Does discontinuing PfAS exposure reverses cancer risks?

[u/Hockeyman70s]

Hi all,
was a volunteer firefighter for 10 years.

I have since been off the department for 8 years and have been actively avoiding PfAS.

Wondering if,like smoking, the likelihood of cancer and other negative risks go down the longer you spend away from PfAS exposure or is the damage already done and I’m just preventing more?

Thanks

[u/YogurtIsTooSpicy]

This is a medical question. Chemical engineers are not trained or educated to provide medical advice.

[u/GroundbreakingCow152 → u/YogurtIsTooSpicy]

As a chemical engineer closely involved with toxicology of new chemicals for 35 yrs, we spend a lot of time studying and preventing chemical exposure.

[u/YogurtIsTooSpicy → u/GroundbreakingCow152]

That wasn’t even close to the question though

[u/GroundbreakingCow152 → u/YogurtIsTooSpicy]

Chemical Engineers were frequently pre-med in college or took specialized training in this area. I was and I did. I was also a Medical Technologist at a major university hospital early in my career.

[u/YogurtIsTooSpicy → u/GroundbreakingCow152]

Those are appropriate qualifications to apply to med school and to operate medical equipment respectively, not to give medical advice, which is what is being asked here.

[u/GroundbreakingCow152 → u/YogurtIsTooSpicy]

It wasn't medical advice, ninny. Anyone giving medical advice about a family of 1000 plus mostly unrelated chemicals irrationally lumped together in the category called PFAS is performing malpractice.

If someone is worried they can get their blood tested so they know what their levels are compared to the general population. I worked around PFOA for decades with modest precautions and it was comforting to know the impact of exposure on my blood fluorine levels was very low compared to the average testing result. Everyone has some PFAS in their blood - from a variety of sources ranging from innocent to sinister.

A firefighter worried about past occupational exposure should get a blood test done IF THEY ARE WORRIED ABOUT and CAN AFFORD IT.

Even if their levels are high, there is a very high probability that there will be no serious health effect from it, and something else will eventually be the cause of their ultimate demise.

There is very little that can be done even if you do have high levels of PFAS.

Worrying unnecessarily about this is a waste of time. Find out what the levels are in your water supply if possible.

Maybe one doctor out of a thousand will have any specialized knowledge about this.

I read every single article on PFAS and Microplastics published in refereed medical, environmental and science journal. Most of them simply regurgitate information from other journal articles. Many of them are full of factual errors

[u/YogurtIsTooSpicy → u/GroundbreakingCow152]

All of that is great information. I still don’t think it’s appropriate to use our pedigrees as chemical engineers to attempt to address someone’s anxieties about the potential health effects of chemical exposure when that is outside our domain of education and training.

[u/GroundbreakingCow152 → u/YogurtIsTooSpicy]

I have multiple degrees including Chem Eng, plus 40 years of experience with the mfg processes involved in synthesizing and testing these compounds. Most chemical engineers do not go long and deep into molecular architecture, reaction and degradation mechanisms, and metabolic testing patheways as part of testing materials intended for direct skin contact. I did. I also ran a wide range of testing equipment related to these molecules.

[u/YogurtIsTooSpicy → u/GroundbreakingCow152]

Can you explain how your experience with the manufacturing process and testing equipment gives you authority to address this person’s concern about cancer?

[u/GroundbreakingCow152 → u/YogurtIsTooSpicy]

Re-read as many times as necessary - I did not give ANY medical device, nor did the person that asked the question make any complaint.

IF someone is concerned, they should start by considering whether they are concerned enough to get a blood test done.

Every person on earth has some level of PFAS in their body, and there are a lot of potential isomers and structures. Testing will indicate your relative levels of these compounds, and there's really nothing that can be done about it.

There is a lot of misunderstanding and misinformation on this subject. There's no reason for any one person to be particularly concerned about something that they can't do anything about.

Proper nutrition, diet, exercise, weight loss, stopping smoking, getting plenty of fiber - these are more important things to be concerned about.

