A new study has found that some face masks contain trace amounts of Per- and Polyfluoroalkyl Substances (PFAS). The study was published in Environmental Science & Technology Letters, an online-only peer-reviewed scientific journal that publishes brief research reports about topics in the field of environmental science and technology.

The study utilized mass spectrometry to test nine types of face masks for PFAS levels. The masks tested consisted of six cloth masks, one surgical mask, one N95 mask, and one heat-resistant firefighter’s mask. Graham Peaslee, a professor of physics and biochemistry at the University of Notre Dame, spoke about the results to E&E News, stating, “We didn’t really find a real smoking gun.” Professor Peaslee has spent years researching PFAS.

After comparing the mass spectrometry results to animal studies in order to determine the long-term health problems based on chronic exposure, researchers found eight of the nine masks tested did not exceed PFAS exposure levels that are considered safe. The exception to these results was the mask marketed to firefighters, which exceeded the safe dosage level when worn for 10 hours or more. PFAS is a common chemical used to make clothing and furniture fire-resistant.

According to the study, “These preliminary findings indicate that wearing masks treated with high levels of PFAS for extended periods of time can be a notable source of exposure and have the potential to pose a health risk.” The study also noted, however, “Despite modeled annual disposal of [approximately] 29–91 billion masks, and an assuming 100% leaching of individual PFAS into landfill leachate, mask disposal would contribute only an additional 6% of annual PFAS mass loads and less than 11 kg of PFAS discharged to U.S. wastewater.”

This means that although the trace amounts of PFAS in masks will contribute to the overall environmental presence of PFAS in the environment, it will not contribute more than 6% of all PFAS that is expected to be dumped into the environment. Environmental exposure is a concern for environmental researchers due to PFAS’ status as “forever chemicals” that don’t break down easily. 

Courtney Carignan, an exposure scientist and environmental epidemiologist who teaches at Michigan State University, completed the section of the study dedicated to exposure and risk assessment. According to her, “Exposures from masks are small compared to other pathways such as drinking water.” Carignan also emphasized the importance of using masks to control the spread of infectious diseases.

The study did note that exposure and risk appear higher for children and individuals who perform physical activity for extended periods of time while masked. Carignan supported these claims, noting that these factors increased the risk of inhalation exposure.

The news that PFAS are in some masks does not actually come as a complete shock to some. In July 2021, E&E News reported that PFAS were in some masks, with the company 3M Co. confirming the chemicals are used in certain face coverings. Trace amounts of PFAS were already a known quantity for certain masks and mask components, such as the headbands of some models of 3M’s N95 respirator masks. This contamination was due to processing aids.

PFAS is also an accidental contaminant in some masks. Since PFAS are present throughout the manufacturing facilities and in the environment, accidental exposure can occur. PFAS chemicals also appear in food and drinking water. 

The initial results of this study were first obtained in 2020. However, after the researchers found PFAS in some of the masks, they worried that the results would be weaponized to deter people from using masks to combat the spread of SARS-Cov-2.