A senior California lawmaker on Monday said the administration was trying to "stack the deck" against his state's proposal to impose tough standards on motor vehicle emissions, and urged the White House to repudiate what he called a questionable lobbying effort.

Rep. Henry Waxman, D-Calif., chairman of the House Committee on Oversight and Government Reform, said documents and interviews showed that the White House approved a behind-the-scenes lobbying effort to urge members of Congress and state governors to oppose EPA approval of the new California standards.

That lobbying campaign, Waxman said in a letter to James L. Connaughton, chairman of the White House Council on Environmental Quality, "sends an unmistakable message: the administration is trying to stack the deck against California's efforts to regulate greenhouse gas emissions from motor vehicles."

The council's spokeswoman, Kristen Hellmer, said the issue comes in the context of President Bush's call for a national program to replace 20 percent of the nation's gasoline use in 10 years through fuel efficiency and alternative fuels.

"Outreach by federal officials to state government counterparts and members of Congress on issues of major national policy is an appropriate and routine component of policy development," she said.

In December 2005 California sent the Environmental Protection Agency a request to waive the Clean Air Act so it could implement new greenhouse gas emissions standards on cars and light-duty trucks aimed at reducing global warming pollution from new vehicles by almost 30 percent by the year 2016.

Eleven other states have adopted the California standards but can't enforce them unless the EPA grants the waiver.

The auto industry is opposed to the waiver, arguing that there should be one federal standard for tailpipe emissions. California officials have reproached the EPA for putting off a decision, which the EPA now says will come before the end of the year.

California Attorney General Jerry Brown said in an interview that he planned to sue the EPA next month over the "unconscionable delay." He said the Waxman disclosures revealed that "a far-reaching and very solid effort on the part of California is being frustrated by covert sabotage by the Department of Transportation."

Waxman's letter cited numerous e-mails and other communications among officials of the Department of Transportation, the Council on Environmental Quality and the EPA that he said showed the clear intent of the administration, led by Transportation Secretary Mary Peters, to lobby against the waiver.

He said former Transportation Department deputy chief of staff Simon Gros, in an interview with committee staff, related that five department staffers contacted between 20 and 25 members of Congress, and that Peters personally called two to four governors.

Waxman, in his letter, said Peters and Connaughton were free to make public comments to the EPA on the merits of the California standards, but "it is not an appropriate use of taxpayer dollars to organize a lobbying campaign to politicize this vital regulatory decision."

He said coordination with the EPA, "would be especially problematic" because the EPA is charged with making an independent and objective decision.

The Transportation Department, in a statement, said its efforts to inform elected officials were "legal, appropriate and consistent" with its long-held positions. "For over 30 years, the department has supported a single national fuel economy standard as part of our effort to save fuel, ensure safety, preserve the environment and protect the economy."