Researcher Responds to Claims About PFAS, Firefighter PPE

Firefighter with PPE holding a hoseline

Dr. Graham F. Peaslee, professor of physics at the University of Notre Dame and lead researcher on a study about the health impacts of “forever chemicals” in firefighter turnout gear, offered his response to a release that ran on the FireRescue site. You can read Dr. Peaslee’s response to Fire Engineering Editor in Chief Bobby Halton in full below.


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Dear Bobby,

Thank-you for allowing me to respond to the criticisms raised in the opinion piece “Research and Independent Testing Shows Firefighters’ Turnout Gear Remains Safe Despite Claims” by Paul Chrostowski. First, I would encourage everybody to look up the author of any opinion piece that they read, to see who wrote it. In this case, the opinion’s author has two peer- reviewed publications since the year 2000, one on biosolids and one on pool shock, with 8 citations of that work. I could not find a single publication about PFAS ever before. He also states that he is being paid by Lion to write this piece. This means his contractor has a direct interest in what is being said in the piece.

My recent article is entitled almost the exact opposite: “Another Pathway for Firefighter Exposure to Per- and Polyfluoroalkyl Substances: Firefighter Textiles,” and it just appeared in the leading US environmental science journal, and your readers are welcome to look at my credentials on the web, as I have over 100 peer-reviewed publications since the year 2000, with more than 5,000 citations of that work, and about 20 of those publications concern PFAS. I was not paid by anybody to publish this article – I did the work because people I met in the fire services asked me to do so, and I felt it was important to remain independent.

As is typical in opinion pieces, lots of commonly accepted facts are stated, which are entirely correct, but then some erroneous conclusions are drawn from the stated facts – and it is often difficult for the reader to distinguish where fact and reasonable conjecture ends, and disinformation begins. The purpose of this rebuttal is to just point out a few of the mistakes in the logic as presented in this piece, and again, I would encourage all your readers simply to do their own fact checking – the internet is a wonderful resource and most scientific literature more than a year old is available freely on the web.

Starting at the beginning, the author implies that turnout gear has been subjected to “frequent independent study and found to contain only trace levels of PFOA”, and while the word frequent and independent are questionable, this statement is basically correct. The misinformation begins when it is stated that “these trace amounts of PFOA are not nearly enough to cause concern”. Whenever PFOA is identified at part-per-billion levels in textiles, and it is not part of the structural gear itself (as the author correctly states), then it is free to migrate off the gear. Any source of PFOA at a part per billion level is a very concerning source of this chemical directly linked to two forms of cancer and 4 other diseases in a court of law. More importantly, PFOA is only one of hundreds of PFAS (the general class of chemicals) that are routinely found on this gear, and the other PFAS are there in higher concentrations and may be more dangerous than PFOA when the clinical studies are all done. This statement is followed by the statement that PFOA is no longer used in the manufacture of this gear, which is another partial truth – Dupont agreed to phase out use of PFOA in manufacturing in 2012, but our research paper shows that the outer shell sheds long-chain PFAS that are known to decay into PFOA with exposure to sunlight and water, or within the bloodstream. Not only are a significant number of firefighters still wearing gear manufactured before 2014 or so when PFOA stopped being used, but we observed PFOA and lots of other PFAS in all gear – even the most recent unused gear because of this source of “precursor” PFAS – those longer chain PFAS that turn into PFOA. We don’t know how dangerous this source of PFAS will be to the firefighter, but minimizing the firefighter’s exposure to these chemicals seems like a precautionary approach until gear can be manufactured without PFAS at all.

The author then takes a swipe at me for working on this study for two years and not publishing it. This point is relatively moot now, because it was published in the Journal of Environmental Science and Technology on June 23 ( It is available for the world to see, and to replicate. The entire process of getting the gear, testing it in our lab, and then contracting independent commercial labs to confirm our hypotheses takes a lot of time. As does the peer review process. I should also mention that I have a day job to do as well as this unfunded study, so it took some time to publish. I apologize to the firefighters that it took so long, but I wanted to be very sure of these results before I recommend that we consider policies to reduce exposure to this source.

