Ask the expert: N95 respirator reuse

By: May 5th, 2009 Email This Post Print This Post

Q: Regarding N95s, one of our physicians stated that they could be used for up to eight hours before disposing of them. Is this accurate?

A: Because disposable N95 respirators are designed for one-time use, neither the manufacturers nor NIOSH, which certifies respirators, guarantees protection for extended or multiple use.

In 2006, the Institute of Medicine (IOM) published Reusability of Facemasks During an Influenza Pandemic: Facing the Flu in which it acknowledged that a pandemic situation may require extended use, multiple use, or even decontamination of disposable face masks and respirators.

While the IOM could not come up with definitive findings, it cited four studies that suggested an N95 could function properly when worn over the course of a work shift, depending on the circumstances.

Other IOM suggestions for individuals to reuse his or her own disposable N95 respirator include:

  • Protect the respirator from external surface contamination when there is a high risk of exposure to influenza (i.e., by placing a medical mask or cleanable faceshield over the respirator so as to prevent surface contamination but not compromise the device’s fit).
  • Use and store the respirator in such a way that the physical integrity and efficacy of the respirator will not be compromised.
  • Practice appropriate hand hygiene before and after removal of the respirator and, if necessary and possible, appropriately disinfect the object used to shield it.

These recommendations are also consistent with the CDC Interim Domestic Guidance on the Use of Respirators to Prevent Transmission of SARS.

Need help in responding to the swine flu pandemic? Visit HCPro’s Emergency Management and Infection Control Preparedness Resources Web page.


By Shelly Stanley on May 14th, 2009 at 4:16 pm

The facility that I work for issues each nurse one N95 mask to be used “until visiably soiled or damaged”. We are instructed to use them, place them in a plastic bag and then reuse them for the next patient. According to our infection control nurse it is appropriate to use the same mask for a TB pt, meningitis pt, N1H1 patient. So long as our mask is not visiably damaged we cannot get another mask. I have had the same mask for over a year now. No extra masks are kept in the department only behind locked doors. The reason I have been getting for not providing more of these masks is that they are expensive and we must “try to manage our resourses”. Does this policy seem okay?

By David LaHoda on May 14th, 2009 at 6:03 pm

This sounds iffy on infection control and occupational health and safety and health principles and pennywise and pound foolish on the conservation of resources position.

Ask if this policy is explained in your employer’s respiratory protection plan. OSHA says that the employer must have a written plan if it requires employees to wear respirators. The plan must be available to employees. See “Cramming for swine flu respiratory protection plan 101” for what must be included in the plan.

Also, just this week, the FDA posted an FAQ on personal protective equipment (PPE) for pandemic influenza which cautions against the routine extended use or reuse of disposable N95s.

PPE is a hot topic with OSHA right now. So much so that OSHA can fine employers on violations per affected employee. That could get expensive, and your employer should know that, and make sure its policy is solid on OSHA compliance.

By Peggy Sheffer on September 24th, 2009 at 2:01 am

The hospital where I work requires nurses to reuse N95 masks – forever. Mine is 7 years old and has been used on several patients, put in a plastic bag, and placed in my locker as per policy. They are now telling nurses to place a surgical mask over the N95 and reuse forever. I suffer from asthma and find it very difficult to breathe with the mask on and sweat profusely which in turn makes the mask wet. The last time I took care of a TB patient I passed out in the room due to lack of oxygen. Additionally my mask has had to hang and dry out several times. The health nurse and nurse manager state the mask is still good to use. I question this infection control policy.

Thank you,

In too question the N95 replacement, maintenance, and storage policy of your organization. which, by the way, must be in writing and presented at least annually as part of your training, according to OSHA. I also question whether your organization is in violation of OSHA standards by not reassessing your ability to wear that type of respirator through a medical evaluation and why those questions are not addressed during your annual fit test. I think you employer, or at least the administrator of your respiratory protection has a lot to worry about.

Suppose a hospital uses only non-reusable N95 filtering facepiece respirators (FFR). What would be the most pragmatic way to determine how many FFR’s would be needed to protect direct patient care staff against transmission of say H1N1 given the number of patients attended to per unit time?

I previously worked at a TB hospital. Policy there was that the N95 mask was to be reused by a single user, unless visibly soiled or moist, for up to 8 hours. The policy for SARS or other infections capable of surviving on fomites was that they were for single use only. I am now in a general hospital and the head of occupational health wants the N95 masks to be single use for TB patients as well. Often the nurses contact with TB patients is very short. Many times patients are on precautions waiting for AFB results, and are not confirmed cases. >70% of these turn out to be negative. In these circumstances can N95’s be reused? Is there any literature to suggest reuse to be a source of infection, when it comes to TB specifically?

