Why Ricin Is the Domestic Terrorist's Toxin of Choice

Federal agents wearing hazardous material suits and breathing apparatus inspect for ricin outside a Mississippi home in April. (National Journal)

The deadly toxin ricin is behind attacks on high-profile officials once again, this time in letters addressed to President Obama and New York City Mayor Michael Bloomberg.

This isn't the first time this year that someone has used ricin, either in the form of an oily substance or a powder in an envelope. But what makes ricin the toxin of choice for domestic terrorists? It's because producing ricin is so simple that almost anyone can home-brew it.

Unlike with anthrax, for instance, the process of producing ricin is not chemically complicated, nor is the toxin as potent and dangerous.

There are many recipes online that give step-by-step instructions for how to make ricin into a powdery substance, which would likely be what is put into the letters sent to politicians. Ricin is produced by removing the skin of the castor bean, blending with a nail polish-type liquid, fermenting, filtering, and drying. In four days, someone can theoretically produce a deadly amount of ricin.

Because the process is so simple, anyone with access to castor beans and widely used chemicals could make this "crude" formulation, said Scott Gottlieb, a Food and Drug Administration official in the George W. Bush administration.

"This is a reasonably accessible agent to people who aren't very sophisticated," said Gottlieb, now a resident fellow at the American Enterprise Institute. "You could conceivable manufacture very poor-quality ricin from the source bean with rudimentary equipment in your house."

But producing ricin through a home brew is unlikely to yield enough to severely harm recipients breathing in a light amount of powder. If it is ingested or injected, however, it can kill an adult in a matter of a few days. Even more worrying for officials is that there is no vaccine, no test for exposure, and no antidote.

Once ricin is ingested, the symptoms include nausea, vomiting, internal bleeding, liver and kidney failure, and eventual failure of the circulatory system, causing death. If inhaled, ricin can cause pulmonary edema, filling the lungs with liquid. Ricin contamination of the skin or eyes is painful but not fatal.

Those who were exposed to the ricin-contaminated letter sent to Bloomberg have complained of diarrhea and stomach pains.

Ricin has also been used for assassinations and assassination attempts outside the U.S. In 1978, Bulgarian dissident and journalist Georgi Markov was killed by a Bulgarian secret police agent who rigged an umbrella to shoot a ricin pellet into Markov's leg. Markov, living in London at the time, died several days later from the poison. Markov had been critical of the Communist leadership in the country.

Ricin is not the only byproduct of castor beans. Castor oil has several uses in manufacturing, food supply, and pharmaceuticals, and is easily attainable. When treated and processed, castor oil is used in lubricants, hydraulic and brake fluent, biodiesel, food additives, and laxatives.

Though ricin is deadly when properly produced, and in mass quantities, it is "not an optimal weapon of terrorism," Gottlieb said. It is not on the list of threats for which the Health and Human Services Department has developed countermeasures. Those sending the letters most likely know this.

"At the end of the day, whoever sent this to the president knew it wasn't going to reach the president," Gottlieb said. "This is more of a political statement, in my view."

Gottlieb warns that the technology for weaponizing different agents is becoming more and more ubiquitous. It doesn't take a high level of sophistication to develop a crude formulation for these chemicals, including ricin.