The blue typical mask depicted in the photograph contain Teflon and other chemicals. A Facebook friend reminds us: 1. Masks are “sterilized” with Ethylene Oxide — a known carcinogen. Many teachers in various school boards have been experiencing significant symptoms as a direct result of the effects of this chemical. 2. The masks contain (not sprayed with) PTFE which makes up Teflon along with other chemicals. I found and have posted the US patent to allow manufacturers to use PTFE as a filter in commercial masks… “breathing these for extended periods can lead to lung cancer.”