Health officials today confirmed that the deadly toxin ricin was found in the mailroom of Senate Majority Leader Bill Frist.
The discovery of a suspicious powder in the Dirksen Senate Office Building on Monday led to the closure of several Senate buildings today as Capitol Hill employees awaited the final results of tests of the substance's potency.
There were no reported cases of injuries although dozens of Capitol Hill employees were briefly quarantined and underwent decontamination.
At a news conference in Washington today, U.S. officials confirmed that the lab tests for ricin were positive.
Addressing his colleagues on the Senate floor earlier today, Frist indicated that the ricin was confined to the mailroom and noted that the incident was being treated as a criminal activity.
Ricin is a poison extracted from the bean-like seeds of the castor plant, beans that are used to make castor oil, used as a laxative and industrial lubricant. Ricin made separately is a potent poison, and a small dose can be fatal if swallowed, injected or inhaled.