Three U.S. Senate office buildings are closed, and congressional business has been disrupted a day after a suspicious powder, believed to be the poison, ricin, was discovered on Capitol Hill.
Authorities are awaiting definitive results from tests conducted on the white substance found in a mailroom in the Dirksen Senate Office building Monday. Eight tests on the material have already been done, and six of them came back positive for ricin.
Although Senate office buildings closed as a precautionary measure, the Senate is in session. "Somebody, in all likelihood, manufactured this with the intent to harm, and this is a criminal investigation that will be under way," majority leader Bill Frist told fellow senators.
The Capitol building is open, although public tours have been canceled. House office buildings are also open. Mail delivery to Capitol Hill has been suspended.
Senator Frist said it appears the contamination has been isolated. "All air sampling, all environmental studies to date are negative with the exception of what was found in that single office at that site," he said.
But suspicious powder was also found at a postal facility in Connecticut, where anthrax spores were found in 2001. A series of anthrax-tainted letters were mailed to locations in the eastern United States that year, including to Senators Tom Daschle and Patrick Leahy. Five people died. No one has been arrested in those incidents.
No illnesses have been reported in connection with the discovery of the white substance on Capitol Hill, or in Connecticut.
Inhaling significant quantities of ricin can result in death within a day or two. There is no known antidote.