By David LaHoda on February 10th, 2010 at 12:13 pm

I don’t know of a study specific to your question on TB. Multiple and extended use of disposable N95s has been a hot topic lately with H1N1 and limited supplies of N95s. My advice about not following or amending the FDA-approved instructions accompanying disposable respirators is to have documentation from regulators or studies accompanied by site-specific risk assessments supporting extended or multiple use either on a permanent or temporary basis.

If you are facing an exposure investigation, and the investigator asks to see your plan, policy, or documentation on why your facility chose to disregard CDC or FDA instructions, and you don’t have one…well, you can imagine the consequences.

is reuse of N95 mask acceptable, if the answer yes for how long , and for how many times

i have to use a N95 mask every day at work as we deal with airborne pathogens like TB and SARS. the N95 respirator/mask should only be used once

the mask should be used for 8 hours max
if the mask is soiled/damp throw it away
if you take the mask off you have to dispose of it.
if the respirator is damaged throw it away

never reuse the respirators or put them in a bag then use again!! once they have been used for 8 hours or a soiled damaged or have been removed discard of them.

By Thomas Albuquerque on July 19th, 2012 at 2:38 am

I am employed as an Infection Control Officer in an Opd Clinic in India that treats Coinfected patients Hiv / Tb ( Mdr-Tb )
I would like to know as to how long can we use an N95 Disposeable Resperator.

By David LaHoda on July 19th, 2012 at 1:43 pm

The FAQ section of the CDC Guidelines for Preventing the Transmission of Mycobacterium tuberculosis in Health-Care Settings, 2005 addresses the question.

Q: How long can I use my respirator for TB exposures before I discard it?
A: Disposable respirators can be functional for weeks to months and reused by the same HCW. Reuse is limited by hygiene, damage, and breathing resistance, and manufacturer instructions should be considered.

can we use UV light for sterilization daily and reuse N95 mask.

By steve basham on January 19th, 2016 at 5:29 pm

Can I use a full face respirator, clean, put on the shelf and issue it to somebody else later?

I want information for how long I can use a N95 on a TB patient room with a 1:1 Sitter Backer act. My shift are for 12.

By Paulette D'Aunoy on August 30th, 2017 at 1:36 pm

Any new recommendations for the reuse of N95 respirator in long term care? These would basically be used for influenza pandemic.

If they can be reused how are they to be stored and how long can they be reused if not visibly soiled or wet?

Which doctors would be made to use a N95 Mask. From what I get, the doctors that ONLY those required to wear a respirator in performance of duties. Also, how often should they be re-fitted?

Can a N95 disposable respirator be washed and reused? I use them as an individual. I am not using them in a medical facility.

Can a N95 disposable respirator mask be washed and reused? I use them as an individual. I am not working at a medical facility.

Is May 2015 the last time Mr. Palmer provided suggestion for reuse of N95 mask?

By Kevin Young on January 31st, 2020 at 5:16 am

I bought 10 boxes 3M N95 8210
back in 2013, now after 7 years, can I still use the one I left in my store? It was kept properly without any damage.


To Kevin Young, I’d check on those masks sooner rather than later. The elastic may decay and you may want to source alternative elastics to staple on. If the masks have been stored well, the main part will not be affected. Any expiration is likely for the elastic only. That’s my opinion as a longtime surgical staff member.

By Jacqueline Glover on February 27th, 2020 at 5:30 pm

Our hospital has a cache of N95s provided to use >10 years ago. The straps are physically ok, the cloth is ok but they are not adequate for use as an N95, they do not pass fit testing.
Can these old, not acceptable as N95 respirators be used as medical masks? For droplet isolation etc? NOT Airborne just for the cloth barrier on the lower face. Thank you

By John Klepetka on March 17th, 2020 at 4:44 am

A new directive has been issued that multiple care-givers are to share a single N95 mask for the duration of a shift. Seems very dicey to me.

By Tom Franklin on March 17th, 2020 at 1:10 pm

Are there any sprays or solutions that can be used to clean N-95 masks?

can UV-C ultraviolet light @ 150-260nm with ozon production be used on N-95 masks ? This wavelength is used in hospital operating rooms to clean sterilize as well as hospital heap filtered air(minus ozone production). We can conserve masks at what price ? yours or mine ?

can disposable N95 masks be sterilized?

