How can Ricin Be Used as a Biological/Chemical Terrorist Weapon
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In Washington, DC, on February 3, 2004, laboratory tests confirmed that “white powder” found in the mailroom of Senate Majority Leader Bill First’s office was the deadly plant toxin, ricin. That same day, it was disclosed that, in November 2003, a letter containing ricin was sent to the White House, but it was intercepted at an “off-site mail facility.” On October 15, 2003, Greensville, SC, postal authorities discovered an envelope containing a metal canister with ricin in it. On January 13, 2004, French police broke up an Islamic terrorist cell which was said to be planning ricin attacks in France and Britain. Why was ricin toxin used in all of these cases? It is cheap, relatively easy to produce, and does not have to be highly purified or weaponized to be effective.
What Is Ricin Toxin?
Ricin is a protein material which is extracted from the beans of the common castor bean, ricinus communis. The protein toxin is composed of two polypeptide chains. When the toxin enters a cell, it rapidly inactivates protein synthesis by inactivating the ribosomes, a key component of the cell’s synthetic machinery.
Castor beans are grown for their oil which is used in various industries, including paints, cosmetics, textiles, and others. The main countries producing castor beans are India, China and Brazil. Ricin can be extracted directly from the castor bean or from the “wet mash” by-product produced by crushing and extracting the castor oil. The annual world production of castor oil is 460,000 tons, requiring over 1.1 million tons of seeds and producing 550,000 tons of wet mash. Thus, a tremendous amount of raw material exists at a cheap price for terrorists to use for ricin production. Only five percent by weight of the wet mash is ricin. However, from 100 pounds of this material, you can extract up to five pounds of ricin. Ricin is over a thousand times more poisonous than cyanide and 30 times more potent than the chemical warfare nerve gas agent, VX. In its pure form, an amount no bigger than a grain of table salt can kill an adult. Ricin can be either a white powder or a colorless, tasteless solution. It is soluble in water, can be aerosolized, and is stable in soil or in the environment for approximately three days.
The US Army called ricin toxin “Agent W.” Ricin is considered a biological agent because it is prepared from a biological source. However, unlike most biological agents, such as anthrax, it is not a living organism and can’t reproduce and increase its presence after an attack. It is also considered a chemical agent because it is a chemical, a protein, and is much like sarin or other nerve agents. It is probably best to consider ricin a biochemical agent, like the botulism toxin which is extracted from the bacteria, clostridium botulinum. Ricin is listed as a “Category B Bioterrorism Agent,” and a “Schedule 1 Chemical Warfare Agent.”
Ricin Production – The Clandestine Laboratory
It is important for law enforcement personnel to be able to recognize a clandestine toxin production operation. For the most part, such an operation will look very similar to any other illegal drug lab. Flasks, beakers and other standard laboratory glassware would be present, but the more complicated glass stills and distillation glassware would be absent. What would be present are large containers (glass or metal pots) where the mash could be made into a slurry with water. There would also be some type of large filter devices; these could be standard laboratory funnel filters or something as simple as large kitchen spaghetti strainers into which filter paper is placed. The basic procedure for ricin production could be carried out in a garage, basement or even a bathroom. The oil is removed from the castor bean by crushing it and then running the material through rollers which squeeze the oil out of the solid material. The remaining wet “cake” of solid material is the starting material for toxin production. This process involves the following steps: 1) slurring the cake in water at an acidic pH – the toxin is water soluble; 2) filtering the slurry; 3) precipitating the toxin from the water solution with sodium sulfate; 4) filter again, then resuspend and precipitate the material several additional times [depending on the degree of purity which is wanted in the final product]; and 5) finally, the resulting cake is dried and then ground to a fine powder. Grinding would be done in a ball mill apparatus. Alternatively, a more finely powdered material can be produced by passing a water solution of toxin through a spray drying machine. This type of equipment is widely used in the pharmaceutical and food industries. Used equipment is available for pennies on the dollar from used equipment sales companies. To produce highly purified material requires someone with a greater degree of skill than the average terrorist; although, this skill could be easily learned by working in a pharmaceutical plant or in a food plant which makes candy or instant drinks, like powdered hot chocolate. However, ricin can be effectively used in an impure form which could be developed as a “home brew” by unskilled people. The toxicity of this material will be lower, but greater quantities can be produced and more material delivered to an attack site; this would achieve the same result as using a highly purified agent.[Editor’s Note: To those who are concerned about the information contained in this article describing the production of ricin, please note that this same information is available from a multitude of sources; most notably, the Internet.]
