"This three-judge panel has done the world a favor and helped save lives," said Connecticut Attorney General Richard Blumenthal, one of many attorneys general who joined a lawsuit originally brought by New Jersey.
Senator Patrick Leahy, a Vermont Democrat, said the court did the right thing.
"This ruling is a big win for healthier air and water for everyone, and especially for a whole generation of the most vulnerable Americans, our children," Leahy said. "When the question is allowing old power plants to keep on polluting, there is only one right answer, and the Bush administration got it wrong. Their mercury rule was of, by, and for the powerful special interests who want to continue polluting."
The court unanimously struck down the cap-and-trade policy and the Environmental Protection Agency's plan to exempt coal- and oil-fired power plants from regulations requiring strict emissions control technology to block emissions. Before instituting the new regulation, the court held, the government was required to show that emissions from any power plant would not harm the environment or "exceed a level which is adequate to protect public health with an ample margin of safety."
The EPA argued it was not required to follow that rule, a stance the court held was "not persuasive."
The agency defended the rule, saying it represented the nation's first attempt to control such emissions and that it would reduce mercury emissions by 70 percent.
"Keep in mind, the US now has no national mercury emissions regulation for these plants," EPA spokesman Jonathan Shradar said, adding that the EPA would consider whether the cap-and-trade policy could be resurrected under a different regulation. "It's good for America and it's good for the environment. We want to be a global leader on this issue," he said.
Industry organizations strongly supported the plan.
"The court's decision represents a major setback for federal efforts to establish clear mercury regulations for coal-fired power plants," said Dan Riedinger, a spokesman for Edison Electric Institute, an association of power companies. "Now EPA has to go back to the drawing board, pushing mercury regulations far off into the future."
The states argued the cap-and-trade system would endanger children near some plants that pollute but use credits to do it legally.
"This means the EPA is going to have to go back and do a real job of regulating all the toxics coming out of these plants," said James S. Pew, a lawyer who argued the case on behalf of several environmental organizations that filed documents in the case.
Joining in the suit were California, Connecticut, Delaware, Illinois, Maine, Maryland, Massachusetts, Michigan, Minnesota, New Hampshire, New Mexico, New York, Pennsylvania, Rhode Island, Vermont, and Wisconsin.
