Islander Jim Whitney, medical services officer for the Redmond Fire District, said that keeping up morale among first responders has been a priority since day one of the COVID-19 pandemic.

“The anxiety and fear associated with COVID at the onset were pretty high,” he said.

But now, a tool designed by researchers working in the University of Washington’s Engineering Innovation in Health program (EIH) and manufactured on Vashon will allow emergency medical services staff to reuse invaluable N95 respirator masks, seen as the best line of defense against transmission of COVID-19 for essential workers and those on the frontline.

With assistance from Public Health – Seattle & King County and multiple agencies and foundations, UW collaborated with Vashon’s own Burn Design Lab, an island-based nonprofit that develops cookstoves for use in developing countries, and Meadow Creature, a manufacturer of steel agricultural equipment and metal parts, to design custom-built, plug-in and durable decontamination boxes that can sanitize up to 15 N95 masks at a time using a process known as ultraviolet germicidal irradiation.

The boxes use ultraviolet light (UVC) cast from four long, thin UV bulbs arranged around reflectors made from a special grade of aluminum to thoroughly destroy pathogens including SARS-CoV-2, the virus responsible for triggering the respiratory illness that, to date, has killed more than 205,000 Americans, including 2,100 people in Washington.

The devices are clad in sheet metal and weigh in at 100 pounds. They resemble large appliances such as industrial toasters and are able to get the job done quickly and effectively, decontaminating masks in only a half an hour so they can be used again up to five more times, per guidance from the Centers for Disease Control and Prevention.

Building one decontamination box requires approximately 12 hours of shop labor, said Meadow Creature Executive Director Bob Powell, adding that current decontamination systems for PPE available in the marketplace are intended more for hospital and laboratory settings rather than firehouses.

“I can speak on behalf of our employees that they were all excited to be part of doing something useful for the public goods in response to the COVID crisis,” he said. “It was a really rewarding opportunity to work in this kind of intense collaboration among so many people with such a wide range of expertise.”

For Whitney, the virus hit close to home right from the start. He oversees Redmond Medic One, which provides basic and advanced life support for all of the communities in Northeast King County. Back in March, seven medics from the same unit were quarantined after responding to the Life Care Center of Kirkland, where residents began exhibiting flu-like symptoms, Whitney recalled, in what is now regarded as one of the earliest known outbreaks of the virus in the United States.

“During that first wave, we were the EMS system that got really hit the hardest,” he said, noting that as many as 30 firefighters in Redmond were ultimately quarantined out of an abundance of caution for possible exposure to the virus, while the rest of the Seattle & King County Emergency Medical Services System looked on. Then the virus reached other communities.

Conversations began immediately about sourcing more personal protective equipment or finding ways to extend the life of what limited supplies the department had in stock, since first responders would need clean and genuine masks and PPE for every call they were on.

The district relied heavily on its existing cache of PPE, stockpiled over the years in the wake of concerns about Avian Influenza more than a decade ago.

But not everyone was comfortable with the district’s initial method for sterilizing masks, sending them off-site with a private contractor for as long as a week to be returned in a condition safe to use again.

“I get my mask back and, granted, it has my name on it. But I don’t know where it’s been the entire time,” Whitney said.

The decontamination box will make first responders safer, he added, and bring them some peace of mind. EMS staff are wrapping up their training on how to use the boxes, load masks inside and clean and service them. The district has ordered more, with the hope of sharing several across the seven fire stations in Redmond for crews to drop in and use as needed.

UW mechanical engineering doctoral student Ben Sullivan (right) shows first responders how the decontamination box for N95 masks works (Andy Freeberg Photo).

“There’s a sense of security in knowing that, ‘this is my equipment, and I’m putting my equipment in this box, and I’m closing the door and starting the timer. And 30 minutes later, I’m responsible for pulling it out of that box, and I know it’s mine,’” he said. “[There is] a lot more confidence [for first responders] in that something actually happened that made it better.”

A study published in May funded by the National Institute of Health tested ultraviolet radiation levels powerful enough to inactivate SARS-CoV-2. It found that coronaviruses are particularly UV sensitive, concluding that the SARS-CoV-2 virus — as well as possible future mutations — will very likely be highly UV sensitive and susceptible to common UV disinfection procedures.

