No, you shouldn’t try to decontaminate N95 masks in your oven


decontaminate n95 masks
Do not put used N95 masks in your oven.
Photo: Charlie Sorrel/Cult of Mac

As the coronavirus pandemic spreads, N95 filtration masks are in short supply worldwide. It remains unclear whether wearing a mask as a prophylactic is necessary, but that isn’t stopping people from strapping them on when they venture outside their homes. And if you are infected with the COVID-19 virus, or you are working closely with infected people, then you probably do want a mask.

Can these masks be reused? New guidance from Stanford Medicine says yes, you can sterilize N95 masks — by “baking” them in a low-temperature oven. However, you should definitely not do this at home.

Safe and effective N95 mask sterilization

If protective masks can be safely reused, then it’s an effective workaround for an insufficient supply. In a report titled “Addressing COVID-19 Face Mask Shortages” (.pdf), Stanford scientists Amy Price and Dr. Larry Chu outline the requirements for N95 mask reuse:

To be useful a decontamination method must eliminate the viral threat, be harmless to end-users, and retain respirator integrity

Possible decontamination methods include soaking in a bleach solution, microwaving the masks, or just quarantining the masks themselves until any virus has died off. However, these methods have their own problems. Bleach, for example, leaves residual bleach gasses. Microwaves melt the masks.

Don’t try this at home

However, one effective method is to heat the masks in an oven. But not, the authors stress, in your home oven. Clearly, sterilizing hazardous medical material in the same place that you cook food is a terrible idea. In a hospital setting, however, a dedicated oven could be just the ticket. Also, steaming masks also works.

70C /158F heating in an oven (not your home oven) for 30min, or hot water vapor from boiling water for 10 min, are additional effective decontamination methods.

It’s important to note that this report is for guidance only. It is not a peer-reviewed paper, nor is it a recommendation to donate your oven to a local hospital. And, at the risk of banging on, you should not do this at home. In fact, the authors revised their earlier article to specifically address this misinterpretation:

Our reports do not advocate for people to disinfect masks for reuse by heat treatment in home ovens. We also caution in our report that disinfected masks must be retested for proper fit prior to reuse. We state that disinfection methods are not approved by NIOSH.

Finally, we state that we do not advocate or advise specific treatments or approaches and recommend that hospital policy and procedures be respected and adhered to.

Coronavirus safety measures

So, what can you do? The same report lists four effective things you can do to minimize bringing the virus into your home, according to Stanford infection-control experts:

  1. Wash your hands before you leave work.
  2. Wash your hands when you get home.
  3. Wear different shoes at home and at work, or wash your hands as soon as you take off your shoes.
  4. Disinfect the common touch surfaces in your home and in your car once each day.

And one bonus warning:

  1. Don’t disinfect cutting boards or any item that comes into contact with food.

More ways to stay safe during coronavirus lockdown

Looking for more ways to stay safe during these unsettling times? Here are more tips for disinfecting yourself and all your Apple gear:

Stay safe.