Are Sanitized N95 Masks Safe for Reuse?

[J.Adderton]

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?

[Rogue1]

At my hospital: (as of April 9) we get one N95 mask to be worn for 3 shifts, after which you get to turn it in for UV sanitizing We are to use them through 10 UV treatments, which means 33 wearings (considering you can wear it 3 more times after the final UV sanitizing). If you work 12 hours shifts, that is 394 hours for a mask that I believe was meant to be used for 8 hours max (from one manufacturer's website). I just assume the UV sanitizing works, but who in the world knows what all that moisture is doing to the masks' filtration capability??

Our national PPE problem is nowhere near solved. How many times are we going to have to repeat that sentence? It's ridiculous.

[MeganMN]

I have not seen any responses about resting masks. Our facility is issuing us up to three masks. We wear a mask for an entire shift, then turn it in. The next day, we use a new mask for the entire shift, then turn it in. The third day, we get another new mask and then it in at the end of shift. These three masks then get "rested" for five days and packaged for us to use again. We just keep rotating The same three masks over and over. The CDC apparently stated the virus does not live on the mask longer than 72 hours. This practice freaks me out! Who decides how long it can be reused for? How many shifts before it gets thrown away? 5, 10, 20? This whole thing seems bonkers. Anyone else using this method?

[Marisette, BSN, RN]

On 4/29/2020 at 12:27 PM, 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.

Nice article but I'm not inspired.

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

The land of milk and honey ! If you want a test for covid 19, you get a test ? If you need an N95 mask, you get a mask ? From news reports, it would appear there was so much PPE made available to healhthcare workers, that this problem was resolved, and if there is a problem, it's within the particular health care facilities distribution of supplies ? I've been furloghed for awhile, but my experience was one N95, to be used only when doing a procedures like nose or throat cultures. Otherwise, we were sopposed to use surgical mask.

[AutumnLeaves, MSN, RN, NP]

That is what we are supposed to do where I work. We get one paper surgical mask a week and are only to use the N95 for aerolizing treatments/procedures. I know that some nurses wear the N95 under the paper masks in the ICU,but they have been getting into trouble for it. Our union has picketed but it does no good.

On 5/17/2020 at 12:35 AM, Marisette said:

The land of milk and honey ! If you want a test for covid 19, you get a test ? If you need an N95 mask, you get a mask ? From news reports, it would appear there was so much PPE made available to healhthcare workers, that this problem was resolved, and if there is a problem, it's within the particular health care facilities distribution of supplies ? I've been furloghed for awhile, but my experience was one N95, to be used only when doing a procedures like nose or throat cultures. Otherwise, we were sopposed to use surgical mask.

[MeganMN]

Just read this today, this whole thing depresses me......

Health Workers Risk Exposure to Dangerous Chemicals by Reusing Protective Gear

As if it is not bad enough to worry about getting sick from reusing masks, now I have to worry about getting sick from breathing chemicals from my face shield.

[42pines]

18 hours ago, MeganMN said:

Just read this today, this whole thing depresses me......

Health Workers Risk Exposure to Dangerous Chemicals by Reusing Protective Gear

As if it is not bad enough to worry about getting sick from reusing masks, now I have to worry about getting sick from breathing chemicals from my face shield.

We’re referred to an article from The Guardian titled: “Health workers risk exposure to dangerous chemicals by reusing protective gear."

Take a look at the article: Immediately we see a nurse, whose eyes, at least to me, look fearful—alarming, indeed!

We next hear that healthcare workers at a NY hospital have taken to spraying their reusable gowns with Virex II 256, a “highly potent,” designed only for hard surfaces”. Next, we hear of “quaternary ammonium compounds (QAT), which release formaldehyde,” and “…can cause asthma, fertility issues and birth defects, and irritate the skin, eyes and lungs.”

It’s an interesting article and Hallie Golden, the author might not have intended it to be an alarmist article, but, for me it comes across that way. Hallie likely did not choose the “fearful,” (clickbait) Getty image and an editor may have done what editors do, “edit it,” to increase click count.

I don’t often put people down, but in the case of Virex II, I’d refer to those “workers,” as idiots. Every nurse here has been told that she can obtain, for every single chemical in the hospital, the SDS (safety data sheet). For every hospital that uses Virex II, I guarantee that the SDS is right there, accessible within a few minutes—you’ve all been told this. Here is what the SDS says, “Avoid contact with skin, eyes and clothing.” (2) Use this on gowns and I may not say it, but I’ll think you’re an idiot. Don’t do that!

