A healthy house turned out Wednesday for the opening night of the Thin Line Film Fest, the three-year-old documentary film festival in downtown Denton.

“There are almost tears in my eyes to see this place this full,” said festival director Joshua Butler, who told the press he was concerned that crowds might be thin for the five-day event. “Thank you.”

The Campus Theatre was indeed fairly full for the opening documentary, GasLand, a cautionary movie about the dangers of natural gas drilling shot partly in Denton County. GasLand won the Special Jury Prize last month at Sundance Film Festival, and also earned the highest critical rating of any competition piece at Sundance.

The film details air and water pollution from Colorado to Louisiana, and the film crew struggled to amass evidence from affected families — many of whom said they had been intimidated by gas company representatives, or were gagged by nondisclosure agreements.

The audience was polite but lively during the screening, with spontaneous applause and cheers erupting during a scene in Wyoming, where farmer John Fenton insisted that natural gas companies constitute a sort of Goliath, and that the people who are suffering from health effects and struggling with contaminated water need to start loading their slingshots with some serious stones.

Dish Mayor Calvin Tillman was in the documentary, sharing the findings of an independent air quality test from his town. Natural gas wells dot the landscape around Dish — and around Fort Worth — and residents demanded officials investigate the air, after reports of health crises among the residents stirred up suspicions. Tillman gave his case: The suspicions are correct.

During a question-and-answer session with filmmaker Josh Fox, the audience appeared to be decisively against the natural gas drilling that has surged into North Texas — mostly without private or government regulation. One audience member wondered aloud where Denton’s elected leaders were, and others shared personal stories of their experiences with gas companies and drilling sites.

“The bottom line is that you only see a few stories in the film, and it could take regulatory agencies 10 to 15 years to investigate the cases presented in the film,” Fox told the audience.

Fox also talked about a bill still in Congress casually called “the frack act,” a reference to the hydraulic fracturing method used to extract natural gas from shale plates across the country.

The bill would require oil and gas companies to adhere to the Clean Water Act in their practices. The companies were exempted from the act (and the Safe Drinking Act and Clean Air Act) in 2005, an effort driven mainly by Vice President Dick Cheney, who was the chief executive officer of Halliburton, which leases drilling equipment.

One viewer asked Fox about the challenge of working against nondisclosure agreements, which prohibit some landowners from discussing contamination and health effects with media. Fox said the agreements weren’t always about money.

“We found that in some states, people signed nondisclosure agreements in exchange for water,” he said. “When their wells and drinking water were contaminated, the gas companies would rush in and disconnect their wells and replace them with cisterns and tanks in exchange for nondisclosure.

“Some people say that demanding silence in exchange for a basic human right is extortion, not to mention a First Amendment violation. And in some instances, we found that people signed nondisclosure agreements in exchange for two years of water.”

Why don’t the affected families move? In the film, property owners — many of whom didn’t own the mineral rights affecting their land — showed that the drilling makes their property unsellable, thanks to scarred landscapes, intolerable noise and putrid odors.

Another viewer was disturbed by an infrared view of vapors being released from compression station tanks in Texas.

“If there’s a vent on a piece of equipment, it’s not for aesthetics,” said former oil field worker and activist Lionel Millberger, who contributed to the film. “If there is a vent, something’s coming out of it. It might not be 24/7, but it might be 23/7.”

No oil and gas companies approached by Fox would agree to an interview for the documentary.

For more information about the film, visit www.gaslandthemovie.com.

For tickets or more information about the Thin Line Film Festival and a festival schedule, visit www.thinlinefilmfest.com.

LUCINDA BREEDING can be reached at 940-566-6877. Her e-mail address is cbreeding@dentonrc.com.