"On February 2, 2004, the deadly toxin ricin was detected in the Dirksen Senate Office Building. Ricin, derived from castor beans, has been identified as a potential bioweapon. Ricin is extremely toxic by ingestion, inhalation, and injection. No treatment or prophylaxis currently exist, though research into new therapies and vaccines against ricin exposure continues. Additionally, research to improve ricin detectors is ongoing. Although the potential of ricin as a military weapon was investigated, it has predominantly been used in small quantities against specific individuals. Most experts believe that ricin would be difficult to use as a weapon of mass destruction, but do not discount its potential as a weapon of terror. Ricin is on the Select Agent list, and its possession, transfer, or use is regulated under domestic and international law. This report will not be updated."
CRS Report for Congress, RS21383