DENVER -- Facing federal pressure because of worsening air pollution, the state Sunday approved the first-ever statewide emissions controls on the booming oil and gas industry.

The Colorado Air Quality Control Commission said the new rules would reduce emissions by 68 percent from tanks that collect the liquids and other byproducts. They will take effect in May 2008 if the Legislature approves them.

An environmental group said it would have liked lower limits but was content. "But this is the first emission regulation rule (on oil and gas companies) in the state ever," said Bruce Baizel, staff lawyer for the Durango-based Oil and Gas Accountability Project.

But other environmental groups criticized the decision not to adopt rules as stringent as those along the Front Range, from the Denver area north.

"We do not understand why the industry is allowed to pollute the Western Slope but held to a higher standards on the Front Range," said Duke Cox a Garfield County resident and member of the Western Colorado Congress.

The commission said it would conduct annual reviews of the level of emissions, when the tanks are vented, and the health impacts of the industry.

The commission also strengthened pollution rules already in place in a nine-county area along the Front Range, stretching from the south Denver area to parts of Weld and Larimer counties, to meet federal ozone levels. Oil and gas companies will have to cut emissions by 75 percent, more than the existing 47.5 percent requirement and more one outlined in an industry-backed compromise.

Companies will also have to keep weekly records and inspection logs on the tanks and report the information to the state air pollution control division.

"It's a bitter surprise. It was a compromise coming in and then we were compromised even further," said Ken Wonstolen, general counsel for the Colorado Oil and Gas Association trade group.

Wonstolen said companies will have only about 130 days to make sure their tanks are in compliance.

But Jeremy Nichols, director of Rocky Mountain Clean Air Action, called the commission's action "a great step forward."

After 44 years of restrictions ranging from the banning of trash burning to pollution controls on cars, it had appeared the area's notorious brown cloud was history.

Officials, who four years ago said the smog problem was gone, say the booming oil and gas industry has brought it back and it is a problem in western Colorado as well. Ozone, a primary component of smog, is a colorless gas and is itself a threat to people with asthma and children.

Mike Silverstein, manager of planning and policy for the state air pollution control division, has said much of the problem stems from oil and gas wells. And the problem is expected to worsen without new controls.

The state had predicted emissions of 146 tons a day by next year, but revised that upward to 233 tons. The emissions react with sunlight to form ozone.

Wonstolen said the oil and gas industry is being unfairly singled out. He said if the state keeps tightening environmental guidelines, "then it won't just be us for long."

"We anticipate there will be more regulation," Wonstolen said.

State officials have said that emissions from other sources have declined, and local communities also support emission controls.

The Environmental Protection Agency has given the state until July to come up with a plan to reduce ozone along the populous Front Range. Meanwhile, rising energy demand has led to increased drilling north of Denver.

The EPA has agreed to put off declaring the Front Range and other communities in violation of the Clean Air Act if they meet certain milestones.

Colorado is headed toward a record 4,650 permits for new oil and gas wells this year, up 6.5 percent from the record set last year.

On the Net:Colorado Air Quality Control Commission: http://www.cdphe.state.co.us/op/aqcc

This story appeared in The Daily Herald on page D6.