Ricin was the particular worry of the day. Preliminary tests indicate that letters sent to President Obama and to Sen. Roger Wicker (R) of Mississippi were both laced with the deadly poison. Postal screening facilities outside Washington had intercepted the mail before it reached federal office buildings.
Both letters were postmarked in Memphis, Tenn., according to the Associated Press. Both said “to see a wrong and not expose it, is to become a silent partner to its continuance.” Both were signed “I am KC and I approve this message”.
Sen. Claire McCaskill (D) of Missouri said the Capitol Police have a particular suspect in mind in this case. It is someone who “writes a lot of letters to members” she said, according to the Associated Press.
Where ricin is involved, preliminary tests can be inaccurate. Full laboratory tests will be needed to confirm the poison’s presence.
Lawmakers were made even more nervous by reports from some states that district offices were also getting questionable mail. Republican Sens. Jeff Flake of Arizona and John Cornyn of Texas both said that letters set aside as suspicious by staff members back home had been tested by law enforcement and found harmless. Democratic Sen. Carl Levin of Michigan said a letter sent to his Saginaw office was still being checked.
Meanwhile, at least three questionable packages turned up in Senate office buildings, according to the AP. Capitol Police retrieved them while establishing a series of rolling lockdowns throughout some areas of the Senate side of the Capitol Hill complex. Confused Senate aides took to social media to share which corridors were open and which closed.
Ricin is a potent toxin found in the seeds of the castor plant. Touching it can produce a rash that is irritating but not fatal. Inhalation or ingestion of ricin particles is more dangerous, leading to death in three to five days if the dose is sufficiently large.
Ricin is not difficult to extract – the production of castor bean oil results in a mash that is approximately 5 percent ricin, for instance. Recipes for making the poison are readily available on the Internet and from commercial bookstores.
As a weapon of mass destruction ricin is unsuitable, according to a 2010 report on its production and dangers produced by the Congressional Research Service. It would be too hard to handle and too difficult to spread.
But scientists have long warned that it might be used in terrorism.
“Although causing mass casualties would be difficult, many experts agree that ricin could be a formidable weapon if used in small-scale attacks…. Although a string of attacks targeting dozens of victims at a time may not produce mass devastation, they might instill terror in the population, causing local economic disruption,” wrote CRS specialists Dana Shea and Frank Gottron in 2010.
The most notable past use of ricin occurred in 1978, when Bulgarian dissident Georgi Markov was assassinated by someone wielding an umbrella tipped with ricin pellets in London. Shortly thereafter, another Bulgarian exile, Vladimir Kostov, was found to be suffering from non-fatal ricin poisoning.
In the United States, in 2008 a man trying to produce ricin in a Las Vegas hotel room poisoned himself, according to CRS. He recovered and was convicted of charges of possessing an illegal biological toxin.