Ricin plot not feasible, expert says

According to biodefense experts, the alleged plot by four Georgians to successfully pull off a deadly terrorist attack using ricin was highly unlikely to succeed.  
While castor beans are relatively easy to obtain and recipes for extracting ricin from them can easily be found on the internet, the challenges involved in delivering deadly doses of the toxin to large numbers of people are insurmountable for amateurs, Raymond Zilinskas, a microbiologist and expert on biological and chemical weapons, said, the Washington Post reports.
The likelihood of success was "absolutely zero," Zilinskas, the director of the Chemical and Biological Weapons Nonproliferation Program at the James Martin Center for Nonproliferation Studies in Monterey, Calif., said according to the Washington Post. "No one has done it, as far as we know. It is beyond the capabilities of anyone except professional weapons scientists."
Ricin is one of the world's most toxic natural substances. It is so poisonous that a dose as small as a few grains of salt can kill. It was used in the assassination of Bulgarian novelist and defector Georgi Markov in 1978 when it was injected into him in pellet form by a suspected Bulgarian agent using a modified umbrella.
Even governments with dedicated weapons laboratories have had difficulty creating a ricin weapon to kill on a large scale. The scientists of former Iraqi president Saddam Hussein abandoned an effort to do so during the late 1980s, finding that it was too difficult to convert ricin into a fine mist or powder, according to records uncovered by U.N. weapons inspectors.
Officials for the Justice Department said that one of the men involved in the latest case got so far as obtaining castor beans and the four men had talked about using ricin in attacks on several U.S. cities.