In June 2018, German security services uncovered an alleged terrorist plot involving ricin by a Tunisian extremist living in Cologne, suspected of being inspired by and in contact with the Islamic State. This incident marked a significant milestone as it was the first time a jihadi terrorist in the West successfully produced the toxic biological agent, ricin. This case highlights the persistent threat of bioterrorism in Europe.

Ricin, a poison derived from the waste left over from processing castor beans, can be presented in various forms such as powder, mist, pellet, or dissolved in water or weak acid. Notably, ricin remains stable under extreme conditions, including very high or low temperatures. This characteristic distinguishes ricin from other biological threats, such as the anthrax scare in 2001, where spores of the bacterium B. anthracis, which causes anthrax, were manipulated for distribution and aerosolization. The threat of ricin intoxication through indirect contact, such as via a letter, is significantly lower compared to the risk of anthrax infection through inhalation of spores.

The castor bean plant, Ricinus communis, is cultivated globally for castor oil production. However, ricin, a by-product of this process, is one of the most poisonous naturally occurring substances known. Only a few grains of ricin are required to be lethal to a human. Furthermore, ricin can be transmitted through various means including food, water, and air, making it a potent bioweapon.

Ricin has been explored as a lethal weapon by various terrorist groups due to its deadly effects, ease of preparation, and potential for aerosol delivery. When introduced into the pulmonary system, ricin can cause severe pathological changes in the lungs, similar to those observed in acute respiratory distress syndrome (ARDS). Early response cytokines, such as TNF-α and IL-1, are involved in this process. Although ricin is less toxic by weight compared to other agents like BoNT or SE, studies suggest that its toxicity varies depending on the route of exposure, with inhalation and intravenous exposure being the most dangerous.

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