Microwaves are good for some things, but sterilizing vital personal protective equipment is not one of them. Ontario's Fire Marshal had to warn residents not to ding their face masks in a misguided attempt to clean them. And a video posted on Twitter of staff microwaving face masks on Thursday evening shows exactly what can happen.\nAnd, to be honest, it's pretty much what you would likely expect to happen.\nThe social media PSA comes just three days after the provincial Fire Marshal felt the need to issue a statement directly warning people not to microwave face masks and other personal protective equipment to try to render them safe to reuse.\nThat was apparently the result of several ill-advised attempts to do just that, as well as an alarming spike in the number of fires reported in recent weeks.\nThe video, shared by the province's Assistant Deputy Fire Marshal Steven Wilson, shows a forensic engineer talking through why it's such a bad idea.\n"Earlier this week, the Fire Marshal issued a warning about putting your personal protective equipment in a microwave. Let me show you what can happen if you put your N95 mask in a microwave."\nThe video then proceeds to do just that and — surprise, surprise — it ends in a fire. The mask ignites within seconds.\nEarlier this week, the Fire Marshal @jonpeggOFMEM issued a warning to never sterilize your face mask in the microwave. In this video, Forensic Engineer James Bennett shows us what can happen. #KeepingYouSafe pic.twitter.com/70bThVz0SZ— Steven Wilson (@A_Deputy_OFMEM) May 7, 2020\nThis is a neat visual reminder that microwaves are not meant to heat up clothes or similar materials.\nAnd disposable face masks, even non-N95 masks, generally have metal wires or staples holding the straps together.\nPer CBC, Ontario's Associate Medical Officer of Health Dr. Barbara Yaffe stressed on Tuesday that if you need to clean cloth masks, approaching it as if it is "regular laundry" is the best idea.\n"Definitely don't put it in the microwave. That's a fire hazard," she said.\nYep, so we've now seen.\nFor what it's worth, Fire Marshal office spokesperson Ryan Betts told CBC the office is not aware of any fires that have been caused by microwaving masks in Ontario.\nHowever, he said he has heard reports of it being a problem in other countries like the U.S. and the U.K.\nThey still felt the need to issue first a written and then a visual warning, though.\nSo, if you didn't know already, now you do. Microwaving a face mask is a very serious fire hazard.