I believe that some or possibly a lot of the WMDs were those we gave Saddam during his fight with the Iranians in the ‘80s. My guess.
There was very little material support given to Iraq during their war with Iran. Mostly what we gave them was analysis of where to hit Iran so as to disrupt their economy and war-fighting ability.
We weren’t really supporting Iraq, we were encouraging and enabling both iraq and Iran to expend themselves.