TORONTO -- Ontario’s Fire Marshal is warning people not to microwave personal protective equipment (PPE) as the province reports a spike in fire-related fatalities since the start of 2020.

"Heating a face mask in a microwave, in an effort to decontaminate it, is a potential fire risk and should never be done," Ontario Fire Marshal Jon Pegg said in a news release issued Tuesday.

Pegg’s comments come in response to suggestions that microwaves can be used to sterilize masks for re-use.

The Office of the Fire Marshal and Emergency Management says that microwaves are not designed to heat cloth materials, which could overheat and catch fire. Additionally, the office noted that many disposable masks are equipped with a metal nose wire or staples that can cause fires if heated in a microwave.

“Ontarians need to be especially vigilant about fire prevention as fire and smoke can travel so quickly that firefighters may not be able to rescue someone in time.”

Between Jan. 1 and May 4, Pegg said there have been 51 fire fatalities in Ontario, which represents a 65 per cent increase over the same time last year.

Pegg said 17 Ontarians died in fires in this past March alone.

“The Fire Marshal is reminding everyone that fire safety is especially important during the COVID-19 pandemic when so many families are staying at home and doing more cooking.”

Speaking to CTV News Toronto, the Office of the Fire Marshal could not definitively say that there have been more fires following the onset of COVID-19, but said that information would become available as more and more municipal fire departments report their data back.

The office says that they are not currently aware of any incidents of residents microwaving masks in Ontario, but say they have heard of claims and recommendations that masks can be sterilized in this way.

"That, coupled with the fact that this has emerged as an issue in other jurisdictions (U.S. & U.K.) prompted this warning."

"We are trying to avoid any incidents here based on misinformation or unsafe advice."

What’s the best way to sterilize your mask? Ontario’s Associate Chief Medical Officer of Health says that a thorough cleaning should do the trick.

“If we’re talking cloth masks, every time after you use it, you should wash it, launder it, in hot water,” Dr. Barbara Yaffe said Tuesday.

“Regular laundry. Definitely don’t put it in the microwave. That’s a fire hazard.”