A squad leader of my Army platoon once had a crate of about 30 compasses that had radium markings. Anyway, he had the box in his truck, left the gate at Fort Benning then when he returned later, he set off the radiation detectors at the entry gate. Caused a full base lockdown and needless to say, he didn’t have a very pleasant time until they figured out that the compasses set off the detectors. This was in 2004 when we were on a high alert for dirty bombs.