Ricin Toxin (Ricinus Communis) – W

Ricinus communis plant’s toxic castor beans have been used by medicine for thousands of years. This toxin is later discovered and named Ricin. This natural poison has been developed and tested for military use and it is also known as W-agent. Ricin became a cheap and easy tool for food sabotage and terror.

Ricin Toxin Biological Agent Description

Ricin is a poison found naturally in Ricinus communis plant’s castor beans. Despite the name “beans” these are actually seeds. Castro beans are used all over the world to make ricin oil. Ricin is the “mash” of the oil production. Ricin toxin can be in the form of the seed itself, a pellet, a powder, a mist or it can be dissolved in water or in weak acid. In normal conditions it is a stable substance, but it can be inactivated by heat above 80ºC.

Castor is a plant that produces seeds (beans). Castor oil is produced by pressing ripe seeds that have had their outer covering (hull) removed. The hull contains a deadly poison called ricin.

In normal conditions the castor beans ingestion is the only way of exposure to ricin toxin. Ricin could be used to expose people through the air, food or water, but it needs to partially purified or refined into terrorist or biological warfare use. Ricin poisoning is not contagious and ricin-associated illness cannot be spread from person to person through casual contact. Castor beans contain approximately 1 to 10% of ricin. The minimum lethal dose for an adult is 8 to 10 beans, but for a child even 2 beans can be lethal.

Ricin poisoning effects depend on whether it was inhaled, ingested, or injected. When ricin gets inside body cells, it prevents cells to produce proteins. Without proteins cells will die, affecting the whole body and death may occur.

Ricin Toxin Historical Background

Ricin plant’s castor beans have been used in traditional medicine in Mediterranean and eastern ancient cultures. It has been used as anti-inflammatory, anthelmintic, anti-bacterial, laxative, abortifacient, for wounds, ulcers and other many applications.  According to the ancient Egyptian Ebers papyrus dating back to before 1500 BCE, castor beans are indicated also for other uses such as a remedy for abscessual illness and baldness. The Egyptians knew about the beans toxicity, and drug preparations recommended only small amounts. Also, the father of western medicine Hippocrates knew how to use castor beans oil detoxifying actions. In Chinese traditional medicine seeds were recommend for their anthelmintic activity.

At the end of 1800’s, Schmiedeber’s laboratory in Strasbourg began investigating the castor beans toxicity. Their toxin could be extracted with water but they lost the toxicity using wrong methods. In 1888, at the Medical Faculty of Dorpat (now Tartu, Estonia), the German scientist Petr Hermann Stillmark was finally able to purify the extremely toxic protein from castor seed and named it as Ricin toxin.

German physician and scientist Paul Ehrlich made his experiments in immunology by feeding mice with small amounts of ricin, until they were accustomed and became resistant to the it. These studies, together with those on the immunity to bacterial toxins, led him to formulate his side-chain theory of antibody formation and to win, in 1908, the Nobel Prize.

In modern medicine the ricin has been used experimentally in medicine to kill target cancer cells.

Ricin Toxin Usage

It is possible to extract a non-toxin oil from castor seeds that has multiple uses in many sectors, including cosmetic, pharmaceutic, mechanical, and chemical industry. Castor oil production is increasing worldwide because of its versatile application, low cost, availability, and biodegradability.

Ricin’s lethal effects, the relative ease of preparations, and availablility of castor-oil plants made it as a potential biological weapon. Many countries have had own programs and experiments of use of ricin in artillery shells and bombs to disperse ricin powder clouds. The major powers continued the research during the Cold War, but stockpiles were destroyed under the terms of the Biological Weapons Convention of 1972. In some reports ricin has possibly been used as a warfare agent in the 1980’s in Iraq. Due to its needs for large quantity and the compound degradation under heat of firing and exploding, makes it a poor military weapon. It has been estimated that eight tons of ricin would have to be aerosolized over a 100 km2 area to achieve about 50% casualty, whereas only a kilogram of anthrax spores would cause the same effect.

In 1978 Bulgarian exiled, writer and journalist Georgi Markov was poisoned in London. A Bulgarian agent used a KGB designed special umbrella to stab a tiny hollow sphere containing ricin into Markov’s body. Within three days he died.

In 1991 four people were arrested planning to kill a U.S. marshal in Minnesota, by mixing ricin and commercial solvent.

A terrorist group was arrested in Manchester, England, in 2002 because of using an apartment as a ricin laboratory.  In next year Chechen separatists were arrested in London because of attempting to use ricin in an attack to the Russian embassy.

