As the article says, it was gone by 2003 when the place was raided. Plenty of time to clean house, at least on that scare; Bush gave multiple warnings over the airwaves instead of adhering to some of the most basic principles of war, among them being secrecy and diversion.
Chemical weapons, we only have to ask Assad.
The article is rather poorly worded - it is unclear. Now that I re-read it, it is possibly as you say, that they mean that everything was cleared away before the federal agents raided. That, at least, would make sense.
However, as it is written, it seems to make the assertion that everything was cleared away by the federal agents at the time of the raid. Which would be passing odd.
I do hope that Assad has some harsh weapons to drop on the heads of the head chopping savages who have invaded Syria.
These are dark days. I really believe that we could see WW3 break out in the Middle East.