As I've said, Saddam had chemical weapons and used them in the 1980s, so it is hardly a stretch to assume he continued to have them until we defeated his regime.
And is it really so far fetched as to assume we might still find something underground? Well:
To the west of the capital, the 2nd Marine division said its forces had discovered 50 weapons and ammunitions caches over the past four days in restive Anbar province. The military said the find included a recently used "insurgent lair" in a massive underground bunker complex that included air-conditioned living quarters and high tech military equipment, including night vision goggles.
That bunker was found cut from a rock quarry in Karmah, 50 miles west of Baghdad. The Marines said the facility was 170 yards wide and 275 yards long.
In its rooms were "four fully furnished living spaces, a kitchen with fresh food, two shower facilities and a working air conditioner. Other rooms within the complex were filled with weapons and ammunition," the announcement said.
The weapons included "numerous types of machine guns, ordnance, including mortars, rockets and artillery rounds, black uniforms, ski masks, compasses, log books, night vision goggles, and fully charged cell phones."
Imagine that? In an area we've been occupying for two years, we find a large bunker that was being used. During a decade of no-fly zones, we taught the Iraqis to burrow underground.
This will not be the last hidden bunker we find. One day, we will hit pay dirt.
