Like “Erin Brockovich” and “A Civil Action,” “Deep Waters” is about a lawyer fighting for a poor plaintiff whose life has been irreparably damaged by a big corporation’s environmental pollution. In this case, the company was Dupont, the biggest employer in a small West Virginia town, which was also dumping a toxic “forever chemical” into the water table adjacent to one of its landfills.

Rob Bilott was a lawyer who had spent years working on the other side of the table, for a firm that defended chemical companies. But when farmer Wilbur Tennant — a friend of his grandmother’s — went to his office with a box of videotapes showing what had happened to the cows and other livestock on his property, Bilott switched sides and began to fight for Tennant and other victims in cases that lasted years.

Mark Ruffalo plays Bilott as a principled man single-handedly taking on the villainous chemical company. “Dark Waters” is a far departure from his work in the Marvel movies, but Ruffalo — an environmental activist as well as actor — imbues Bilott with such honesty and dignity that you can’t help but root for him. Tennant is played by Bill Camp, who has had quite a career since his his role as a police detective in HBO’s mini-series, “The Night Of,” racking up more than 15 feature-film credits in just three years. As great character actors do, Camp embodies the struggling West Virginia farmer who’s at the end of his rope.

The rest of the cast includes Tim Robbins as Bilott’s boss, Victor Garber as the Dupont big shot who ends up in the crosshairs, Bill Pullman as another attorney drawn into the case, Anne Hathaway in an underwritten role as Bilott’s wife, and Mare Winningham as just one of the many other victims of Dupont’s poisoning.

“Dark Waters” was directed by Todd Haynes from a screenplay by Mario Correa and¬†Matthew Michael Carnahan, based on Nathaniel Rich’s 2016 NY Times article, “The Lawyer Who Became DuPont’s Worst Nightmare.” It is a taut thriller, as Bilott keeps digging and fighting while Dupont denies and stonewalls. I was glad to see that Haynes didn’t drive the movie towards a happy ending with a big victory, but rather with small settlements — and a shocking revelation for anyone who’s ever used a Teflon frying pan.

I give “Dark Waters” an 8.5 out of 10.