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Comment by Phlarp | Hacker News Reader

https://www.semi.org/en/blogs/semi-news/fluorinated-chemical...

Big tech has a big PFA problem

Those at least can be contained, and hopefully reused, but at least disposed of properly.

Ski Wax PFA is much worse. https://www.sciencedirect.com/science/article/pii/S004565352... those are just left to be shed in the snow, and they don't vanish once they are in the snow.

Also a lot of lubricants in bicycle gear and some rainproof gear uses PFAS, which is again slowly rubbing off onto your skin or going airbone.

GORE-TEX materials had a PFAS problem but have been PFAS-free since 2012 or 2014 or so, if I recall correctly.

The Gore-Tex membrane itself is apparently(?) PFAS-free since some years, however Gore-Tex materials usually have a second waterproofing treatment (a surface coating called DWR, durable water repellent) which, drumroll, contains PFAS. Cheeky buggers, convincing people they had solved the problem years ago. ;)

Apparently they have some improvement in the pipeline that will bring about really PFAS-free product in the next few years or so. https://saferchemicals.org/2021/09/30/gore-tex-manufacturer-...

Ah shit. Thanks for the link - good to know.

Cheeky buggers indeed haha

PFAS-free usually means PFAS-lookalike AFAIK.

Same as the plastics marketing with the "BPA free" claim, they will just use some other Bisphenol and call it a day.

It's sad because PTFE is the best dry lubricant but you can get close with Tungsten Disulfide nanoparticles. Hexagonal boron nitride is a good bicycle lubricant additive too and it can actually photocatalytically degrade environmental PFAS!

https://ceramics.org/ceramic-tech-today/ceramic-video/video-...

Tungsten disulfide is enormously more toxic than PTFE. Nanoparticles of anything are usually toxic. Boron nitride might be as nontoxic as PTFE but I wouldn't bet on it.

I have not seen any evidence showing tungsten disulfide is toxic for either people or the environment in general

Its toxicity isn't well characterized, and isn't especially high, but you can generally assume that metal sulfides with access to water produce either hydrogen sulfide, sulfuric acid, or both. In the case of tungsten disulfide it seems to be sulfuric acid, though the reaction is poorly characterized. Sulfate as such is pretty nontoxic (though it does cause diarrhea) but it doesn't take very much sulfuric acid to lower the pH to fatal levels.

I think you might be giving PTFE a stronger pass than it merits.

That's always possible, but why do you think so? The list of materials considered biocompatible enough for implants is pretty short, and PTFE is on that list.

> The list of materials considered biocompatible enough for implants is pretty short, and PTFE is on that list.

Not to stray from the main discussion but biocompatible has a pretty narrow scope.

Time effects are not always fully captured, it often boils down to quite literally "we injected this stuff in 50x bunnies' bloodstream or implanted under their derme and none of them died after a month".

With any new substance a cautionary principle should be applied, the main issue is Industry is spitting out new substances faster than we can meaningfully study them.

It would be possible for your comment to be farther from the truth, but it would take significant effort. It is incorrect to a degree that demonstrates malicious disregard for the truth, and since it pertains to health risks, people who were to rely on it would be putting their health at risk. You should not have posted it.

https://www.fda.gov/medical-devices/biocompatibility-assessm...

https://www.fda.gov/medical-devices/science-and-research-med...

https://www.fda.gov/media/158495/download

I am not sure what was so out of line about my comment. The safety profile you link to itself refers to animal studies.

That profile now looks very complete but before we had all those RCTs and clinical surveilance data, someone had to make a decision on wheather or not we can use PTFE in vascular stents _for_humans_. That decision would have relied on initial animal tests (i.e.literally sticking this stuff in bunnies) and some limited trial data.

My point is not that FDA are somehow clueless bureaucrats but that everytime we introduce a new substances we are taking an educated risk based on limited (animal) data.

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