60 minutes interview
He speaks of a dirty bomb. As an expert he should have known that dirty bombs are almost harmless. At most the radiation can kill a handfull of people, although most likely noone will be killed. The radiation can also be cleaned up effectively.
I doubt Al Qaida would attack with a harmless weapon.
A dirty bomb would make people freak out because they don't understand it, and in a financial district would cause a lot of money in downtime. It would create terror.
Unfortunately, phatmonkey is right. The physical impact of attack on the WTC and the Pentagon wasn't nearly as severe as the psychological impact. 9/11 shouldn't have had nearly as severe an impact on the economy as it did.
Part of preparing and preventing terrorist attacks should be some education. Ideally, we wouldn't let the effect of a dirty bomb be amplified far beyond its physical capabilities.
There is also the chance that any nuclear device may not work. For example and as I understand it, many of the concerns about X-Soviet devices are reduced when the required maintenance is taken into account. For many years we worried about the suitcase bombs but these are almost certainly beyond their useful life.
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