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California Hospitals Begin Sterilizing Previously Worn N95 Masks for Reuse, but Nurses Call Them Unsafe

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A nurse holds up a sign to protest the lack of personal protective gear available at UCI Medical Center amid the coronavirus pandemic on April 3, 2020 in Orange, California. Hospitals nationwide are facing shortages of PPE due to the COVID-19 outbreak. (Mario Tama/Getty Images)

How does California plan to stem a personal protective equipment shortage? Hospitals will sterilize previously worn N95 respirator masks and reuse them.

Across California, hospitals are readying machines to spray down masks with disinfectant, but nurses fear wearing previously used respirators may expose them to COVID-19 infection.

Some nurses claim the sterilization machines are untested, unproven and could put their lives at risk — the California Nurses Association plans to protest their use at two Kaiser Permanente hospitals in the Bay Area this week.

The two sterilization machines that will be employed across the state were granted emergency authorization by the Food and Drug Administration in the last two months in response to the pandemic.

While the FDA authorized the use of the machines, it issued a strict warning to producers of both machines that they cannot “represent or suggest that this product is safe or effective for the prevention or treatment of COVID-19.”


Yet Gov. Gavin Newsom and the hospital chain Kaiser Permanente said the sterilization method is necessary to help shore up an ongoing shortage of personal protective equipment for health care professionals on the front lines of the pandemic.

Nurses Outraged

One of the machines is produced by defense contractor Battelle, which is based in Columbus, Ohio, and will be used in public hospitals. Another respirator sterilization machine, Sterrad, produced by the Irvine-based company Advanced Sterilization Products, will be used in Kaiser hospitals. Both machines sanitize single-use N95 masks with hydrogen peroxide up to two times.

The California Nurses Association is opposing the use of Sterrad in Kaiser hospitals across California. Similarly, nurses represented by Service Employees International Union Local 1021 fear the use of Battelle’s sterilization techniques in public hospitals.

Kaiser Permanente has already issued nurses masks sterilized by Sterrad machines. One of Kaiser’s first California hospitals to get the machine was in Roseville.

“Battelle is providing critical support to our healthcare professionals across the country who are in desperate need for N95 respirator masks,” said Matt Vaughan, Battelle’s contract research president, in a press statement about its decontamination technology.

But Joanne Imwalle, a Kaiser Permanente nurse in Roseville, said the sterilization techniques for N95 masks haven’t been tested enough to grant her assurances that she won’t contract COVID-19 or spread the virus. Imwalle has worked in and out of hospitals for 37 years.

On the phone with KQED News, the nurse’s voice shook with fury.

“When I talk to my neighbor or go into a grocery store, could I infect my neighbors and community members? It’s so egregious to me it’s overwhelming at times,” Imwalle said. “I went into this to save lives, not to sacrifice mine.”

One representative of SEIU Local 1021, which represents roughly 4,000 nurses in the Bay Area, called the method “dangerous.”

“There is no plausible rationale for recycling (personal protective equipment),” said Sasha Cuttler, a nurse at San Francisco’s Laguna Honda Hospital, which experienced an outbreak of COVID-19 in early April. Cuttler, who is also the Registered Nurse Chair of SEIU Local 1021, warned sterilized masks may pose a new threat.

Statewide Shortage

Advanced Sterilization Products conducted its own tests of the Sterrad system in partnership with N95 mask manufacturers, a company spokesperson said, and submitted those test results to the FDA in order to obtain its emergency use authorization.

“FDA may issue an (emergency use authorization) when certain criteria are met, which includes that there are no adequate, approved, available alternatives, and based on the totality of scientific evidence available, it is reasonable to believe the ASP Sterrad Sterilization System may be effective at decontaminating compatible N95 respirators,” a company spokesperson wrote to KQED News.

Battelle did not respond to a request for comment.

The decontamination system produced by Battelle is based on research that Battelle itself performed for the FDA in 2015 to assess the feasibility to decontaminate N95 respirator masks in the event of a personal protective equipment shortage resulting from a pandemic, according to a public statement on the company’s website.

More Coronavirus Coverage

While the first Battelle sterilization in California began in Burbank, Newsom told KQED News on Friday that “quite literally as we speak” another Battelle sterilization unit is being assembled in Northern California.

“One of those masks arrived that was sterilized off that line from Burbank today, and was presented and shared with our team in our morning meeting, and it looks as new as any other mask,” Newsom said.

But, addressing the nurses’ worries, the governor added, “I appreciate sterilization, up to 20 times per mask, is not everybody’s first choice.”

Battelle’s own reports show its technology had 99.9% efficiency in killing bacterial spores and sterilization could be performed up to 20 times before damaging a respirator, according to the Centers for Disease Control and Prevention.

Speaking on behalf of Kaiser Permanente, David Witt, MD, said Kaiser’s “top priority” is the safety of its patients, members and staff.

“Given the global shortage of protective masks during this pandemic, we are taking every action possible to make sure our staff have the equipment they need to deliver care safely,” Witt said in a statement. “Kaiser Permanente currently uses Sterrad to sterilize N95 masks, which aligns with the CDC guidance for decontamination methods.”

Despite assurances from the CDC, nurses are concerned the FDA issued a list of risks to health care professionals for use of both sterilization methods, Sterrad and Battelle, which included the warning that “Reused respirators may not have been effectively decontaminated of SARS-CoV-2 or other pathogens.”

Unlike Kaiser, some California public hospitals issued assurances to staff that sterilization methods would not be used unless absolutely necessary. For now, they’ve said they have enough masks — but that’s dependent on the number of patients remaining low.

In an email to hospital staff obtained by KQED, UCSF, which runs departments at San Francisco General Hospital, wrote “UCSF remains committed to sourcing and distributing new N95 respirators. Redistribution of reprocessed N95 respirators will be initiated when UCSF reaches crisis levels and other options have been exhausted.”

Shifting Standards

That’s small comfort to Havilah Smith, a nurse at Kaiser Permanente San Francisco Medical Center on Geary Boulevard, who is the CNA’s chief nurse representative, and has herself treated COVID-19 positive patients.

Smith has been told Kaiser will begin distributing masks sterilized with Sterrad next week.

In the beginning, nurses disposed of an N95 mask after seeing each patient. Then they were guided to wear the masks with multiple patients and for longer periods, keeping their respirators in paper bags where Smith fears the virus may spread more easily.

“Nurses are being treated as more disposable as a health care professional than a mask,” Smith said.

As of Friday, 5,743 health care workers in California tested positive for COVID-19, according to the California Department of Public Health, with 31 health care workers confirmed dead from the virus.


KQED reporter Marisa Lagos contributed to this report.

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