CHICAGO (CBS)– The Illinois Department of Public Health is investigating after two possible cases of Legionnaires’ disease were reported at Mercy Hospital & Medical Center in Chicago.

The patients may have been exposed at the Bronzeville hospital.

There is also a report of “Legionella” in the hospital’s water system.

According to the IDPH, Legionnaires’ disease is a serious lung infection that people can get by breathing in small droplets of water containing Legionella bacteria. Outbreaks are comment at locations with complex water systems like hospitals, hotels and cruise ships.

Crews have flushed the hospital’s system, replaced water fixtures, and put filters on sinks.

In a statement, Mercy Hospital said the hospital and its patients are safe.

“The hospital has followed guidelines for safe water management set forth in the ASHRAE ‪188-2018 standard and the Centers for Disease Control toolkit for Legionella water management program,” the statement read. “We fully support investigations by the Illinois Department of Public Health and the Chicago Department of Public Health.”