I ma sure that there are many underground shelters or weapons burial sites that we did not uncover yet. Iraq is the size of California, unless we get very lucky or get a tip from someone or find some documents, we will not know about where the WMD or Precursors for WMD were found.
I remember reading somewhere that Saddam was obsessed with building as many bunkers as possible and there might be hundreds of them as much as a hundred or so feet underground.
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