The next disinformation campaign in this piece comes straight from the chemical industry that makes PFAS, claiming that the short-chain PFAS that were found in high abundance in the gear (at the part per million level – a thousand times higher than the part per billion levels of PFOA) are perfectly safe. This claim is made based on the lifetime of the short-chain chemicals like PFBS in the human body compared to PFHxS or PFOS. It is true that PFBS generally lasts only weeks in the human body after exposure, while the C6 and C8 PFAS tend to last 3 – 6 years in the body on average. An exposure scientist could reasonably claim that this makes it hundreds of times “safer” than PFOA. But this is based on the idea of a single exposure. If you use AFFF foam once, and accidently get covered with it, then you will get an exposure that you may measure for years. But most civilian firefighters don’t use AFFF that often, so it will decay away in their bloodstream. However, if PFBS is used on the gear (which it is), and you wear your turnout gear every day (which you do), then you are potentially exposed to this toxin regularly – and there is no study out there than shows what chronic exposure to these chemicals does to a human. Again, the precautionary approach would be to say let’s minimize exposure until we can find gear that works without these chemicals in them.

The next opinion is a particularly brazen claim, given the current scientific literature – including the four articles referenced by the author himself. Firefighters have been studied many times, and they have been found to have elevated levels of PFAS in their blood, relative to comparison populations. Most of this has been attributed to AFFF use and exposure, which is probably a correct concern, but to say that “that firefighters are not exposed to PFAS at levels greater than control groups” is simply not supported by the current literature – including the author’s own cited references. For example, in his first reference, the C8 study found statistically significantly elevated PFHxS in the 37 firefighters in their study, two other PFAS were elevated as well (PFNA and PFOS), but with only 37 identified firefighters out of 69,000 subjects who drank PFAS contaminated water, it would be very hard to tease out any correlations – as the authors of that study suggest. However, these authors still say “The study suggests that fighting fires can be a risk of exposures to PFAAs, especially PFHxS.” These statements available on the C8Study website as well. The second study listed (Dobraca et al.) only found a 4% increase in PFOA for the 101 firefighters involved, but what was omitted from this result was the PFDA concentrations in firefighters were 3 times higher than the general population, which led to this concluding sentence in the same paper referenced in this opinion piece: “Firefighters may have unidentified sources of occupational exposure to perfluorinated chemicals.” Somehow this staggering conclusion was overlooked in trying to find studies where the PFOA isn’t significantly elevated. Similarly, the cohort study of 86 female fighter fighters in San Francisco found that “firefighters had higher geometric mean concentrations of PFAS compared to office workers” for PFHxS, PFUnDA, PFDA, and for firefighters compared to equipment drivers, PFOA was found to be elevated as well. The last reference is not peer reviewed yet, but already the website has this statement as a conclusion of the data: “PFAS levels in NCFF participants who were deployed to the Northern California fires were higher than those who were not deployed.” So all four articles which can be found online state that firefighters suffer higher PFAS concentrations in their blood than non-firefighters. There are others as well – but again – none can ascertain the source of the PFAS, and most likely AFFF use will be a primary exposure source. I would encourage your readers just to look at the publications –the abstracts and conclusions are very plainly written.

Lastly, the author of this opinion piece, makes the statement that “the connection between PFAS and cancer is extremely weak”, which is a very odd statement to make – considering that the C8 Study linked kidney cancer and testicular cancer to PFOA and PFOS with so much certainty that Dupont had to pay over $671M in settlement to 3500 claimants and admit in a court of law that this connection was valid. Indeed, this massive epidemiological study of 69,000 participants is the very reason C8 PFAS are no longer used in the US manufacturing processes directly. It is troubling to me that a form of C8 PFAS is still used on the outer shell to make fluoropolymers there. It is not technically PFOA when manufactured, so it is legal, but when it wears off in the atmosphere or gets sorbed into blood, it will turn into PFOA and this represents a threat to all firefighters. And again, while the animal and human studies have conflicting conclusions about which cancers are directly correlated with which PFAS – this is entirely normal in science until enough studies are done – the author neglected to mention the series of studies done by Philippe Grandjean and others that show than PFAS concentrations in blood are inversely related to the immune system health of the individual. This would explain a lot of inconsistency in the other cancer studies, because if the immune system is compromised due to the presence of PFAS in blood, then those individuals with genetic or environmental co-factors in their cancer risk may develop those opportunistic cancers more readily. In other immune suppressed populations (such as transplant patients) there are statistically higher levels of myeloma, leukemia and prostate cancer, the same diseases that plague the fire services.

We are not toxicologists, and cannot state that the gear has anything to do with the cancer rate among firefighters, but there is a wealth of published evidence out there that PFAS are insidious toxins in many ways, and their use to make turnout gear waterproof should be re- examined. I would argue that if we can make safer gear, why wouldn’t we do that? In the meantime, we can reduce our exposure risk – just as firefighters do already for combustion products- and work together to find the best alternatives for the future. Thank you for taking the time to read through this – I would be happy to answer questions at FDIC or any other forum.


Dr. Graham F. Peaslee
Professor of Physics

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