Last updated: April 1, 2020
The APSF recognizes that there is great interest and need for re-using N95 masks during this period of mask shortages. A variety of cleaning and decontamination processes have been reported. The CDC provides guidance on the short-term and long-term re-use of N95 masks (https://www.cdc.gov/niosh/topics/hcwcontrols/recommendedguidanceextuse.html).
It may be possible to reduce or eliminate coronavirus from N95 masks. Three documented approaches to decontaminating coronavirus from N95 masks include the use of hot air and/or room air drying, ultraviolet light, and hydrogen peroxide vapor-linked processing.
There is still controversy as to whether these processes completely eliminate viable SARS-CoV-2 while having no negative impact on the filtration/fit properties of N95 masks. To provide context, we have provided a link to the official statement on “Disinfection of Filtering Facepiece Respirators” from one of the major manufacturers of the common N95 masks, 3M and published on March 20, 2020.
- Peter Tsai, emeritus professor of the University of Tennessee and the inventor of the filter media used in N95 masks, provides his insights on how to re-use N95 masks during the COVID pandemic (https://utrf.tennessee.edu/information-faqs-performance-protection-sterilization-of-masks-against-covid-19/). Drying masks that have not been directly soiled with hot air (70°C or 160° F for 30 minutes) or in room air for 3 days may kill any coronavirus and allows for re-use of the masks. Note: The CDC does not support the use of hot air (e.g., an oven) to dry and decontaminate N95 masks. It suggests that the dry air heating process may reduce the viral filtering capability of N95 masks (https://www.cdc.gov/coronavirus/2019-ncov/hcp/ppe-strategy/decontamination-reuse-respirators.html).
- Duke University has found that the use of hydrogen peroxide vapor results in successful decontamination of commercially available N95 masks. The university believes that N95 sparing and reuse practices are important but not sufficient given the current COVID pandemic and thus will begin reuse after decontamination using hydrogen peroxide vapor on a large scale.
- Multiple reports suggest that ultraviolet (UV) germicidal irradiation will reduce or eliminate coronavirus from N95 masks. Examples of these reports may be found at:
- “Effects of Ultraviolet Germicidal Irradiation (UVGI) on N95 Respirator Filtration Performance and Structural Integrity”: https://www.ncbi.nlm.nih.gov/pubmed/25806411
- “Ultraviolet germicidal irradiation of influenza-contaminated N95 filtering facepiece respirators”: https://www.ncbi.nlm.nih.gov/pubmed/29678452
- N95 Filtering Facepiece Respirator Ultraviolet Germicidal Irradiation (UVGI) Process for Decontamination and Reuse” (Nebraska Medicine): https://www.nebraskamed.com/sites/default/files/documents/covid-19/n-95-decon-process.pdf
- 3M, a major manufacturer of N95 masks, has expressed concern that any of these processes may damage the filtration/fit capabilities of masks.