State health officials said Thursday they are investigating four cases of Legionnaires’ disease linked to Advocate Christ Medical Center in Oak Lawn.

State public health department officials said two of the cases involve people who were patients at the hospital within the past two months.

Officials said they are working with the hospital to collect information and further investigate the cases, including an onsite inspection of the hospital’s water system.

The Legionella bacteria happen naturally in the environment, department officials said, and that water containing the bacteria can be aerosolized through cooling towers, showers and decorative fountains.

The bacteria can cause a serious lung infection when inhaled, although most healthy people do not get Legionnaires’ disease after being exposed, public health officials said.

Health department officials said the hospital is working with the department “to strengthen its water management plan and implement multiple control measures.”

Officials said they have recommended the hospital inform potentially impacted patients and their families about the bacteria and “conduct surveillance to identify other potential cases and to ensure appropriate testing and clinical management.”

Hospital officials said they are working closely with public health officials and that “our top priority is to provide the safest and highest quality care for the patients and communities we serve.”

“Our facility is safe for our patients, visitors and team members,” hospital officials said in a statement.