Ricin, which was found in a U.S. Senate office building this week, is considered one of the deadliest poisons.
Senate Majority Leader Bill Frist of Tennessee knows something about ricin, thanks to his background as a medical doctor and a book he authored about bioterrorism. "Ricin is a toxin, it is a poison. It comes from the castor bean itself, the same bean that people make castor oil from. People work in castor-oil making factories and never get sick from it. On the other hand, if you take the castor bean and pulverize it and make it into a powder, it can be made into a form that can be inhaled," he said.
At a news conference Tuesday, Senator Frist said ricin can pose a serious threat. "It has no antidote or specific treatment, which makes it an agent that is challenging to manage if there is exposure and if injury begins to occur," he said.
Senator Frist's staffers Monday discovered the suspicious white powder that has been confirmed to be ricin in their office mailroom. It appears no one has gotten sick as a result of the contamination.
The Senate Majority Leader said ricin can be inhaled, ingested or injected. "Never to the best of my knowledge has anybody died from inhalation of a derivative of the castor bean. But in animal models it is deadly, and it can be very progressive. The [human] deaths that have been reported in the past have been from intravenous use, directly into the blood beneath the skin. There was a famous case in 1976," he said.
Senator Frist was referring to the case of Bulgarian dissident Georgi Markov, who died in London four days after he was jabbed with an umbrella that was tipped with a ricin pellet.
Experts say ricin is hard to distribute, making it unlikely to be used as a weapon of mass destruction.
The U.S. Centers for Disease Control says symptoms of ricin poisoning begin within eight hours of exposure, and vary depending on whether it is injected, inhaled or ingested.