Are Sanitized N95 Masks Safe for Reuse?

Have you had doubts about the safety of reusing decontaminated N95 masks?  A new study tested four methods of sanitization to determine if they could safely be reused.  Read on to learn more about the study results.

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Are Sanitized N95 Masks Safe for Reuse?

The unprecedented shortage of personal protective equipment (PPE) is an unsafe burden placed on healthcare workers. To protect ourselves against the highly contagious coronavirus, N95 masks are essential in stopping the virus droplets from entering through our mouth and nose. Unfortunately, the worldwide pandemic has the healthcare industry struggling to extend the use of their current N95 supplies. To be used safely, the masks are generally designed for a single-use. However, workers are having to use the same mask over multiple shifts, adding to their risk of COVID-19 infection.

Putting Sanitization to the Test

Robert Fischer, PhD, with the National Institute of Allergy and Infectious Diseases in Montana, along with his colleagues, conducted a study to compare four methods of mask decontamination to determine which is the most effective. Specifically, the researchers compared the rate that SARS-CoV-2 virus is eliminated on the filter fabric of an N95 mask to virus decontamination on stainless steel. The methods used included:

  • Vaporized Hydrogen Peroxide (VHP)
  • Dry heat
  • UV lighting
  • Ethanol

After 3 uses, the masks were tested again to see if they maintained an effective fit and seal. Laboratory volunteers wore the decontaminated masks for 2 hours before testing fit.

Finding a Reliable Method

The researchers found that all four methods removed detectable SARS-CoV-2 virus from the mask's fabric. However, they did find the following variations among the four methods.

VHP

  • Fastest decontamination time (10 minutes)
  • Could be used up to 3 times and function properly

Dry heat

  • Required 60 minutes for decontamination
  • Could be used up to 2 times and function properly

UV lighting

  • Required 60 minutes for decontamination
  • Could be used up to 3 times and function properly

Ethanol

  • Not recommended
  • Mask did not function properly after decontamination

Currently, UV light and VPH are the most widely used methods for decontamination. UV light has been used for years to disinfect hospital rooms, making it easily accessible. And, hydrogen peroxide has continued to be available without extreme shortages.

Study Limitation

The researchers tested disinfected N95 masks after clinicians wore the mask for only 2 hours. However, we know that N95 masks are worn for much longer periods of time.

FDA Emergency Use Authorizations

On March 28, 2020, the FDA issued an Emergency Use Authorization (EUA), at Battelle Memorial Institute, to allow decontamination of N95 masks using a VPH method. Since then, EUAs have also been issued for Steris V-PRO system and STERRAD systems, with both using VPH method for sterilization.

CDC Recommendations for Decontamination

According to the CDC, only manufacturers can reliably provide procedures for decontamination without impacting t performance. Also, the CDC doesn't recommend N95 masks be decontaminated for reuse as a standard practice. However, the agency does recognize the pandemic is a time of crisis and options for disinfecting may need to be considered when N95 masks are in short supply.

CDC Recommendations for Reuse

The CDC has approved wearing the same N95 mask for repeated patient contact without removing the mask between patients. The approval is only for periods of crisis, such as pandemics, when mask supplies become scarce. The CDC has published the following Guidelines for Wearing N95 Masks for an Extended Period of TIme.

  • Discard N95 respirators after a patient has an aerosol procedure
  • Discard if contaminated with bodily fluids
  • Discard after close contact with any patient co-infected with an infectious disease requiring contact precautions
  • Consider using a cleanable face shield over an N95 respirator when feasible
  • Hand used respirators in a designated storage area or keep in a clean, breathable container, such as brown paper bags.
  • Clean hands after touching or adjusting the respirator
  • Avoid touching the inside of a respirator.
  • If contact is made with the inside, discard the respirator and perform hand hygiene
  • Use a pair of clean gloves with donning a used mask

More Research Needed

Healthcare workers understandably have reservations about wearing respirators that have been decontaminated. N95 masks will continue to be in short supply with the evolving pandemic. To ensure the safety of patients and workers, additional research is needed to evaluate procedures for both extended and reuse of respirators.

I work in a facility that is now reusing N95 masks and many workers are leery of this practice. What has been your experience?

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J.Adderton

About J.Adderton, BSN, MSN

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Experienced nurse specializing in clinical leadership, staff development and nursing education.

