(AP) -- The Obama administration took a major step Monday toward imposing the first federal limits on climate-changing pollution from cars, power plants and factories, declaring there was compelling scientific evidence that global warming from manmade greenhouse gases endangers Americans' health.
The announcement by the Environmental Protection Agency was clearly timed to build momentum toward an agreement at the international conference on climate change that opened Monday in Copenhagen, Denmark. It signaled the administration was prepared to push ahead for significant controls in the U.S. if Congress doesn't act first on its own.
The price could be steep for both industry and consumers. The EPA finding clears the way for rules that eventually could force the sale of more fuel-efficient vehicles and require plants to install costly new equipment - at a cost of billions or even many tens of billions of dollars - or shift to other forms of energy.
No analysis has been conducted by the EPA on costs of such broad regulations, although the agency put the price tag of its proposed climate-related car rules at $60 billion, with an estimated benefit of $250 billion.
Energy prices for many Americans probably would rise, too - though Monday's finding will have no immediate impact since regulations have yet to be written. Supporters of separate legislation in Congress argue they could craft measures that would mitigate some of those costs.
Environmentalists hailed the EPA announcement as a clear indication the United States will take steps to attack climate change even if Congress fails to act. And they welcomed the timing of the declaration, saying it will help the Obama administration convince delegates at the international climate talks that the U.S. is serious about addressing the problem. Obama will address the conference next week.
But business groups said regulating carbon emissions through the EPA under existing clean air law would put new economic burdens on manufacturers, cost jobs and drive up energy prices.
"It will choke off growth by adding new mandates to virtually every major construction and renovation project," declared Thomas Donohue, president of the U.S. Chamber of Commerce, which in recent months has been particularly critical of the EPA's attempt to address climate change.
The EPA signaled last April that it was inclined to view heat-trapping pollution as a threat to public health and welfare and began to take public comments for formal rulemaking. That marked a reversal from the Bush administration, which had refused to issue the finding, despite a conclusion by EPA scientists that it was warranted.
EPA Administrator Lisa Jackson said Monday, "There are no more excuses for delaying," adding that the so-called endangerment analysis from global warming had been under consideration at the agency for three years. After the official finding, she said the agency is now "obligated to make reasonable efforts to reduce greenhouse pollutants under the Clean Air Act."
White House spokesman Robert Gibbs said President Barack Obama "still believes the best way to move forward is through the legislative process" - something Obama has expressed on a number of occasions as he has pressed Congress to shift the nation's energy priorities away from fossil fuels and to reduce climate-changing pollution.
The EPA said scientific evidence clearly shows that greenhouse gases "threaten the public health and welfare of the American people" and that the pollutants - mainly carbon dioxide from burning fossil fuels - should be reduced, if not by Congress then by the agency responsible for enforcing air pollution.
"These long-overdue findings cement 2009's place in history as the year when the United States government began addressing the challenge of greenhouse-gas pollution," said Jackson.
She rejected claims by climate skeptics that the science of global warming remains in doubt, an argument given additional attention in recent weeks with the disclosure through intercepted e-mails that a British scientist had privately discussed ways to shield certain climate data from public scrutiny.
"The vast body of evidence not only remains unassailable, it has grown even stronger," said Jackson.
Sen. John Kerry, D-Mass., a lead author of a climate bill before the Senate, said of the finding: "This is a clear message to Copenhagen of the Obama administration's commitments to address global climate change. ... The message to Congress is crystal clear: Get moving."
Sen. Barbara Boxer, D-Calif., also a co-author, said, "The Senate has a duty to act."
Business groups have strongly argued against tackling global warming through the Clean Air Act, saying it is less flexible and more costly than the cap-and-trade legislation being considered by Congress. Any regulations from the EPA are certain to spawn lawsuits and a lengthy legal fights.
"Such regulations would be intrusive, inefficient and excessively costly, chill job growth and delay business expansion," argued Jack Gerard, president of the American Petroleum Institute, which also has been critical of the climate legislation before Congress.
"The Clean Air Act can complement legislation," said Jackson. In fact, if Congress were to cap greenhouse gas emissions, the EPA probably would be given the responsibility of implementing the law.
The EPA's involvement in reducing climate-changing pollution, stems from a 2007 Supreme Court decision that declared that carbon dioxide and other greenhouse gases are pollutants under the Clean Air Act. But the court said the EPA would have to determine if these pollutants pose a danger to public health and welfare before it could regulate them.