— Oklahoma Attorney General Scott Pruitt has filed a motion in federal court trying to block implementation of a rule designed to reduce pollutants emitted from the state’s oldest coal-fired power plants.

The motion, filed Wednesday with the 10th U.S. Circuit Court of Appeals in Denver, was submitted on behalf of the state, Oklahoma Gas and Electric Co. and Oklahoma Industrial Energy Consumers.

The move drew fire from members of the Sierra Club, which has intervened in the federal lawsuit. They questioned Pruitt’s decision to team up with the public utility and a special interest group.

“OG&E has ignored its responsibilities to Oklahomans for too long, and now our Attorney General is siding with OG&E,” said Charles Wesner, the chairman of the Oklahoma Chapter of the Sierra Club. “Our health and our economy suffer from haze and ozone pollution. This lawsuit is just delaying cleaning up our air, which Oklahomans need and deserve.”

Pruitt challenged the legality of the regional haze rule, which the U.S. Environmental Protection Agency adopted last December after state officials failed to submit a plan that met designated criteria.

The goal of the regional haze rule is to reduce emissions of fine particulates, which limit visibility in national parks, and sulfur dioxide, which can harm public health. The rule requires operators of three coal-fired power plants to upgrade emissions-reduction technologies or switch to cleaner burning fuels within five years.

OG&E owns two of the three coal-fired plants affected by the EPA plan. One is between Muskogee and Fort Gibson. The second is south of Ponca City. The third plant, in Rogers County, is operated by American Electric Power-Public Service Company of Oklahoma.

EPA officials say those three plants spew thousands of tons of sulfur dioxide into the sky annually. This, they say, endangers public health and contributes to low air quality and poor visibility.

Although the federal implementation rule incorporates core parts of the state’s plan that deals with aesthetics, it imposes stricter standards for sulfur dioxide emissions than what the state had allowed.

The Sierra Club filed a motion to intervene in the challenges filed by Pruitt, OG&E and AEP-PSO. The environmental group has cited statistics it says shows the detrimental effects caused by sulfur dioxide emissions from coal-fired plants.

Whitney Pearson, a Sierra Club spokeswoman, criticized Pruitt’s move in a media release Thursday, saying the attorney general “seems to have forgotten who he represents.”

“He is not counsel for Oklahoma Gas & Electric,” Pearson said. “Instead of spending taxpayer money on pointless lawsuits, Oklahoma should instead work to comply with the Clean Air Act. ”

Pollutants emitted by coal-fired plants, clean-air advocates say, contribute to asthma attacks and other respiratory illness. Wesner has said nearly 80,000 children and more than 230,000 adults are diagnosed with asthma in Oklahoma each year. In 2007, hospitalizations from asthma cost Oklahoma citizens $57.9 million in health-care expenses and lost productivity.

Reach D.E. Smoot at (918) 684-2901 or dsmoot@muskogeephoenix.com.