From your linked article:
"U.S. Central Command, which oversees the war in Iraq, said in a statement that troops were examining several "sites of interest," but said it was premature to call the Najaf site a chemical weapons factory."

As for the SCUDS. As far as know the missiles which were fired were not neccessary missiles which had a missile range which exceeded the UN restrictions. These missiles are ballistic and enter space, but aren't the long range SCUDS. The recent UN problems were with these missiles and which the Iraqi were attempting to extend their range (which would make them illegal, btw if these longer range missile were actually used (fairly unlikely because they were in development opposed to production) it would be difficult to distingish them, unless you knew where they were launched from.