Polonium on a plane

"Small traces of radiation" have been found on two British Airways planes.

"The airline now faces a logistical nightmare tracking down 33,000 passengers who used more than 200 affected flights over the past month, as well as 3,000 staff."

The connection to the death of Alexander Litvinenko isn't clear yet.

Update (November 30, 2006): Now we're up to five "planes of interest".