population. So even if PFAS were found in their turnout gear, at this time there is no credible evidence that it ends up in firefighters bodies in amounts that would be higher than the general population. The federal Agency for Toxic Substances and Disease Registry (ATSDR) stated in its most recent guidance, “Dermal absorption of PFAS through the skin is limited and is of minimal concern as an exposure route.” They also state “Epidemiological and toxicological research on PFAS as a risk factor to human health is ongoing. The correlation of PFAS as human health risks are building a body of evidence. However, the evidence does not establish a causal relationship between PFAS exposure and disease.”[3]
A common misperception is that all PFAS are the same. But in fact, federal guidelines based on the most current scientific research treats the exposure limits for these materials differently based on the type of chemical being discussed. There are many differences between how PFAS materials get in the bloodstream, how fast they leave the body, and where they come from.
Moreover, the connection between PFAS and cancer is extremely weak. The few peer-reviewed epidemiological studies that have found an association were not statistically significant and inconsistent with other studies. Studies in laboratory animals were similarly equivocal and only revealed cancer at extremely high doses and only for PFOA which is not found in turnout gear. There have been no published clinical or epidemiological studies showing an increase in cancer among firefighters that could be attributed to PFAS exposure.[4]
To put this into context, it is important to realize that we, all members of the general public, are constantly exposing ourselves to low doses of potentially hazardous substances on a daily basis, but the low level of these exposures do not cause health risks. For example, we absorb acrylamide from consuming cooked foods. The mere fact of exposure does not by itself mean a chemical causes a disease, but scientists look at different levels of exposure and study those levels of exposure and their association with a negative health effect and many other scientific criteria. Epidemiological studies are complex scientific procedures that must be carefully performed in controllable conditions and must be reproducible and verifiable by the scientific community.
Another common misperception that needs to be corrected is referring to drinking water standards when discussing firefighter protective clothing. While the drinking water limits appear to be low, the exposure limits for water are based on lifetime exposures to drinking water, very different from the scenarios involving the wearing of turnout gear for which dermal absorption does not occur for PFAS trace substances.
Finally, the major manufacturers of outer shell materials, thermal barriers, and moisture barrier components that are used in nearly all turnout gear sold today have received certificates of compliance to the independent Swiss organization OEKO-TEX’s Standard 100 for PPE and Materials for PPE. The OEKO-TEX certification process tests for the presence of unsafe levels of trace materials, including PFOA. The requirements in the OEKO-TEX standard 100 are based on the most current European safety regulations. In 2019, the NFPA PPE Technical Correlating Committee established at task group that is currently working on setting a North American standard for restricted substances in firefighter protective clothing.
At this point, it would be irresponsible to dissuade firefighters from using their protective gear out of fear of cancer. The materials used in turnout gear are the safest materials available, and without them, firefighters would be at extreme risk for burns and exposure to known cancer-causing toxic chemicals present on the fireground, as well as metabolic heat stress.
Alternative materials tried by the U.S. fire service thus far have proven to be unsafe. Back in the early 2000’s, for example, the NFPA rewrote the NFPA 1971 standard after many fire departments and the IAFF expressed concern that the urethane-based Breathe-Tex moisture barriers degraded from exposure to UV light. The product was subsequently withdrawn from the market by the manufacturer, which ultimately went out of business.
Industry is continuing to look for and test materials for firefighter turnout gear may be better for the environment. But the consequences of switching to less-safe and unproven materials would be far worse than anything found in existing turnout gear now used by North American firefighters.
Paul Chrostowski, Ph.D., QEP is an environmental health scientist with more than 40 years of experience in assessing health risks from exposure to chemicals in the workplace and environment. He is an expert who has examined hundreds of scientific studies on PFAS and their associated health effects. He is a consultant to Lion, a leading manufacturer of firefighter personal protective equipment.
