Archive for the ‘Supply Chain’ Category

N95 Mask Sterilization Idea

March 19, 2020

SARS-CoV-2_without_background2This is an urgent call for expert help to quickly test a possible method to sterilize used N95 masks.  

In many places, hospital staff, first responders and others are at grave risk due to inadequate supplies of N95 masks. Already, some hospitals even in the U.S. report running out of N95 masks and face reusing possibly contaminated masks. My local fire department has about 20 N95 masks total available, as they face transporting patients to the hospital. People are faced with reusing masks without sterilization. I offer an idea that might alleviate the critical shortage. I have run this idea past my pulmonary care doctor of many years who believes that the idea may be viable, but everyone on the front lines of the epidemic are already working flat out.

I sent the letter below to Dr. Anthony Fauci that sets the context.

People with the right expertise are needed to vet the idea and ensure that it is safe and effective as quickly as possible.

Anthony S. Fauci, M.D., NIAID Director
NIAID Director
National Institutes of Health

Dear Dr. Fauci,

N95 masks are in critically short supply. Sterilization of disposable masks N95 could be a way to greatly stretch the supply during the Covid-19 pandemic. 

I recently bought a SoClean 2 device to sterilize my CPAP equipment. It is ozone based, and convenient to use and the SoClean device is in mass production. The SoClean functions by circulating ozone through the CPAP tube, humidifier and through a box where the CPAP mask and headgear is easily deposited. Ozone is used in other medical devices for sterilization; e.g. the Genlantis products. These devices might be useful to stretch the supply of N95 masks.

Multiple masks could be sterilized once; the machine takes my full face mask and headgear, which is quite bulky. with space left over.  The SoClean device could be simply modified to use a much larger capacity box, enabling many more masks to be sterilized each cycle.

However, testing is needed to verify that ozone does not damage the masks, length of time required to inactivate the Sars-CoV-2 virus, whether there are limits on how many times a disposable mask might be sterilized, and the length of time required for sterilization. Some N95 masks contain activated charcoal to remove odors or volatile compounds. Activated charcoal is used in the SoClean machines to inactivate the ozone; guidelines are needed to specify which masks types are compatible. 

For example, using 10 minutes/cycle (the default cleaning cycle for CPAP is 7 minutes), and if 10 masks fit in the machine each cycle, a single unmodified SoClean machine might sterilize as many as 1440 masks per 24 hours, thereby stretching supplies significantly. I know that if we have to nurse Covid-19 at home that I will try this; it can’t be worse than nothing…


Jim Gettys

The SoClean machines are sold to CPAP users without prescription, and already present in many hospitals. There are other similar technology machines on the market, as well as one based on UV light. When I asked my doctor if I should bring my machine for testing, he said he already had access to several at his hospital. 

If you have been looking for some way to help, and have the right experience (are a present or former ICU/pulmonary doctor, have experience with virology, medical devices, materials science, 3D printing) and facilities, please join the effort. This could save many lives, particularly of first responders and medical people who are on the front lines of the epidemic.

We need the right people with the right expertise, facilities, and time available to vet the idea. Hospitals that might normally look into such ideas are either overwhelmed or preparing for incoming patients, and their people are at risk.

If you believe you have the experience, expertise, time or facilities to test this idea, please join the discussion at To subscribe, visit:

This effort is dedicated to the memory of Li Wenliang.