The National Institutes of Health (NIH) are recommending three methods to decontaminate N95 facepieces for reuse. Researchers at the agency successfully tested the effectiveness of these methods, as well as the function of the masks after repeat decontamination.
To help conserve masks during the COVID-19 pandemic, OSHA released a memo on using expired respirators and other alternatives. The researchers aimed to find the best ways to extend the use of N95 face masks by testing four decontamination methods: Vaporized hydrogen peroxide, 70° C dry heat, ultraviolet light, and 70% ethanol spray.
They took small sections of N95 filter fabric that had been exposed to the coronavirus and tested each decontamination method.
Also tested were “fully intact, clean respirators,” with the same methods, to examine their reuse durability. Decontamination was repeated three times, and volunteers wore the masks for two hours to test for proper seal and fit.
An April 15 NIH press release states that “all four methods eliminated detectable viable virus from the N95 fabric test samples.”
However, ethanol spray damaged the integrity of the respirator’s fit after two decontaminations, so it is not recommended.
Recommended Decontamination Methods for N95 Masks
Here are the recommended decontamination methods for getting the most use out of N95 masks:
- Vaporized hydrogen peroxide: This proved to be the most effective method of decontamination, as no virus could be detected on the mask fabric after only a 10-minute treatment. The respirators showed no issues during the integrity testing process, suggesting it could be decontaminated three times.
- UV light and dry heat: Both of these methods were acceptable as long as they were applied for at least 60 minutes. The respiratory began showing fit and seal issues after three decontaminations, so it is only recommended to use this method twice.
The NIH also stated that anyone using decontamination methods should check the fit and seal before each reuse.
The study has not yet undergone a peer review, but it was released to assist in the public health response to COVID-19. It was published online on April 15 by medRxiv, an online archive and distribution server for complete but unpublished manuscripts in the medical, clinical and related health sciences.
About Worksite Medical
In most cases, OSHA requires medical surveillance testing, and at no cost to employees.
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We conduct on-site respirator fit tests (including N95 masks), as well as pulmonary function tests and heavy metal lab work, right on your job site. We also keep accurate, easy-to-access medical records for your convenience. You’ll keep your employees at work, and stay ahead of OSHA inspections.
With Worksite Medical, a mobile medical testing unit — we can bring all the resources of a lab to you. Our certified lab technicians can perform both qualitative and quantitative respirator tests to ensure a perfect fit.
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