Fact check: Masks won’t give you lung cancer; some masks do include chemicals

The claim: The chemicals in your face mask are giving you lung cancer

As health officials around the country encourage mask-wearing to slow the spread of COVID-19, a Facebook post is claiming masks can give wearers cancer, according to USA Today.

“THAT MASK IS GIVING YOU LUNG CANCER,” reads the Oct. 15 Facebook post, written by Guy Crittenden. As a source, Crittenden cites his time as former editor of the Canadian trade publication HazMat Management, which in part focuses on issues related to occupational safety and waste management.

He also asserted his claims are backed up by “OSHA mask experts” Tammy Clark and Kristen Meghan, two women with backgrounds in environmental health and safety who appeared on anti-vaccine personality Del Bigtree’s webcast “The HighWire.” The two women spoke out against face masks, though notably did not address the supposed cancer-causing chemicals Crittenden’s post mentions. Bigtree has used his program to push various COVID-related conspiracy theories.

Crittenden’s post been shared across a number of platforms, with Pennsylvania State Rep. Russ Diamond sharing a link to it via The Human News Network, a website that claims to “carry the load vacated by the Fake Media.”

Crittenden claims wearing masks causes oxygen deprivation (experts say it doesn’t) and that chemicals used on masks will give wearers cancer.

Masks won’t lead to lung cancer. But USA Today found that other claims about chemicals and face masks may be true but require some context.

Ethylene oxide used to sterilize masks?

One of the chemicals Crittenden mentions is ethylene oxide, a “known carcinogen” he claims is used to sterilize surgical masks.

According to the World Health Organization, ethylene oxide is a “potent neurotoxin, a known human carcinogen, a potential reproductive hazard, and an allergic sensitizer” that can cause health problems with acute overexposure and chronic exposure. Lymphoma and leukemia are the cancers most commonly linked to occupational exposure to ethylene oxide, although stomach and breast cancers may also be associated, according to the National Cancer Institute.

At the same time, “ethylene oxide sterilization is an important sterilization method that manufacturers widely use to keep medical devices safe,” according to the U.S. Food and Drug Administration. Ethylene oxide may sometimes be the only method of effectively sterilizing equipment that would otherwise be damaged in other sterilization processes, the FDA notes.

About 50% of all sterile medical devices in the U.S. are sterilized with ethylene oxide, according to the FDA. The FDA encourages medical device makers to follow consensus standards to ensure residual levels of ethylene oxide are within safe limits.

There are a limited number of online listings where manufacturers claim their masks are sterilized with ethylene oxide, also known as oxirane. However, according to the FDA, face masks sold to consumers (including cloth masks) are generally not sold as sterile, and surgical masks are not typically provided as sterile.

When surgical masks are sold for use by health care professionals, they may sometimes be packaged in bulk for terminal sterilization — when products are sterilized in their final packaging — and will be labeled as sterile, the spokesperson explained. If sterilized, face masks or surgical masks would likely be sterilized using ethylene oxide.

As with other medical devices sterilized using ethylene oxide, FDA guidance helps ensure any remaining levels are within safe limits.

Early on in the pandemic, Illinois-based medical supplies manufacturer and distributor Medline Industries sought FDA approval to resterilize used masks using ethylene oxide. Crucially, however OSHA recommends against using ethylene oxide for resterilizing single-use filtering face piece respirators — masks like N95s — due to risks associated with the chemical. 3M, which manufactures masks and personal protective equipment, also warns against using ethylene oxide to decontaminate masks because wearers could breathe in residual amounts.

We rate this claim as PARTLY FALSE, based on our research. It is false to state that a mask will give its wearer lung cancer. Crittenden correctly states some masks include PTFE, but misleads readers about potential health risks associated with this material, especially when it comes to chemicals remaining in the finished product. Similarly, ethylene oxide is a known carcinogen, but it’s not used to sterilize masks as widely as the original post claims.