What is Ricin?

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On April 16, 2013, sources reported that an envelope laced with ricin had been intercepted before it could reach its intended recipient: Republican senator Roger Wicker of Mississippi. It was by far not the United States' first encounter with ricin. On Feb. 29, 2008, a man lay in critical condition as the result of exposure to the biological weapon in his Las Vegas hotel room. The FBI says it is treating the situation as a criminal case and doesn't believe the deadly toxin was part of a terrorist plan, though it has yet to identify why the substance was in the room. Three hotel employees, three police officers and a person who came to collect some items from the room were all taken to the hospital to be decontaminated.

In February 2004, ricin was found in a Senate mail room. Three senate buildings were temporarily closed as authorities from the Department of Health and Human Services conducted tests to determine if all of the fatal powder had been eliminated. While several people were exposed to the toxin, no one suffered any ill effects.

What is ricin?

Ricin is a toxin that is fatal to humans in extremely small doses. Just 1 milligram is a deadly amount if inhaled or ingested, and only 500 micrograms of the substance would kill an adult if it were injected (CDC). Ricin comes from the castor bean plant (Ricinus communis) -- it is present in the mash that is left over after grinding castor beans into oil. It can be delivered as a powder, a mist or a pill.

Ricin is a ribosome-inactivating protein -- it irrevocably damages the ribosomes that carry out protein synthesis in cells. The ribosome-inactivating proteins found in the castor bean plant are extremely powerful, and ricin poisoning can do serious damage to major organs.

What happens if I'm exposed?

Ricin can be fatal if it is inhaled, ingested, or injected. While skin or eye contact with ricin can cause pain, it is typically not fatal in that type of exposure.

The initial symptoms of ricin sickness, which may appear anywhere from three to 12 hours from the time of exposure, include coughing, fever and stomach pains.

If ingested, main symptoms within the first hours are stomach ache, gastroenteritis, bloody diarrhea and vomiting. Over the course of the first days after exposure, the victim may experience symptoms of dehydration and low blood pressure.

Ricin inhalation can manifest as lung damage, including pulmonary edema (fluid in and swelling of the lungs).

Other possible symptoms include seizures and problems with the central nervous system.

If the exposure is fatal, the victim most likely will die within five days. If death does not occur in that time, the victim will most likely recover. There is no known antidote for ricin poisoning.

For more information about ricin and other biological agents, visit the next page.

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More Great Links


  • "CBRNE - Ricin." eMedicine. http://www.emedicine.com/emerg/topic889.htm
  • "Criminal probe launched in Vegas poison discovery." CNN. 2/29/2004. http://www.cnn.com/2008/US/02/29/ricin.hotel/
  • "Facts about Ricin." Centers for Disease Control and Prevention. http://www.bt.cdc.gov/agent/ricin/facts.asp
  • "Ricin scare closes 3 Senate buildings." CNN. 2/3/2004. http://www.cnn.com/2004/US/02/03/senate.hazardous/index.html
  • "Ricin Toxin from Castor Bean Plant." Cornell University. http://www.ansci.cornell.edu/plants/toxicagents/ricin/ricin.html

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