A federal court rejected the appeal of a ruling that lets carmakers such as General Motors Corp. and utilities such as American Electric Power Co. avoid federal standards for emission curbs under the 1977 Clean Air Act.

The U.S. Court of Appeals for the District of Columbia Circuit voted 4-3 yesterday to deny a petition for a review by the full court. That rejection came after a three-judge panel had ruled in July that the Environmental Protection Agency acted properly in rejecting a plea by 12 U.S. states to require reductions in gases linked to global warming.

New York and Massachusetts were among the petitioners that asked the EPA to enforce federal rules on carbon dioxide and other greenhouse-gas emissions for new cars and trucks. The EPA said in 2003 that even if it had the power to set emissions standards, it wouldn't, partly because of questions about the extent to which humans contribute to global warming.

"EPA looked to the (Clean Air) Act for congressional direction to regulate domestic sources to control the international issue of global climate change and found none," said Lisa Jaeger, a partner at Bracewell & Giuliani LLP in New York and a former acting general counsel at the agency.

President Bush has opposed mandatory regulations to curb greenhouse gases in favor of voluntary plans. Bush rejected the 1997 Kyoto Protocol, which would require greenhouse gases be cut 5.2 percent below 1990 levels by 2012, because he said it would cost jobs and hurt the U.S. economy.

The states along with several environmental groups may now appeal to the U.S. Supreme Court, said Terence Burke, spokesman for Massachusetts Attorney General Tom Reilly.