Decontamination methods can damage N95 masks
Click Here to Manage Email Alerts
Some decontamination methods — specifically, methods using high concentrations of gas plasma hydrogen peroxide — can substantially damage N95 masks after only one process, according to study data published in Infection Control & Hospital Epidemiology.
“As this pandemic took hold, it was clear our supply chains were unable to keep up with N95 demand that would be needed to keep frontline clinical workers safe. In response, the FDA approved a series of decontamination methods, virtually overnight, with no further respirator performance testing required,” Richard E. Peltier, PhD, associate professor of environmental health sciences at the University of Massachusetts, told Healio.
Source: Adobe Stock
“These respirators are, and have always been, designed to be disposable,” Peltier said. “As a scientist who is both an atmospheric chemist and an environmental health scientist, I was skeptical that all these methods that FDA assumed would be safe would work. It turns out that some methods do damage respirators and leak particles through the N95 mask material, and someone wearing this decontaminated respirator would never know it.”
For their study, Peltier and colleagues obtained N95 respirators — mostly 3M brand 1860 or 1860S models — from hospitals that were using various decontamination techniques. To test the effects that decontamination had on the masks, the researchers placed the respirators on a foam-covered mannequin inside an exposure chamber “and flooded it with polydispersed combustion aerosol.”
“Air was sampled through the mask at 85 L/minute and alternated between chamber and mask-occluded sampling, consistent with a method in our prior work,” they wrote. “Aerosol samples were delivered to a scanning mobility particle sizer ... which characterized particle size distribution from 16.8 nm to 650 nm and provides much more detailed respirator performance information than standard filtration efficiency testing.”
They burned incense in a separate combustion chamber and delivered diluted incense aerosol to the exposure chamber. They decontaminated the respirators off-site using standard hospital protocols.
The study demonstrated that decontamination methods including ultraviolet light treatments are safe for respirator treatment for several repeated cycles, Peltier explained. However, after nine cleanings, the masks begin to fail. Peltier said some methods that use high-concentration gas plasma hydrogen peroxide a “very harsh decontamination method” can damage the respirators immediately.
“But there are still perhaps a dozen other types of decontamination treatments being used by hospital groups and government contractors that have not been adequately evaluated,” Peltier said. “And by that I mean an independent assessment of respirator performance.”
He said workers, and occupational hygienists tracking disease “need to be vigilant in monitoring respirator performance.”
“Using personal protective equipment that hasn’t been independently vetted could pose a risk to respirator wearers. We know that some methods of decontaminating cause irreparable damage, so we would be wise to be more proactive in protecting our front line from this hazard across all decontamination techniques.”
Collapse
Read more about
Click Here to Manage Email Alerts