NIH Study Evaluates Decontamination Methods for Re-Use of N95 Respirators

N95 respirators can be decontaminated effectively and maintain functional integrity for up to 3 uses, according to a study by the National Institutes of Health (NIH).

Researchers at the NIH's Rocky Mountain Laboratories (RML) in Montana and the University of California, Los Angeles tested decontamination methods for N95 filter fabric that had been exposed to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in small sections. Decontamination methods tested included vaporized hydrogen peroxide (VHP), 70-degree Celsius dry heat, ultraviolet light, and 70% ethanol spray.

Each method eliminated detectable viable virus from the N95 fabric test samples, according to the study authors. Fully intact, clean respirators were treated with the same decontamination methods to test their reuse durability. Volunteer RML employees wore the clean masks for 2 hours before decontamination was repeated 3 times with each mask using the same procedure.

Ethanol spray damaged the integrity of the respirator's fit and seal after 2 decontamination sessions, and, therefore, is not recommended for N95 respirators, according to the study authors. Fit and seal problems occurred after 3 decontaminations with ultraviolet (UV)-and heat-treated respirators, suggesting that these respirators could be re-used twice, according to the study.

The study authors concluded that the VHP treatment was the most effective decontamination method, as the masks experienced no failures during their test run with the RML volunteers. No virus was detected after only a 10-minute VHP treatment, whereas UV and dry heat were acceptable decontamination procedures as long as the methods were applied for at least 60 minutes, according to the study authors.

Anyone who is decontaminating an N95 respirator should check the fit and seal over the face before each re-use, as recommended by the study authors.

REFERENCE

NIH study validates decontamination methods for re-use of N95 respirators. NIH. https://www.nih.gov/news-events/news-releases/nih-study-validates-decontamination-methods-re-use-n95-respirators. Published April 15, 2020. Accessed April 16, 2020.