WINNIPEG -- Manitoba researchers have found that N-95 masks can be safely sterilized and reused, but not as often as other studies have found.

A team with the St. Boniface Hospital’s Albrechtsen Research Centre found the masks can be safely sterilized and reused only once, according to an announcement on Wednesday. The full study will be published in the Journal of Hospital Infection.

“What we found was that daily wear dramatically reduces the number of times you can actually reuse these masks,” said Dr. Mike Czubryt, the lead author of the study.

The study was launched at the beginning of the COVID-19 pandemic. Other studies suggested N-95 masks, which help filter out particles for healthcare workers, could be sterilized and reused up to 10 times.

Czubryt said the Winnipeg study looked at the daily wear and tear through an eight-hour shift.

“We actually found after a single sterilization cycle, we would get all of the masks still passing fit testing – that’s the test that we do to make sure the mask still works and can do their job,” he said. “After a second round of sterilization, we started to get masks failing.”

Czubryt said despite the results of the study, the stockpile of masks for healthcare workers could be doubled.

“We are optimistic that we can stretch our supplies of masks much further than we thought, so if you manage to salvage 10,000 masks, you can get a second use out of those, and have another 10,000 uses, but only that one cycle,” he said. “You could not do it beyond that, which we were curious about.”

The published study will include a detailed guide on how the sterilization process can be rolled out in other healthcare facilities.