'Dark Waters': Mark Ruffalo explains why he changed his approach to playing a real person in legal drama (exclusive)

Mark Ruffalo said he broke his own rules for portraying a real, living person in Dark Waters, a story that is still very much ongoing.

Ruffalo plays environmental lawyer Rob Bilott in the new film from Carol director Todd Haynes, which traces the litigation from its humble origins as the case of a single farmer through to the nationwide class action Bilott is currently pursuing through the US courts. In the past, Ruffalo says he would avoid contact with the real life person he’s playing.

“The prevailing thought in my industry is to keep the [real] person off the set,” the 52-year-old Avengers: Endgame star said.

He added: “I wanted Rob there as much as he was available because he was such a wealth of information.

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“There's such a huge responsibility for the people who are fighting this now, who are living with it.

“This giant corporation would love to find any inconsistencies to poke holes into the veracity of the film. The level of responsibility is really high.”

Bilott, the real-life subject of the legal thriller has said he “couldn’t think of anybody better” than Mark Ruffalo to portray him on the big screen.

Bilott has been crusading for more than 20 years to hold the DuPont company to account for the accumulation of chemical compound PFOA in the water surrounding a factory in West Virginia.

The chemical has been shown to be toxic to humans and linked to various illnesses, including kidney and testicular cancer.

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The lawyer told Yahoo Movies UK that Ruffalo “did an absolutely fantastic job” in the film.

He added: “His talents and passion for the whole project were just really amazing. I couldn't think of anybody better.”

Bilott admitted it was “strange” to see himself depicted on the big screen, but said it was crucial that people are “finally being able to see this story” and understand the scale of the issue.

He said: “[I wanted] to really bring this information out to the rest of the world and to see folks finally seeing the scope of the contamination problem that goes way beyond West Virginia.

“It's affecting all of us.”

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In an investor call prior to the film’s US release in November, DuPont executive chairman Ed Breen said the company’s “legal folks” were “looking at” the film, but no action has thus far been taken.

As well as Ruffalo, the movie stars Anne Hathaway, Tim Robbins, Bill Camp and Bill Pullman.

Dark Waters is released into UK cinemas on 28 February.