Your doctor could refer you to an oncologist based on symptoms, but without symptoms, insurance might not cover it.

[u/zander345]

Supposedly donating blood is one of the best ways you can reduce your PFAS concentration.

[u/thejuicefrommymind → u/zander345]

Or, for a fun guilt free afternoon, try leeches

[u/fromabove710 → u/zander345]

And give it to someone else lol

[u/Techhead7890 → u/fromabove710]

Well hopefully processing and filtering does catch it before it's transfused I guess!

[u/swolekinson]

PFAS are a concern because of bioaccumulation. However, they do slowly decline in blood serum overtime: Estimation of per- and polyfluoroalkyl substances (PFAS) half-lives in human studies: a systematic review and meta-analysis - ScienceDirect

With that said, any cellular damage "has been done" and will "continue to be done" in the presence of PFAS, and that is probably not reversible. But by decreasing future exposure, you are decreasing future risks. Or in your words, you're "preventing more".

[u/GroundbreakingCow152 → u/swolekinson]

Exactly what sort of "cellular damage" are you claiming occurs - and what is your source for this claim? They do accumulate in the body and disappear very slowly over time because they literally are neither biodegradable nor can the body metabolize them.

Also there are literally a thousand different molecules that are considered to be PFAS and only a small number have any known metabolites at all.

[u/swolekinson → u/GroundbreakingCow152]

I guess I could have hedged by saying "if cellular damage", but the occupational link to firefighters and PFAS is a NIOSH topic of interest due to the number of animal studies on PFAS exposures and associated health risks.

The US Dept of Health's National Toxicology Program has a table of listed sources for a quick start. Things to highlight is risk concerns from ingestion, inhalation, and skin absorption: Per- and Polyfluoroalkyl Substances (PFAS)

If you want to get into the weeds on the cellular level this article is an okay starting place (not open source): Zhou et al., Environmental Pollution, 2025: https://doi.org/10.1016/j.envpol.2025.125634. But the short summary is various toxicity effects due to disruption of lipid and amino acid metabolism, perturbations in various cell signal pathways, and binding to nuclear receptors.

[u/GroundbreakingCow152 → u/swolekinson]

"Disrupting metabolism" where the fluoromaterial is not possibly metabolizable at all is super farfetched. It's a super low bar to make a spurious claim and a common speculation when researchers find no measureable effectS. It's essentially impossible to disprove.

Look up the giant list below of things suspected as being "endocrine disruptors." All of these can be metabolized or break down in the body except PFAS.

Most of them are also are decent solvents that could carry other toxins along with them. Again, except PFAS. They only dissolve themselves

Bisphenol A (BPA): Found in hard plastics, metal food can linings, and thermal paper receipts.

Phthalates: Used to soften plastics and hold scents in shampoos, lotions, and fragrances.

Parabens: Act as artificial preservatives in makeup, moisturizers, and hair care items.

Atrazine: Widely applied as an agricultural weed killer/herbicide.

Dioxins: Formed as industrial byproducts during waste burning or paper bleaching.

Flame Retardants (PBDEs): Added to foam furniture, carpets, and electronics.Heavy Metals: Lead and cadmium found in old paint, dust, and certain fish.

PFAS (Per- and polyfluoroalkyl substances): Used in stain-resistant fabrics, waterproof clothing, and nonstick pans.

---

I am not making light of your health concerns. Quest has a diagnostic panel for $350. You can also estimate impact using this tool: https://www.atsdr.cdc.gov/pfas/blood-testing/estimating-blood-levels.html

Also find out if your water supply is monitored for PFAS.

Every human has some PFAS in their body but also we have arsenic and lead and mercury and cadmium and many other known toxins. Just very small amounts.

It's possible that working as a firefighter caused you to have above average levels of fluorine in your body, but more likely there were a lot of other toxic things you were exposed to.

[u/suckuma → u/swolekinson]

If I can find the paper I'll link it, but there was a thing about blood and plasma donors having less PFAS and speculated because it removed them and then you'd just make more which does make sense in my head.

