My family's lived in mid-michigan for four generations now, going on five. I've known a lot of people from the St. Louis (Velsicol Chemical Corp) and Midland (Dow Chemical Corp) areas. Heard a lot of stories. Chemical release alarms go off occasionally and everyone shuts their windows as the cloud rolls through town. Mysterious mass bird, amphibian, fish, and insect die-offs. Strange dusts covering everything. Cancer and birth defect rates above average.

The EPA has been heating the ground in St. Louis to above boiling, with a giant rubber cap on top to boil off volatiles and collect them: https://www.youtube.com/watch?v=smHnFXrhSvM and that's after dredging the river, capping the whole site with clay and concrete, and other remediational work. People will never be able to drink the well water there again.

Take-away is that I'd like to live as far away from chemical plants as I can afford.