On 16 April 2013, it was reported that a letter sent to Republican Senator Roger Wicker of Mississippi had tested positive for the deadly poison ricin. The letter was found at a facility that handles mail going to the US Capitol, which had been set up in 2001 after mail laced with anxthrax was sent sent to congressional offices and elsewhere. On 17 April 2013, US law enforcement officials said that a letter addressed to President Barack Obama had preliminarily tested positive for the poison ricin. On 18 April 2013, the FBI said that it had arrested Paul Kevin Curtis in Corinth, Mississippi as a suspect in the ricin laced mail.
Ricin poison is a stable substance extracted from 3-5% of the waste "mash" from the processing of beans from the castor bean plant Ricinus communis into castor oil. The plant, a 4 to 12 feet tall herb, favors warm climates worldwide. In the United States, the plant is used for ornamental purposes. The poison, which harbors potential medical uses in bone marrow transplants and cancer treatments, can be stored in powder, mist, or pellet form and can be dissolved into water or a weak acid. In the human body, ricin toxins inhibit protein synthesis in cells which leads to cell death.
As a biological weapons agent, ricin has the potential to be inexpensive and easily produced in large quantities, lethal with no known vaccine or treatment, and has potential to be distributed in aerosolized form. The process of extracting ricin poison involves chromatography, a skill mastered by most undergraduate chemistry students. However, the training required to purify ricin to a level at which it becomes a serious threat is not easily mastered.
In addition, ricin cannot spread from person-to-person so each victim must be infected with the toxin separately. Ricin poison is less toxic than botulinum toxin A, which is the preferred strategic and tactical agent. Ricin is a popular and effective agent in small scale operation and assassinations, and symptoms of ricin poisoning can be easily misdiagnosed. However, mass quantities of castor beans and substantial facilities would be required to make enough ricin for large scale operations.
The lethality of castor beans, as well as the therapeutic value of castor oil as a laxative and a treatment for sores and abscesses, has been explored by civilization for millennia. Castor oil developed into an important ingredient of manufacturing processes and remains a laxative and a lubricant. In the 18th Century, Carl Linnaeus named the plant Ricinus meaning 'tick' to describe castor bean's appearance, and communis meaning 'common' to describe the plant's distribution worldwide. 'Ricin' was the name German scientist Peter Hermann Stillmark gave to the toxin he derived from castor beans in 1888. In describing the agglutinating properties of ricin, Stillmark was the first to describe lectin, a protein that binds sugars. The ricin toxin was also a tool in early immunology studies.
History of Ricin as a Biological Weapon
During World War I, the United States explored ricin as a potential offensive biological weapons toxin at the American University Experimental Station. Two methods of weaponizing ricin were explored: bullets and shrapnel coated with ricin toxins or a 'dust cloud' of toxin toxins inhaled into the lungs. The thermal sensitivity of ricin to heat posed a problem as the firing of bullets and shrapnel would disable the toxin. Military authorities decided to delay development of the dust cloud until an antitoxin was created. The ethnical debate behind using poison to kill dictated that ricin bullets and shrapnel should only be used in retaliation against German poisons. The war ended before the toxin could be weaponized and tested.
Early in World War II, a joint British and Canadian project explored the possible use of ricin in 4 pound bursting bomblets. While the French also studied the toxin, they decided weaponized ricin would be too unsafe without a viable antitoxin. In 1942, the National Defense Research Committee reopened investigations into ricin as a possible offensive toxin. In 1944, the United States tested weaponized ricin at Dugway Proving Ground in Utah. The mass of raw ricin, known as 'crude' ricin, had to be dissolved in solvent or milled into fine powder. The latter was the preferred method, and the agent was spray-dried and then mixed in a chilled grinder so that the heat typically induced in the milling process did not destroy ricin's toxicity. Three field tests of weaponized ricin, known as Agent W, were conducted in Dugway Proving Ground at the G-2 Canyon Test Site in May 1944. Two tests used the 4 pound bursting bomblets design while the other one used tail-ejecting spraying munitions. A new plant was designed in 1944 that could produce 26 pounds of ricin a day for $13 per pound. The war ended without ricin being used and more lethal toxins such as botulinum toxin A replaced ricin in the US arsenal.
From the patent filed by the military scientists involved, there is significant evidence these individuals did not have a complete grasp of what they were working with. The development of ricin as a weapon by the United States was well before methods for handling and purifying trace proteins, or enzymes, were in use. The bursting and spray delivering methods further indicate this as exposing the ricin proteins to a detonation would denature them and grinding or otherwise creating a composition for spraying would also have a negative effect. The fragile nature of the ricin toxin was likely a factor in the fact that it was never determined by the US government to be a viable weapon against groups of people. Ricin remains primarily as a hazard to single people in assassinations, or if some mixture is put into food.
