What was claimed
Blue surgical masks are sprayed with PTFE, which is harmful to humans.
Our verdict
Some masks contain PTFE, but ordinary surgical masks are often made from other materials. PTFE is not generally harmful to humans.
PTFE in masks does not pose a health risk, unless you get it very hot
What was claimed
PTFE in masks can lead to symptoms such as fever, chest tightness, shortness of breath, headache, cough, chills, sore throat.
Our verdict
This appears to be describing polymer fume fever, which only happens if someone is exposed to PTFE heated to high temperatures.
A post on Facebook has claimed that disposable masks are sprayed with Polytetrafluoroethylene (PTFE) - and that exposure to this can lead to symptoms including fever, chest tightness, shortness of breath, headache, cough, chills and a sore throat.
It is true that PTFE is used in some masks, but it is extremely unlikely to cause illness during normal use.
PTFE is found in items such as non-stick cookware, some clothing, and various medical instruments, and is most commonly associated with the brand name Teflon. However, the Teflon brand refers to a number of products, not all of which are PTFE, and not all PTFE is Teflon.
Blue surgical face masks, like the ones featured in the Facebook post, are most commonly made out of a different type of plastic called polypropylene rather than PTFE, although PTFE is used in the making of some reusable masks, and some disposable masks can have PTFE filters.
The post seems to be referring to the symptoms of polymer fume fever, which is a rare ailment caused by inhaling fumes from PTFE heated above 300 to 400 degrees Celsius, such as when a PTFE pan is overheated. Symptoms can resemble flu, like those in the post.
There is no evidence that anyone would suffer from this condition as a result of the normal wearing of a mask made with PTFE.
Correction 13 November 2020
A previous version of this article used PTFE and Teflon interchangeably which is not accurate as not all Teflon-branded products contain PTFE and not all PTFE is Teflon. The article has been updated to reflect this.
This article is part of our work fact checking potentially false pictures, videos and stories on Facebook. You can read more about this—and find out how to report Facebook content—here. For the purposes of that scheme, we’ve rated this claim as partly false because PTFE can only cause these symptoms if it is heated to a very high temperature.