As the FBI reports that a second letter containing ricin was sent to President Obama following the Tuesday night discovery of a similar letter to Sen. Wicker (R, Miss.), here are some facts you should know about the substance known as ricin:

What it is:

  • Ricin is a poison found naturally in castor beans. If castor beans are chewed and swallowed, the released ricin can cause injury. Ricin can be made from the waste material left over from processing castor beans.
  • It can be in the form of a powder, a mist, or a pellet, or it can be dissolved in water or weak acid.

How it works:

  • Ricin works by getting inside the cells of a person's body and preventing the cells from making the proteins they need. Without the proteins, cells die. Eventually this is harmful to the whole body, and death may occur.
  • Effects of ricin poisoning depend on whether ricin was inhaled, ingested, or injected.
  • As little as 500 micrograms -- an amount the size of the head of a pin -- can kill an adult
  • There is no specific test for exposure and no antidote once exposed.

How you could be exposed to it:

  • It would take a deliberate act to make ricin and use it to poison people. 
  • Unintentional exposure to ricin is highly unlikely, except through the ingestion of castor beans.
  • If made into a partially purified material or refined into a terrorist or warfare agent, ricin could be used to expose people through the air, food, or water.
  • Ricin poisoning is not contagious.
  • Ricin-associated illness cannot be spread from person to person through casual contact. 
  • However, if you come into contact with someone who has ricin on their body or clothes, you could become exposed to it.

What happens if someone is exposed:

  • If authorities suspect that people have inhaled ricin, a potential clue would be that a large number of people who had been close to each other rapidly developed fever, cough, and excess fluid in their lungs. 
  • These symptoms would likely be followed by severe breathing problems and possibly death.
  • Because no antidote exists for ricin, the most important factor is avoiding ricin exposure in the first place.
  • If exposure does not prove fatal within 3-5 days, the victim will usually recover.

Signs and symptoms of ricin exposure:

  • The major symptoms of ricin poisoning depend on the route of exposure and the dose received, though many organs may be affected in severe cases.
  • Initial symptoms of ricin poisoning by inhalation may occur as early as 4- 8 hours and as late as 24 hours after exposure. Following ingestion of ricin, initial symptoms typically occur in less than 10 hours.
  • Inhalation: Within a few hours of inhaling significant amounts of ricin, the likely symptoms would be respiratory distress (difficulty breathing), fever, cough, nausea, and tightness in the chest. Heavy sweating may follow as well as fluid building up in the lungs (pulmonary edema). This would make breathing even more difficult, and the skin might turn blue. Excess fluid in the lungs would be diagnosed by x-ray or by listening to the chest with a stethoscope. Finally, low blood pressure and respiratory failure may occur, leading to death. In cases of known exposure to ricin, people having respiratory symptoms should seek medical care.
  • Ingestion: If someone swallows a significant amount of ricin, he or she would likely develop vomiting and diarrhea that may become bloody. Severe dehydration may be the result, followed by low blood pressure. Other signs or symptoms may include seizures, and blood in the urine. Within several days, the person's liver, spleen, and kidneys might stop working, and the person could die.
  • Skin and eye exposure: Ricin is unlikely to be absorbed through normal skin. Contact with ricin powders or products may cause redness and pain of the skin and the eyes. However, if you touch ricin that is on your skin and then eat food with your hands or put your hands in your mouth, you may ingest some. 
  • Death from ricin poisoning could take place within 36 to 72 hours of exposure, depending on the route of exposure (inhalation, ingestion, or injection) and the dose received.

Where and how is it produced?: 

  • Ricin can be produced relatively easily and inexpensively in large quantities in a fairly low-technology setting. 
  • Worldwide, one million tons of castor beans are processed annually in the production of castor oil; the waste mash from this process is 5-10% ricin by weight.

 

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(Source: CDC, Facts About Ricin)
(Source: VA Department of Health)
(Source: Federation of American Scientists (FAS), Ricin Fact Sheet)