Two Recent, High-Profile False Positives for RicinS

Early Tuesday evening, news broke that a letter sent to Sen. Roger Wicker (R-Miss.) tested positive for the poison ricin. Considering yesterday's bombings and the deadly anthrax-filled letters sent after 9/11, this is scary stuff, right? Maybe. But there's a history of false positives with ricin.

The most notable case occurred in January of 2003, when investigators found what they then believed to be traces of ricin during a raid of the London apartment of alleged al Qaeda operatives. Authorities used the discovery – from a mortar and pestle in the apartment – to declare the suspects a "poison cell." Despite the fact that the apartment contained the ingredients necessary to make ricin – including castor beans and acetone – as well as instructions, it was later discovered that the substance found was not ricin. Of course, this discovery, which was made shortly after the raid, was not publicly revealed until April 2005, over two years later.

In the two years before the false positive was publicly disclosed, public officials in the UK and the United States used it to connect the five men arrested to eventual al Qaeda member Abu Musab Zarqawi, whom the US was then attempting to link to Saddam Hussein and a camp in Iraq where ricin was made. From the Washington Post:

Vice President Cheney, speaking of Hussein and his terrorist allies, told a Chamber of Commerce audience on Jan. 10, "The gravity of the threat we face was underscored in recent days when British police arrested . . . suspected terrorists in London and discovered a small quantity of ricin, one of the world's deadliest poisons."

A week later at the White House, then-press secretary Ari Fleischer told reporters, "When you read about people in London being arrested for possession of ricin, there clearly remain people in the world who want to inflict as much harm as they can on the Western world and on others."

In his Feb. 5 speech to the U.N. Security Council, Secretary of State Colin L. Powell put up a slide that linked a "U.K. poison cell" to Zarqawi.

After U.S. troops seized the northern Iraq camp linked to Zarqawi, Gen. Richard B. Myers, chairman of the Joint Chiefs of Staff, told CNN's "Late Edition" on March 30: "We think that's probably where the ricin that was found in London came [from]. . . . At least the operatives and maybe some of the formulas came from this site."

Naturally, authorities had known about the false positive "well before the outbreak of war in Iraq" in March 2003, according to a key witness for the defendants in the trial.

There was another high profile false positive for ricin in 2006, when a student at the University of Texas discovered a "whitish-brown powder" on a roll of quarters in a college laundry room. An initial test of the powder indicated it was ricin. Panic ensued on the campus: the dormitory was evacuated, the quarter machine removed and a haz mat team was called to the scene to investigate. Subsequent tests for the poison were negative.

An NBC News story about a ricin-laced letter in 2004 mentions another possibility for today's incident with Senator Wicker.

A possible explanation for the positive reading also has emerged. The sources said that investigators have determined that non-toxic byproducts of the castor bean plant - the raw material for ricin - are sometimes used in making paper. Because tests performed on congressional mail are highly sensitive, they could have picked up minute traces of products derived from the castor plant - not actual ricin, according to this theory.

Of course, none of this means the letter sent to Sen. Wicker wasn't laced with ricin. CNN is reporting that three tests found traces of the poison, and a similar ricin-by-letter incident occurred in 2004, when a letter to Bill Frist tested positive for the poison. But it's worth considering the possibility of a false negative before we rush into a panic or, you know, invade another country.

[Image of Sen. Roger Wicker via AP]