Many a documentary feeds off political upheaval, but it is rare that such a film leaves societal change in its wake. At the rate it’s going, Josh Fox’s “Gasland” — already a Sundance Film Festival Special Jury Prize winner and HBO featured documentary, even though it has yet to be released in theaters — may be the next to do so.

The subject first drew attention last year when videos of people lighting their tap water on fire appeared online. Now, Fox says, the film’s revelations about the disastrous risks of a widespread method of natural gas extraction are sparking grass-roots activism across the country.

Rep. Maurice Hinchey presented a screening Tuesday of “Gasland,” along with an expert panel featuring Fox, to help raise support for the Fracturing Responsibility and Awareness of Chemicals Act that the New York Democrat co-sponsored last summer. The act would create a system of oversight on the hydraulic fracturing (or “fracking”) process, which Fox estimated has pumped 40 trillion gallons of water, infused with almost 600 different chemicals, into American soil and groundwater.

Under the Energy Policy Act of 2005, oil and gas drilling companies were exempted from following the Safe Drinking Water Act and the Clean Air Act, as well as from revealing what specific chemicals they pump into the ground. Then-Vice President Dick Cheney spearheaded this deregulation, according to Fox and Hinchey, by commissioning an Environmental Protection Agency study on the safety of gas drilling in which five of the seven authors had conflicts of interest.

The EPA came to a conclusion that was “patently ridiculous,” EPA environmental engineer Weston Wilson said in the film. “They said it was toxic and then said it didn’t need to be regulated.”

Fox’s fact-finding journey began when a natural gas company offered him $100,000 for the right to drill on his land. He wanted to know what that would mean for him, so he set out on the road with his video camera.

What he found was a pattern of problems seemingly caused by the fracking process, in which companies such as Halliburton loosen and extract natural gas by pumping millions of gallons of water, sand and chemicals thousands of feet underground to explode shale formations. The chemicals released are largely kept secret, but they include known carcinogens and neurotoxins — and when they reach water wells, they have the potential to destroy livelihoods.

“I actually put out a call to the industry, saying, ‘If you’ve got a town with over 100 [gas] wells where everything’s going fine, then take me there and I’ll make an amendment to the film,” Fox said after the screening. “So far no takers on that. And I’ve been saying it for, I don’t know, three months now. Because I don’t think it exists.”

Each family, farmer and rancher Fox talks to follows a similar script. The company promised the drinking water would be safe, the water turned brown, the family was forced to foot the bill for clean water and, in the meantime, air and water contamination caused an array of maladies: body aches, loss of smell, loss of taste, irreversible brain damage. A common anecdote was that government officials or corporate representatives would make a house call to vouch for the water’s safety but then refuse to drink it themselves. One cattle rancher lamented that his cows, which he raised for human consumption, had no choice but to eat grass grown from toxic soil and water.

“Nobody’s watching over” the gas companies, said one person living among fields of gas wells. “It’s a free-for-all.”

The FRAC Act would regulate fracking and uncloak its secrecy, which Hinchey said will allow citizens to hold companies accountable. As the law stands, companies “will contend that they had nothing to do” with well water contamination, Hinchey said, “because they didn’t have to reveal what they put in the ground.”

“Gasland” and the FRAC Act are two of the most visible parts of a groundswell of activism around natural gas regulation. The EPA is conducting a new study on how fracking affects water quality. This month, Food and Water Watch published a report called “Not So Fast, Natural Gas: Why Accelerating Risky Drilling Threatens America’s Water” in which it recommended that Congress establish an agency for fossil fuel industry oversight.

“This is not a choice of what area we want to mess up or not mess up,” executive producer Debra Winger said. “This is our water. This is the last frontier. … It doesn’t matter who you are. We are all connected because water is the one thing, throughout America, that connects us all.”