The U.S. Congress conducted its regular business Tuesday, despite an anthrax scare that forced the closure of part of a Senate office building housing the office of Majority Leader Tom Daschle.

Capitol police decided to close part of the Hart Senate office building and relocate about a dozen Senators' offices Tuesday after a letter opened in Senator Daschle's office tested positive for anthrax.

The Senator says none of the staff members in the office at the time has tested positive for the anthrax exposure.

"All of the conclusions are very encouraging," he said. "All of the tests have been negative. There has been no indication there is a health or medical problem among any of my staff. I am quite confident that will remain the case."

Republican Minority leader, Senator Trent Lott, says the case appears to be an isolated one. "It is this one incident so far, and no indications of others," he said.

Still, the Capitol's doctor urged anyone who may have been in the area at the time to get precautionary anthrax tests.

For the second straight day, mail delivery and public tours in the Capitol building were suspended.

But Capitol police spokesman Dan Nichols noted that legislative business was not disrupted.

"It is going to be business as usual, to the extent that we can within the Capitol complex," he said. "The symbolism of this building is very important to everybody in the nation. It is important to the United States' Capitol police. But the symbolism of Congress being able to do its work is important also. That is what we are here to ensure."

Lawmakers say they are determined to stay in session to complete their work, despite the concern raised by the anthrax-laced letter.

Officials from the Federal Bureau of Investigation briefed lawmakers on precautions against the potentially deadly anthrax bacteria, and most said they felt reassured.