For ten years, a company dumped millions of gallons of chemical wastes on its property in Tennessee.

Question:

For ten years, a company dumped millions of gallons of chemical wastes on its property in Tennessee. The state shut down the site. Residents around the property sued the company, claiming that their drinking water was contaminated.
What basis for suit did they have, and could they win? [Sterling v. Velsicol Chemical, 647 F. Supp. 303, W.D. Tenn. (1986)]