Dry Heat as a Decontamination Method for N95 Respirator Reuse

A pandemic such as COVID-19 can cause a sudden depletion of the worldwide supply of respirators, forcing healthcare providers to reuse them. In this study, we systematically evaluated dry heat treatment as a viable option for the safe decontamination of N95 respirators (1860, 3M) before their reuse. We found that the dry heat generated by an electric cooker (100 °C, 5% relative humidity, 50 min) effectively inactivated Tulane virus (TV, >5.2-log₁₀ reduction), rotavirus (RV, >6.6-log₁₀ reduction), adenovirus (AdV, >4.0-log₁₀ reduction), and transmissible gastroenteritis virus (TGEV, >4.7-log₁₀ reduction). The respirator integrity (determined on the basis of the particle filtration efficiency and quantitative fit testing) was not compromised after 20 cycles of a 50 min dry heat treatment. On the basis of these results, dry heat decontamination generated by an electric cooker (e.g., rice cookers, instant pots, and ovens) could be an effective and accessible decontamination method for the safe reuse of N95 respirators. We recommend users measure the temperature during decontamination to ensure the respirator temperature can be maintained at 100 °C for 50 min.