Are there any sprays or solutions that can be used to clean N-95 masks?

Yeah, I need an answer for this question as well. Anything like that that I can use without destroying the integrity of the mask?

Wonder what the answers to these questions would be now in the middle of Covid-19?

We are an elevator company in NYC and we have a maintenance service and new construction depts. We service maint n erect new buildings in NYC. The N95 respirator that we issue as part of our voluntary respirator program, we now have questions due to 19 how long are the good for. With limit supply can we reuse as long as keep in a plastic zip lock bag, clean it out after daily use with a Clorox bleach free hand sanitizer / alcohol and reuse. Your response will be greatly appreciated. TY Ray D

Could a commercial grade ozone machine be used to decontaminate a m95 mask?

I used an N95 mask took it off at end of shift then sprayed it with bleach solution (1/10 bleach 9/10 water) on “both sides” then hung it up to dry. I hope germs are killed and it can be reused until I see wear and tear. In this situation, I would need 2-3 to last me for a long time. Just need the soaking wet mask to air dry. Please let me know if this is reliable way to reuse a 3m N95 mask.

See the following guidance from CDC on N95 re-use :

Hope it helps. Does not recommend using after any aerosol generating operations. I personally am interested in the UV disinfection and want to know how feasible that would be in times of N95 shortage.

By T.J. Atnip on March 27th, 2020 at 4:46 am

Microwave method, (sans metal parts) throughly wet mask and microwave on high for up to 4 minutes, adjust time until dry. Works well for sterilization of sponges as an old kitchen remedy. Should have same effect. I am sure research would bear out.

By Peggy Shumsky on March 27th, 2020 at 11:06 am

Per CDC: masks may be used for extended use and reuse. Please see the CDC website, information for hospitals, PPE use for guidelines. They have specific instructions for how this is to be done.

By John R Miller on March 28th, 2020 at 7:13 pm

Can you dry clean N95 masks ?

By Alma G. de la Cruz on March 31st, 2020 at 12:26 pm

Is the possibility of Sterrad sterilization acceptable?

By Kenneth Baiko, DDS on March 31st, 2020 at 1:06 pm

N95 masks can be easily, reliably, quickly and inexpensively sterilized dozens of times without ANY degradation in filtering performance.

Extensive research at Stanford University has repeatedly tested and confirmed:

158F/70C in ANY oven for 30 minutes sterilized the mask without any degradation in filtering nor any damage to any part of the mask. Even after more than a dozen sterilizations on the same mask, the mask performs to the same specifications of a new mask.

If the outside of the N95 can be kept free of blood spatter (wear a standard surgical mask over the N95 as a barrier to any splatter … breathing not compromised), the mask can be reused indefinitely.

How much less expensive is it to simply put the mask in an oven or toaster oven or purchase a new mask for each health care provider for each and every patient??? Another consideration: How many N95 masks are currently available and how much extra money do you have to waste compared to sterilizing what you already have for almost free?

By Jeffrey Simone on March 31st, 2020 at 2:14 pm

Can N95s be sterilized using high dose ozone if there are not otherwise compromised?

Are o-Zone type cleaners effective against Cove is 19?

By Richard Heckmann on April 5th, 2020 at 4:15 am

I cannot find the link now, but about a week ago saw a post by the man who invented the N95 mask. He said it is a polyethylene weave, and thus must NOT be exposed to UV, which will destroy the filtration function of the mask. He said that since the virus cannot live on polyethylene for more than 72 hours, ideally a person would have 4 masks and use them in a 4-day rotation. Preferably store them in a cabinet or other dark place to avoid exposure to sunlight. I would avoid baking, microwaving, chlorox spray or immersion,unless these techniques are known to be safe for the particular polyethylene weave used in these masks.

By Mary Murphy on April 5th, 2020 at 5:52 pm

If the corona virus can only survive for 72 hours on disposable masks, would hanging them out in the sunlight for a recommended time make them safe to reuse? If so, how long would an unsoiled but used mask need. I am a retired RN and Infection control in LTC was part of my job. I am asking about private use now. It is very difficult and expensive to locate and purchase masks and it would be a blessing to be able to reuse the few I have.

ER is currently directing employees to place their N95 in paper bag at the end of their shift, put it (still in paper bag) in the oven on 160 degrees for 1/2 hour, then reuse during the next shift.

Thought I would add some links to help clarify some of the comments:
It is not advised to use organic alcohols (ethanol or isopropanol) to disinfect the masks as they will reduce the integrity of the electret membrane:



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