WASHINGTON -- When Gov. Martin O'Malley signed legislation last spring imposing tough new standards on automobile emissions, Maryland became the latest of a dozen states on the cutting edge of the fight against global warming. If enforced, state officials say, the controls eventually would reduce greenhouse gas production in Maryland by 7.8 million tons per year - the equivalent of shutting down a 1,200-megawatt coal-burning power plant.
But the regulations, first approved by California and subsequently adopted by 11 other states, can't be enforced without a go-ahead from the federal Environmental Protection Agency. The EPA has yet to give its OK.
The California controls, the first attempt to limit tailpipe emissions of greenhouse gases, represent the latest effort by states to take on climate change in the absence of action by Washington. Congress, which has debated new energy legislation this year, has not been able to agree on raising fuel economy standards; their prospects for approval this year are unclear.
Automakers oppose the state standards, saying that they would drive sticker prices up by thousands of dollars while forcing manufacturers to produce smaller cars. They have gone to court to try to block their enforcement.
Congressional supporters of the California regulations are now trying to force the EPA to make a decision.
"It's very important that states be able to move forward, particularly until we can have an enforceable federal cap in place," said Sen. Benjamin L. Cardin, a Maryland Democrat who is one of the lawmakers backing legislation that would require the agency to issue a ruling by Sept. 30. "Unfortunately, inaction is action."
EPA Administrator Stephen L. Johnson has said that he will decide the matter before the end of the year. By then, two years will have passed since California first requested action. An EPA spokeswoman says the agency is reviewing more than 60,000 written comments and thousands of pages of technical and scientific documents.
But given the time it has taken the agency to address the request - and the active opposition of the Department of Transportation, which has lobbied members of Congress on the issue - supporters of the new regulations are not optimistic.
"This is the Environmental Protection Agency under this administration that has claimed for six years that there's no such thing as global warming," said David Bookbinder, director of climate litigation for the Sierra Club, "and if there is, it's certainly not caused by human beings, and if it's caused by human beings, there's certainly nothing we can do about it, and carbon dioxide is not a pollutant, and we have no authority, and we shouldn't do anything.
"Presumably they say no, and we go to court."
Federal law since 1967 has given California - the most populous state, with long experience in regulating emissions - the authority to develop its own air-quality standards, subject to EPA approval. Once the federal government approves a "California Waiver," other states can choose to enforce the same rules - and often do. It's the process by which California gave the nation the catalytic converter, low-emissions vehicle standards and the "check engine" light.
The limits on tailpipe emissions of carbon dioxide developed by the California Air Resources Board are the first attempt in the United States to reduce automobile production of greenhouse gases, which scientists believe contribute to global warming. Cars are the nation's second-leading manmade source of such emissions, after power plants.
Maryland has joined New York, Pennsylvania, New Jersey, Massachusetts and other states in adopting the regulations that California approved in 2004. Officials in Florida and Illinois, among other states, say they plan to follow.
"If we can find some ways to mitigate in small ways the things that we do in the aggregate, like burn carbon fuel, if we can limit that even just a little bit, it can have a salutary impact," said state Sen. Brian E. Frosh, a Montgomery County Democrat who sponsored the legislation in Maryland. "The way that that works the best is to have national standards. And when you can't have that ... having states do it individually is the second best way."
But the automobile industry says such an approach is unworkable. The California regulations address average emissions among all vehicles in a state. But because that average is affected by the mix of models sold in a state, and because that mix varies from state to state, industry officials say that the regulations effectively establish a different standard in each state that adopts them.
"What we're trying to avoid is a patchwork quilt," said Charles Territo, a spokesman for the Alliance of Automobile Manufacturers in Washington. "It would make it very difficult for manufacturers to offer the same types of vehicles to consumers they currently offer."