Website editor’s note: This article contains some good info about “dirty bombs” … what they are, what they aren’t. Here’s an excerpt:

“Dirty bombs are far easier to construct than nuclear bombs and do not use fissile material such as enriched uranium or plutonium. Extracting plutonium requires a reactor and enriching uranium is no easy task. Dirty bombs (security forces all them “radiation dispersal devices”) use conventional explosives such as car bombs to scatter radioactive materials through a densely populated area.

The physical damage is limited and the threat of dying from radiation exposure very small with such a device. But a dirty bomb would cause extensive economic damage and social upheaval while instilling panic and fear in civilians.”

http://www.foxnews.com/tech/2013/03/15/dirty-bomb-material-secured-at-site-in-philadelphia/