Let’s go back to the article for the next scary item, the QAT, “which release formaldehyde.” Now you, may think that I’m going to come down on someone. This time, if there’s a bad actor, it’s whoever is in charge of infection control. C’mon, you should have a protocol for every PPE and that should include what and how face shields are decontaminated.

If there’s an idiot here, it’s the person who created the protocol and taught each nurse how to use PPE for Covid-19. That person has a responsibility to at least try to ascertain what works and what doesn’t--safely. However, that clearly was not done, because whatever the substance that was used—damaged the face-shield.

We’re told it was Cavi-wipes, but it probably wasn’t. I suspect that someone used something different with an oil-based carrier. Why? Pull up the SDS for Cavi Wipes (c.) and right off we see the largest component as the carrier is Isopropanol, which we refer to as Isopropyl alcohol—we use it every day (alcohol wipes). Isopropyl alcohol does not interact with most plastics. In fact, it is recommended to disinfect acrylic, polycarbonate and PETG.

It really doesn’t make a difference as to what really what fogged the face-shield because a protocol should have been made and any cleaner should have been defined—and it wasn’t. It’s not hard to do, in the case of face shields (most of them) see: https://www.curbellplastics.com/Research-Solutions/Technical-Resources/Technical-Resources/Disinfecting-Acrylic-Polycarbonate-and-PETG-Sheet. It should not be a nurse job to check compatibility.

Now, let’s go back the other alarming item which is QAT’s. Fearful sounding stuff, those QAT’s, keep them away from me! Oh crap—I just got some all over my hands. Darn!

If I’m allowed, I’ve attached a photo of ICEE hand sanitizer, which comes in many “candy flavors.” It’s clearly marketed at children, but OMG—it lists Benzalkonium chloride (BAK) (one of the QAT’s) 0.1% as the active ingredient. I did, earlier, use some on my hands.

Wait! How can we put this on a child’s hands if it’s so deadly?

The answer is in the old saying, “the dose in the poison.” How about this deadly poison, would you use this substance to wipe down your face shield? It “can cause confusion, nausea, seizures, coma and death.” And, dear reader, you just ingested some of this nefarious substance, it’s called “water.”

“Water intoxication … occurred in a healthy 22-year old male prisoner, after he drank 6 liters of water in 3 hours.” (d) Now, you may think, “well, that rarely happens…” Think again, “out of 488 participants in the 2002 Boston Marathon, 13% had hyponatremia symptoms, and 0.06% had critical hyponatremia.” (d). Note: 3 of the 488 had critical hyponatremia. Nurses should be somewhat careful about saying “drink more…more is better…”

Well, the case with QAT’s is similar. Get a child to drink enough and they’ll die, but put some on their hands, even if they lick it—nah… One older fellow did die after drinking some, I can’t remember now exactly how much but I suspect that to extrapolate to a 0.1% concentration, he’d have to drink about 20 Liters. Again, the dose is the poison. I’ll look at it this way. If a hand-disinfectant uses a QAT, it’s likely that the QAT is BAK and since Romanowski et al (d) suggested that 0.1% BAK be investigated as an ocular (in the eye) agent to treat ocular adevovirus, I am not going to worry about this QAT on my hands or on the inside of my face shield.

Here’s the real problem: QAT’s are a group of chemicals and indeed, some do release formaldehyde. I suspect that even if you wiped down a table with a QAT that did, ten minutes later you’d be hard pressed to pull one ppb formaldehyde vapor in the ambient air. (OSHA’s short-term exposure (STEL) is 2 ppm (parts per million) over 15 minutes, and an 8-hour time weighted average (TWA) of 0.75 ppm. (e)

I don’t believe that BAK releases formaldehyde, it destroys virus by affecting virus lipid layers damaging the virus itself. (Wikipedia). But, there are other QAT’s that do release formaldehyde and I believe that the author is unintentionally mixing up one that does which is not frequently used in hand-disinfectants with one that does release formaldehyde that you’re more likely to find in the cosmetics that you wear.

Quartenrium-15 is a QAT. It is antimicrobial by release of formaldehyde and, “Formaldehyde releasers are often used as an antimicrobial preservative in cosmetics” (f) Different QAT, different story—Once again, your infection control person should be working with safety and/or the Occupational Health RN to make sure that all segments of infection control, including that is used to decontaminate is safe.

The take-away. Nurses on the Covid-19 front lines should have faith in their infection control methods. They should be able to ask questions—and get good answers, in a timely way. They should not need to worry about dangers other than the virus itself. And they should be making $60 or more per hour for hazardous pay...

