U.S. Sends Out 'Dirty Bomb' Patrol

(CBS/AP)  The U.S. - concerned that terrorists might attempt to detonate a "dirty bomb" during the holidays - sent nuclear scientists to five major cities to search for the radiological devices, the Washington Post reports.

The newspaper said the casually dressed scientists concealed detection equipment in golf bags and briefcases while they looked for evidence of the bombs in New York, Washington, Baltimore, Los Angeles and Las Vegas.

Last November, it was announced that government investigators had documented 1,300 cases of lost, stolen or abandoned radioactive material inside the U.S. over the past five years. The investigators concluded there was a significant risk that terrorists could cobble enough together for a dirty bomb.

[A dirty bomb is not a nuclear weapon. It is a conventional explosive packed with radioactive material that spews forth when the bomb is detonated.]

The Post said the possible use of such a weapon by terrorists has been a major concern of U.S. officials.

On Dec. 19, the day the terror threat level was raised to orange, or "high," the Homeland Security Department sent out hundreds of radiation monitors to police in Washington, New York, Los Angeles, Las Vegas, Chicago, Houston, San Diego, San Francisco, Seattle and Detroit.

Department of Energy radiation experts were also dispatched to five cities to covertly look for evidence of a "dirty bomb." Beginning on Dec. 22, the teams of scientists took measurements in the cities 24 hours a day.

The only "spike" occurred in Las Vegas on Dec. 29. The Post said five tense hours followed, until investigators determined that a cigar-size radium pellet used to treat cancer was in the possession of a homeless man who did know what he had.