WASHINGTON (AP) Investigators said they have discovered anthrax in a new location in the Hart Senate office building yesterday evening, even as another Senate building became the first to reopen since a letter contaminated with the bacteria was discovered last week on Capitol Hill.

Capitol Police Lt. Dan Nichols said anthrax was found on a first-floor freight elevator bank in the Hart building"s southwest quadrant. The anthrax-laden letter was opened in the office of Senate Majority Leader Tom Daschle (D-S.D.), which is on the fifth and sixth floors of that same building but in its southeast quadrant.

Nichols said investigators would be trying to determine how the anthrax reached the elevator bank. The Hart building and all other congressional office buildings have been closed since the evening of Oct. 17.

Though Congress" five other office buildings remained closed, wary workers were allowed back into the Russell Senate office building across the street from the Capitol yesterday morning. The building houses the offices of 36 of the Senate"s 100 members.

House leaders were hoping to begin reopening some of their buildings on Thursday. Daschle (D-S.D.) said he hoped another Senate building would be usable as early as tomorrow.

"We want to get as back to normal as quickly as we can," Daschle told reporters. "Allowing senators the opportunity to get back into their offices is a part of our ability to do that."

Earlier yesterday, Postmaster General John Potter said he can"t guarantee the safety of the mail, and he and other postal officials began suggesting Americans wash their hands after handling letters.

Improved safety gloves and masks are being sent to mail workers as the Postal Service awaits next week"s delivery of its first high-technology equipment to sanitize mail.

Worries have mounted about mail safety because of anthrax cases in Florida, New York, Washington and New Jersey, at least some of them stemming from mailed items.

Deborah Willhite, a senior vice president of the Postal Service, said the agency is simply urging people to use common sense.

"We believe that people should wash their hands in soap and water after they handle their mail every day, just to make sure that if anything is on the envelope, that they"re clean," she said in an interview.

"We have no reason to believe that there would be anything on them, but what"s the problem with clean hands?"

Later, Willhite urged organizations that send bulk mail through a contaminated Washington post office to have their employees tested for anthrax.

The tests have focused on postal workers so far, but she said that should be extended by up to 200 more people, including employees of operations like the International Monetary Fund and Humane Society of the United States, who collect large volumes of mail at the center.

Potter stressed the agency has delivered more than 20 billion pieces of mail since Sept. 11, and that only a handful of anthrax cases have been reported. However, he admitted that he could not guarantee the safety of all mail.

The post office is scrambling to tighten its health and safety systems after two workers died of anthrax and others became ill.

"We are taking concrete steps immediately to protect employees and the public through education, investigation, intervention and prevention," Potter said yesterday.

But Sen. Charles Grassley (R-Iowa) questioned whether the Postal Service and the Centers for Disease Control and Prevention did enough to protect postal workers and the mail still being delivered in the Washington area. The agencies have been criticized for waiting several days before testing people for anthrax at the contaminated Washington distribution center.

"It is critical that your agencies retrace your steps to ensure that no one else dies from this scourge," Grassley wrote to Potter and CDC director Jeffrey Koplan. "It is up to public health authorities and the U.S. Postal Service to demonstrate that mail delivered in Washington, DC is not dangerous."

Tom Ridge, the newly named director of homeland security, told CBS News that public health officials didn"t make the safety of postal workers a lower priority.

"I"m absolutely positively, 1,000 percent convinced that they weren"t looking at the collar of the shirts, whether it was a white collar or a blue collar challenge," Ridge said. "They were looking at a medical challenge."

The Postal Service is at war, Potter has said, insisting that the agency will continue to deliver the mail.

Willhite said the post office is expected to deliver universal mail service. "We are going to provide safe and secure mail service everywhere in the United States," she said.

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