Congressional leaders closed the House of Representatives a day before the scheduled weekend break after medical tests showed 31 people were exposed to anthrax from a contaminated letter mailed to Daschle.
All House and Senate office buildings also were ordered closed until at least Monday so investigators could comb the area for any additional evidence of anthrax. Senators, however, vowed that bioterrorism scares would not close their chamber.
"We will not let this stop the work of the Senate," Daschle said at an afternoon news conference. Senate Minority Leader Trent Lott added: "There is no risk there in the Capitol, and we feel confident we can continue to get our work done while taking necessary precautions to affect the people that work with us."
News of the exposure cases in Washington came as federal scientists said strains of the anthrax contained in a threatening letter to NBC news anchor Tom Brokaw were genetically identical to anthrax spores that killed a photo editor at a Florida-based tabloid newspaper and as the anthrax scare continued to spread across the country.
In Baltimore, police went on high alert after the FBI forwarded a vague threat it had received warning that anthrax would be released somewhere in the city after 1 p.m. The hour passed and no release was detected.
And in New York, Gov. George E. Pataki announced that early tests had revealed anthrax spores in one room of his Manhattan offices.
Pataki said the bacteria, identified yesterday as anthrax, were found in a room used by his state police security detail. No one had been found to be infected, he said, but more than 75 troopers, staffers and Pataki himself had begun treatment with antibiotics.
"I honestly believe the likelihood of contamination is very slim, but we're going to have everybody take Cipro as a precaution," he said.
Cipro is an antibiotic used to treat anthrax.
Pataki said the sweep was ordered Monday after his secretary voiced concern about a letter she had received Sept. 25. The governor said the letter contained no threat and was unlikely to be the source of the anthrax.
Suggesting another possibility, Pataki said the troopers in his security detail have been involved in the city's responses to anthrax incidents at the New York offices of NBC and ABC. They could have come into contact with the spores then, he said, and inadvertently carried them back to the office.
In Washington yesterday, officials said that 23 members of Daschle's staff and five Capitol police officers had "positive nasal swabs," indicating an exposure to anthrax, officials said. Three staffers for Sen. Russell Feingold, a Wisconsin Democrat whose office is next to Daschle's, also tested positive.
None of the Capitol Hill workers showed signs of the anthrax disease, but all were being treated with antibiotics as a precautionary measure, officials said.
Initial tests on the letter sent to Daschle indicate that the anthrax it contained was "professionally made," a senior federal bioterrorism expert said yesterday. But so far, laboratory analysts have said they cannot conclude that the bacteria were "weapons grade," he said.
So far, according to the Centers for Disease Control and Prevention, those questions have not all been answered. CDC epidemiologist Dr. David Fleming said yesterday that the bacteria in the Daschle letter have been found to respond to all antibiotics, and "that is very good news."
The bioterrorism expert, who would speak only on condition that he not be identified, said investigators have "substantive leads," about where the anthrax originated, although he declined to elaborate. FBI officials have said that the anthrax investigations so far have not turned up any direct links to organized terrorism, but that has not been ruled out.
The FBI has said the letter sent to Daschle's office bears similarities in content and handwriting to another letter, also tainted with anthrax, that was mailed last month to Brokaw.
Separately, the CDC's Fleming announced yesterday that preliminary testing indicated the strain of anthrax found in the letter mailed to Brokaw in New York "appears to match" the strain found at the tabloid newspaper company in Boca Raton, Fla. Fleming said it is not yet clear whether the Washington anthrax comes from the same strain.
Several senators said yesterday that the anthrax in the Daschle letter was described to them as being very pure and highly concentrated. Maj. Gen. John Parker, who heads the military lab at Fort Detrick, Md., which conducted initial tests on the anthrax from the Daschle letter, said the powder in the letter was "pure spore."
Officials in Washington rushed to assure worried employees and an anxious city that the anthrax strain found in Daschle's letter was "eminently treatable."
"Things are very much under control," said Sen. Bill Frist, a Tennessee Republican and a physician. "Everybody's going to be OK."
Washington lawmakers started the day yesterday much shakier. At a routine White House breakfast with congressional leaders, President Bush first raised the idea of shutting down the Capitol complex to allow for thorough environmental testing, according to congressional sources.
Leaders from both chambers were sympathetic to the idea, and a few hours later, House Speaker Dennis Hastert announced that he would do just that on the House side. He was spurred in part by a worker in his office, who recalled receiving a suspicious envelope.
She notified her supervisor early yesterday, and the FBI was called in to investigate. The trash bags were taken away, but it was not clear last night whether the letter was found. Members of Hastert's staff working on the fourth floor of the Capitol in his mail room and administrative officers were sent to the nurse's office for anthrax testing and treatment.
That development was enough to convince Hastert and House Democratic Leader Richard A. Gephardt that the House should recess until next week to give security teams time to thoroughly check out the buildings.
"We thought this was the prudent thing to do," Hastert told a news conference. Gephardt agreed.
"This is a new type of war we are in," he said. "But we are approaching it in a manner that is calm and collected."
Hastert also raised concerns that traces of anthrax could be in the Senate ventilation system and could easily spread to other areas. Later in the day, however, health officials and senators said that was not the case, and senators said that they would keep their side of the Capitol building open.
"I think there is a very strong desire by 100 senators to send a message to the country that the Senate is going about the important business of the country and that there is no panic," said Sen. Ron Wyden, an Oregon Democrat.
Rep. Benjamin L. Cardin, a Maryland Democrat, said he did not believe the Capitol buildings needed to close to keep official Washington secure and worried that the House shutdown could communicate a sense of panic.
"I think there are people who are concerned about the image it gives to the American people," he said. "I personally think there's no safety reason to leave the Capitol
complex. I think there may be a mixed message."
But others still felt the House decision was correct, and some even questioned why the offices had remained open yesterday.
Rep. Steny H. Hoyer said the early recess would not slow official business and added that the House always intended to break Friday and Monday, meaning that only Thursday's work would be lost.
The Maryland Democrat insisted there was calm in the House - "no one's running out of the building," he said - and likened the unscheduled break to a "snow day" for his staff.
"We'll be in recess a day early - that's business as usual," he said.
The Senate planned to stay open today, with votes scheduled on presidential appointments and a military construction bill. But disruptions were expected there, as well.
With all three Senate office buildings closed, committee meetings were moved to the nearby Library of Congress or to the Capitol building and senators scrambled for a home base.
"I'll operate out of a Starbucks if I need to," said Maryland Democratic Sen. Barbara A. Mikulski, who had been tested for anthrax exposure with her entire staff. "We're going to keep working."
In all, about 1,400 people who were in the Hart Senate Office Building on Monday when the Daschle letter was discovered underwent exposure testing Tuesday. Yesterday, hundreds more lined up at a nursing station inside the Capitol.
As much of Washington worried about anthrax scares in the nation's capitol, federal officials cracked down on anthrax hoaxes in other parts of the country. Two men, one in Rhode Island and the other in Utah, were charged with creating phony anthrax letters.
Sun staff writers Frank D. Roylance and Ellen Gamerman contributed to this article.