Note: BAK does have some history as causing allergic skin reactions and there is some question about it's use relative to asthma. If I had kids I'd use 70% alcohol rather than BAK. If you had a history of asthma I'd say, "don't use it."

(b) SDS for Virex II. http://www.swishclean.com/products/media/pdf/3062784MS.PDF

(c.) SDS for Cavi-Wipes: https://www.metrex.com/sites/default/files/content/education-file/education-file-upload/CaviWipes Canadian MSDS (7-14-2015).pdf

(d) Benzalkonium Chloride Demonstrates Concentration-Dependent Antiviral Activity Against Adenovirus In Vitro. https://www.ncbi.nlm.nih.gov/pubmed/30969148

(d) Hyponatremia among Runners in the Boston Marathon. https://www.nejm.org/doi/10.1056/NEJMoa043901?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%3dwww.ncbi.nlm.nih.go

(e) https://en.wikipedia.org/wiki/Formaldehyde_releaser

[MeganMN]

@42pines.

Thank you for the very informative post. I am often reactionary in my thinking and it is never a bad thing for me to think twice about things. Any thoughts on the resting and reusing of N95 masks? Thanks for your thoughts!

The biggest challenge in our facility is a general lack of trust in the people making decisions. In some instances, the floor nurses had more up to date information than the people supposed to be protecting us! That makes it more difficult not to question or have anxiety about their decisions. I, personally, also lost some faith in the CDC when they recommended bandanas as an acceptable alternative to masks if no masks were available. Many facilities are not responding well or gracefully to employees questioning the practices being implemented!

[42pines]

On 5/19/2020 at 11:06 PM, MeganMN said:

@42pines.

Thank you for the very informative post. I am often reactionary in my thinking and it is never a bad thing for me to think twice about things. Any thoughts on the resting and reusing of N95 masks? Thanks for your thoughts!

The biggest challenge in our facility is a general lack of trust in the people making decisions. In some instances, the floor nurses had more up to date information than the people supposed to be protecting us! That makes it more difficult not to question or have anxiety about their decisions. I, personally, also lost some faith in the CDC when they recommended bandanas as an acceptable alternative to masks if no masks were available. Many facilities are not responding well or gracefully to employees questioning the practices being implemented!

From what I've heard here an allnurses I agree wholeheartedly--that there are clinics/hospitals where there is a lack of trust.

I agree with losing faith with CDC, however if you read it, it's pretty much aimed at a "last resort," that no nurse in America should ever have to contend with:

"HCP use of homemade masks:

In settings where facemasks are not available, HCP might use homemade masks (e.g., bandana, scarf) for care of patients with COVID-19 as a last resort. However, homemade masks are not considered PPE, since their capability to protect HCP is unknown. Caution should be exercised when considering this option. Homemade masks should ideally be used in combination with a face shield that covers the entire front (that extends to the chin or below) and sides of the face.

You state: "Many facilities are not responding well or gracefully to employees questioning the practices being implemented!"

For these facilities, I recommend a nurse, or preferably a group of nurses, in writing, send a letter of concern to their state OSHA (or local Federal OSHA) office, asking for anonymity. OSHA will honor that. If half a dozen signatures are on such a note--OSHA will move!

For anyone interested in a long read, here's my POV on N95 reuse:

On 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

Please note the above list is “should NOT use…

Instructables.com has a Do it yourself UV-C decontamination unit that impresses me. “If” materials are available (they were a month ago but might not be today) this unit can be proven to decontaminate typical N95 masks in one minute! Proven by a meter that measures Ultraviolet intensity. For instance the lamp on the item in the article gives: “So for a 36W bulb , we would have ~12W UVC (12,000,000μW) over an area of ~1440cm2 gives 8,300 μW/cm2. Over 1 minute this doses the items with ~ 500,000μW/cm2 or 0.5J/cm2.” Find a local electrician or computer tinkerer to make one.

See: https://www.instructables.com/id/UVC-Sterilizer-for-COVID-19-Emergency/

Here’s a rather amazing one that was made by Nebraska Medicine (2 hospitals, >1000 doctors and 40 clinics!

https://www.nebraskamed.com/sites/default/files/documents/covid-19/n-95-decon-process.pdf

This is a pretty neat .pdf article/paper on a huge (room size) N95 decontamination set-up.

Does it quantifiably work? I say, definitely!

