A National Guard Civil Support team, whose primary role is identifying weapons of mass destruction hazards, has been deployed to Spokane to investigate the discovery of several threatening letters that have preliminarily tested positive for Ricin.
Ricin is a highly toxic substance made 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 known antidote.
The 10th Civil Support Team, a full-time National Guard unit whose role is to identify and assess weapons of mass destruction, has deployed 20 personnel and nine vehicles to Spokane to investigate the letters found at the downtown post office earlier this week.
The unit is the state's first responder team in supporting local civil authorities in domestic chemical, biological, radiological, nuclear and high-yield explosive incidents, and deploys typically within three hours of being notified of an incident.
The Guardsmen are responding to the discovery of those two letters, which the American Postal Workers Union alerted employees about on Wednesday.