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We get one N95 for the shift. Some people take them off, place in paper bags, and then put them back on. I, personally, am not comfortable with this, as I think the greatest risk of exposure comes from doffing/donning. My choice is extended wearing. As in, I put my mask on after I get report, pull my meds, and stock my cart, and then I don't take it off until after I've given report to the next nurse. The biggest issue is that I can't eat or drink, and I get thirsty, but I'd rather deal with thirst than increase my risk of infection.

The other catch is that the N95s we use have plastic head-loops that stretch out, but do not retract back. Not a design flaw when you consider the masks were meant for disposal after a single use, but taking them off means they are too stretched out to create a good seal when reapplied. We are not saving our masks for decontamination at this point. I'm hoping it doesn't come to this. If it does, I would probably be okay with a decontaminated mask, as long as we have a solution to the current fit issue.

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1 hour ago, turtlesRcool said:

The biggest issue is that I can't eat or drink, and I get thirsty, but I'd rather deal with thirst than increase my risk of infection.

Dang, maybe plan to take at least one break so you can get a drink of water. This is so sad that we have to weigh these decisions. When I wear this one I do take it off when I leave the unit for a sec, even if it's just to take in some air. It's really hard for me to breathe and my throat gets dry wearing this all shift.

Nice article but I'm not inspired.

Just please make some more dangit! This is the land of milk and honey right?

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20 minutes ago, HiddenAngels said:

Dang, maybe plan to take at least one break so you can get a drink of water. This is so sad that we have to weigh these decisions. When I wear this one I do take it off when I leave the unit for a sec, even if it's just to take in some air. It's really hard for me to breathe and my throat gets dry wearing this all shift.

If I take it off, I can't get a seal with it when I put it back on. Not worth it. If I could, I probably would take a break. But since there elastic does not contract, the straps are permanently stretched to their longest length, which means there's no way for me to safely rewear it. The whole point of an N95 is the seal. If that's compromised, so is my protection. I'd rather be thirsty. (Well, actually, I'd rather be able to change into a new mask, but given the options, I'd rather wait to drink until I'm done with patient care.)

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5 minutes ago, turtlesRcool said:

But since there elastic does not contract, the straps are permanently stretched to their longest length, which means there's no way for me to safely rewear it.

Can you cut an re-tie them?

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6 minutes ago, turtlesRcool said:

If I take it off, I can't get a seal with it when I put it back on. Not worth it.

Really? Which N95 do you have? I have the aqua blue colored one

3 minutes ago, Wuzzie said:

Can you cut an retie them?

I think it would mess up the seal since we are fitted to them

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1 hour ago, HiddenAngels said:

Really? Which N95 do you have? I have the aqua blue colored one

I think it would mess up the seal since we are fitted to them

We have the Kimberly Clark ones that look like duck bills. Actually, this is the first time I've googled them, and it looks like the headbands are polyurethane, which explains why they just stretch and don't retract.

I think the fit is based mostly on the size/shape of the mask. The small fits me very well. As long as I could get the straps tight enough, I don't think the fit would be compromised by re-tieing them.

We did get some different ones from the state that have more traditional elastics, and my colleagues who wear those can take them on and off without problems, but we didn't even bother to do a formal fit test for me, because my glasses were fogging when I exhaled, so I know the seal wasn't good with those.

https://www.kcprofessional.com/en-us/products/scientific/respiratory-protection/46727

1 hour ago, Wuzzie said:

Can you cut an re-tie them?

I don't know. I might be able to. I don't know how far they stretch. It could be worth a shot.

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Specializes in Clinical Leadership, Staff Development, Education.

It is so interesting reading everyone's experience. We are given 1 mask (not fit tested) and must wear until it breaks or visible soiled with body fluids. We must "sign out" each mask we received. Therefore, they are worn multiple shifts and to get a 2nd one, you must turn in the one you have in a paper bag. It is very frustrating... same with surgical masks. They are all locked up and we are given 1 with the expectation it will be worn multiple shifts.

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26 minutes ago, J.Adderton said:

It is so interesting reading everyone's experience. We are given 1 mask (not fit tested) and must wear until it breaks or visible soiled with body fluids. We must "sign out" each mask we received. Therefore, they are worn multiple shifts and to get a 2nd one, you must turn in the one you have in a paper bag. It is very frustrating... same with surgical masks. They are all locked up and we are given 1 with the expectation it will be worn multiple shifts.

I'm sorry. That's terrible, and scary. Where are you working?

What are your thoughts about possibly sanitizing and reusing them, as mentioned in the article? Would you want to use a sanitized mask for a shorter period, not knowing who wore it first, or would you prefer to keep your own, even if you have to reuse it?