In October 2003, a threatening letter with ricin was discovered in a post office in Greenville, South Caroline. In the next month, ricin was discovered in the White House mailroom. In February 2004 Senate Majority leader Bill Frist’s got ricin in his mailroom, and U.S. Senate building was closed. Luckily no one was injured in these cases.

In Georgia, on November 2011, four men were arrested for plotting to disperse ricin in many locations in the U.S.

In 2013, Mail Facilities in Washington D.C. got suspicious powder letters according to the FBI reports. The letters were tested as positive for ricin toxins. The letters were addressed to the U.S. President. Also, two mail handling facilities were tested as positive.

In 2021 in USA, biomedical engineering PhD has been charged for buying hundreds of ricin seeds to extract ricin toxin.

As the use-cases above indicated, ricin is still considered to be a possible weapon for disturbing, terror and assassination.

Ricin Toxin Transmission & Dispersion

Given the practical limitations of the toxin, some possible terrorist scenarios might be the inoculation of ricin into a food or water supply to contaminate groceries, or the dispersal of ricin as fine particles in a confined indoor space. If ricin is released into the air as fine particles, it has the potential to contaminate agricultural products. Such attacks would cause limited casualties but might sow broad panic and trigger major emergency responses.

Ricin Toxin Exposure Symptomology

Ricin poisoning major symptoms depend on the route of exposure and the dose.

Initial symptoms may occur as early as 4 to 8 hours and late as 24 hours. Ricin ingestion symptoms typically occur in less than 10 hours.

Inhalation exposures likely symptoms are breathing difficulties, fever, cough, nausea and tightness in the chest. Heavy sweating and pulmonary edema may follow and skin might turn blue. Finally, low blood pressure and respiratory failure may occur leading to death.

Ingestion of a significant amount of ricin would likely develop vomiting and diarrhea that may be bloody. After severe dehydration follows low blood pressure. Other symptoms may be seizures and blood in urine.  Within several days’ liver, spleen, and kidneys might stop working and could lead to death.

Ricin won’t be absorbed through normal skin. Contact with ricin powder or products may cause redness and pain of the skin and the eyes.

Ricin poisoning death could take within 36 to 72 hours of exposure.

Ricin Toxin Treatments

There is no antidote against ricin, the most important factor is then getting the ricin off or out of the body. The only treatment method is to give supportive medical care depending on the poisoning route. The care could include breathing support, intravenous fluids, drugs to treat for seizure and low blood pressure, stomachs flushing with active charcoal or washing eyes.

Response & Protection Actions Against Ricin Toxin

Unprotected people should move to fresh air right away. Those that were exposed to ricin toxin should remove clothing to avoid spreading the agents from the clothes and entering to the eyes and respiratory system, rapidly wash the entire body with water and soap and get medical care as quick as possible.  If someone has ingested ricin, do not induce vomiting or give fluids to drink.

First Responders should wear Full protection suits and SCBA when entering an area with in unknown contaminant or concentration is unknown.

Weak hypochlorite solutions and/or soap and water can decontaminate skin surface. Ricin is not volatile, so secondary aerosols are generally not a danger to operators.

Did You Know?

Ricin is currently monitored as Schedule 1A of the Chemical Weapons Convention (CWC) and is a Category B substance under the Biological and Toxins Weapons Convention.

Ricin Toxin have CAS# 9009-86-3 and also UN 3462 number for solid toxins extracted from living sources and Not Otherwise Specified.

NFPA 704 Signal Heath:4 / Flammability:1 / Reactivity:0 / Special:

Ricin Toxin Fact Box

Agent type Toxin
Infectiousness No
Person-to-Person No
Incubation period 4-8 hours
Infectious dose (aerosol) 3 – 7 µg/kg
ENVI Assay Sensitivity 5 ng/ml sample buffer
Lethality High
Therapy No vaccine, no antidote

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The views and opinions expressed in Bertin Environics Blog are those of the authors and do not necessarily reflect the official policy or position of Environics Oy. Any content provided by the authors are of their opinion and are not intended to malign any religion, ethnic group, club, organization, company, individual, neither they serve as a scientific statement.


Toni Leikas

Training Manager

I am Toni, a CBRN professional with over 20-year experience in training and educating Security and CBRN matters. I have trained operators from over 50 different nationalities, from a wide range of occupational areas from First Responders to Scientists.

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