What Is Ricin?

ricin in senate
Hazmat workers enter the Russell Senate Office building on Capitol Hill Feb. 4, 2004, in Washington, D.C. after ricin-contaminated mail was found in the Dirksen Senate building. Mannie Garcia/Getty Images

On Oct. 1, 2018, the Pentagon mail facility received two suspicious packages that were later confirmed to have tested positive for ricin. The envelopes were addressed to Secretary of Defense James Mattis and to Chief of Naval Operations, Admiral John Richardson.

This is by far not the United States' first encounter with ricin. In 2013, sources reported that an envelope laced with ricin had been intercepted before it could reach its intended recipient: Republican Sen. Roger Wicker of Mississippi. 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, check out the links below.


Lots More Information

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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