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3 hours ago, J.Adderton said:

It is so interesting reading everyone's experience. We are given 1 mask (not fit tested) and must wear until it breaks or visible soiled with body fluids. We must "sign out" each mask we received. Therefore, they are worn multiple shifts and to get a 2nd one, you must turn in the one you have in a paper bag. It is very frustrating... same with surgical masks. They are all locked up and we are given 1 with the expectation it will be worn multiple shifts.

This was how they tried to approach us Mid-March when there were just a handful of Covid patients admitted. Someone told us that at night this big truck backed up into one of our loading docks removing tons of PPE (wipes, sanitizer, etc) to take to one of warehouses until the big wave came. (I know sounds like a movie right)...Once it hit us hard, things changed quick. I'm not sure if it was because nurses were starting to quit or if they were just waiting for the big wave (which is what we believed), the PPE reappeared we got addtl PPE a lot since then.

Do you remember your size mask from your fit test before Covid? I wear 3M small and your facility or Outpatient center where you usually get tested should have the correct size you were tested for prior to Covid. If you have hard copies of your physicals and tests it would be on there as well.

"Until it is visibly soiled with body fluids" or Turn in the one you use in a "paper bag", the dirty one.? I guess this is where the resterilization is taking place." So far we don't turn ours in, we just dispose of them when we feel they are beyond saving especially when those straps start to hang on by a thin thread..

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Specializes in Occupational Health; Adult ICU.

It’s a minefield and I wouldn’t approve any method without many hours of research, reading and validation. Make a mistake, and someone might die.

Fischer, et al’s article can be read at:

https://www.medrxiv.org/content/10.1101/2020.04.11.20062018v2.full.pdf

From the article:

“…It will therefore be critical that FDA, CDC and OSHA guidelines with regards to 60 fit testing, seal check and respirator re-use are followed.”

On Friday, April 23rd OSHA released “Enforcement Guidance on Decontamination of Filtering Facepiece Respirators in Healthcare During the Coronavirus Disease 2019 (COVID-19) Pandemic”

See: https://www.osha.gov/memos/2020-04-24/enforcement-guidance-decontamination-filtering-facepiece-respirators-healthcare

From this non-copyrighted document:

“If respiratory protection must be used, and acceptable alternatives are not available for use in accordance with OSHA’s previous COVID-19 enforcement memoranda, NIOSH has identified limited available research that suggests the following methods offer the most promise for decontaminating FFRs:

Vaporous hydrogen peroxide;[9]

Ultraviolet germicidal irradiation; and/or

Moist heat (e.g., using water heated in an oven).

If such methods are not available, the above-referenced NIOSH-evaluated research showed the following methods could also be suitable decontamination options:

Microwave-generated steam; and/or

Liquid hydrogen peroxide.

Based on the above-referenced NIOSH-evaluated research, employers should ***not***(emphasis added) use the following methods unless objective data that sufficiently demonstrate the safety and effectiveness of such methods become available:

Autoclaving;

Dry heat;

Isopropyl alcohol;

Soap;

Dry microwave irradiation;

Chlorine bleach; and/or

Disinfectant wipes, regardless of impregnation (I.e., chemical saturation); and/or

Ethylene oxide (EtO).[10]

Please note the last list is “should NOT use…

Now consider, we have Fischer et al’s article recommending isopropyl alcohol and dry heat, and then telling us to follow all OSHA guidelines for respirator re-use, which tells us not to use dry heat and isopropyl alcohol. Or does Fischer's article provide the objective data to oppose OSHA's "do not use...?"

Frankly, vaporized hydrogen peroxide seems the only truly preferable method. Also “UV radiation kills the virus more slowly and preserves comparable respirator function.” There is no mention of intensity/dose versus time, and any such device that uses UVC should be quantified with a UVC meter (which could be done, so this is a second allowable method). Moist heat, microwave steam and liquid hydrogen peroxide could work also.

What a mess.

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Specializes in Hospice, corrections, psychiatry, rehab, LTC.
On 4/29/2020 at 8:49 AM, turtlesRcool said:

The other catch is that the N95s we use have plastic head-loops that stretch out, but do not retract back. Not a design flaw when you consider the masks were meant for disposal after a single use, but taking them off means they are too stretched out to create a good seal when reapplied.

Fortunately, ours have rubber band-type loops, so fit isn't an issue. Sometimes the bands snap, though.

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