COLUMBUS, Ohio (July 9, 2020)—The largest decontamination effort is overseen by Battelle Memorial Institute, an Ohio nonprofit company.
Will Richter, a microbiologist and principal research scientist with Battelle, said the company has decontaminated about 1.2 million N95 masks at centers across the nation.
In April, Battelle was awarded a contract from the Defense Department, worth up to $415 million, to open and operate 60 decontamination centers that would sterilize respirators sent by health-care providers.
Richter said Battelle found that 20 different models of N95 mask, and 10 foreign-made masks, remain effective through 20 cycles. The company has also cooperated with 3M and the CDC’s National Institute for Occupational Safety and Health to evaluate the Battelle system.
Battelle’s systems use vaporized hydrogen peroxide. Each system can sterilize about 5,000 masks at a time in a process that takes about 24 hours, Richter said.
While the CDC has approved Battelle’s methods for up to 20 sterilization cycles, Richter said, the company has its own quality controls. Masks that are stained, often from makeup, or otherwise appear soiled, aren’t processed. Also pulled out are masks with apparent material flaws such as broken straps.
After a batch of masks has been decontaminated and “air washed” to allow residual gas to dissipate, workers use gas detectors to determine if the amount of hydrogen peroxide gas is below the OSHA permissible exposure limit, Richter said. The OSHA limit is 1.0 parts per million, but Battelle enforces a stricter limit, 0.8 parts per million.
Of the 1.2 million masks Battelle has processed and returned, the company has received complaints about fewer than 0.5% of the masks, Richter said.
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