The answer is surprising. Spread out the radioactivity enough and the deaths from radiation illness disappear completely.On the whole, this is good news. One terror tactic, that is of great concern, can be downgraded as a threat. However, Muller continues, pointing out that the terrorist groups do careful cost benefit analysis of their tactics and strategies. When one mode of operation is denied them, they adapt.
People exposed would have a slight increase in the risk of eventually contracting cancer, but there would be no dead bodies at the scene - except those killed by the dynamite. Diluted radiation loses its potency.
We measure radiation dose in units called rem. Above 1,000 rem, incapacitation occurs within minutes, followed by extreme fatigue and nausea, then death. For smaller doses, 300 to 500 rem, about half of the victims die within a month.
But reduce the dose a little more, down to 100 rem, and the effects are very mild. At 50 rem, nobody even gets sick.
This 'threshold effect' creates problems for the terrorist. He can put radioactive material into a bomb - but concentrated radioactivity kills fast, so he'll have to protect himself with a ton of lead.
Then he must deliver the bomb, take it out of the lead shield and explode it with dynamite so the radioactive material spreads into the air. Muller continues:
Consider Jose Padilla, the Chicago thug who was trained by Al Qaeda and came to America planning to make a dirty bomb.Terrorists are not all powerful, there are enormous limitations - social, physical, and logistical - on what they can do. It is important not to overestimate their technological capabilities. But at the same time, we cannot underestimate their adaptability and their continuing capacity for low-level, practical innovation.
According to the US Justice Department, Al Qaeda had doubts about the practicability of such an attack, so it directed him to abandon the dirty bomb and blow up two apartment buildings using natural gas.
He wants the wind to carry it around the city, but has to hope it doesn't spread too much or it won't kill anyone.
What worries me about this story is that it suggests Al Qaeda understands the limitations of dirty bombs better than government leaders and many scientists.