Researchers Identify N95 Respirator Decontamination Method Using a Microwave

N95 Face Mask

Researchers have developed a standardized and effective decontamination method for hospitals and healthcare centers dealing with shortages of N95 respirators.

Due to the rapid spread of COVID-19, there is an increasing shortage of personal protective equipment (PPE) crucial to protecting health care workers from infection. N95 respirators are recommended by the CDC as the ideal protection method from COVID-19 and, although traditionally single-use, PPE shortages have necessitated the need for reuse. New research published recently in mBio an open-access journal of the American Society for Microbiology, describes an effective, standardized method of decontamination for hospitals and health care centers facing N95 respirator shortages.

The researchers, from Beth Israel Deaconess Medical Center, Harvard University, and Massachusetts General Hospital, have detailed a reproducible decontamination approach that all health care workers would be able to utilize. “We identified an effective method of N95 decontamination by microwave-generated steam utilizing universally accessible materials. Our method resulted in almost complete sterilization after only 3 min of treatment and did not appear to affect the integrity of N95 filtration or fit with repeated treatment,” the researchers write.

Reference: “Microwave-Generated Steam Decontamination of N95 Respirators Utilizing Universally Accessible Materials” by Katelyn E. Zulauf, Alex B. Green, Alex N. Nguyen Ba, Tanush Jagdish, Dvir Reif, Robert Seeley, Alana Dale and James E. Kirby, 25 June 2020, mBio.
DOI: 10.1128/mBio.00997-20

38 Comments on "Researchers Identify N95 Respirator Decontamination Method Using a Microwave"

  1. Then share the freaking method. What a worthless article.

  2. Teeter Totter | June 30, 2020 at 10:14 am | Reply

    It’s your reading and research skills that are worthless. The article links it’s sources. 😂 😂 😂

  3. Rachel Marcotte | June 30, 2020 at 11:23 am | Reply

    The link is at the bottom. Great article

  4. It is my understanding that one of the methods by which an n95 mask is effective against very small particles is by an electrical charge that is on the mask layers. I wonder what effect this method has on that. In fact, I wonder how effective the mask is at trapping small virus size particles or small droplets after this kind of treatment. I did not see any tests that were run to determine the effectiveness of the mask after such treatment.

  5. Dont try this at home! I placed the mask with a container of water in the microwave for 3 minutes and it created a huge fire. Just glad my microwave didnt explode!

  6. This article links directly to the study, it’s easy to read. The study makes it clear how to do it. But here’s a link explaining how to do it without the entire methodology, etc

  7. Assumption: it is the temperature of the steam that kills the virus. The microwave is a means to heat the water. If this assumption is untrue, don’t waste your time reading on. My theory is invalid, then.
    Couldn’t this be just as effective by, somehow, hanging the mask over a pot of boiling water?

    Thank you Tony for pointing out the danger of putting metal in a microwave. You probably saved a lot of people a lot of money. The fire department should thank you,too.

  8. donald gillies | June 30, 2020 at 12:59 pm | Reply

    I read that most of the benefit of an n95 respirator for mid sized particles was from electrostatic charges in The mask which would be ruined by steam. I think these people do not know what they are talking about

  9. NightNurseICUwithCovidPatients | June 30, 2020 at 1:43 pm | Reply

    Donald and David, I to have been reading up on the electrostatic charge as well and have concerns about wearing reprocessed masks. I read one study by a lab that made their own N95 equivalent fabric, charged it and sandwiched it between two non charged pieces of the same fabric. According to their studies, humidity decays the electrocharged layer in over 5 hours. I’m guessing that’s why before Covid, when we wore these masks with TB patients, they were meant o be used once and then away i.e. wear a new mask every time we enter the room. I feel so protected now. (sarcasm in case it wasn’t noted)

  10. I wonder, would the SoClean2 machine work for sanitizing N95 masks?

  11. Rustie Rothstein | June 30, 2020 at 2:02 pm | Reply

    What about the metal nose bridge? Doesn’t that cause problems in the microwave?

  12. Howard Fersko | June 30, 2020 at 3:35 pm | Reply

    Jusr hang your mask on your rearview mirror in the sun for a few hours.

  13. Note re metal nosepiece in microwave concerns.”It is important to note that the microwave treatment did not result in sparks even when there was metal present on the N95, which is consistent with previous reports (4)

  14. Kim Kaberline | June 30, 2020 at 4:26 pm | Reply

    Seemed like a good idea in theory, but as was pointed out does not work in practice. There is a metal nose strip. I forgot about this, and managed to put out the fire. One ruined mask. One ok microwave. One lesson learned. Seems to me they should have thought of that.

  15. Julie Fleiser | June 30, 2020 at 4:46 pm | Reply

    Putting a wet toothbrush in the microwave for one minute will kill germs on the brush. Make sure that there is no metal on it.

  16. You can use an OZONE generator. It fills a closed space with ozone leaving no oxygen. Kills bacteria, germs, viruses, etc. Nothing new about it. Can get a decent one around 100$ or less. It’ll disinfect anything within it’s contained area.
    Will not Cure Covid, You can’t breathe without oxygen don’t try😅

  17. They DID share the method. The link is right at the bottom of the article, complete with descriptions and even photos to show how they did it.

  18. ELIZABETH McCormick | June 30, 2020 at 5:33 pm | Reply

    Whoever’s want those N95,KF94 masks I will provide for you who is ready.
    Over around 1millio-3millions possible.

