Three decontamination methods for N95 masks – as discussed in decontamination and reuse webinar


Because of the shortage of N95 masks, institutions have implemented their own procedures for decontamination and reuse. The pros and cons of the three most common decontamination methods were discussed in the webinar, with the emphasis that there is no replacement for using new masks, and decontamination and reuse of the masks is an emergency practice only to be employed during the COVID-19 pandemic. Additionally, this webinar was a discussion, and does not make up an official recommendation for practice.

Heat and humidity approach

-has been used for influenza and SARS-CoV-1 in the recent past

-heat is effective for inactivating viruses, but is less effective for bacterial and mold spores

-conditions that kill virus while maintaining integrity of mask filter: 60 minutes at target temperature between 70-85 °C and target relative humidity between 50-85%

-no FDA-approved process yet

-challenge in retaining high enough level of humidity

-masks should be returned to the same users

-more details found at n95decon.org

Ultraviolet light approach

-germicidal UV-C region of electromagnetic spectrum: inactivates pathogens by damaging their genomic material

-evidence shows that a dose of UV-C irradiation, , inactivates viruses similar to SARS-CoV-2 on the majority of tested N95 pieces, shown at n95decon.org

-not effective for all the respirators

-high dose because inner filtration layers see a much lower dose

-N95 pieces can undergo 10-20 cycles of this dose

-masks returned to same user

-must be aware of shadows or creasing in the material that could block the UV-C

Hydrogen peroxide approach

-powerful sterilant and readily available at hospitals

-generates dangerous vapors so N95 masks must be aerated and free of the vapors before use

-when exposed to biological materials, it reacts with proteins like the coating of SARS CoV-2 and can destroy DNA and RNA

-can penetrate small spaces

-requires expensive equipment and trained personnel

-different protocols based on different equipment and what is available in different facilities

-five methods approved by FDA

The webinar was hosted by N95DECON,AAMI, AORN, and IAHCSMM, and can be found at https://www.aami.org/news/news-detail/2020/04/29/n95-mask-decontamination-and-reuse-webinar.

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