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Deadly ricin: poisonous but clumsy weapon

Ricin is a deadly poison and fairly easy to make, but it’s a crude and clumsy weapon, according to bioterror experts.

A letter sent to President Barack Obama tested positive for ricin, officials said Wednesday, and it was sent by the same person who mailed a letter that tested positive for the poison to Mississippi Sen. Roger Wicker.

Ricin is made from castor beans -- it’s a natural byproduct of making castor oil. When purified using sophisticated methods, it can be lethal and hard to trace. It’s best known as the poison used to kill Bulgarian journalist Georgi Markov in London in 1978 by an agent who poked him with an umbrella tipped with an injector.

The U.S military also considered developing ricin as a biowarfare agent in the 1940s.

Dr. Eric Toner of the Center for Biosecurity at the University of Pittsburgh Medical Center, says he doubts anything this sophisticated is involved in the letters sent to Wicker and the White House.

“That is totally different from what we think is going on now, which is home-brewed ricin, not very potent,” Toner told NBC News. And Markov was killed by an injected pellet -- a much more certain method than putting powder into a letter.

“It is not actually clear you can get anybody sick from ricin-containing letters,” Toner added. "It is probably a crackpot. It certainly is unsophisticated.”

Recipes for making ricin abound online. But fiction aside -- in an episode of AMC's "Breaking Bad," Walter White whips some up -- it's not a big threat.

“It’s been used many times mostly by domestic terrorists and lone wolves,” Toner said. “It is easy to make some ricin. You get some castor beans, make it in your kitchen, you can produce a batch of stuff that has some ricin in it. It is not very pure. It is not very potent. As near as we can tell it has never actually made anyone sick.”

This week’s letters recall the anthrax attacks that killed five people and made 13 sick in October, 2001, after the Sept. 11 attacks. The anthrax attacks were very different, Toner says. They used highly purified anthrax spores -- living organisms that can get into the air and cover surfaces and that killed victims who breathed them in.

When inhaled, anthrax spores can sprout in the lungs and pump out a poison. By the time victims start to become ill, it’s almost always too late to save them. Two of those who died were postal workers In Washington D.C.  who got infected after the spores got caught up in mail processing equipment.

The attacks changed the way mail is processed in Washington and by some big companies -- media companies, including NBC, were also targeted by the attacks. Officials also installed "sniffers" around Washington, including in the Metro rail system and on the National Mall.

“The federal government now screens all mail that comes to certain high-value locations,” Toner said.

“It is my understanding that the screening tests, like all screening tests, are designed to be very sensitive but not necessarily specific.” That means that a false positive is possible, he said -- meaning the letters may not be tainted with ricin after all.

Toner suspects more letters will turn up with the contamination. But unlike the anthrax spores, ricin powder isn’t likely to spread in the mail and sicken people, he says. In theory, ricin could be used to attack people in this way, according to the Centers for Disease Control and Prevention. It can be injected, used to poison food, or spread in the air as a fine powder.

“Within a few hours of inhaling significant amounts of ricin, the likely symptoms would be respiratory distress (difficulty breathing), fever, cough, nausea, and tightness in the chest. Heavy sweating may follow as well as fluid building up in the lungs (pulmonary edema). This would make breathing even more difficult, and the skin might turn blue,” the CDC says.

“If authorities suspect that people have inhaled ricin, a potential clue would be that a large number of people who had been close to each other rapidly developed fever, cough, and excess fluid in their lungs. These symptoms would likely be followed by severe breathing problems and possibly death.”

There’s no antidote for ricin. The CDC advises anyone who thinks he or she may have been exposed to ricin to wash off as quickly as possible, breathe fresh air and seek medical care. Doctors may give intravenous fluids and perhaps charcoal to help people vomit any ricin they may have eaten.