  19. ELIZABETH McCormick | June 30, 2020 at 5:36 pm | Reply

    Whoever’s want those N95,KF94 masks I will provide for you who is ready.
    Over around 1million-3millions could be possible.

  20. A question here is are u sure it’s the steam that’s killing the virus or the microwave. Did u try just with microwave.

  21. I keep my mask in a zip log bag and place it in the sun on the dark dashboard in the car. I don’t know if it works but I think the heat created inside would kill the Coronavirus. I have 4 masks and use a different one every day, so they are in the sun for 4 days.

  22. Todays science community is ridiculous. First we are lied to about n95 masks being ineffective against covid. Now we are told of a method to decontaminate an n95 masks that destroys the adhesive leaving a gap between the filter and plastic, as well as causing a potential fire hazard because of the presence of a metal strip. You are all being lied to ladies and gentlemen. Ozone and UVC are effective methods of decontaminating a mask and not a microwave. I understand that hospitals need n95 masks, UV, Ozone equipment and supplies, but to mislead the public is a terrible thing to do.

  23. Yes, there is a link to the article that ultimately describes the process, but whomever described the article as an “easy” read is on a cocktail of drugs! I’ll bet some biochemical engineers would get lost in all that verbiage!

  24. Carol Thomas-Knowles | July 1, 2020 at 12:09 am | Reply

    Microwave steam decontamination of N95 mask

    Mesh from produce bags (multiple variants were utilized in this study) were secured across the top of a glass container with rubber bands. The glass container (Snapware 4-cup food storage container made with Pyrex glass) is roughly 17 cm × 17 cm × 7.5 cm (6.5 in × 6.5 in × 3 in).

    The glass container was filled with 60 ml (1/4 cup) of distilled water for steam generation. N95 respirators were placed outward facing side down, onto the mesh, for direct suspension above the steam.

    The N95 respirators were then treated for 3 minutes in either a 1,150-W or a 1,100-W microwave, with a turntable.
    Our method resulted in almost complete sterilization after only 3 min of treatment. The integrity of N95 filtration nor the fit of the respirator were effected with repeated treatment.

    Cumulatively, fit, seal, and filtration were preserved even after 20 consecutive treatments.

  25. One would think perhaps it is the steam that is doing the sterilizing. I wish they would do a study just suspending the masks over a steaming pot on the stove top.

  26. Basil J F Andrea | July 1, 2020 at 1:12 am | Reply

    The method is correct but has an issue, There is aluminium in N95 this generate a point of high heat this damaged the mask,
    even in a surgical mask, there is a conductive material and wires this also generates a hot point.
    Yes FM eq will help but they have to cover the aluminium or metal in the mask,

  27. There is no rapid spread of this Corona virus. A large increase in testing is producing a large increase in individuals with antibodies of the virus which means they had A Corona virus at some point in the past. It could have been from 3 or 4 years ago. Corona viruses make up 7 to 15 percent of seasonal flu every year. This virus will be with us forever, occasionally it will return. We are almost to the point where we have achieved herd immunity to it and its potency is waning as it gets warmer. Now is the time people need to be exposed to a weakened strength of the virus so their immune system can create a defense to it in the future.
    You don’t need to wear a mask. Only if you are working in a health care setting where you are near people that would be at high risk if they got or had the virus.

  28. please do not try the Microwave Generated Steam (MGS) method. in addition to metal strip producing large electric field followed by sparks, the water can become superheated and explode causing severe burns. if the steam is causing the effect, try a bamboo steamer ($20.00), much safer BSGS method.

  29. These masks are one time use. Microwave will melt the meltblown fibers. The real reason our government is pushing this snake oil is to not have to depend on Chinese KN95 masks so Trump can sustain his trade war.

  30. Ultimately, we selected a generic glass container sized at 17 × 17 × 7.5 cm (length [L] × width [W] × height [H]) that had an opening large enough to expose the entire N95 respirator to the vertical column of generated steam. As with the ceramic mug, we secured mesh from a produce bag over the top of the container with a rubber band and added 60 ml of distilled water to the basin (Fig. 3A and B). We repeated a sterilization time course against 1-cm2 N95 respirator coupons in 1-min increments. After 2 min of microwave steam treatment, we were unable to detect residual viable phage on the coupons (Fig. 3C). This represents a 1-min reduction in sterilization time compared to the ceramic mug decontamination assay, indicating that the glass container is a more efficient decontamination system.

    FIG 3
    Open in new tab
    Download powerpoint

  31. Elizabeth McCormick you have several N95 Masks available is that correct based on your comment? How do I get ahold of you?

  32. John Chapman | July 2, 2020 at 1:55 am | Reply

    Has any one tried a pressure cooker?

  33. This is an interesting article, but unfortunately it does not reflect real world use. We found that disposable N95 respirators are damaged simply by wearing the mask. Nearly half of respirators were did not pass an OSHA fit test and were unable to effectively block aerosolized particles after 4 days of use. Another group quoted in the linked paper found similar results.

  34. Your article will surely help many people, thanks for sharing!
    Covid-19 is a disaster for the whole world, may all come through it safely

    For some questions about microwaves and Covid-19, see this article.

  35. zeeshan yameen | May 2, 2021 at 3:50 am | Reply

    Thanks for sharing such a wonderful knowledge. nice article

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