After decades of wrangling, a lawsuit involving environmentalists, the U.S. Forest Service and a helicopter-skiing business has landed in federal court.

U.S. District Judge Ted Stewart presided Monday over a hearing in which Citizens' Committee to Save Our Canyons and the Utah Environmental Congress claimed that the Forest Service had violated federal rules in 2005 when it reissued a five-year permit to Wasatch Powderbird Guides.

The permit allows commercial helicopter skiing — in which the choppers ferry skiers to selected sites — in Wasatch-Cache National Forest's tri-canyon area near Salt Lake City.

Forest Service officials did not adequately analyze the impact of noise on other backcountry users of the forest and failed to weigh deeply enough the danger of using explosives in the operation, the lawsuit claims. Plaintiffs say the Forest Service did not properly tally the number of other users of the forest.

They also faulted Wasatch-Cache National Forest's handling of destruction of trees that might result from the avalanches started by explosives.

"There are a great number of others enjoying the backcountry" who might be affected by the noise and potential danger of helicopter operations, said William B. Lockhart, lawyer for the plaintiffs. But the analysis did not adequately examine safety issues they may face, he said.

Instead, according to Lockhart, the environmental-impact statement simply said that since nobody's been hurt yet, it won't happen. It relies on the helicopter company "being able to locate people before using explosives," he said.

Jared Bennett, representing the federal government, said plaintiffs had not exhausted administrative remedies. In other words, they should have appealed through other avenues available to them before suing.

The environmental-impact statement, filed in 2004, says timber may be inadvertently destroyed, Bennett said. "They knew about it."

The issue should have been raised with the Forest Service before this, he said. Because the plaintiffs did not raise it earlier, they can't rely on that argument in court, according to Bennett.

He noted that helicopter skiing is nothing new: "This is an activity that has been going on for 30 years."

Bennett defended the adequacy of the environmental review and said the Forest Service looked at the rise in sales of equipment and other indications of increased backcountry use.

"These explosives are not the howitzers" that ski resorts and the Utah Department of Transportation use to clear dangerous snow accumulations, he said. "They're hand charges," and people setting off the explosives check to see if there are others in the area.

Stewart took the matter under advisement, saying he would rule later.