They aren't even weapons at this point. (You know, the "W" in "WMD")
They are toxic waste.
Saddam had ammo dumps everywhere. Saddam wasn't a big fan of maintenance and upkeep, so you are going to find a lot of old, dangerous junk in these places.
The NY Times article suggests that the Pentagon did not crow about these finds precisely because they were pre-1991 junk and not the WMDs that we were promised. The press would have laughed at them. As to keeping the number of injured servicemen secret, that is the default behavior of the Pentagon going back to Agent Orange in Viet Nam. I have heard rumors that the Pentagon is keeping the number of servicemen injured by depleted uranium secret, also.
I believe that the Pentagon actually thought that Saddam had an active chemical weapons program going on when we invaded Iraq. A modern army such as the U.S. army has little to fear from chemical weapons. What they didn't know was that Saddam had given up making chemical munitions when Clinton bombed all the chemical plants.
AC above is totally wrong. Saddam was cooperating fully with the inspectors when we attacked him. He was begging us to inspect whatever we wanted. There were UN inspectors on the ground when George W. Bush told them to get out because he wanted to start bombing.