The Bush administration yesterday invoked executive privilege and refused to turn over key documents sought by a House investigative committee, escalating a fight over the White House role in U.S. policy on greenhouse-gas emissions and ozone air quality standards.

    Congressman Henry L. Waxman (D-Calif.), chairman of the House Oversight and Government Reform Committee, called off a threatened contempt of Congress vote against Environmental Protection Agency Administrator Stephen L. Johnson and a White House budget official while congressional Democrats decide how to respond.

    Lawmakers say the two Bush administration officials refused to respond to subpoenas for documents about communications between the White House and EPA. The papers concern White House intervention in Johnson's December decision to overrule EPA officials who were in favor of granting California and 17 other states permission to mandate a reduction of vehicle emissions by 30 percent by 2016.

    In March, the EPA also issued tougher health standards for smog, but they were not as strict as levels recommended by an EPA science advisory board after President Bush sided with the White House Office of Management and Budget in opposition.

    "Administrator Johnson has repeatedly insisted he reached his decisions on California's petition and the new ozone standard on his own, relying on his best judgment," Waxman said. "Today's assertion of executive privilege raises serious questions about administrator Johnson's credibility and the involvement of the president."

    In a letter to Waxman released yesterday, OMB Director Jim Nussle called the committee's threat of a contempt vote an "unjustified course" that failed to respect and balance the interests of a co-equal branch of government. Separately, EPA Associate Administrator Christopher B. Bliley told the committee that the administration turned over the "vast majority" of responsive documents, withholding fewer than 25 of more than 10,000.

    Nussle wrote that the government is acting "to preserve the confidentiality that is essential to the ability of current and future Presidents to receive candid analyses, advice and recommendations" from senior advisers.

    In addition to Johnson, House investigators sought records from Susan Dudley, administrator for information and regulatory affairs at the OMB.

    Administration critics are trying to obtain the waiver California needs through a federal lawsuit and congressional legislation.

    The confrontation is the latest showdown between Congress and the administration over executive privilege, under which presidents can prohibit executive branch officials from testifying or can withhold documents from Congress involving internal deliberations.

    Earlier this year, the House sued former White House counsel Harriet E. Miers and chief of staff Joshua B. Bolten, seeking to compel them under subpoena to turn over information about the firing of nine U.S. attorneys. A hearing is scheduled for Monday in federal court in the District.

    The House Judiciary panel also is engaged in a tug of war with former White House policy aide Karl Rove, who maintains through his attorney that he cannot answer questions about the U.S. attorney documents because of the privilege issue.

    Peter Shane, a law professor and executive privilege expert at Ohio State University, said the conflicts are "part and parcel of a larger effort to reinstate what the Bush administration believes to be the proper scope of executive power."

    In the EPA case, Shane said, Congress appears to be conducting an investigation of a policy decision that already has been made, a factor that he said ultimately could give lawmakers "an upper hand."