On October 15 , 2001 , several suites of this building became contaminated by the release of anthrax powder from an envelope mailed to Senate Majority Leader Tom Daschle in the 2001 anthrax attacks . The building was closed October 17 , 2001 , displacing hundreds of Senate staff . The building was decontaminated using chlorine dioxide gas from November to December 2001 , and the building reopened January 23 , 2002
2001 anthrax attacks
2001 anthrax attacks
Hart Senate Office Building