CNN: Envelope Sent to Senator Tests Positive for Deadly Poison RicinDaniel Jackson Although very little information has been released, CNN has already speculated that this could be another act of terrorism, striking fear in the hearts of Americans still dealing with yesterdays horrific attacks at the finish line of the Boston Marathon. Senators were briefed on the matter Tuesday evening and told the congressional post offices would be temporarily shut down. It was caught in the screening facility. Thats why we have an off-site screening facility for mail, said Sen. Claire McCaskill, D-Missouri. Ricin is a highly toxic substance derived from castor beans. 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. It can be produced easily and cheaply, and authorities in several countries have investigated links between suspect extremists and ricin. But experts say it is more effective on individuals than as a weapon of mass destruction. Update: CNN is now reporting that officials are not fully sure that ricin actually was detected (which completely contradicts their original report which made it seem like yet another act of terrorism). Stay tuned as more information is released. Read other articles by Daniel Jackson Here linkwithin_text=Related Articles: 