About 24,000 pages of documents released Friday show that federal Environmental Protection Agency officials knew about the presence of Legionnaire’s disease bacteria in Flint’s water supply in March 2015, about 10 months before Michigan Gov. Rick Snyder informed the public. Nine people died from the outbreak of pneumonia-causing bacteria that spawned after the city changed its water supply from a Detroit source to the Flint River. Following the April 2014 change, Flint reported nearly 40 cases of the disease, a huge jump from previous years. In a March 26 conference call, an expert in Legionella from the EPA’s Cincinnati office said his research indicated that changes in water chemistry can “destabilize” piping systems. On that call, he offered to study the origins of Legionnaire’s in Flint, but state and county officials apparently never accepted.