During the Cold War, the Soviet Union studied ricin as a possible biological weapons agent. Records suggested that Iraq experimented with the toxin in artillery shells. It was reported that ricin was found in Afghanistan following the collapse of the Taliban Government in 2001.
Ricin as a Terrorist Weapon
In 1978, two attempts to assassinate Bulgarian exiles were conducted with ricin toxin. Georgi Markov, a Bulgarian writer who had defected to the West in 1969, worked in London as a broadcast journalist for the BBC, Radio Free Europe, and the German Deutsche Welle. Markov's blunt critiques of the Bulgarian communist regime under Zhivkov Todor inspired Todor's wrath. Dimiter Stoyanov, minister of the interior, with the help of the KGB was given the job to silence Markov. While two previous attempts failed, on 7 September 1978, at a bus stop by the BBC headquarters in London, a middle aged foreign man stabbed Markov with an umbrella tip on the back of the leg. A red swelling was visible on his thigh, and upon returning home, Markov had a high fever. The following day, he was admitted to St. James' Hospital in Balham and diagnosed with septicaemia. Markov died the next day, the third day after the umbrella incident.
The autopsy revealed Markov's lungs were full of fluid and he had suffered heart failure due to blood poisoning. Small hemorrhages were found all over his heart, intestines, and lymph nodes. Upon examination, a small metal sphere was discovered in Markov's 2 millimeter wound. The metal sphere was 1.52 millimeter in diameter, 90% platinum and 10% iridium. The sphere had two holes, each 0.28 millimeters in diameter to hold the poison. The sphere had once been a watch bearing. The ricin poison was wrapped in a wax coating designed to melt at body temperature. After the fall of the USSR, it was disclosed that the Soviets did develop an umbrella injection mechanism with a cylinder of compressed air to fire the toxin pellets. Two former KGB agents Oleg Kalugin and Oleg Gordievsky admitted to KGB involvement in the assassination, which was carried out by a hired Italian hit man.
Vladimir Kostov and his wife Natalya had also fled from Bulgaria. In August 1978, two weeks before Markov was attacked, Vladimir Kostov was shot in the back with a poisoned bullet near the Arc de Triumph in Paris. He developed a high fever and was hospitalized but survived the attack. After Markov's assassination, Kostov's wound was examined and an identical metal sphere was discovered.
In 1991, 4 members of the Patriot Council were arrested and convicted in Minnesota for planning to kill a US marshal with ricin mixed in DMSO (solvent dimethyl sulfoxide). The perpetrators, members of an extremist group with anti-tax and anti-government leanings, planned to smear the liquid poison over the door handles of the marshal's vehicle. Ricin, being a protein, is too large to be a contact poison absorbed through the skin. The hope, though entirely unfounded, was that mixing with DMSO could produce the desired effect.
In 1995, a man from Alaska entered Canada with several guns, $98,000, and a container of white ricin powder. In 1997, in the basement of a man who shot his stepson, authorities discovered a makeshift laboratory that manufactured agents such as nicotine sulfate and ricin.
In December 2002, British authorities arrested suspected terrorists in their Manchester apartment where a 27-year-old chemist was producing ricin toxins. In January 2003, two police raids on a Wood Green apartment near London uncovered a possible plot by Chechen separatists to attack the Russian embassy with ricin toxin. In the apartment, authorities discovered 22 castor seeds and notes with recipes for ricin and several other poisons. The plan, similar to that of the Patriot Council in 1991, was to smear the a mixture including ricin on door handles.
On 3 February 2004, ricin poison was discovered in Senate Majority Leader Bill Frist's mailrooms and the US Senate building was shut down though there were no injuries. The day following the closure, the Secret Service revealed that in November 2003, ricin was also discovered in the White House mailroom. In October 2003, poor quality ricin was discovered in a post office in Greenville, South Carolina, in an envelope addressed to the Department of Transportation (DOT). The enveloped was labeled 'Caution: Ricin poison,' and included a letter protesting a federal law to limit the number of hours a trucker may remain at the wheel. Both 2003 ricin letters were signed 'Fallen Angel.'
In April 2005, a jury found Kamel Bourgass guilty of conspiracy to commit a public nuisance but hung on charges of conspiracy to murder. George Smith, a senior fellow for GlobalSecurity.org, pointed out in a 2005 article that the 5 grams of castor beans seeds would make only one lethal dose of injected ricin toxin. In addition, there was no proof, argued Smith, that ricin toxin could be toxic through the unbroken epidermal layer. No traces of ricin or other toxic weapons were discovered in the accused's apartment.
On 1 November 2011, federal authorities arrested four men in the US state of Georgia, including an accused ringleader of a North Georgia militia group, on terrorism charges. The four men were accused of plotting, among other attacks, to disperse ricin toxin in Altanta, Georgia and elsewhere throughout the US.
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