At issue is whether the Clean Air Act gives the EPA authority to regulate carbon dioxide and other greenhouse gas emissions as a way to address climate change. Utah and the other seven states supporting the EPA in a case say the law doesn't allow such regulation.

Utah Assistant Attorney General Fred Nelson said Tuesday the problem with the case, now before the U.S. Supreme Court, is that if the EPA is required to consider carbon dioxide as a pollutant, states would have to implement countermeasures on a local level.

"We think that's better handled on a national level, because carbon dioxide is not like a local pollutant that causes an inversion," Nelson said. The case began in 2003 when the EPA turned back the petition submitted by New York, California, Connecticut, Maine, Massachusetts, New Mexico, Oregon, Rhode Island, Vermont, Wisconsin and Washington, D.C., several conservation groups, the Union of Concerned Scientists and the U.S. Public Interest Research Group.

The plaintiffs claim the federal agency violated the Clean Air Act by not adopting emission standards to reduce carbon dioxide air pollution from new power plants across the nation. Carbon dioxide is the primary "greenhouse gas" that contributes to global warming.

Massachusetts Attorney General Tom Reilly, whose state took the lead in Supreme Court case, said in an April news release that legal action was necessary because the Bush administration "acknowledges that global warming poses serious dangers to our environment and health, but continues not to do anything to regulate greenhouse gas emissions." In 2005, the U. S. Court of Appeals in Washington, D.C., sided with the EPA in a 2-1 decision. The states supporting the ruling - Utah, Michigan, North Dakota, South Dakota, Alaska, Kansas, Nebraska, Texas and Ohio - are joined by energy industry groups and auto manufacturer associations.

Nelson said Utah doesn't believe global warming shouldn't be addressed. But the Clean Air Act essentially regulates pollutants people breathe, not climate change.

A better way to approach the problem would be a federal law, or an amendment to the Clean Air Act to include climate change concerns, Nelson said.