Exposing contaminated N95 respirators to vaporized hydrogen peroxide (VHP) or ultraviolet (UV) light appears to eliminate the SARS-CoV-2 virus from the material and preserve the integrity of the masks' fit for up to three uses, a National Institutes of Health (NIH) study shows.
Dry heat (70° C) was also found to eliminate the virus on masks but was effective for two uses instead of three.
To test durability over three uses, researchers treated intact, clean masks with the same decontamination method and assessed function via quantitative fit testing.
The researchers found that masks that had been decontaminated with ethanol spray did not function effectively after decontamination, and they did not recommend use of that method.
By contrast, masks decontaminated with UV and VHP could be used up to three times and function properly. Masks decontaminated with dry heat could be used two times before function declined.
Results indicate that N95 respirators can be decontaminated and re-used in times of shortage for up to three times for UV and HPV, and up to two times for dry heat.