A healthcare worker with active tuberculosis (TB) may have exposed more than 1,000 newborns and staff members to the disease at a maternity unit.

Kaiser Permanente is notifying affected employees at its San Francisco Medical Center and the babies’ mothers about the situation, according to the San Francisco Chronicle.

The risk of TB infection is low for those who were potentially exposed, Kaiser said in a press release.

"We have confirmed the San Francisco Medical Center followed all of the appropriate preventive screening procedures when hiring this employee, who stopped working on August 10 and is no longer with the organization," Kaiser said. "We are continuing to investigate this matter. We do not tolerate any employee who puts the health of patients or coworkers at risk."

Officials at the hospital told the Chronicle that the worker in question passed a screening, and a cough the worker had may have been written off as some other illness.