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Report: Decontamination Methods for 3M N95 Respirators

Publication Date: 2020

During this public health emergency of the COVID-19 pandemic outbreak, many healthcare institutions are experiencing shortages of N95 respirators. The U.S. Center for Disease Control (CDC) has issued Strategies for Optimizing the Supply of N95 Respirators. In this document the CDC recommends conventional capacity strategies, contingency capacity strategies (during expected shortages) and crisis strategies (during known shortages).

Contingency and crisis strategies include use of N95s past their shelf life, extended use of N95s, use of other types of respirators, use of respirators from other countries, and re-use of respirators, ahead of decontamination of respirators.

The CDC discusses reuse and extended use of N95s as a Crisis strategy at Recommended Guidance for Extended Use and Limited Reuse of N95 Filtering Facepiece Respirators in Healthcare Settings and has published new guidelines on Decontamination and Reuse of Filtering Facepiece Respirators. CDC says research indicates the virus survives for up to 72 hours on a variety of surfaces. Therefore, CDC is recommending a wait and reuse approach before consideration of other decontamination approaches.

Per the CDC guidelines, a number of sterilization companies are assessing decontamination processes for N95 filtering facepiece respirators (FFRs). The U.S. Food and Drug Administration (FDA) is evaluating granting Emergency Use Authorizations (EUAs) for such decontamination systems during the COVID-19 outbreak. Issued EUAs for Personal Protective Equipment with regards to COVID-19 will be available on the FDA website: Personal Protective Equipment EUAs 3M is collaborating with several sterilization companies and institutions that are investigating ways for hospitals to safely decontaminate 3M’s N95 FFRs in line with the CDC guidance on Decontamination and Reuse of Filtering Facepiece Respirators. 3M has been studying ways to sterilize, disinfect or decontaminate filtering facepiece respirators for years.

There are at least four key aspects of successful decontamination reprocessing of respirators, and many published studies do not take all four into consideration. The method must:

• inactivate the target organism, such as the virus that causes COVID-19; • not damage the respirator’s filtration; • not affect the respirator’s fit; • and be safe for the person wearing the respirator.

If, as a result of decontaminating a respirator, 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, FFP2, etc. In 3M’s work with external manufacturers of sterilization/decontamination equipment, 3M relies upon the method developer to confirm the germicidal efficacy of the method and to provide information on potential hazards to the respirator user.

To that effect, 3M is testing certain 3M N95 FFRs regarding the effect of the decontamination processes on fit and filtration performance. We are in the process of testing treated 3M respirators from multiple sterilization companies and institutions.

Methods under evaluation include Vaporized Hydrogen Peroxide, Ultraviolet light (UV), and Low Temperature Moist Heat, amongst others, as reflected in the CDC Guidance. Other methods of decontamination are being discussed in public forums, including liquid chemical decontamination, ozone, and time-based methods but 3M is not prioritizing investigation of these methods at this time.

Additional information about many decontamination methods can be found in the CDC guidance on Decontamination and Reuse of Filtering Facepiece Respirators, but again, many published studies have not considered all four of the aforementioned aspects of acceptability. 3M remains committed to providing data to the health care community as soon as possible.

The full report can be found here:

About the Mask-Sanitizer:

The Mask-Sanitizer is a Portable On-Site Face Mask Disinfection Chamber for disposable face masks. The disinfection method is eight (8) germicidal UV-C bulbs positioned in front of and behind the N95 face masks. 10 face masks can be disinfected during each 15-minute cycle. The Mask-Sanitizer can be used at hospitals, fire stations, police stations, nursing homes, etc., and can be located near the actual point of use. One or more mask-sanitizers can be located at each station, department, wing, hallway or emergency room, so there is no need to handle and disinfect mass numbers of masks at a central or off-site location. The Mask-Sanitizer is simple to operate, easy to roll around, and versatile enough to be transported in the back of a minivan or SUV.

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