For those of you not 100% up to date on your ricin knowledge, we thought a quick refresher course might be useful.

Pictured above is the lowly castor bean, harvested and processed in the millions every year, and used in everything from castor oil to perfume. Nearly five percent of the waste product (“mash”) in castor bean (bean being loosely used here – its actually the seeds of the plant Ricinus communis) production is the toxin ricin. Ricin can be synthesized as a powder, in aerosol form, dissolved in water, or as a pellet, the latter of which was used in the assassination of Bulgarian dissident Georgi Markov.
Castor beans alone are extremely potent, with just a handful of beans capable of killing an adult human. The toxin ricin is several times more lethal – less than 2 mg of ricin is thought to be capable of killing a human. Although extremely lethal, ricin is comparably easy to manufacture (Breaking Bad anyone?), making it a common weapon of choice for criminals and terrorists.
Ricin’s incubation period ranges from 4 to 24 hours, depending on the route of exposure. If exposed to a fine enough powder, inhalation of the toxin may occur, resulting in flu-like symptoms – fever, cough, difficulty breathing – and gradually escalate to profuse sweating, pulmonary edema (fluid accumulation in the lungs) and eventually respiratory failure.