P.S. Or they simply didn't know how to extract it safely without killing themselves so they just blew it up and hoped for the best.
Officials in Washington said another shell -- this one containing mustard gas -- was found 10 days ago in Iraq.
No other evidence of possible chemical weapons has been found in Iraq. The Bush administration cited weapons of mass destruction as a key reason for its invasion.
SOURCE: CNN.COM
I think your PS is reasonable.
I doubt sincerely that the average al-Queda or al-Sadr lacky has any idea how to use chemical weapons beyond just trying to get them to spread. If they had more knowledge they would have been manufacturing and using their own supply for the last few years.
More likely. You have to remember these aren't crack troops that we are fighting. They are mean and can do a lot of damage but they aren't that well trained.
There is also the fact that during the first part of the war we found lots of equipment for handling this stuff. Just maybe, when they hid it, they forgot to hide the proper safety equipment with it.