Mass General/Harvard Lab Using Hydrogen Peroxide Vapor to Decontaminate N95 Masks

by Elizabeth Hofheinz, M.P.H., M.Ed., April 24, 2020

They didn’t secure 500,000 test kits from South Korea. They did something equally and perhaps even more exciting—they created a way for nearly any facility to become self-reliant in the decontamination of N95 respirator masks during a global shortage of personal protective equipment.

When Lauren Hoogendyk, Executive Director for Mass General Orthopaedics, approached Orhun Muratoglu, Ph.D., Director of the Harris Orthopaedics Laboratory at Massachusetts General Hospital, she was bringing a message from the hospital leadership: it’s time to figure out a way to 3D print a ton of N95 masks.

A materials scientist goes to work…

But Dr. Muratoglu, part of the team that developed highly crosslinked polyethylene used in most of today’s joint replacements, was convinced there was a better way. Surmising that COVID-19 isn’t disappearing anytime soon, Dr. Muratoglu was thinking “reuse” instead of “create new.”

“N95 masks are very high tech and have an electrostatically charged filter that keeps out the particulate matter in the air. Typically a single-use mask, an N95 is difficult to reuse because they must be thoroughly decontaminated. I began with testing electron beam irradiation to decontaminate the masks using the same World War II era electron beam I used to crosslink ultra-high-molecular-weight polyethylene (UHMWPE) about 20 years ago at MIT. Unfortunately, with this technique, the electrostatic charge disappeared. In essence the masks became N25, thus allowing 75% of particulate matter through.”

The Harris Lab team then looked at ethylene oxide gas, hydrogen peroxide gas, heat, and UV radiation.

And the winner was?

“We selected hydrogen peroxide vapor because it has the capability of achieving six orders of magnitude of kill on the virus while maintaining N95 filtration and fit efficacy. We linked up with the National Emerging Infectious Diseases Laboratories (NEIDL) at Boston University and asked them to spike masks with COVID-19 and then decontaminated them using this vapor. We achieved complete eradication of the virus within 3 hours of exposure to the hydrogen peroxide vapor with no compromise of mask function. We just disseminated our findings in a preprint.”

Self-starters…and some help…

“We decided to build a special room at Mass General with our own hydrogen peroxide generator. The capacity of each ‘run’ was 2,000 masks—good, but not enough. This same week, we learned that Battelle, a defense contractor that does a lot of bioterrorism-related research, had just received an emergency use authorization from the FDA to run a high throughput hydrogen peroxide vapor system with the capacity to decontaminate 80,000 N95 masks per day. We signed an agreement with Battelle a few days later, identified an old Kmart facility to setup Battelle’s outfit, and a week later we had Battelle’s shipping containers flooded with hydrogen peroxide vapor decontaminating our first batch of N95 masks from Mass General and Partners Healthcare System front-line healthcare workers.”

Gaining traction…

Now with the system in place, the team had to gain traction with clinicians to re-use their N95 mask. Dr. Christopher Bono, Executive Vice Chair of the Department of Orthopaedic Surgery, first broached the topic with his cross-department surgical colleagues. “At first, the general surgeons didn’t seem to notice the significance of the effort. How could the orthopaedic department possibly help with a medical disease? They became increasingly interested over time as our supply challenges loomed. In the end, if I did anything, I helped others gain some comfort in using a previously used mask.”

Following this model, the team brought in nursing, anesthesia, medicine and other clinical champions to educate a broader audience.

Soon enough, with every department clamoring for its masks to be put through this process, Dr. Muratoglu and his team had to ramp up their efforts. “We soon received 5,000 masks from three Partners Healthcare hospitals.”

Describing the process in detail, Lauren Hoogendyk states, “The Battelle system is now being used for all Partners Healthcare facilities. When someone takes a new N95 they write a unique identifier along with their name, they use it, and then it goes through Battelle. Then the sterile processing department staff repackages it and returns it to the index user. We have also been asked to do this for Boston’s first responders and have made the system available to the entire state of Massachusetts and are getting numerous phone calls from other states.”

Taking it international…

Orhun Muratoglu is now leading a global group on the reuse of N95 masks. “Partners Healthcare System has started the COVID Innovation Center. I’ve been leading the Reuse work group at the Center, holding daily meetings with many academic, industry and hospital representatives from around the country and the globe. Our goal is to provide assistance in low resource countries on how to decontaminate masks using dry or moist heat and UVC radiation for safe reuse.”

So in Massachusetts and beyond…if the virus is there, the Mass General Harris Orthopaedic Lab will be there as well.