“In our decontamination process, used N95 FFRs are subjected to UVGI at a sensor exposure of 300 mJ/cm2. Exposure mapping of our system indicated N95 FFR received a dose of double the measured dose from each side of the N95 FFR. Single-stranded RNA viruses, such as SARS-CoV-2, are generally inactivated by UVGI exposure of 2-5 mJ/cm2 (2). Thus, the UVGI exposure we have chosen exceeds, by at least several fold, the amount of exposure needed to inactivate SARS-CoV-2 and provides a wide
margin of safety for surface decontamination”

Frankly, I’m astonished that, by now, any hospital would not have determined a workable, approved, by its nurses, method of decontamination. Here, you see two sizes of UVB N95 decontamination units, from small to huge. Any hospital should be able to quantify that any re-use of N95 is adequate.

If I worked on a unit that did the “once ever so many days,” long ago, my State/local OSHA office would have received a complaint.

https://www.CDC.gov/coronavirus/2019-ncov/hcp/ppe-strategy/face-masks.html

[brandy1017, ASN, RN]

They started with the TB mask to wear for an entire shift. Then switched to a simple mask following the new CDC recommendations that it was acceptable, except for aerosolizing procedures. Then the TB masks were supposed to be kept in a brown paper bag for multiple use with the nurses name on it.

While RT was using PAPRS and more were ordered for them, not the nurses, on the rationale that they were intubating patients and giving breathing treatments. Meanwhile PAPRS were sitting unused in the basement and RN's were using simple masks for long periods in patients rooms without CNA's to limit their exposure.

Inevitably nurses started to get sick and even be hospitalized with pneumonia! Heard even a family of one was infected. Finally they switched to PAPRS for the nurses as well. Sad it had to take nurses getting sick to do the right thing!

No one at my hospital has died, but can't speak for the hospital system itself and since we're not unionized don't know how accurate any reporting of illness and even deaths would be done or reported to the rest of us re sister hospitals. Don't know if they are required to give stats to the CDC, OSHA, etc.

Yes they did mention they planned to reuse and resanitize TB masks as well, don't know by which method. Don't see why this would be necessary if we are using PAPRS, especially since they provide more safety, even if a little cumbersome.

They did also ask for volunteers to go to a sister hospital for their covid surge and shortly after we started surging as well. They don't want to extend travelers as they were getting crisis pay and, of course, wait for it, not in the budget! We too have seen some nurses quit and more are planning yet we do not have enough nurses to work at our own hospital, yet alone volunteer elsewhere! That is what travelers, agency or pool are for. They do have regional and state pool, but clearly not enough.

We do have some support staff of nurses and techs working thru the labor pool while clinics etc are shut down, but that is temporary and I don't know how much longer it will last. A few nurses can actually take assignments, but most are helpers.

I'm happy for the extra help, but there has been some friction where techs mainly claim they can't do much of anything as they weren't trained and aren't willing to go the extra mile to learn with our help. Instead we are the bad guys for expecting them to do simple things like take vitals and help turn and clean patients. How dare we expect this! Yet we are constantly put outside our comfort zones and expected to learn and do new things and more! Instead of giving the support staff a crash course in how to do such simple things as work as CNA, they are basically being paid to sit around and do nothing. Sad!

[42pines]

4 hours ago, brandy1017 said:

...there has been some friction where techs mainly claim they can't do much of anything as they weren't trained and aren't willing to go the extra mile to learn with our help. Instead we are the bad guys for expecting them to do simple things like take vitals and help turn and clean patients. How dare we expect this! Yet we are constantly put outside our comfort zones and expected to learn and do new things and more! Instead of giving the support staff a crash course in how to do such simple things as work as CNA, they are basically being paid to sit around and do nothing. Sad!

I really don't understand why they don't simply keep some CNA's. Most CNA's go that extra mile, and are already trained in basic care.

A few months ago, when asked, "should I stay and work as an RN (or LPN, etc.) my answer was "of course." However, as time has gone by and I've seen such poor responses in some facilities, I wouldn't fault those nurses who quit. It's difficult, very difficult.

[techarrows]

Thank you for this article and clarifications.

[NRSKarenRN, BSN, RN]

On 5/24/2020 at 12:42 PM, brandy1017 said:

Don't know if they are required to give stats to the CDC, OSHA, etc.

OSHA Form 300A (Summary of Work-Related Injuries and Illnesses). is required to be filed and posted yearly in place of employment for healthcare facilities with 10 or more employees. Includes death stats. https://www.osha.gov/recordkeeping/

Often posted by employee dining room/ time clock.

Forms 300, 300A, 301 Excel format : https://www.osha.gov/recordkeeping/new-osha300form6-30-16.xls