In April 2014, Flint, Michigan, switched its drinking-water source from Lake Huron to the Flint River while under state-appointed emergency management. The new water was not properly treated with corrosion inhibitors, allowing lead to leach from aging pipes. Engineer Marc Edwards identified the corrosion problem in 2015, while pediatrician Mona Hanna analyzed electronic medical records and found that the share of Flint children with blood-lead levels above 5 micrograms per deciliter rose from 2.1% to 4% after the switch, with the largest increases in areas reporting the highest water-lead levels.
Hanna disclosed the findings at a September 24, 2015, press conference before peer review. A Michigan Department of Environmental Quality spokesperson initially accused her of “splicing and dicing numbers,” but the state issued a health advisory the next day and later acknowledged the crisis after Detroit Free Press reporting corroborated her results. Her study was published in the February 2016 American Journal of Public Health and confirmed by a July 2016 CDC report, which described the findings as an underestimate of exposure. The disaster prompted roughly $100 million in federal aid and $250 million in state funding, while the Flint Registry and long-term lead-exposure programs tracked continuing health consequences.