CHICAGO (CBS) — The Illinois Department of Public Health is investigating two cases of Legionnaires’ disease in two people who were patients at Rush Oak Park Hospital.

One person was a patient in May and the other in mid-July, the department said in a statement. Both were patients at the hospital during the time when they could have been exposed to the bacteria.

READ MORE: Chicago Police Union President Urges Aldermen To Repeal Mayor's Vaccine Mandate For City Workers, Judge Denies Request To Extend Gag Order

IDPH sampled the facility’s water this week, and previous water samples collected by the hospital showed results positive for Legionella bacteria.

READ MORE: Chicago Weather: Most Locations To Remain Dry Overnight

According to the release, the hospital said it routinely conducts water testing and has taken steps to reduce potential exposure, including adding disinfectant to the water, flushing pipes and installing point-of-use filters.

The hospital is also working to identify other potential cases and ensure appropriate testing.

MORE NEWS: Illinois State University Student Jelani Day's Death Ruled A Drowning