An image shared on Facebook claims wearing a face mask causes cancer due to oxygen deficiency and an imbalance in the body’s pH levels.

Verdict: False

Public health experts have debunked the claim that masks cause cancer. They also say that masks do not cause oxygen deficiency or alter the body’s pH levels.

Fact Check:

The Centers of Disease Control and Prevention (CDC) advises people wear cloth face coverings in public settings to help curb the spread of COVID-19, the disease caused by the new coronavirus. Misinformation about face coverings has circulated widely on social media during the COVID-19 pandemic.

The American Lung Association (ALA) stated in a blog post addressing false claims about masks that “masks are designed to be breathed through and there is no evidence that low oxygen levels occur.” The University of Maryland Medical System similarly concluded that properly fitted masks offer enough airflow to prevent carbon dioxide from getting trapped under the cloth.  (RELATED: Viral Post Claims People Can Contract Legionnaires’ Disease From Wearing Face Masks)

The image attempts to link the claim that masks cause cancer to Otto Heinrich Warburg, a German scientist who won the Nobel Prize in 1931 for his research on cancer cells. His work on the metabolism of cancer cells, later named the “Warburg Effect,” found that “cells turn into cancer cells by switching from respiration to fermentation,” which can happen “if the enzymatic machinery required for respiration is damaged or respiration is not possible due to a lack of oxygen,” according to the Lindau Nobel Laureate Meetings website.

Public health experts at the Meedan Digital Health Lab also dismissed the claim that wearing a face mask can cause cancer due to oxygen deficiency or a pH imbalance. “Because of how tiny oxygen and carbon dioxide molecules are, face masks neither decrease the amount of oxygen that enters a mask nor increase the amount of carbon dioxide that stays in a mask,” the expert analysis reads. “As a result, face masks do not disrupt the body’s pH levels, affect the bloodstream, or alter one’s body in any way that would put someone at higher risk of cancer.”

Health care workers have worn masks for extended periods of time both during and prior to the COVID-19 pandemic with no documented adverse health reactions, according to Mayo Clinic family medicine expert Dr. Kimberly Frodl.