WASHINGTON - The Bush administration made it easier yesterday for power plants and other polluting industries to boost their output without having to undergo costly upgrades to curb their dirty emissions.
The administration argues that a Clean Air Act provision - requiring older plants to improve pollution controls when output is expanded - imposes burdensome regulations on many industries without reducing emissions.
Easing those rules, officials said, will lead to greater energy efficiency and less pollution.
The long-awaited step, perhaps the most significant environmental action yet by the administration, was immediately challenged by environmentalists. They condemned the decision as a political gift to power companies that would likely allow industrial plants to increase their foul emissions.
Environmental groups were joined by a chorus of officials from East Coast states whose air is most affected by the flow of dirty emissions from Midwest industrial plants. Several of those states - from Connecticut to Maryland - said they would jointly file suit, challenging the decision as an illegal rewriting of a law written by Congress.
The decision was announced without fanfare on a quiet Friday, after Congress had adjourned for the year and while President Bush continued a trip in Europe.
In a brief statement, Christine Todd Whitman, administrator of the Environmental Protection Agency, asserted that the Clean Air Act has often "deterred companies from implementing projects that would increase energy efficiency and decrease air pollution."
Administration officials said that by easing parts of the law, they will spare industries the legal battles they often encounter when they renovate and modernize their facilities. Industries, they said, would also act aggressively on their own to find cost-efficient ways to cut pollution.
That argument reflects the environmental stance taken by the president, who has long argued that regulatory hurdles do more harm than good, discouraging industries from making investments on their own that could make them cleaner.
But Democrats and other critics disputed that notion. Sen. Tom Daschle of South Dakota, the departing Senate majority leader, called yesterday's move "the most serious attack on the Clean Air Act in its nearly 30-year history." The decision, he said, would eliminate an important legal tool for "cash-strapped cities and states struggling to reduce air pollution."
"It's no accident that the EPA is announcing these changes after the election," Daschle said. "Had voters been given a chance, they would have rejected these damaging changes."
Gov. Parris N. Glendening of Maryland, who along with the state's attorney general, J. Joseph Curran Jr., announced that Maryland would join the states' lawsuit, called the administration's action "unacceptable."
"Maryland's air quality is greatly affected by pollution floating in from other states," said Glendening, a Democrat. "Weakening air pollution laws will allow those states to continue to poison our citizens and the Chesapeake Bay."
Maryland's incoming Republican governor, Robert L. Ehrlich Jr., who was traveling in California, said he had not yet studied Bush's decision and could not say whether he would back it. Ehrlich suggested that in general, as governor, he would have authority to order Curran to drop a lawsuit - but he gave no indication that he had plans to do so.
The administration's decision focuses on a provision of the Clean Air Act called "new source review." That provision requires older industrial facilities - from power plants to oil refineries to paper mills - to upgrade their pollution controls whenever they expand their output.
Under the Clinton administration, the EPA used the provision as a legal weapon against older and dirtier coal-fired power plants. It filed lawsuits, arguing that several dozen of the plants underwent major renovations to increase output without modernizing their pollution controls.
The companies that own the plants complained vociferously, saying the Clinton administration was interpreting new source review too strictly. Utilities and other companies said they were being discouraged from doing any renovations - even those that would cut dirty emissions. They called for the government to revise its interpretation of new source review.
Bush administration officials essentially sided with the energy industry, which lobbied for the changes and has generously supported Bush and the Republican Party over the years. The officials said the changes - most of which take effect immediately - will give industry more flexibility to perform maintenance and renovations without the risk of a legal battle.
For example, one change will exempt industrial plants from new source review as long as they keep their dirty emissions below a certain cap. But environmentalists argue that the old rules would have forced plants to reduce their emissions far more.
Another change will allow a power plant that installed modern pollution controls over the past decade to in some cases sidestep new source review requirements.
Critics note that under the old interpretation, plants had to install the most modern pollution controls anytime they renovated. Under the new approach, a plant can comply if it has anti-pollution technology as old as a decade.
The administration also proposed a change that could take effect next fall that will expand the definition of "routine maintenance." It will make it harder for the EPA and state governments to sue power plants that claim to be performing everyday upkeep rather than renovations that expand capacity.
Jeffrey Holmstead, the assistant EPA administrator for air and radiation, disputed environmentalists' claims that the proposed change would sharply increase dirty emissions. He said that easing clean air rules will encourage plants to put their own pollution controls in place.
But Holmstead acknowledged that a preliminary study suggested that if the proposed change were put in place, power plant emissions of nitrogen oxide could rise, though slightly.
He said the administration hoped eventually to phase out new source review for power plants and instead set new national limits on power plant pollution. Those limits would give companies wide latitude on how to comply.
"You manage a plant how you want to," Holmstead said, "as long as you guarantee your emissions are going to come down."
State officials and environmental groups disputed the administration's contention that its changes would not produce more overall pollution.
Local and state air regulators said they were losing important legal tools that they used often to pursue older, polluting industrial plants.
State attorneys general said they were filing suit on grounds that the EPA exceeded its regulatory authority, and is violating Congress' intent in passing the 1970 Clean Air Act, by allowing air pollution levels to rise.
Curran, Maryland's attorney general, said in an interview that Maryland's difficulty in attaining cleaner air in the Baltimore-Washington corridor lies with 11 older electrical utilities in Ohio and West Virginia that have failed to upgrade their pollution controls.
The state has sued the utilities to try to force them to upgrade their pollution curbs, and Curran said he feared that yesterday's changes could derail those efforts.
"I'm concerned that if we're in court," he said, "it would not be unreasonable for the judge to say, 'Maybe they were out of compliance with these rules before they were changed, but aren't they in compliance with the rules as they are now?'"
Sun staff writer David Nitkin contributed to this article.