The Hart Senate Office Building will re-open at noon Friday, nearly three months to the day after it closed following the discovery of an anthrax-tainted letter in the office of Senate Majority Leader Tom Daschle.

A memo has gone out to staffers who work in the building that says it is "expected" to re-open at noon. The memo also says that prior to Friday, chiefs of staff and staff directors will be permitted to go into the building to try to determine what additional clean-up might be needed in their offices.

The memo also assures staffers that the building is safe, saying that based upon review by working group officials, including administrators from the Centers for Disease Control and the Environmental Protection Agency, the Hart building has been "successfully remediated."

"The cleanup achieved the goal of eliminating viable anthrax spores detected in the Hart building and that it is now safe and clean to release to the Architect of the Capitol for rehabilitation and subsequent re-occupancy," says an e-mail message from the Senate sergeant-at-arms.

A letter opened by a staff member in the personal office of Daschle, D-S.D., exposed more than two dozen people to anthrax spores and led to the closure of the Hart Senate Office Building. The Hart building, which is across the street from the Capitol, has been closed since hazardous materials workers started fumigating the building in an effort that failed twice before.

The contaminated quadrant of Hart tested positive for traces of anthrax spores after the first fumigation effort Dec. 1. A second fumigation attempt on Dec. 16 failed when workers could not create the necessary levels of humidity for the gas to work properly.

"Senator Daschle's suite where the anthrax spill occurred was fumigated successfully with chlorine dioxide gas," a second memo from the Senate sergeant-at-arms office says. "The (heating, ventilation and air conditioning) system in the southeast quadrant of the Hart Building was also fumigated successfully using chlorine dioxide gas. Post-remediation sampling including air sampling of Senator Daschle's suite and HVAC system achieved the goal of zero viable spores detected.''

The chlorine gas has been removed and rendered nontoxic, the second memo said.

Cleanup and testing efforts included floor vacuuming, wiping of desks, tables, walls and other surfaces, sample swabs taken from monitor screens and air conditioning grills, air sampling and the use of chlorine dioxide liquid, chlorine dioxide gas and anti-bacterial foam.

Senators will be briefed Thursday on the reopening, the memo says.

After the tainted letter was opened, more than 5,000 environmental samples were taken in offices and common areas in the Hart building. In addition, more than 6,000 nasal swabs were taken from people who may have come in contact with anthrax spores from the letter.

"Three months have passed since the initial incident and no one in the Capitol Hill community has become ill with anthrax," the memo says.

The Associated Press contributed to this report.