The search continues for the person who sent ricin-contaminated letters to President Barack Obama and a U.S. senator, now that criminal charges against a Mississippi man originally taken into custody for the incident have been dismissed.
Paul Kevin Curtis, 45, who works as an Elvis impersonator, reportedly told journalists that he was innocent, and that he didn't know what ricin, a poison, was.
Ricin has a lower profile than other biocrime agents, such as anthrax, because it is not considered to be the same level of threat. Still, it is one of the most commonly used biocrime agents, said Dr. Eric Toner, an internist and emergency physician who is a senior associate at the Center for Biosecurity of UPMC in Baltimore. The academic center, founded in 1998, joined UPMC in 2003.
"It's been used many, many times in the past," Dr. Toner said. "Almost never, does it hurt anybody. But it has been used much more than anything else."
Part of the reason for its frequent use, he said, is that getting the ingredients for ricin isn't difficult.
Ricin is a protein, and it comes from the beans of the widely available castor plant, which is also used to create castor oil. Recipes for ricin are easily searchable online, and castor beans can be ground up in a household item such as a food processor.
The powder resulting from a home-brewed batch will not likely yield a high or pure quantity of ricin, he said.
Inhaling a significant amount of ricin could result in symptoms including respiratory difficulties, fever, cough, nausea and low blood pressure, and could lead to death. Still, it's unlikely anyone could inhale a sufficient amount of the powder, he said.
"No one has ever gotten sick from a ricin letter before," he said.
The bigger threat from ricin comes from injection. In the most well-known use of ricin, in London in 1978, a KGB agent jabbed a Bulgarian journalist with an umbrella rigged to inject a pellet of the poison, killing him.
But, Dr. Toner pointed out, a state-sponsored organization can likely produce a more lethal concentration of ricin than someone brewing it.
Ricin, unlike other agents such as anthrax, is not a weapon of mass destruction, he said.
"It's better to think of ricin as a poison, than it is to think of it as a bioweapon," he said. 'It can effectively poison or harm perhaps a few people with ricin. But it would be very hard to make a large number of people sick."
Associated Press contributed. Kaitlynn Riely: firstname.lastname@example.org or 412-263-1707. This story originally appeared in The Pittsburgh Press. To log in or subscribe, go to: http://press.post-gazette.com/