Is the fit of N95 facial masks effected by disinfection? A study of heat and UV disinfection methods using the OSHA protocol fit test.

Amy DPhil Price; Yi Cui; Lei Liao; Wang Xiao; Xuanze Yu; Haotian Wang; Mervin Zhao; Qiqi Wang; Steven Chu; Larry F Chu

OSHA states, "The N95 filtering facepiece respirator is a "disposable respirator." It must be discarded after use, or when it becomes damaged or soiled. It cannot be cleaned and disinfected according to Appendix B-2. OSHA is presently not aware of any alternate procedures provided by respirator manufacturers in their user instructions that would allow for cleaning and disinfecting their filtering facepiece respirators." 6 The largest N95 respirator manufacturer 3M admonishes that disinfection be effective against the target organism, such as the virus that causes COVID-19, retain respirator filtration, not affect the respirator's fit; and be safe for the person wearing the respirator. If the filtration is damaged or the respirator does not fit, it will not help reduce exposure to airborne particles at the level indicated, such as N95. They report on March 27,2020, no disinfection method met all four of these key criteria, and without all four, the method is not acceptable 7 .