N95 Mask Decontamination using Standard Hospital Sterilization Technologies

AbstractThe response to the COVID-19 epidemic is generating severe shortages of personal protective equipment around the world. In particular, the supply of N95 respirator masks has become severely depleted, with supplies having to be rationed and health care workers having to use masks for prolonged periods in many countries. We sought to test the ability of 5 different decontamination methods: autoclave treatment, ethylene oxide gassing, low temperature hydrogen peroxide gas plasma treatment, vaporous hydrogen peroxide exposure and peracetic acid dry fogging to decontaminate a variety of different N95 masks of experimental contamination with SARS-CoV-2 or Vesicular stomatitis virus as a surrogate. In addition, we sought to determine whether masks would tolerate repeated cycles of decontamination while maintaining structural and functional integrity. We found that one cycle of treatment with all modalities was effective in decontamination and was associated with no structural or functional deterioration. Vaporous hydrogen peroxide, peracetic acid dry fogging and autoclave treatments were associated with no loss of structural or functional integrity to a minimum of 10 cycles for the mask models tested. The molded N95 masks however tolerated only 1 cycle of autoclaving. The successful application of autoclaving for layered fabric, pleated masks may be of particular use to institutions globally due to the virtually universal accessibility of autoclaves in health care settings.