A White House document shows that executives from big oil companies met with Vice President Cheney's energy task force in 2001 -- something long suspected by environmentalists but denied as recently as last week by industry officials testifying before Congress.

The document, obtained this week by The Washington Post, shows that officials from Exxon Mobil Corp., Conoco (before its merger with Phillips), Shell Oil Co. and BP America Inc. met in the White House complex with the Cheney aides who were developing a national energy policy, parts of which became law and parts of which are still being debated.

In a joint hearing last week of the Senate Energy and Commerce committees, the chief executives of Exxon Mobil Corp., Chevron Corp. and ConocoPhillips said their firms did not participate in the 2001 task force. The president of Shell Oil said his company did not participate "to my knowledge," and the chief of BP America Inc. said he did not know.

Chevron was not named in the White House document, but the Government Accountability Office has found that Chevron was one of several companies that "gave detailed energy policy recommendations" to the task force. In addition, Cheney had a separate meeting with John Browne, BP's chief executive, according to a person familiar with the task force's work; that meeting is not noted in the document.

The task force's activities attracted complaints from environmentalists, who said they were shut out of the task force discussions while corporate interests were present. The meetings were held in secret and the White House refused to release a list of participants. The task force was made up primarily of Cabinet-level officials. Judicial Watch and the Sierra Club unsuccessfully sued to obtain the records.

Sen. Frank Lautenberg (D-N.J.), who posed the question about the task force, said he will ask the Justice Department today to investigate. "The White House went to great lengths to keep these meetings secret, and now oil executives may be lying to Congress about their role in the Cheney task force," Lautenberg said.

Lea Anne McBride, a spokeswoman for Cheney, declined to comment on the document. She said that the courts have upheld "the constitutional right of the president and vice president to obtain information in confidentiality."

The executives were not under oath when they testified, so they are not vulnerable to charges of perjury; committee Democrats had protested the decision by Commerce Chairman Ted Stevens (R-Alaska) not to swear in the executives. But a person can be fined or imprisoned for up to five years for making "any materially false, fictitious or fraudulent statement or representation" to Congress.

Alan Huffman, who was a Conoco manager until the 2002 merger with Phillips, confirmed meeting with the task force staff. "We met in the Executive Office Building, if I remember correctly," he said.

A spokesman for ConocoPhillips said the chief executive, James J. Mulva, had been unaware that Conoco officials met with task force staff when he testified at the hearing. The spokesman said that Mulva was chief executive of Phillips in 2001 before the merger and that nobody from Phillips met with the task force.

Exxon spokesman Russ Roberts said the company stood by chief executive Lee R. Raymond's statement in the hearing. In a brief phone interview, former Exxon vice president James Rouse, the official named in the White House document, denied the meeting took place. "That must be inaccurate and I don't have any comment beyond that," said Rouse, now retired.

Ronnie Chappell, a spokesman for BP, declined to comment on the task force meetings. Darci Sinclair, a spokeswoman for Shell, said she did not know whether Shell officials met with the task force, but they often meet members of the administration. Chevron said its executives did not meet with the task force but confirmed that it sent President Bush recommendations in a letter.

The person familiar with the task force's work, who requested anonymity out of concern about retribution, said the document was based on records kept by the Secret Service of people admitted to the White House complex. This person said most meetings were with Andrew Lundquist, the task force's executive director, and Cheney aide Karen Y. Knutson.

According to the White House document, Rouse met with task force staff members on Feb. 14, 2001. On March 21, they met with Archie Dunham, who was chairman of Conoco. On April 12, according to the document, task force staff members met with Conoco official Huffman and two officials from the U.S. Oil and Gas Association, Wayne Gibbens and Alby Modiano.

On April 17, task force staff members met with Royal Dutch/Shell Group's chairman, Sir Mark Moody-Stuart, Shell Oil chairman Steven Miller and two others. On March 22, staff members met with BP regional president Bob Malone, chief economist Peter Davies and company employees Graham Barr and Deb Beaubien.

Toward the end of the hearing, Lautenberg asked the five executives: "Did your company or any representatives of your companies participate in Vice President Cheney's energy task force in 2001?" When there was no response, Lautenberg added: "The meeting . . . "

"No," said Raymond.

"No," said Chevron Chairman David J. O'Reilly.

"We did not, no," Mulva said.

"To be honest, I don't know," said BP America chief executive Ross Pillari, who came to the job in August 2001. "I wasn't here then."

"But your company was here," Lautenberg replied.

"Yes," Pillari said.

Shell Oil president John Hofmeister, who has held his job since earlier this year, answered last. "Not to my knowledge," he said.

Research editor Lucy Shackelford contributed to this report.