Can You Reuse N95 and KN95 Masks Safely? Experts Weigh In

Can You Reuse N95 and KN95 Masks Safely? Experts Weigh In
  • Federal health officials have officially recommended N95 and KN95 masks to the public as these respirators provide more protection to the public.

  • These masks are most protective and effective when they're worn once, but health officials have previously published guidance for reusing these respirator masks.

  • You shouldn't wear a N95 mask more than five times on separate occasions, according to current guidance — KN95s face a similar suggestion.

  • If you choose to reuse a respirator mask, you'll need to ensure they're sanitized before wearing them again, with experts sharing a system below that many turned to in 2020 for best results.


Federal officials at the Centers for Disease Control and Prevention (CDC) updated mask guidance this week to suggest Americans choose N95 or KN95s if possible, as respirators better stem the spread of SARS-CoV-2 spread this winter.

Experts have previously confirmed that Omicron spreads at a faster, more effective rate compared to earlier virus variants, and respirators like the N95 provide those in public a boost in subsequent filtration abilities if worn correctly.

Unlike cloth masks, however, most N95s and even KN95s haven't been designed to be effectively worn more than once. Like surgical masks, these disposable options may carry instructions to be worn once only — yet, medical experts during the PPE supply shortage in 2020 were forced to use them more frequently, and CDC officers have suggested that multiple uses are acceptable. The frequency, and how these masks end up being reused, often varies among experts.

"I don't think that the extended reuse of an N95 respirator is really a recommended practice by the CDC," says Kimiyoshi Kobayashi, M.D., chief quality officer at UMass Memorial Health, who explains that respirators were commonly sanitized by doctors using hydrogen peroxide gas and UV light in hospital settings. "I wouldn't recommend any of the practices that were used during the pandemic for consumers."

Where's the risk in wearing these respirators more than once, you may ask? And if you decide to take federal health officials' suggestions into account, how many times can you safely reuse a respirator mask? We're breaking down below when you should be changing your N95 or KN95 mask and tips for keeping them sanitary as the pandemic progresses.

Can you reuse an N95 face mask? How many times can you wear a respirator?

Current CDC guidelines published online suggest that respirators including N95s and alternatives like KN95s shouldn't be worn more than five times. Since they need to be fit correctly, however, some healthcare experts stress that five-plus uses of an N95 or KN95 may be too many. Issues like the elasticity of the masks' ties becoming loose make fitting a respirator mask to the face correctly near impossible, and that's a possibility after just one use.

A more concrete rule you may need to follow, according to Dr. Kobayashi, is checking for a soiled or cruddy mask front. "If you were working in a healthcare setting, a comparable example would be blood splatter or any sort of fluid — in this instance, maybe it's that your N95 has landed in a puddle on the ground. At this point, it shouldn't be re-worn," he says.

If you're particularly high-risk for severe complications stemming from a COVID-19 infection, you may wish to skip reusing masks altogether — this is also true for anyone working in a high-risk environment, like hospitals, retirement homes, or high-trafficked public buildings. At the very least, those who choose to wear an N95 or KN95 mask more than once can reduce the risk of any SARS-CoV-2 exposure by storing respirators correctly.

Can you clean an N95 or KN95 mask? What's the best way to extend its use?

Previously published CDC-sponsored guidance suggests that N95 masks may be cleaned by heating the mask in a dry oven, or boiled without plastic straps, USA Today reports. But it's widely discouraged since it's likely that you'll damage the construction of the mask or, worse yet, start a fire (masks can't be heated above 158 degrees). Rather, Dr. Kobayashi says doctors often used a dry, secure paper bag to "quarantine" masks for at least four to five days after their use.

"It's a simple way to decontaminate the mask, as virus particles will no longer be viable or infectious on the mask at this point," he says, adding that the same approach can be used for KN95 masks.

You'll need to be sure that your mask remains isolated from other clean, unused options for at least 5 days for best results. Using this method, Dr. Kobayashi says you can rotate through a few different respirators at a time, working to save your supply if you're having trouble securing more masks for you or your loved ones.

Washing a respirator including N95s or KN95s will invalidate their design, as they're not designed to get wet; don't try washing them in the same way you wash reusable cloth masks.

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