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The following four epidemiologic studies evaluated PFAS in the blood of firefighters compared to different control groups. These studies do not support assertions that wearing firefighter turnout gear has led to increased levels of PFAS in firefighters’ blood.
- In 2011, as part of the C8 Science Panel, 37 firefighters were analyzed for exposure to PFAS. The study concluded that serum concentrations were only statistically higher in firefighters for PFHxS, an ingredient in firefighting foams, carpets and other building materials. Other PFAS were not statistically higher than other employment groups. (Jin, C-F 2001. Perfluoroalkyl acids including perfluorooctane sulfonate and perfluorohexane sulfonate in firefighters. J. Occup Environ Med 53(3):324-8.)
- In the Fox biomonitoring study of 101 California firefighters, geometric mean PFOA blood serum levels were 3.75 in firefighters, vs. 3.61 in the general population, a slight 3.8% and statistically insignificant increase. (Dobraca, D. et. al.2015. Biomonitoring in California Firefighters. JOEM 57:88.)
- A recent study of female firefighters in northern California found that PFOA was measured in the firefighter’s serum at levels consistent with those in the general population or a comparison group of office workers.(Trowbridge, J et. al. 2019. Exposure to perfluoroalkyl substances in a cohort of women firefighters and office workers in San Francisco. medRxiv preprint; doi: http://dx.doi.org/10.1101/19005652.)
- An ongoing study of firefighters working at the urban-wildland interface in northern California found that only PFOS and PFHxS were higher in deployed firefighters. These PFAS chemicals are not found in turnout gear, but are traced to the use of fire retardant foams. Levels of these PFAS chemicals were higher in firefighters who had been deployed to fires compared with those who had not been deployed, suggesting that the source of the exposure to PFOS and PFHxS is the firefighting environment, not time spent exposed to dust at fire stations. (Morello-Frosh, R. 2019. Tubbs Fire (NCFF) study results. https://www.biomonitoringcollaborative.org/blog)
[1] EPA 2016. Drinking water health advisory for PFOA. EPA 822-R-16-005. Luz, A.L., Anderson, J.K., Goodrun, P., Durda, J. 2019. Fluorohexanoic acid toxicity, Part I: development of a chronic human health toxicity value for use in risk assessment. Reg Toxicol Pharm 103:41-55. French Agency for Food, Environmental, and Occupational Health & Safety (ANSES). June 2017.
Luz, A.L., Anderson, J.K., Goodrun, P., Durda, J. 2019. Fluorohexanoic acid toxicity, Part I: development of a chronic human health toxicity value for use in risk assessment. Reg Toxicol Pharm 103:41-55. Borg, D., Lund, B-O, Lindquist, N-G, & Hakansson, H. 2013. Cumulative health risk assessment of 17 PFASs in the Swedish Population. Environ Intl 59:112-123. Zeilmaker, M.J., Fragki, S., Verbruggen, E.M.J. & Bokkers, B.G.H 2018. Mixture exposure to PFAS: A relative potency factor approach. National Institute for Public Health and the Environment (RIVM). Bilthoven, The Netherlands.
[2] See summary of studies at the end of this article
[3] PFAS: An overview of the Science and Guidance for Clinicians on Per-and Polyfluoroalkyl Substances (PFAS) ATSDR, Agency for Toxic Substances and Disease Registry. Revised 12/6/19
[4] This is based on review of many research studies too numerous to list here in entirety. Among the most representative are the following: Arrieta-Cortes, Farias, Hoy-Vadillo, Kleiche-Dray. Carcinogenic risk of emerging persistent organic pollutant perfluorooctane Sulfonate (PFOS): A proposal of classification. Regulatory Toxicity and Pharmacology 83 (2017) 66-80, and Chang, Adami, Boffetta, Cole, Starr, Mandel. A critical review of perfluorooctanoate and perfluorooctanesulfonate exposure and cancer risk in humans. Critical Reviews in Toxicology, 44:sup1,1-81, DOI10.3109/10408444.2014.905767
