WASHINGTON (Reuters) - A leading U.S. Senate Democrat accused the Bush administration on Tuesday of a “cover-up” aimed at stopping the Environmental Protection Agency from tackling greenhouse emissions.

In this file photo a U.S. flag flutters in front of cooling towers at the Limerick Generating Station in Pottstown, Pennsylvania May 24, 2006. A leading U.S. Senate Democrat accused the Bush administration on Tuesday of a "cover-up" aimed at stopping the Environmental Protection Agency from tackling greenhouse emissions. REUTERS/Kevin Lamarque

“This cover-up is being directed from the White House and the office of the vice president,” said Sen. Barbara Boxer, the California Democrat who chairs the Senate Environment and Public Works Committee.

At issue is a preliminary finding by the EPA last December that “greenhouse gases may reasonably be anticipated to endanger public welfare,” according to Jason Burnett, the agency’s former associate deputy administrator who appeared at a news conference with Boxer.

Such a finding would be an early step toward government regulation aimed at protecting public health.

Boxer said that unless EPA documents were released, it was likely that within the next two weeks her committee would try to subpoena the material. She did not know whether Republicans on the panel would block the effort.

Burnett, who resigned on June 9, told Boxer’s committee the White House tried pressuring him to retract an e-mail in which he detailed the finding. Burnett said he refused.

Democrats say that since then, the EPA finding has been left “in limbo.”

White House spokesman Tony Fratto said many federal agencies, departments and offices normally review any initiatives being developed to check for “factual inaccuracies” or “discordant” policies.

Without getting into specifics, Fratto said “views are frequently discussed and worked out in ways that make sense.”

Senate Democratic Leader Harry Reid, asked about the administration’s actions, said, “I don’t know if that is criminal. I doubt it. OK. But I know it is immoral.”

“The health of my grandchildren, my children and me are affected by this head-in-the-sand that global warming doesn’t exist,” Reid told reporters.

Boxer acknowledged she wanted to gather information so that the next administration could get a jump on global warming initiatives quickly after it takes office on January 20, 2009.

She has been trying since last October to obtain related documents to show that planned congressional testimony on global warming by Dr. Julie Gerberding, director of the Centers for Disease Control and Prevention, was censored by the Bush administration.

Boxer said Gerberding’s testimony would have detailed the direct impact of rising global temperatures on human health, including mortality and the spread of disease.

Burnett told the congressional committee the administration’s Council on Environmental Quality “and the office of the vice president were seeking deletions to the CDC testimony.” He refused to say who in Vice President Richard Cheney’s office was involved.

Responding to Burnett’s charges, Fratto said, “Jason Burnett is not the EPA administrator” and that it was up to EPA chief Stephen Johnson to oversee environmental policy.

Asked at Tuesday’s news conference about his support for Democratic candidates and whether he was trying to embarrass the Republican administration, Burnett said, “Following the law and responding to the Supreme Court is not a partisan issue.”

Last year, the U.S. Supreme Court ruled the Clean Air Act gives EPA the authority to regulate carbon dioxide and other greenhouse gases.

In October, White House spokeswoman Dana Perino said Gerberding’s draft testimony to Congress “did not comport” with science contained in an International Panel on Climate Change report and that “a number of agencies had some concerns with the draft.”

On Tuesday, Boxer said Gerberding’s planned testimony, which has since been detailed in media reports, and the IPCC report “matched identically.”