3M, others may have unmasked a solution to future N95 shortages

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3M, others may have unmasked a solution to future N95 shortages

A handful of companies including 3M are working to ensure that a scramble for disposable masks never happens again. The face of the next pandemic could be A handful of companies including 3M are working to ensure that a scramble for disposable masks never happens again.

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The face of the next pandemic could be very different than that of COVID-19, thanks to a handful of companies that have redesigned reusable industrial face masks to better protect healthcare workers and help prevent mask shortages.

The makers of reusable elastomeric half-mask respirators designed them for industrial use with two inhalation valves flanking an exhalation valve. The exhalation valve enables wearers to breathe out comfortably and keeps the rubber masks from becoming too hot. Some healthcare workers had been using them during the pandemic, but the FDA became concerned last year about the possibility of spreading the virus through the exhalation valves.

Three companies — 3M, MSA Safety and Dentec Safety Specialists — recently gained NIOSH approval for elastomeric respirators they redesigned by either removing the exhalation valve or fitting it with a new filter and valve to trap the virus inside. HHS plans to buy some of the redesigned masks.

The proposed fixes may sound easy, but the companies had to figure out where and how to safely and comfortably channel wearers’ outbreaths without leaving them uncomfortably warm, according to NIOSH.

How 3M did it
Maplewood, Minn.–based 3M developed a new exhalation filter and valve to fit its 6000 series of elastomeric half-mask respirators, which had been used occasionally in healthcare before the pandemic, according to Nikki Vars McCullough, director of application engineering and regulatory affairs in the company’s personal safety division.

In addition to selling new respirators, the company wanted to offer the new exhalation filter and valve to those who already owned them.

“That was really important to us because anytime you buy a new facepiece or a new design, the healthcare workers have to go through what’s called a fit test,” McCullough said. “We didn’t want people who already had these respirators to have to go through another fit test. We didn’t want them to have to go through new training.”

With the 3M elastomeric half-mask respirators, it’s possible to remove the inhalation and exhalation valve filters and wipe them off as well as separately submerging the facepiece in water for cleaning. “Once the (virus) particles are captured by air filter media, they stick to those fibers. They don’t come back off. They’re really, really stuck,” McCullough said.

Determining the best filter media to capture virus particles and still be comfortable for breathing was another challenge for 3M. Company engineers had to make sure the new exhalation valve filter would seal properly and that it would not impede the wearer’s line of sight. Plus, the company had to develop new machines to manufacture the new exhalation valve filter and scale that manufacturing capability to meet demand.

NIOSH approved the product in January 2021, and 3M has begun selling it to healthcare providers.

“NIOSH hadn’t really approved an accessory like this before. These were not ever needed before,” McCullough said. “This was a solution that we came up with in a short period of time. I’m very proud of it.”

Smaller companies take up the challenge
MSA Safety, based near Pittsburgh in Cranberry, Pa., developed a half-mask respirator with no exhalation valve for use in healthcare settings. MSA also worked with Allegheny Health Network, a 12-hospital system based in Pittsburgh, to test the masks.

MSA engineers had to figure out how to redirect exhaled breath through the inhalation filters at the same high filtration level while ensuring the breathing resistance was still low, according to Zane Frund, executive director of product research and development for the company.

To test its reusability, MSA staff also immersed their respirator in several types of disinfecting solutions for up to two weeks, then reassessed it for fit and function, Frund said.

NIOSH approval, which typically takes a few months, took just weeks for MSA’s healthcare-appropriate respirator, MSA Advantage 290. The company has since sold it to more than 20 hospitals and hospital networks in the U.S. and Canada and is working with a medical consultant on European medical approvals, Frund said.

Meanwhile, Allegheny Health has switched its entire staff to MSA’s elastomeric half-mask respirators. It is working with NIOSH (as is the University of Maryland) to develop best practice guidelines for other healthcare organizations to use them.

Making masks personal
A third company, Dentec Safety Specialists (Newmarket, Ontario), has been making elastomeric half-mask respirators for industrial use for 40 years in its Lenexa, Kan., factory, according to president Claudio Dente.

Dentec designed its new Comfort-AirNx series with two-way filtration through the same filters rather than having a separate exhalation filter.

To test it out, company employees wore the new mask and measured the temperature inside it at 45-second, one-, two-, five- and 10-minute intervals to see how quickly it heated up. They concluded it was more comfortable to wear than a disposable respirator.

The mask wearer then walked at a brisk pace for 500 steps, simulating a healthcare worker’s movement, then breathed hard for 20 breaths and did temperature readings inside the mask five and 10 minutes later. Repeated tests showed the ComfortAir Nx MD elastomeric mask produced a temperature slightly below that of a disposable N95 mask without an exhalation valve, according to the company.

“It’s all about how hard it is to breathe,” Dente said. “We wanted to measure the heat buildup inside the mask versus an N95 disposable versus a 3-ply disposable surgical mask.”

The new mask’s material is also different. When the virus first hit New York City and the country shut down, people frantically called and emailed Dentec, begging for respirators. Dente watched the TV coverage of overwhelmed hospitals and PPE-encased workers hovering unrecognizably over sick and dying patients and vowed to do something — manufacture new respirators out of white elastomeric rubber instead of the usual black.

“I made it in white on purpose so you can write a message,” Dente explained. “You can say, ‘I care for you.’ It was about having to have some type of humanity.”

Uncle Sam is buying
In mid-February 2021, the U.S. Department of Health and Human Services posted a request for bids to supply the Strategic National Stockpile with 375,000 elastomeric half-mask respirators that meet the new NIOSH requirements. 3M, MSA Safety and Dentec Safety Specialists all submitted bids by the March 17 deadline. HHS has yet to award the contract(s).

NIOSH will send a portion of the respirators it buys under the contract to about 90 healthcare organizations to test the best practice guidelines drawn up by Allegheny Health and the University of Maryland, according to Maryann D’Alessandro, who directs the National Personal Protective Technology Laboratory for NIOSH in Pittsburgh. NIOSH will then use that information to draw up best practices for healthcare providers nationwide.

“Our hope is, by offering these elastomerics and the powered air-purifying respirators and putting some good best practice guidelines in place for hospitals … there’s some relief provided to the inventory of respirators to the healthcare organization,” D’Alessandro said.

HHS acknowledged that these elastomeric masks cost more than disposables, but also noted that they last much longer. As part of its study, Allegheny Health concluded that the cost of the reusable masks was 10 times less per month than disposable N95s and that the cost-benefit increased the longer they are needed.

“In addition, elastomeric masks can be stored for future surges and should be considered an essential part of all healthcare facilities’ supply of personal protective equipment,” the Allegheny Health researchers reported in an article published in September in the Journal of the American College of Surgeons. “Implementation of the program has eliminated our dependence on disposable N95s to maintain normal operations during the global pandemic.”