I don't think there was any proof of what was in those semis...
Courtroom proof, no, but there were reports from ex-Saddam folks and Russians who said that’s what was in them. And there were literally hundreds of reports of small amounts of WMD being found in Iraq, just not the large quantities the media expected. Mostly mustard gas, but there was some nerve gas found. At least, when you except the one large site is such poor condition that we were too scared to check out its contents. ISIS has that site now.