Sterilization-grade masks do not contain carcinogens, only that the sterilization process involves the participation of ethylene oxide, but masks produced by regular manufacturers generally do not contain carcinogens. The so-called claim that the masks have carcinogens mainly refers to the fact that the masks are sterilized with ethylene oxide, which is a carcinogen, hence such a claim. However, generally after the use of ethylene oxide sterilization, the masks will be air-dried, due to its own volatility is large, so the possibility of still having a large amount of excessive ethylene oxide after air-drying is relatively small. Secondly, if you buy sterilization masks produced by regular manufacturers, you are generally able to follow the regular process, so it is recommended that you buy sterilization masks produced by regular manufacturers to minimize the possible dangers.