Archaeologists and the lead advocacy group for protecting the unique antiquities in Nine Mile Canyon say a letter from the U.S. Environmental Protection Agency perfectly sums up the impact study of oil and gas drilling there: inadequate.

The federal government's attention and response to a petition to make the area a National Historic District has been largely ignored, and even the EPA letter itself is yet another example of federal oversight that is lacking at best, said Pam Miller, chairwoman of the Nine Mile Canyon Coalition.

"It makes me cautiously optimistic that there is some recognition that the original impact statement was severely flawed," Miller said, noting that the coalition does not oppose the gas development or drilling in the area. "What we're opposed is not knowing exactly what effect all this is having and not having any serious discussion of alternative truck routes."

The coalition has offered to hire a road engineer to determine alternative roadways to what is now the main thoroughfare for more than 100 tanker trucks and pickups servicing the gas wells. The road runs the length of Nine Mile Canyon, which is actually a 70-plus mile corridor dubbed "the world's longest art gallery" for the thousands of petroglyphs, graneries and rock art depictions there. They are the last remnants of the Fremont Indians who somehow thrived in the desolate areas of present day Utah, Idaho, Colorado and Nevada from 700 to 1300 A.D. then disappeared.

What the federal Bureau of Land Management has pronounced "the greatest concentration of rock art sites" in the country is also a source of oil and gas. Several dozen wells had been drilled there since the 1950s. Six years ago, Denver-based Bill Barret Corp. paid about $8 million for leases on 47,000 acres around the West Tavaputs Plateau. The area now has 100 to 110 active natural gas wells by the BLM's estimate, and the agency is proposing to allow roughly 700 to 800 more to be drilled over eight years.

Traffic along the narrow gravel road through the canyon would increase from about 107 vehicles per day now to a maximum of 441 per day during peak development, which would probably last two to three years, according to BLM estimates.

Bill Barrett estimates the full-field development project would yield 1 trillion cubic feet of natural gas during more than 30 years of drilling. The yield is equivalent to about 17 days of supply at today's national consumption level.

Carbon County has spent thousands of dollars paving short sections of the road to limit the dust, and the section of road that once ran right beneath the Hunting Scene Panel — it was rerouted by the gas company to give the rock art some protection. But Miller says much more must be done. If not, she fears, the energy boom may spell the end of one of the world's great outdoor museums.