The incident has been called "the most important sub-state use of radiological material."

Specialists in chemical, biological, radiological and nuclear materials were deployed to Berezovsky's home as a "precaution".

(8) Locate, seize, and control illicit or excess radiological materials.

He was accused of involvement in a plot to build a "dirty" bomb using conventional explosives and radiological materials.

All inbound travelers, baggage, and cargo are screened for radiological materials.

"There are many recent indications that Al Qaeda's planning includes the use of chemical, biological and/or radiological materials."

Albright, confirmed the abandoned documents included plans for a nuclear bomb, and extensive training notes on the handling of radiological material.

"We did not find any type of serious radiological material," one Pentagon official said.

A "dirty bomb," a crude device that releases radiological material, would presumably damage just a few blocks.

Abandoned radiological material is periodically found in cities elsewhere in the world.