Entire state of Michigan was poisoned in 1973 1974 by cattle feed.
Weirdly memory-holed.
Poisoning Michigan: Author revisits PBB crisis 30 years late
The accidental poisoning of Michigan dairy cattle in the 1970s sparked the largest chemical contamination in United States history.
Nine million residents consumed contaminated meat and milk for a year after a Michigan chemical plant mistakenly added PBB (polybrominated biphenyl) – a toxic fire retardant – to dairy cattle feed, and distributed it to farms throughout the state.
https://greatlakesecho.org/2010/06/04/poisoning-michigan-an-author-revisits-the-most-widespread-contamination-30-years-later/