Ricin as a weapon
LONDON, England -- Ricin has been developed as a weapon for the best part of 100 years.
The U.S. Chemical Warfare Service began studying the poison as a potential weapon of war during World War I.
During World War II, a ricin bomb was developed by the British military at the top-secret Porton Down biological weapons establishment in Wiltshire, western England.
Ricin was then code-named Compound W. The weapon, dubbed the W-bomb, was tested but never used on soldiers or civilians.
More recently, the toxin has found its way into the arsenals of extremist individuals, groups and governments.
Plans by the al Qaeda terror network to produce ricin were found in the Afghan capital, Kabul, in November 2001.
Iraq is also known to have included ricin in its biological weapons programme.
Experts point out that ricin has mainly been used in the past as a biological weapon for assassination purposes, and it has never been deployed as a weapon for mass destruction.
However, Andy Oppenheimer, a chemical and biological weapons expert at Jane's Terrorism and Security Monitor, said terrorists could potentially kill large numbers of people with ricin if they put it into aerosol -- a job he described as tricky but not impossible.
A crowded, enclosed environment like the London subway would probably be the most appealing target, he added.
"It's just one of these horror scenarios which people are very frightened of at the moment," he said. "You only need milligrams to kill somebody."
In 1978 it was used to assassinate Bulgarian dissident Georgi Markov in London. The killer was never caught but the Russian KGB was suspected. (Full story)
In the United States, four members of the Patriots Council, an extremist and anti-government group, were arrested in 1991 for allegedly plotting to kill a U.S. marshal with ricin.
They planned to mix the agent with a solvent and then smear it on the door handles of the victim's vehicles.
Customs officials stopped a man entering Canada from Alaska in 1995 who was carrying the poison in a container as well as several guns.
Two years later, U.S. investigators found ricin in a makeshift basement laboratory belonging to a man who had shot his stepson.