U.S. Senate Offices Closed Because of Toxic Substance

U.S. Senate Offices Closed Because of Toxic Substance: " (Update1)

(Bloomberg) -- U.S. Senate office buildings will remain closed today after a powder found in one of them tested positive for ricin, a poisonous substance.

The Hart, Dirksen and Russell office buildings will be closed, according to the Senate's Web site and a phone operator at the Capitol. Committee hearings have also been canceled. The Capitol itself will be open to essential personnel only.

Administration officials, including Treasury Secretary John Snow and Defense Secretary Donald Rumsfeld were scheduled to testify before the Senate today on the president's $2.4 trillion budget proposal for the fiscal year that begins Oct. 1. The budget seeks a 9.7 increase in spending on homeland security.

Ricin, a poison derived from castor beans, was found in the mailroom of Senator Bill Frist in the Dirksen building yesterday. Frist, a Republican from Tennessee, said at a press conference last night the discovery is being investigated as a criminal act.

Ricin can cause death and has no known antidote. Authorities are concerned the powder may have been inhaled by people who came in contact with it, said Frist, who is also a medical doctor. Symptoms including shortness of breath or chest tightness may appear four to eight hours after exposure, he said.

The U.S. Federal Bureau of Investigation issued an alert about ricin in January last year after authorities in the U.K. found traces in a raid on a London apartment and arrested seven men associated with an Algerian extremist group. Ricin was also one of the toxic substances the Central Intelligence Agency suspected was being made in Iraq."