Officials of 18 states, including Washington and Oregon, are taking the EPA back to court to try to force it to comply with a Supreme Court ruling that rebuked the Bush administration for inaction on global warming.

In a petition prepared for filing Wednesday, the plaintiffs said last April's 5-4 ruling required the Environmental Protection Agency to decide whether to regulate greenhouse gas emissions, including carbon dioxide, from motor vehicles.

The EPA has instead done nothing, they said.

"The EPA's failure to act in the face of these incontestable dangers is a shameful dereliction of duty," Massachusetts Attorney General Martha Coakley said.

The petition asks the U.S. Court of Appeals for the District of Columbia Circuit to require the EPA to act within 60 days.

In last year's decision, the Supreme Court ruled the EPA has the authority to regulate emissions from new cars and trucks under the Clean Air Act, and said the reasons the EPA gave for declining to do so were insufficient.

EPA spokesman Jonathan Shradar said the Supreme Court required the agency to evaluate how it would regulate greenhouse gas emissions from cars and other vehicles but set no deadline.

The EPA plans to include the evaluation in a broader look at how to best regulate all greenhouse gas emissions, not just those from vehicles, he said. Otherwise, a mash of laws and regulations could emerge rather than the "holistic" approach the administration favors.

"We want to set a good foundation to build a strong climate policy of potential regulation and laws we can work toward and actually see some success," Shradar said.

The plaintiffs in the latest court action include Coakley and attorneys general from Arizona, California, Connecticut, Delaware, Illinois, Iowa, Maine, Maryland, Minnesota, New Jersey, New Mexico, New York, Oregon, Rhode Island, Vermont, Washington and the District of Columbia, plus representatives of the Pennsylvania Department of Environmental Protection and the cities of New York and Baltimore, and several environmental organizations.