So-called “anti-fog” products are very useful for people wearing both a mask and goggles to prevent condensation. Faced with this growing craze linked to the COVID-19 pandemic, researchers from Duke University wanted to know if these products sold in the form of spray or wipes contain substances harmful to health. Bad news: these can contain high levels of per- and polyfluoroalkyl substances (PFAS, English per- and polyfluoroalkyl substances) according to their study published in the journal Environmental Science & Technology. The latter constitute a large chemical class of synthetic organofluorine compounds.
The researchers tested the four anti-fog sprays and five top-rated anti-fog wipes on the Amazon site, and found that all nine products contained fluorinated telomeric alcohols (FTOH) and fluorinated telomeric ethoxylates (FTEO), two types of PFAS. However, exposure to certain PFAS, in particular l’acide perfluorooctanoïque (PFOA) and perfluorooctanesulfonic acid (PFOS), is associated with impaired immune function, cancers, thyroid disorders and other health disorders. Pregnant women and young children are particularly at risk from these products, which can affect reproductive health and developmental.
Little studied substances harmful to humans
“Our tests show that the sprays contain up to 20.7 milligrams of PFAS per milliliter of solution, a fairly high concentration. Explains Nicholas Herkert, who led the study. Since FTOHs and FTEOs have been the subject of relatively few studies to date, scientists do not yet know what specific health risks these could pose. But they assume that once the FTOH inhaled or absorbed through the skin, these substances can break down in the body into perfluorooctanoic acid (PFOA) or other types of PFAS known to be toxic. The scientific team was particularly interested the possible effects of OETF.
It turns out that the results showed significant toxicity for cell modification and conversion to fat cells in laboratory tests. “If we were to assume that FTOHs and FTEOs have similar toxicity to PFOA and PFOS, one spray would expose you to PFAS at higher levels than you would receive.” while drinking a liter of water which contains PFAS at the current limit for safe consumption in the country, which is 70 nanograms per liter, ”adds Nicholas Herkert. “It is disturbing to think that the products that people use to insure their safety during the pandemic may put them at different risk. “
What about other chemicals?
The risk is all the more important as certain products require spray on glasses then rubbing with the fingers to make it penetrate. The researchers also deplore the fact that for none of the products analyzed, the list of ingredients is not readily available to see if they actually contain chemical products potentially harmful. This required analyzing them in the laboratory using a technique called “high resolution mass spectrometry”. Due to the small size of the samples tested, they call for additional research on this subject in order to flesh out these initial conclusions, in particular with tests on living organisms.
« Les FTOH et FTEO could be endocrine disruptors, but the only way to find out is to do in vivo tests on whole organisms. We only performed laboratory tests. », Says Nicholas Herkert. Studies with larger samples would also identify other “hidden” chemicals also contained in these sprays or cloths with anti-fog effects. “Due to COVID, many more people are using these sprays and cloths to keep their glasses from fogging up when wearing masks. They deserve to know what’s in the products they use. “, The researchers conclude.