The sprays and cloths designed to keep eyeglasses fog-free may come with more than people bargained for, new research suggests. A small study found that these products can carry high levels of per- and polyfluorinated alkyl substances (PFAS), a class of “forever chemicals” that are suspected of having subtle but negative effects on our health. The findings can’t show how harmful these products may be, but it’s possible that users may be getting exposed to much higher levels of PFAS than they would normally.
PFAS are abundant in the modern world and are often created as a manufacturing byproduct or when materials such as plastics begin to break down. Research has shown that PFAS are a type of endocrine-disrupting chemical, which can mimic and interfere with important hormones in our bodies; they may also mimic fatty acids. The exact level of danger posed by PFAS exposure is still being studied, but they’re thought to increase the risk of various health conditions, including cancer, high blood cholesterol, and reproductive problems.
What’s worse, PFAS do not easily degrade in the environment, meaning people are constantly exposed to them through one source or another. Studies continue to find PFAS showing up just about everywhere in our lives, such as in the water we drink and the air we breathe. And while there have been some efforts to cut down on PFAS use in recent years, this new research indicates that there are plenty of places left for them to crop up, including in the anti-fogging sprays and cloths used for eyewear.
Though these products have been around for a long while, they became more popular during the covid-19 pandemic, thanks to the wide use of face masks that can contribute to condensation on glasses. Researchers at Duke University and elsewhere conducted a test of nine popular brands of anti-fogging sprays and cloths sold through Amazon.
The team found levels of two specific PFAS—fluorotelomer alcohols (FTOHs) and fluorotelomer ethoxylates (FTEOs)—in all nine products. The sprays in particular had high concentrations, far above the levels deemed safe for consumption in drinking water, the researchers noted. The team’s findings were published in the journal Environmental Science & Technology Letters.
The authors point out that little research has been done to study the effects of FTOHs and FTEOs on humans specifically. And their small sample size means that any conclusions should be viewed with added caution. But it’s likely that most consumers don’t even know that PFAS can be found in these products.
Senior author Heather Stapleton, a professor of environmental chemistry and health at Duke, was apparently inspired to conduct the study only after she read the ingredients list on an anti-fog spray bought for her 9-year-old daughter. But none of the other products they tested even had their ingredients listed.
“Because of covid, more people than ever—including many medical professionals and other first-responders—are using these sprays and cloths to keep their glasses from fogging up when they wear masks or face shields,” said Stapleton in a statement from Duke University. “They deserve to know what’s in the products they’re using.”
The team says more research is needed to understand the potential risks of these products and the types of PFAS they carry, including animal studies. Future, larger studies could also better quantify other undisclosed chemicals that can be found in these sprays and cloths. In the meantime, it’s worth noting that at least some glasses fog can be reduced by simply improving the fit of your masks.