Err....Yes, They Did Find Explosives at Al-Qaa Qaa

So, the explosives were gone before they got there? FOX didn't think so at the time.
In this story, the news station mentions that the US 3rd Infantry Division found something it decided was an explosive at the site.

"Col. John Peabody, engineer brigade commander of the 3rd Infantry Division, said troops found thousands of 2-by-5-inch boxes, each containing three vials of white powder, together with documents written in Arabic that dealt with how to engage in chemical warfare.

Initial reports suggest the powder is an explosive, but tests are still being done, a senior U.S. official said. If confirmed, it would be consistent with what the Iraqis say is the plant's purpose, producing explosives and propellants."

In the end, as we know, they concluded it wasn't a chemical weapon. But what does RDX look like? Let's look it up and check our facts, shall we? GlobalSecurity.org defines RDX as

"an explosive nitramine compound. It is in the form of a white powder with a density of 1.806 g/cc. Nitrogen content of 37.84%. The chemical name for RDX is 1,3,5-trinitro-1,3,5-triazine. The chemical formula for RDX is C3H6N6O6 and the molecular weight is 222.117. Its melting point is 205°C. RDX has very low solubility in water and has an extremely low volatility. RDX does not sorb to soil very strongly and can move into the groundwater from soil."

Mind you, it wasn't as if they were looking for it, or at least their brigade commander, Colonel Dave Perkins, doesn't seem to think so. Who do you believe - Colonels Perkins and Peabody and all the evidence, or the spin? I suppose it depends if you're in the reality based community or not. Or perhaps they've just been chewing the RDX:

"Troops have also become intoxicated during field operations from exposure to composition C4 plastic explosive, which contains 91% RDX. These field exposures occurred because C4 was either chewed as an intoxicant or used as a fuel for cooking. Thus, the route of exposure was ingestion or inhalation. At least 40 American soldiers experienced convulsions due to RDX ingestion during the Vietnam War."

Well, whatever turns you on I suppose...