Possession of castor bean seeds is completely legal, but it is illegal to extract ricin from them. Ricin is a Schedule 1 substance under the United States Chemical Weapons Convention, making it illegal for individuals to possess in pure form except for authorized scientific and medical research purposes.
The production and possession of ricin are federal offenses, according to the FBI. Possession of a biological warfare agent is a felony, reports CNN. Penalties may include lengthy prison sentences, especially if the intent to harm others can be demonstrated. A Manhattan man faces life in prison as of August 2015 for attempting to buy ricin over the Internet, according to Reuters.