I've got a few DMs overnight asking about PFAs in masks, and so rather than discuss it all in private, here's my thoughts.

In short:

Yes. Some masks will test positive for PFAs.

No. I don't think it's a big concern.

Here's why. The spreadsheet going around about 3M products, at least the version I've seen, absolutely does list the Aura and some of their filters for some of their reusable masks like the 6503, which I own and use, but in extremely tiny amounts. A cup of water from your sink, unfiltered, probably has more than your mask.

You're, probably, talking tiny amounts that are due to manufacturing. Do I trust 3M about that? No. From professional and personal experience I wouldn't trust 3M if they told me the sky was blue. Don't trust them about anything. Would it surprise me if I later found out that they soaked the Aura in PFAs for a week to make sure it didn't get wet? No. There are some true believers in PFAs in that company who think they're the greatest thing and should be on everything. Do I think that's what's going on? No.

If I found out that they did, in fact, soak them, would I avoid them? Of course. But that doesn't mean you stop masking. Even if EVERY mask in the world tested positive for PFAs, I'd pick my poison and mask up when I needed to.

But, really, manufacturing is a real problem for trace amounts of PFAs. They're everywhere. I once knew a guy who fixed manufacturing machines. He worked for a big company and had a multi-state region where he just travelled around and fixed machines on manufacturing lines when they went down. Back before people worried about PFAs much, he had an SOP he followed, and the last step on most things was to spray the parts he replaced down with a PFA spray. Why? Because it kept grease out of the product on the line. Everything coming off of those manufacturing lines would have some trace of PFAs on them, even though the company who was responsible for the products had no idea.

This hasn't really gotten any better since. Supply chains are absolutely riddled with PFAs. Even companies trying their absolute best have very little control over it in the end.

The paper that's often cited about masks and PFAs is the following, and I believe it's really the only one.

https://pubs.acs.org/doi/10.1021/acs.estlett.2c00019

What you have to realize about this is that if you dig into the supplementary info, there was *some* PFA contamination on the N95 they tested. But the vast majority of it was on "RC-1" through "RC-6", and "FF". RC here stands for reusable cloth, and the FF is a mask designed for, and marketed to, firefighters.

Let's deal with the firefighter's one first. Firefighters are, unfortunately, laden with PFAs. Firefighting foams for Class B fires are basically PFA foams. While they're being phased out, they still exist. Firefighting equipment then is often soaked in PFAs. I assume the mask in the study for firefighters is soaked in PFAs for some fire resistance.

Now, the reusable cloth masks. I hope no one's using those today. But, let's stop and think this through for a moment. If cloth masks have PFAs, what does that say about my clothes? I hate to tell you, but, a lot of clothes have PFAs.

Yes, so does bedding. Carpets. Paints. The seats in your car.

I've had a series of revelations in my life through my research. In the 90's and the following decades I removed everything that I could that off gassed VOCs. Then I removed plastics. Then I got rid of everything that I could find that had PFAs.

Proportionally, the first two weren't that hard. PFAs are damn near impossible.

So what do you really need to focus on? *Not ingesting them*. I think that's intuitively clear. Sure, you don't want to touch poison, but you REALLY don't want to pour a glass of it and drink it, right?

In order of most important:

Clean your water. I think I've discussed this ad nauseam and everyone's probably tired of it.

Remove it from your food sources. Yes, the FDA banned it from food packaging in February, but that doesn't take effect until around 2026. When I worked in the national lab system you know what we called that? Not today's problem. Because anything that was funded or unfunded during the next presidential administration was just as likely to happen as not happen in the end.

Look out for cosmetics. If not ingesting it is the main goal, not rubbing it on yourself everyday is the next goal.