1. What is ricin?
Ricin is a highly toxic, naturally occurring protein found in Ricinus communis, or castor plant seeds.
2. Wait, this stuff is in castor oil? Could someone be accidentally poisoned?
Unless a person ingests castor beans, there is no way to be accidentally poisoned. During the process of making castor oil, ricin is produced as part of the waste “mash” and disposed of. Even if one consumed castor beans, it would take a significant amount to actually cause symptoms of poisoning.
3. How dangerous is it?
Ricin is highly toxic. As little as 7-8 mg has been shown to be fatal in horses, though those were accidental poisonings through castor bean ingestion.
If purified into a powder, mist, or pellet, the toxicity of ricin rises substantially. Ingestion is the most serious exposure method, with inhalation a close second. Luckily skin contact with ricin is not dangerous, though, and it is not contagious to others once contracted.
4. What happens once a person is exposed to ricin?
Once infected, ricin gets inside the cells of the victim’s body and prevents them from making vital proteins. Without them, the cells eventually die. The process is quick, presenting initial symptoms within 4 to 24 hours after exposure. Symptoms include fever, cough, difficulty breathing, vomiting, diarrhea, low blood pressure, and seizures. If the toxicity levels are high enough, organ failure and death follow.
There is currently no antidote for ricin, but human clinical trials have been promising.
For more information, the CDC has a comprehensive fact guide.
5. What’s the history of this chemical weapon?
Ricin was first considered for weaponization during World War I. The U.S. military wanted to coat bullets and shrapnel with the deadly substance but the concept violated the Hague Conventions and the project was dropped.
During World War II, the U.S. and Canada revisited ricin as a bomb ingredient but other toxins were more economically viable.
Sometime after WWII ended, the Soviet Union weaponized ricin and was suspected of using it outside the Soviet bloc, but nothing was ever proven. The only confirmed death from ricin was in 1978, when Bulgarian dissident Georgi Markov was assassinated by the secret police with an umbrella retrofitted to fire a tiny ricin pellet into his leg.