The latest entry into the California derby to find a profitable biofuel crop is one that can kill you, cure all that ails you and get you tossed into jail as a terrorist, if found in your possession.

It was featured in an article in the University California’s California Agriculture magazine as a potential new crop for California agriculture — in 1949.

You guessed it. Castor beans are back in California, at least as the latest research crop that University of California, Davis Cooperative Extension biofuels guru Steve Kaffka is looking at as a possible source crop for making biofuels.

Kaffka, is the director of the California Biomass Collaborative, a statewide assembly of government, industry, environmental groups and educational institutions administered for the state through UC Davis’ Energy Institute.

He is field testing a passel of potential biofuel crops: canola, camelina, meadowfoam, sugar beets, sweet sorghum, sugar cane, and switchgrass among others. Castor is the latest. It is the only one where there is "Do Not Cross" yellow tape circling the experimental plots.

The seed of a castor bean plant, Ricinus communis, contains two toxins that are poisonous to people, animals, and insects. The main toxic protein, ricin, is so potent that a single milligram is sufficient to kill an adult. Ricin is considered both a chemical and biological weapon and is explicitly prohibited by the Biological and Toxin Weapons Convention (BTWC). It is a slow-acting poison, with death occurring after 1-3 days.

The other toxic protein in the castor bean, RCA (Ricinus communis agglutinin), glues together red blood cells. Injection of RCA into the bloodstream essentially causes a person's blood to coagulate internally.

Toxin within the castor seed has been reported as seven times more deadly than cobra venom.

In the 1940s, the U.S. military experimented with using ricin as a possible warfare agent. In some reports ricin has possibly been used as a warfare agent in Iraq and more recently by terrorist organizations in Afghanistan.

The U.S. Centers for Disease Control (CDC) classifies ricin as a Class B biological terrorism threat, identifying it as an agent that can be disseminated relatively easy. U.S. Homeland Security and the FBI carefully monitor interest in castor production for this reason.