By David Young, PA
Fourteen staff at a Northern Ireland health trust contracted coronavirus after having been incorrectly fitted for a protective mask.
The chief executive of the South Eastern Health and Social Care Trust said it was working on the assumption that the staff could have contracted Covid-19 as a result of their failed FFP3 masks.
Seamus McGoran told the Assembly's Health committee that all affected staff had recovered from the virus and were back at work.
Northern Ireland's chief nursing officer Charlotte McArdle later told committee members that none of the other four trusts in the region had recorded Covid-19 infections among staff who required refitting for FFP3 masks.
Last month, the Public Health Agency revealed that an audit review of fit testing had been ordered after it emerged that an independent contractor had not applied UK requirements when fitting some masks.
At the time, the PHA insisted the risk to staff was low.
Mr McGoran was one of three trust CEOs questioned about the audit during their appearance before committee members on Thursday.
Sinn Fein MLA Pat Sheehan said 3,000 of 37,000 fit testing certificates issued had been identified as needing a refit.
Mr McGoran said 464 staff in his trust required a refit.
"Virtually all of those have been retested for an alternative mask and are working with that mask," he said.
"Out of that number actually we had 14 staff who had contracted Covid-19.
"One of the challenges for us is to try and understand the extent that related to the wearing of masks in the workplace or whether it was in respect of something else.
"We're taking the view that we have to make assumptions that it could well have been in respect of their failed mask.
"So we're working with the staff there, they've all had support from their managers, from occupational health, from psychology services, the staff are very happy, and those who have contracted Covid-19 have recovered and are back at work."
Western Health and Social Care Trust Dr Anne Kilgallen said around 500 staff in her organisation required a re-test.
"There was no instance of infection," she said.
Northern Health and Social Care Trust chief Jennifer Welsh said around 200 staff required a retest and she was not aware of any of them having contracted Covid-19.
Mr Sheehan later asked Ms McArdle why the risk to staff had been assessed as low.
The chief nursing officer said: "The risk to staff was low because the mask provided some coverage, it just didn't provide the tight seal.
"It's my understanding, and this is a complicated process, that there are various steps in the process of fit testing - up to, I think, seven steps.
"And the majority of staff would have passed elements of the seven but not all seven steps, which meant that they did have some protection from the mask but not just full protection and that is why we established that the risk was low."