Gov. Chris Gregoire said Thursday that Washington will join other states in suing the federal government over the Environmental Protection Agency's decision preventing the adoption of stricter rules limiting vehicle greenhouse gas emissions.

Without the tighter regulations, "we cannot achieve our goals" for cutting carbon dioxide and other planet-warming pollutants, Gregoire said at a news conference.

On Wednesday, the EPA announced that more stringent greenhouse gas rules from California -- which were going to be used by Washington and 15 other states -- would not be allowed.

The EPA said everyone would have to follow new vehicle efficiency standards approved this week by President Bush. EPA Administrator Stephen Johnson said that prevents a "patchwork" of rules.

Gregoire challenged that characterization, considering the number of states committed to or considering following the California standards.

"We're talking about half of the automobiles sold in the country," she said.

Shortly after the EPA denied California's waiver to implement the stricter rules, Gov. Arnold Schwarzenegger announced that the state would sue the federal government, and officials in Oregon, Vermont and other states also announced lawsuit plans.

"I don't like suing the federal government, but they leave us no option," Gregoire said. "They need to get out of the way and let us lead."

"We're still evaluating the decision and the legal issues and arguments associated with it along with other states in an effort to identify our strongest legal argument," said Janelle Guthrie, spokeswoman for state Attorney General Rob McKenna.

"I'm very confident that states will win on this," said Dennis McLerran, executive director of the Puget Sound Clean Air Agency, a government entity. "It's just unfortunate that EPA Administrator Johnson has put states in that position to have to sue. It appears that this is just a delaying tactic."

Johnson's decision overruled a consensus among EPA's legal and technical staff that denying California's waiver was unlikely to stand up in court, according to government officials familiar with the decision. Johnson's advisers told him that granting the waiver would put the agency in a much more defensible legal position, should automakers sue the EPA.

The officials confirmed a report in The Washington Post that a PowerPoint presentation prepared for Johnson included the prediction, "EPA likely to lose suit," if taken to court for denying the waiver.

Auto company executives told the White House and sympathetic members of Congress that they feared the fuel standards and the California waiver would force them to cut emissions and raise fuel economy on a faster timetable than the federal energy bill that became law.

California is the only state with authority under the Clean Air Act to police air pollution provided it gets a waiver from the EPA. Other states then are allowed to follow the California rules. The EPA has not denied a waiver request in 40 years, and it took two years to make a decision regarding this waiver.

The federal standards favored by the EPA are weaker and begin taking effect in 2011, becoming fully implemented by 2020. The California rules impose stricter restrictions on new vehicles beginning with 2009 models that start selling next year, reaching full implementation by 2016.

Because nearly half of Washington's greenhouse gas emissions come from transportation, leaders here emphasize the importance of curbing vehicle pollution.

Plans are being drafted to reduce the state's releases, and 9.5 percent of the reductions by 2020 were dependent on implementing the California emission standards.

"Transportation is really the 800-pound gorilla in Washington in the emissions game," said Tony Usibelli, energy policy director with the state Department of Community, Trade and Economic Development.

Adopting the California rules meant taking the equivalent of 690,000 cars off the road in this state by 2020. There were 3.6 million cars registered in Washington in 2001, Usibelli said.

"You have to make some significant progress on the transportation front," he said. "The stock of cars does not turn over rapidly, so the sooner you get started and get more efficient cars and lower-emitting cars into the fleet, the sooner you get to those (climate change) goals."

In Washington, D.C., congressional Democrats announced an investigation of the EPA decision.

House Oversight and Government Reform Committee Chairman Henry Waxman, D-Calif., sent a letter to Johnson demanding "all documents relating to the California waiver request."

Waxman told Johnson to order the EPA staff to preserve all records. The decision against California "appears to have ignored the evidence before the agency and the requirements of the Clean Air Act," Waxman wrote. He asked for all the relevant documents by Jan. 23.

Bush stood by the decision of his EPA administrator.

"The question is how to have an effective strategy. Is it more effective to let each state make a decision as to how to proceed in curbing greenhouse gases or is it more effective to have a national strategy," Bush said at a news conference Thursday.

This report includes information from The Associated Press and The New York Times. P-I reporter Lisa Stiffler can be reached at 206-448-8042 or lisastiffler@seattlepi.com. Read her blog on the environment at datelineearth.com.