N95 respirator decontamination: a study in reusability

Wang, C.-G.; Li, Z.; Liu, S.; Ng, C.T.; Marzuki, M.; Jeslyn Wong, P.S.; Tan, B.; Lee, A.; Hui Lim, C.F.; Bifani, P.; Fang, Z.; Ching Wong, J.C.; Setoh, Y.X.; Yang, Y.Y.; Mun, C.H.; Fiona Phua, S.Z.; Lim, W.Q.; Lin, L.; Cook, A.R.; Tanoto, H.; Ng, L.-C.; Singhal, A.; Leong, Y.W.; Loh, X.J.

The coronavirus disease 2019 (COVID-19) pandemic had caused a severe depletion of the worldwide supply of N95 respirators. The development of methods to effectively decontaminate N95 respirators while maintaining their integrity is crucial for respirator regeneration and reuse. In this study, we systematically evaluated five respirator decontamination methods using vaporized hydrogen peroxide (VHP) or ultraviolet (254 nm wavelength, UVC) radiation. Through testing the bioburden, filtration, fluid resistance, and fit (shape) of the decontaminated respirators, we found that the decontamination methods using BioQuell VHP, custom VHP container, Steris VHP, and Sterrad VHP effectively inactivated Cardiovirus (3-log(10) reduction) and bacteria (6-log(10) reduction) without compromising the respirator integrity after 2–15 cycles. Hope UVC system was capable of inactivating Cardiovirus (3-log(10) reduction) but exhibited relatively poorer bactericidal activity. These methods are capable of decontaminating 10–1000 respirators per batch with varied decontamination times (10–200 min). Our findings show that N95 respirators treated by the previously mentioned decontamination methods are safe and effective for reuse by industry, laboratories, and hospitals.