Sarin, a chemical nerve agent, is a highly volatile chemical and very hard to produce and handle in large volumes. Botulinum toxin requires growth of a highly infectious microorganism, clostridium botulinum, under sterile conditions, then a complex extraction. Ricin, on the other hand, isn’t volatile, so handling it and transporting it is relatively safe. It is very stable, so long-term storage is not a problem. Protective equipment for the individuals preparing ricin would consist of a good quality gas mask, protective eye gear and vinyl gloves. No special protective clothing would necessarily be required, as long as the clothing worn was washed immediately after use. The chemicals one would expect to find in a ricin production lab would include sodium sulfate; sodium carbonate; sulfuric acid (concentrated and as a 5% solution); and solvents like hexane, acetone and, possibly, DMSO (dimethylsulfoxide).
Detailed procedures for ricin extraction and use were found in Al-Qaeda’s military manuals seized in safe houses and caves in Afghanistan, according to a recent Monterey Institute of International Studies (MIIS) report. Procedures are available in militant publications like The Poisoner’s Handbook (1988), an underground publication by a militant, antigovernment group here in the US. [H.L. Craig, et.al., US Patent No. 3,060,165 issued in 1962 for “Preparation of Toxic Ricin” is available on the Internet from the US Patent Office.]
It is just as important for law enforcement professionals to realize that the threat from ricin may come as easily from within our borders as from abroad. In such cases, law enforcement may have initial primary responsibility for any incidents. A case in April of 1991 demonstrated that as members of a domestic extremist group called the “Patriot’s Council of Minnesota” set up a lab to manufacture ricin. Their apparent target was federal law enforcement officers. The National Infrastructure Protection Center (NIPC) reported that the lab had produced enough ricin to kill 100 people.
Ricin Toxin – the Bioweapon
Ricin is not a living bioagent and, therefore, is not contagious, so the likelihood of it being spread too far beyond the initial attack site is small. It is not volatile so, in an aerosol attack, the chance of a secondary aerosolization event is unlikely. Other people could be exposed through contact with the clothing of an exposed person or exposed articles from the target site. Wind and rain could also spread ricin from the initial target.
Ricin has not been effectively weaponized like anthrax or smallpox. The weaponization process is very involved, requiring pure material and, in the final steps, the agent is bound to microporous silica particles called “fumed smoke.” The material is so small that it literally floats in the air on release. That is how the weaponized anthrax powder used in the post 9/11 events was able to spread throughout the postal facility. But, ricin toxin is a protein, not a bacteria; binding to the silica particles changes the shape of the toxin protein and renders it inactive (detoxified). The US Army gave up trying to develop a large-scale, weaponized aerosol preparation of ricin; in 1991, Iraq admitted to producing large quantities of toxin, but was unsuccessful at weaponizing it.
Thus, ricin would most likely be used in small-scale events: contamination of an office building or shopping mall by introducing aerosolized material into the ventilation system or release of aerosol into a subway or train station. Relatively simple pressurized sprayers could be used in these areas to deliver a mist of ricin which could be both inhaled and ingested by breathing through the nose and mouth. The aerosol produced would not need to be highly refined in this instance to be effective. Ricin could also be sprayed on foods like fruit or vegetables; or mixed into prepared food at a restaurant, a large catered event, or a food processing plant. However, the toxin is a protein and is destroyed by heating so it would only be effective on uncooked or improperly cooked food products. It is possible that it could be used to contaminate a drinking water well or water supply system. However, this is not practical because the water reservoir for an average-sized city contains about 50 billion gallons of water; this would require addition of several tons of ricin before a toxic concentration would be achieved. Ricin will primarily be used by terrorists to cause chaos, confusion and fear in the target population. This is much like what is accomplished by a suicide bomber who puts on a vest loaded with explosives and nails, then blows up a deli full of people at lunch hour. The relative number of people killed or injured is small, maybe 15 or 25, but the fear generated by such an attack can have a disabling affect on a whole city.
Toxicity and Effects of Exposure
An attack with sarin or other chemical nerve agents produces immediate effects – death and serious injury to people in the target area, just like the suicide bomber. With biological agents like anthrax or plague, or biochemical agents like ricin, the exposed individual does not necessarily know they are exposed for several hours or up to two to three days. Only then does serious illness present itself and the progression to death may take days or weeks. The standard measure of toxicity, LD50 (the “Lethal Dose” which causes death in 50% of the animals tested), for inhalation or aerosol exposure is three micrograms/kilogram. So, for an average-sized man (200 pounds or 91 kilograms), it only takes 0.27 milligrams or an amount the size of a grain of salt to cause death. For the ingestion route of exposure, the LD50 is higher at 30 micrograms/kilograms because some of the toxin is destroyed by the action of the stomach. Skin or dermal exposure to ricin toxin is insignificant, although toxin dissolved in the solvent DMSO will penetrate the skin to a small degree.
With ricin exposure by inhalation, general symptoms first appear eight to12 hours after exposure. Initial symptoms are weakness, fever, cough, and pulmonary edema (water in the lungs). Death occurs within two to three days from severe respiratory distress. Exposure by ingestion (eating or drinking) requires a higher dose of ricin to produce death because, as previously mentioned, some of the ricin is destroyed in the stomach. Symptoms generally occur about six hours after exposure. Initial symptoms are abdominal pain; vomiting and diarrhea; followed in several days by severe dehydration, decreased urine production, and a significant decrease in blood pressure. Death may not occur for up to ten days. Ricin is a cytotoxic agent capable of destroying any human cells; once in the cell, it shuts down the cell’s protein making capability.
