SAN FRANCISCO -- Kaiser Permanente is telling 960 mothers that they and their babies may have been exposed to a San Francisco maternity ward worker diagnosed with active tuberculosis.

Kaiser announced it had started notifying patients Tuesday about the worker formerly employed in the postpartum unit of its San Francisco Medical Center.

Hospital officials said the part-time employee worked at Kaiser from March 10 to August 10 and no longer works for the organization.

Kaiser learned of the employee's diagnosis last week and said the medical center followed all appropriate screening procedures when hiring the employee.

Kaiser's infectious disease chief in Northern California said the infection risk for patients was low and that the worker had a common strain of TB that responds well to antibiotics.

"We're taking all the precautions we can to prevent any potential problems with respect to the exposure" said Dr. Stephen Parodi.

Kaiser officials say the employee was a part-time health care worker on the night shift at the Maternal Child Health Unit in San Francisco.