DETROIT -- The head of a Flint hospital that found Legionnaires' disease bacteria in its water system more than a year ago said he and experts suspected the Flint River was a likely source of the contaminant.
Don Kooy, president of McLaren hospital, said he was surprised that Michigan and local health agencies didn't inform the public about a Legionnaires' outbreak in Genesee County in 2014-15 until just a few weeks ago.
The outbreak occurred while Flint residents were repeatedly complaining about dirty tap water coming from the river -- a crisis that ultimately caused exposure to lead and other health problems.
"It's a public health issue," Kooy told The Associated Press. "There were people in the city of Flint seeing brown water. It would seem logical that there would have been public reporting or public awareness about the Legionella situation."
At least 87 Legionnaires' cases, including at least nine deaths, were confirmed across Genesee County during a 17-month period.
"Did she die because someone didn't want to say, 'Hey, the water might be bad?' That's my questions," Troy Kidd, whose mother Debbie died of Legionnaires' in August, told CBS News earlier this month.
CBS affiliate WWJ reported the Michigan Department of Health and Human Services said Thursday it cannot conclude that the increase in cases is related to the ongoing Flint water crisis nor can the department rule out an association.
Legionnaires' is a type of pneumonia. The bacteria live in the environment and thrive in warm water. People can get sick if they inhale mist or vapor from contaminated water systems, hot tubs and cooling systems.
Kooy said two cases could have been related to exposure to Legionella bacteria found in the hospital. He said "it's very difficult to know" when a patient is exactly exposed but both patients were successfully treated.
"We were concerned that the city water was the source of it," Kooy said, "but to this day I don't think we could make a definitive statement."
McLaren hospital spent more than $300,000 on a water treatment system and also turned to bottled water for patients.
"The change in (Flint) water quality was a likely factor in causing the increase in Legionnaires' disease" in Genesee County, said Janet Stout, a Pittsburgh microbiologist and Legionella expert who advised the hospital.
In April 2015, Laurel Garrison, a Legionnaires' specialist at the U.S. Centers for Disease Control and Prevention, told state officials by email that the outbreak deserved a "comprehensive investigation."
In an email three months earlier, Jim Collins, the head of Michigan's Communicable Disease Division, said the number of cases at that time "likely represents the tip of the iceberg."
Nonetheless, there was no public announcement at that time.
The U.S. Justice Department is helping the Environmental Protection Agency investigate, and the state attorney general has opened his own probe, which could focus on whether environmental laws were broken or if there was official misconduct.