If global terrorism has you concerned that our safety hangs by a thread, consider how thin that thread might be — or how close to home the threat might be.

A dirty bomb attack has long been high on the list of counterterror concerns because such a bomb is relatively simple to make and very portable.

Unlike a typical nuclear detonation, a dirty bomb attack is considered more likely to provoke chaos than direct death. But depending on its size, its radioactivity could poison an entire city center.

The Government Accountability Office investigators incorporated a shell company in Dallas and rented office space to create an address for the license application. Instead of listing their required safety officer, they used a fake name and resume and said they needed the otherwise-prohibited material to power an industrial gauge used in oil and gas exploration.