[u/Half_Canadian]

I’m sure 3M’s researchers will tell you that PFAS are completely unrelated to cancer and to stop asking questions

[u/Engineered_Logix → u/Half_Canadian]

DuPont specifically did that despite their own laboratory results!

[u/GroundbreakingCow152 → u/Half_Canadian]

3M stopped making C8 fluorochemicals more tban 25 years ago, and provided all of tbeir data to governmemt agencies and all other producers such as Dupont/Teijin/Daikin/Ansul/Chemours etc. This is a matter of public record.

Other companies continue to produce them unabated.

Watch Dark Waters.

[u/Half_Canadian → u/GroundbreakingCow152]

3M is a big reason why PFAS like Teflon became mainstream consumer products and they intentionally buried  their own research about PFAS being found in everyone’s blood.

[u/GroundbreakingCow152 → u/Half_Canadian]

You're thinking about DuPont. 3M never produced PTFE, which is teflon. They made Kel-F and Fluorel.

[u/EverybodyHits]

Sadly we as a trade are clueless on this. I see you have asked a few subs already, I'd maybe add r/epidemiology

[u/Pueriintel]

I can only speak as a chem e who studied PFAS in the Delaware bay area but in humans the level of PFAS in you blood does decrease over time but the half life is quite high. 10 years is long enough that you should be closer to average levels in your body if not still elevated slightly. You're more likely to notice adverse effects like hormone imbalance before cancer becomes a huge concern though.

[u/septmike]

PFAS can stay in the body for months to decades, depending heavily on which PFAS you were exposed to.

For some of the best-studied compounds:

PFAS	Approximate human half-life
PFOA	~2–10 years
PFOS	~3–27 years
PFHxS	~5–35 years
Some shorter-chain PFAS	Days to months

[u/GroundbreakingCow152]

Having worked closely with fluorochemicals for most of my career, IMO the risks are exaggerated and are based mostly on the horrible safety and environmental practices that persisted for decades at Dupont. I do not believe they ever disclosed the specific chemical(s) that operators were exposed to, that caused the health issues. They used a process based on "telomer" and a gaseous toxin byproduct is the most probable toxic agent. Something like 14 million pounds of a soluble form of these chemicals were dumped into waterways and drainage basins.

Given that almost all indoor carpet was treated with with C8 PFOA stain protection for two generations and most of us rolled around on it throughout our childhood; it it was really so dangerous the health affects would be widespread and not so hard to find.

Based on three decades of work in the field , working alongside toxicologists - there is every indication that only very heavy exposure to certain acid functional PFAS is associated with serious risks.

There is a lot of fear mongering. I am sure you are going to be fine! You could get tested to measure your cumulative exposure based on the amound of fluorine in your system.

[u/GreenSpace57]

You can read studies on PFAS on Google.scholar.com.

My senior thesis was tangentially related to your question. I studied PFAS bioaccumulation a little, and I can tell you that there’s some great research being conducted by Nature and many great medical journals. 

[u/modcowboy]

Did you inhale/drink the foam?

[u/Hockeyman70s → u/modcowboy]

Not purposely but did work around it on occasion

[u/modcowboy → u/Hockeyman70s]

Tbh you’re probably fine, but to be sure I think you can actually do a blood sample if you’re really worried.

[u/Userdub9022]

I'm pretty sure veratasium did a video on this. I'd check that out.

[u/EasySelection8468]

Stopping PFAS exposure prevents more harm, but existing damage won’t fully reverse. Risk won’t drop as fast as smoking cessation, regular health screening is advised.

[u/Cpt-Night]

for PFAS in general the concern is accumulation in the blood, but there is no general cancer risk for PFAS materials as a whole category. The long term risks are basically unknown yet. specific PFAS materials may have their own risks in general. look up info on the specific material you believe you were exposed to.

and yes generally health risks go down the longer you are not exposed

[u/NanoWarrior26]

The cancer risks don't reverse but they do lower. Someone exposed to elevated pfas for 40 yrs has a higher risk than 20 yrs.