WASHINGTON -- U.S. Sen. Max Baucus, angry over asbestos contamination in Libby, Mont., refused to allow two Environmental Protection Agency officials to testify at a hearing Thursday on the agency's role in cleaning up the town.

EPA staff exchanged heated words with Senate Environment and Public Works Committee aides after two agency officials arrived to speak at the morning hearing. The officials later left when the aides told them several times that they could not testify.

Baucus, D-Mont., who arrived after the exchange, said at the hearing that he had hoped two officials who worked at length in Libby -- Paul Peronard, former on-scene coordinator, and Christopher Weis, an EPA toxicologist -- would testify.

The agency said those employees were not available for the hearing, which focused on documents showing the EPA prepared in 2002 to declare a public health emergency in Libby -- but later reversed course after meeting with White House officials.

In their absence, Baucus said he had hoped EPA Administrator Stephen Johnson would attend. But Johnson sent a letter to Baucus on Wednesday saying he wouldn't be able to testify and would send Acting Regional Administrator Carol Rushin and Libby site manager Mike Cirian on his behalf.

Rushin and Cirian were the officials who left the hearing after being told they could not testify.

Baucus, who originally obtained the documents and chaired Thursday's hearing, said a public health emergency declaration was still needed in Libby, home to the now-closed W.R. Grace & Co. vermiculite mine. The EPA, which has declared the area a Superfund site, first arrived in Libby in 1999, when news reports linked asbestos contamination from the mine to deaths and illnesses.

The vermiculite, used in a variety of household products, contained tremolite asbestos, which was not only used in home insulation but released into the air and carried home on miners' clothing. Lawyers for Libby residents say asbestos has sickened about 2,000 people in the town and killed up to 225.

The emergency declaration would have been the first of its kind, forcing the EPA to clean entire houses and providing extensive health care for those who were sickened.

Instead of declaring a public health emergency, the agency ordered an easier, cheaper and less extensive way to remove asbestos from the attics of residents.

Baucus said the documents, released this week, show a clear pattern of intervention by the White House when EPA was considering the declaration in 2002.

"They have failed the people of Libby, and I am outraged," Baucus said.

The EPA released a statement Thursday addressing the 2002 deliberation.

"After examining the situation in detail, EPA determined that the clean up of the Libby, Montana site could continue without declaring a public health emergency," said spokeswoman Tisha Petteway. "EPA's ongoing cleanup efforts continue to make Libby safer for the community."

The EPA's inspector general, Stephen Nesbitt, did testify at the hearing and told the committee that a two-year internal investigation showed EPA employees and Libby residents questioned whether decisions were based more on budgetary reasons than science or the welfare of the town.

Nesbitt said his office presented their findings of "potential criminal violations" to the Department of Justice, which determined criminal proceedings were not warranted. He did not elaborate on what findings he presented to the department.

According to the documents released this week, the EPA in early 2002 readied a public health emergency declaration.

"I believe CTW wants this PHE announced within 10 days," wrote EPA spokeswoman Bonnie Piper in an April 9, 2002, e-mail, referring to then-EPA administrator, former New Jersey Gov. Christine Todd Whitman. "note: Earth Day is the following week."

Seven days later, a meeting with the White House Office of Management and Budget appears on the schedule of Marianne Lamont Horinko, then the assistant administrator for the EPA's Office of Solid Waste and Emergency Response.

A few weeks after that, the EPA released an "action memo" expanding the agency's current authority to clear insulation from Libby attics but did not declare a public health emergency. According to the EPA documents released by Baucus, the agency released the memo after several contacts with OMB officials who offered suggestions about its wording.

Horinko, the assistant administrator who met with the White House, denied any intervention from the Office of Management and Budget.

"I don't have any recollection of OMB telling us not to do that," she said Wednesday. "It was a public policy decision on Gov. Whitman's part."

Whitman did not return calls seeking comment.