I'm not disagreeing with him particularly, though you do need to get enough fissionable material to build a nuclear bomb which is certain amount of trouble.
I just wanted to point out that what was removed from circulation was the much less dangerous Cesium-137, although even by itself it's dangerous enough in all conscience.
I am laughing, as you sent me back to Google and now I have a new question for you.
Last year, there were reports of jugs of water simply setting in the subway tunnels, appeared out of "no where".
The below search, I see a link to Cesium-137 in ponds, does that mean the water will affect you the same as the dry material in a dirty bomb?
You are correct in the fact that the big one is going to
be harder to buy the needed materials for, I didn't go back
to your first post, to get the names of the materials, as I
knew that the materials were available on the internet.
As the terrorists well know how to use google, I chased the subject last year.
http://www.google.com/search?q=where+to+buy+cesium-137+nuclear+material&btnG=Search&hl=en&lr=&ie=ISO-8859-1&client=googlet