DENVER - The Environmental Protection Agency wants slower gas development in western Wyoming's Jonah Field unless companies cut air pollution from wells by 80 percent.

The EPA says the cut is necessary to protect wilderness areas and Yellowstone and Grand Teton national parks from being blanketed by haze, according to remarks the agency has sent to the U.S. Bureau of Land Management.

The BLM is weighing several approaches for allowing drilling in the area.

In a letter to the BLM, EPA Regional Administrator Robert Roberts said drilling companies should use new, cleaner diesel-engine technology to reduce emissions.

"If emissions are reduced, the operator would be allowed to drill more natural gas wells," he wrote.

The BLM is to rule by January on an EnCana Corp. proposal to drill as many as 3,100 wells in the Jonah Field, which holds one of the region's most concentrated natural-gas deposits.

The 23,500-acre area has 1,006 wells, according to the Wyoming Oil and Gas Commission.

EnCana spokesman Randy Teeuwen said the company had already invested in cleaner diesel engines and was testing a gas-powered drilling rig. With those technologies in place across the Jonah Field, the company will exceed the emission goals, he said.

Under the EPA proposal, EnCana would have to cut nitrogen oxides - a key cause of haze - from 3,206 tons a year to 641 tons.

Bruce Pendrey, public lands director for the Wyoming Outdoors Council, said any decline in air quality is unacceptable.

"It's really hard for anyone who's ever been to Pinedale to say with a straight face that even one day with diminished views is OK," he said. "It's certainly not OK for the people who live here."