There is no effective treatment for ricin poisoning. Medical treatment is generally supportive, aimed at easing the symptoms and simply making the patient comfortable. Not all exposures result in death and some patients do recover. At present, there is no antidote or vaccine for ricin; however, research at a variety of laboratories is encouraging. Researchers at the University of Texas, Southwestern Medical Center, in Dallas, have reported production of a vaccine which protects mice from ricin. The FDA may approve the start of human clinical trials by the end of the summer. Other studies are being carried out at the US Army Medical Research Institute for Infectious Diseases and by Canada’s Military Research Agency.
Protective Equipment Requirements
First responders investigating a suspect lab or an attack area should, at a minimum, wear a gas mask equipped with appropriately rated cartridge filters, eye protection, latex gloves and, if high levels of material are expected, appropriate protective clothing as determined by individual law enforcement units. Where an aerosol has been employed, the rule of thumb is to assume that aerosol will persist for up to 48 hours. Decontamination of ricin contaminated materials is accomplished by washing with a 0.5% hypochlorite solution (bleach) for a contact time of at least 15 minutes, according to the Ricin Response Guidance document released by the National Infrastructure Protection Center. While ricin is not absorbed through the skin, any clothing, hair or parts of the body exposed to the toxin should be completely washed with soap and water.
Ricin Detection Methods
There are several on-site devices available for ricin detection. The on-site kits are designed to provide a “first test” assessment. These tests may produce false positives in the field and, later, more sophisticated analysis may rule out ricin’s presence. However, in these situations, it is better to get a false positive in the field than a false negative and then find out later that the material was present and all the necessary precautionary steps were not taken. These test kits should only be used to establish whether a reasonable threat of ricin exposure has occurred in an incident, thus allowing first responders to take appropriate decontamination and cleanup activity until definitive test results are obtained from a certified laboratory. In the case of ricin, a “reasonable threat” would be the presence of toxin in sufficient quantity to represent a threat to unprotected people in the area.
Handheld detection devices are quite sensitive at detecting low levels of agent. However, the problem is exactly “where to test” in an attack situation. Thus, these devices may be most reliable in situations where a relatively high level of agent is present, i.e., vials of powder; agent spills on a lab bench or in a subway car; suspect visible material released from an air ventilation system; or material in an envelope or package, etc.
Handheld devices for ricin detection are available from a variety of companies, including Alexeter Technologies, LLC (The BioThreat Alert™ Test Strip); Osborn Scientific Group (BADD™ – BioWarfare Agent Detection Devices); New Horizons Diagnostics, Inc. (SMART™ II Ricin), and others. All of the devices are similar in the manner in which a test is performed. A cotton swab is wetted with a diluent and then the area to be tested is swabbed thoroughly. The contaminated swab is replaced in the diluent for a period of time, then a sample is withdrawn with an eyedropper and placed in the well of the small plastic detection device. The device is about the same size as home pregnancy test devices. The sample is left to react for a period of time, usually about 15 minutes. The devices all have two indicator lines – a “control” and a “test” or “sample” line. A test is positive only if both lines turn color; if only the control turns color or there is no reaction, the test is deemed negative.
Unfortunately, handheld devices have come under controversy because of initial unrealistic expectations of their performance. More recently, however, individual law enforcement and first responders groups have come to the realization that these tests do play a vital role in the “first response” decisions at a target site. The US Army has made a strong case for using these devices in the field. The analysis runs between $24 to $40 per test (depending on the kit supplier).
Assessing the Ricin Threat
For law enforcement, the question is, “How real is the threat of a ricin attack in my jurisdiction?” What then do we know about ricin? We know it is a highly toxic poison capable of killing exposed people in three to five days. We know that the raw materials for its production are readily available. We know it can be used as an aerosol or to contaminate food suppliers. We know it is not a weapon of mass destruction, but rather a weapon to be used for small events (more like the suicide bombers). We know that Al-Qaeda, Hamass, and other international terrorist groups all have manuals outlining ricin production and use, and that militant groups here in the US also have this know-how and have considered using ricin. We know that the US Government put out a classified intelligence bulletin to be on the lookout for the biological toxin ricin.
However, to date there have been no real episodes when ricin has been used in a real large-scale terrorist incident. Thus, law enforcement groups are left to decide if ricin is high on their list of security concerns. If there are suspected sleeper cells of Al-Qaeda or militant groups in your area, or individual suspects who might be capable of a domestic attack, then the handheld detection kits should probably be considered among your tools. In any event, the information on ricin provided in this article should be general knowledge for all law enforcement personnel as part of their overall education in this growing issue of bioterrorism.
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