The discovery of what could be the potent toxin ricin at Sen. Bill Frist’s office at the Dirksen Senate Office building is certainly something to be worried about. While mail is now being irridiated to prevent attacks with anthrax, ricin isn’t effected by radiation and even a small dose can kill. I hope whoever may have come into contact with it wasn’t hurt should it turn out to be ricin.
It should be noted, however, that field tests often yield false positives in cases like this – they’re designed to be hyper-sensitive on the theory that it’s far better to have a false positive than a false negative.