But the consequences of the pandemic have presented numerous obstacles to gaining an edge over COVID-19 — a disease that in many ways remains a mystery to health experts — with much of the country still ground to a halt. And the team between Burn Design Lab, Meadow Creature and UW ran into some issues along the way.

A team of a dozen people conceptualized the decontamination boxes at the start of the summer remotely. Hardware was in short supply. And there were certain constraints that complicated the design. Masks cannot overlap when inside the box — otherwise the virus may evade decontamination, imperceptibly tucked away under a shadow and putting first responders at risk. The boxes would ideally be filled to capacity while simultaneously distributing the correct amount of UVC light across the entire curved surface of N95 masks. There were cost considerations — currently, the EIH program has the budget to build 75 boxes.

And they did not have much time to do it all, Daniel Casey, a mechanical engineering student at Northeastern University who joined Burn Design Lab in the spring as part of a six-month co-op program, said.

Casey never expected he would be working to tackle a facet of a global public health crisis as part of his experience on the island or play an integral role in the design and rollout of the decontamination boxes. The concept took shape during a Zoom call a few weeks into Gov. Inslee’s Stay Home, Stay Safe order. He said he jumped at the chance to use his skill set with sheet metal design to help set the project in motion.

“It was like a gun went off,” he said. “There was certainly that intensity because there’s a mounting situation. You’re watching the numbers of coronavirus cases take off in Washington. And there’s a sense of trying to get ahead of it. There’s a sense of not really knowing what comes next,” he said. “This was definitely like a sprint of a design effort.”

For all their labor, the decontamination boxes work. Researchers at UW tested eventual prototypes of the boxes completed in July, using a color-changing UV-sensitive card known as a dosimeter, in tests meant to measure and confirm that every surface of the N95 masks placed inside the boxes received the appropriate UVC dosage to eliminate the virus.

Building one decontamination box requires approximately 12 hours of shop labor. Pictured is a box with a side panel removed, showing some of the inner components of the device (Andy Freeberg Photo).

The team had some trouble with certain features of the box before finishing the project, Casey noted, lacking any direct comparisons to go by. In one instance they had to figure out how the door would seal shut and lock once the masks were placed on the drawer inside, but the original seal would not keep the door closed without applying force.

“When this is in a fire station and our users are actually using it, [we hope] they can count on it, and they don’t hate to use it,” he said. “Every day people are going to be using this. They shouldn’t hate it, they should enjoy the experience.”

Fellow Northeastern mechanical engineering student Jeremy Su recently started his own co-op experience at Burn Design Lab, coming on board to help develop a cleaner-burning shea roaster for use in West Africa. But now that Casey has returned to Boston to pursue his studies, Su is stepping into his role to supervise the next phase of the decontamination box project. The issues the team once encountered don’t phase him much.

“That’s just engineering. It’s problem-solving and working with what you have, basically,” he said.

Jonathan Posner, professor of mechanical engineering and chemical engineering and director of the EIH program at UW, said the N95 mask decontamination boxes were intended to be as user friendly as possible, because as with any safety device, if it is not used properly, then it can’t be assured to do the job it’s supposed to do.

“It’s just very challenging,” he said, noting that he has worked closely with Burn Lab and Meadow Creature in the past. “And then you build it to the best of your knowledge, and then you test it, and if it’s not doing what it’s supposed to do, then you have to modify it.”

On the surface, the project seems unlike anything Burn Design Lab has been involved with before, but Executive Director Paul Means said the detailed assembly and testing of the parts to fit the boxes together falls comfortably within their wheelhouse. Still, it is unusual. Means noted that the scale of production behind the decontamination boxes greatly exceeds the number of small, prototype stoves Burn Design Lab usually develops and manufactures in an ordinary year. Some of that work has been sidelined for now.

“But it’s a good cause. And there’s an immediate need, and we’ve got the capacity to help. And so that’s what we’re doing,” he said. “COVID has caused all kinds of disruption. And [this is] just a way for us to take a step sideways and try to do something to help the immediate need in our area here instead of a place across the world.”