We’ve come across several posts on social media about N95 masks, claiming that a new study has proven they cause cancer.

The origin of this claim can be traced to a Daily Mail article posted on 27 August, which has been shared on social media platforms such as Twitter across the past week.  The Daily Mail article headline claims that a study “published by NIH” (the National Health Institute) links N95 Covid masks with “toxic compounds linked to seizures and cancer.” It further ponders if mask wearing could “make newly instated mask mandates ineffective.” 

We took a look at the original study and found a number of discrepancies. The study, carried out by researchers from Jeongbuk National University in South Korea, was published in the Journal of Ecotoxicology and Environmental Safety and is listed in (rather than published and endorsed by) the NIH database. It set out to study face masks to assess the health risk of compounds produced during the mask manufacturing process.

These compounds are known as Volatile Organic Compounds (VOCs); a varied group of man-made chemical compounds used and produced during the manufacturing process of paints, pharmaceuticals, and refrigerants. VOCs can produce short-term reactions such as eye irritation or after long-term exposure might increase the risk of liver damage or cancer.

The Korean study measured the Total VOC (TVOC) levels in 14 different face masks, finding the highest levels of VOCs in KF94 face masks (represented by B1 and B3 in the chart below). Unlike the circulating claims, N95 masks were not specifically tested – rather, N95s are “functionally equivalent” to KF94s while having different material compositions.

While the author acknowledges this later in the article, framing the headline around N95 masks is inaccurate. Further, as pointed out by Health Feedback, the Daily Mail article mistakenly describes TVOCs as Toxic VOCs rather than Total VOCs – an error that adds a different, much more negative connotation for readers. At the time of writing, this mistake has not been corrected.

The original study did find that two KF94 masks had high-risk TVOC levels based on standards set by the German Environment Agency. However, it also re-tested TVOC levels after the masks were removed from packaging and allowed to sit in air for 30 minutes, finding that the levels fell to a safe range.

Notably, the article fails to include that the study looked further at specifically hazardous VOCs in the masks, finding that those levels were “nearly 100–1000 times less than the recommended exposure limit set by the U.S. National Institute for Occupational Safety and Health.” This omission further skews how the study was reported and subsequently interpreted by readers.

So, has a new study shown that N95 masks cause cancer? The study did not claim to prove N95 masks cause cancer. Instead, it is a small-scale study that, based on their findings, recommended further research and that KF94 masks be aired out before usage. Testing was also not carried out on the direct impacts on mask-users. While it is true that health risks associated with VOCs exist and cannot be ruled out, the framing of the study’s results is highly misleading, with some information omitted and misreported.

We therefore give this a rating of likely false – Several elements of the claim are based on misleading information, rendering it inaccurate. However, questions have been raised by a study about the levels of VOCs in certain masks.

The Daily Mail article specifically paired this study with a discussion on the “mask mandate,” linking the possibility of VOC exposure with the idea that masks might do more harm than good. The way in which the study was reported seems to support this view, potentially pushing an agenda rather than providing complete information for readers who want to make decisions about mask-usage.