Advisory Notice

April 3, 2020


The COVID-19 coronavirus pandemic is causing a critical worldwide shortage of personal protective equipment (PPE). Recently issued Public Health Emergency Guidelines from the FDA and CDC have provided some guidance on coping with these shortages:

Enforcement Policy for Sterilizers, Disinfectant Devices, and Air Purifiers During the Coronavirus Disease 2019 (COVID-19) Public Health Emergency
Enforcement Policy for Face Masks and Respirators During the Coronavirus Disease (COVID-19) Public Health Emergency
Recommended Guidance for Extended Use and Limited Reuse of N95 Filtering Facepiece Respirators in Healthcare Setting

Third-party studies have indicated that some N95 masks could potentially be safely sterilized one or more times at 250°F (121°C) for 15 minutes:

Sterilization of Disposable Face Masks by Means of Standardized Dry and Steam Sterilization Processes
Filter Quality of Electret Masks in Filtering Aerosol Particles after Decontamination
COVID-19 Evidence Service| Addressing COVID-19 Face Mask Shortages [v1.2]
National Institute for Occupational Safety and Health (NIOSH): Evaluation of Five Decontamination Methods for Filtering Facepiece Respirators
Safety of Extended Use and Reuse of N95 Respirators

Midmark and Ritter M9® and M11® steam sterilizers provide a longer pre-programmed sterilization cycle of 250°F (121°C) for 30 minutes (the Packs cycle), a cycle which has been validated and based on the FDA policy linked above is effective to inactivate COVID-19 coronavirus. At this point, we do not have data to confirm that the performance of N95 masks is not compromised after a sterilization process is complete in a steam sterilizer.

There are known risks with sterilizing some N95 masks with steam sterilization including damage to the mask and some filtration degradation. Users should carefully inspect masks prior to use. Please note, some PPE manufacturers have identified similar risks regarding the use of steam sterilization on their products. Disinfection of Filtering Facepiece Respirators

We recommend that clinicians review this data and use their best clinical judgement regarding the use of tabletop steam sterilizers to sterilize N95 masks for reuse during the current pandemic.

Importantly, always refer to the PPE manufacturer’s website and instructions for use as the principle sources of information regarding this issue.

Refer to the Midmark or Ritter M9® and M11® steam sterilizer user guide for cycle parameters and to ensure proper use of the unit. Note that this Advisory Notice does not apply to other Midmark and Ritter steam sterilizers. If you have further questions, please contact Midmark Technical Service at 1.800.MIDMARK.

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