The documentary Company Town opened in New York City on Friday night, for a short run at Cinema Village on East 12th Street. Introducing a sold-out screening, New York state attorney general Eric Schneiderman said co-directors Natalie Kottke-Masocco and Erica Sardarian had captured one of the “quiet tragedies that are taking place all across America all the time”.

The film tells the story of Crossett, Arkansas, a small town dominated by a huge Georgia-Pacific paper mill owned by the Koch brothers, Charles and David, hugely influential Republican donors with a deeply contentious – activists would say appalling – record on the environment. People who live in Crossett blame the mill for the heedless dumping of cancer-causing chemicals they say pollutes drinking water and shortens already straitened lives.

“This is a story that never gets told,” Schneiderman said, “and it takes tremendous commitment to get to the quiet tragedies that are taking place all across America all the time.

“The environmental movement really has not done as good a job perhaps as we should have done carrying the essential message that people who are poor and without power are always on the front lines of pollution and environmental justice.”

Kottke-Masocco, who describes herself as “a documentary film-maker and an activist”, went to Crossett in 2011 to work on a section of Koch Brothers Exposed, a film by Robert Greenwald. Learning of attempts by local pastor David Bouie to hold the Kochs and Georgia-Pacific to account, she stayed on the story. With Cheryl Slavant, a local environmental activist and “riverkeeper”, Bouie is a key presence in the resulting movie.

In some of the film’s most striking passages, Kottke-Masocco and Sardarian show officials from the Environmental Protection Agency (EPA) floundering in the face of impassioned pleas from locals, inertia from state government and Georgia-Pacific and the Kochs’ predictable refusal to engage.

Company Town was alarming enough when it premiered at the LA film festival in June 2016. In November, Donald Trump was elected president. In office, he appointed former Oklahoma attorney general Scott Pruitt to lead the EPA. Federal environmental regulations have come under withering assault from within.

“It’s made the film more urgent,” Kottke-Masocco told the Guardian. “It’s made the story more urgent, it’s made Crossett’s issue more important and urgent. We actually scrambled the last two months and updated the title cards in the film to make them more significant.

“We want people to understand the gravity of Trump taking office because the EPA is threatened more than ever under Scott Pruitt, a man who as Oklahoma attorney general sued the EPA 14 times … this is a person who has a total neglect for the environment and for public health and is now in charge of protecting our citizens. So Crossett is more important than ever.”

Schneiderman has pursued the president on fronts including the Trump University fraud case, which was settled for $25m; a lawsuit by 15 states over the decision to rescind protection against deportation for young undocumented migrants; and reported co-ordination with special counsel Robert Mueller in the investigation into links between Trump aides and Russia.

The story of Crossett has been reported in depth by Newsweek, the New Yorkerand other outlets, to whom Georgia-Pacific and Koch Industries have issued strongly worded denials. Company Town has received positive reviews by the New York Times and the Hollywood Reporter.

Schneiderman said the film showed what can happen when people with “no power, no money”, like Bouie, Slavant and the whistleblower Dickie Guice, a former Georgia-Pacific safety co-ordinator, range themselves “against the most malevolent, powerful forces in our country … with the courage to stand up and step up”.

“To those who say, ‘Oh my goodness, things are so difficult right now,’” he said, “I’ll say that when you see these people, we can all keep going.

“The filmmakers have, and I say this as a state law enforcement official, captured the way the rich and powerful bend government to their will. And the film sends a powerful message, that we need our state actors to stand up, particularly these days if the federal government is not going to do its job. The state actors are critical.

“The federal government depends on the states, you see in the movie the EPA is very dependent on states to enforce the law. The [federal government] can’t enforce their laws, we see this in the sanctuary city fight, they can’t enforce their immigration laws without state and local government.

“So this is an incredible story of courage and of wrongdoing but also a story about how we need to take our government back and our country back.”