Anti-fog products have become more popular than ever during the pandemic, when more than just people wearing glasses—or engaging in sports like swimming, skiing, or scuba diving—have been using them regularly, particularly for face shields in healthcare settings. But a new study finds that the most popular anti-fog sprays and solutions contain per- and polyfluorinated alkyl substances (PFAS), a class of chemicals scientists are still examining to learn about potential effects on human health. The researchers tested four top-rated anti-fog sprays and five anti-fog cloths, and they identified fluorotelomer alcohols (FTOHs) and fluorotelomer ethoxylates (FTEOs) in all nine products. 

Two different PFAS compounds—perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS)—have already been linked in observational studies to various health conditions, including cancer, thyroid disease, and impaired immune function. But scientists don’t know as much about FTOHs and FTEOs. The smallest concentration of total organic fluorine found in the products tested was 190 micrograms per milliliter in the sprays and 44,200 micrograms per gram of cloth. On the high end, one spray contained 20,700 mg/mL, and a cloth had 131,500 mg/mL. 

The problem is that scientists aren’t sure yet what this means. Are these sprays and cloths dangerous to use? Not necessarily. Could extended exposure over time build up to a dose that could contribute to health problems? We don’t know because we have little data on them, but it’s not impossible. We know it’s possible to reduce your exposure to PFAS in the environment, so here’s some additional information on these chemicals and how to minimize your exposure.

‍What Exactly Are PFAS?

Without getting into the nitty gritty chemistry, these are a group of more than 5,000 different manufactured organic chemicals. They’re used in more products than you can imagine: non-stick cookware (like Teflon pans), stain protection products for clothing, fast food wrappers, microwave popcorn bags, firefighting foams, waterproof jackets, water-repelling carpet sprays, and a long list of personal care products, such as waterproof mascaras, eyeliners, sunscreens, shampoos, and shaving creams. 

In short, they’re impossible to completely escape in our everyday lives unless you’re living off the land in a cave, and the CDC has already identified that about 95% of the US population has four specific PFAS: PFOS, PFOA, perfluorohexane sulfonic acid (PFHxS), and perfluorononanoic acid (PFNA). The problem is that these compounds stick around for a long time. PFAS don’t break down in the environment; they can last for decades in both the environment and your body. Despite all the products they’re found in, the most common way they get into our bodies is through drinking water. But food packaging, cookwar‍

What Do We Know About the Health Effects From PFAS?

We have the most data on PFOS and PFOA, two found in nearly everyone in the US. Both have been linked to health issues but are no longer used because of what we’ve learned about them. Most PFAS, however, haven’t been studied enough, and scientists don’t even have ways of detecting all of them. It’s difficult to conduct studies identifying what chemicals are linked to specific health conditions without interference from everything else we’re exposed to. The CDC has collected much of the research on PFAS health effects here. 

Among the conditions linked to PFAS are kidney and testicular cancer, impaired liver function, impaired fertility, chronic intestinal inflammation, thyroid interference, prenatal hypertension and potentially preeclampsia, high cholesterol, impaired fetal development, and weakened immune system. That’s a scary list—but the evidence isn’t clear on whether PFAS cause all these issues or, if they do contribute to them, what levels are required to cause harm. 

Frustratingly, the Environmental Protection Agency doesn’t require polluters, such as manufacturers making products containing PFAS, to notify communities when PFAS are left in the environment. The EPA’s rules on manufacturing with PFAS also don’t require listing them as an ingredient if they’re in low levels or simply byproducts of the manufacturing. 

‍How Can I Reduce My Exposure?

Again, it’s impossible to avoid PFAS completely, and we don’t know how many might be harmful or in what amounts, so obsessing over them will only cause anxiety. There are, however, small changes you can make to your environment to at least reduce how much you’re exposed to them, including the ones we don’t even know much about:

• Use glass or ceramic containers for leftovers instead of plastic.

• Use cookware that does not have non-stick technologies.

• Drink your coffee or water from a ceramic- or glass-lined tumbler or a metal tumbler instead of a plastic one.

• Replace flexible plastic items you use in the kitchen with silicone ones instead.

• Cook as much as possible with fresh foods rather than processed foods stored in plastic packaging. 

• Avoid fast food, especially fast food that’s wrapped and/or greasy (such as burgers), as much as possible. 

• If you do go for fast food, seek out the places that have pledged to remove PFAS from their food packaging, which includes Sweetgreen, Chipotle, Taco Bell, and grocer Ahold Delhaize (owners of Food Lion, Giant, Hannaford, Martin’s, and Stop & Shop) so far. 

• Use waterproof materials and products as little as possible, particularly cosmetics and other personal care products. Product labels that list “fluoro” in the ingredients have PFAS. (Even some dental floss contains PFAS, though we don’t know if they’re harmful or how much.)