On May 19, 2020, a group of engineers and emergency officials gathered at a fire station in Edenville, Michigan to decide what to do about the Edenville Dam, a 97-year-old hydroelectric structure about a mile upstream on the Tittabawassee River. Over the preceding two days, heavy rains had swelled the river, filling the reservoir to its brim and overwhelming the dam’s spillway. The group was just about to discuss next steps when the radios went off, recalled Roger Dufresne, Edenville Township’s longtime fire chief. “That’s when the dam broke.”

“Up at the dam, Edenville residents watched as a portion of the eastern embankment liquified. Muddy water gushed through the breach. Over the next few minutes, that water became a torrent, snapping trees and telephone poles as it rushed past town, nearly submerging entire houses further downstream.

About 10 miles and two hours later, the flood wave bowled into a second aging dam, damaging its spillway, overtopping, and then breaching the embankment.

Al Taylor, then chief of the hazardous waste section within the state’s Department of Environment, Great Lakes, and Energy, was following the situation closely as the surge swept 10 miles further downstream into the larger city of Midland, where it caused a Dow Chemical Company plant flanking the river to shut down, and threatened to mix with the plant’s containment ponds. Taylor, who retired at the end of January, worried that contamination from the ponds would spill into the river. But that was just the first of his concerns.

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