According to WikiLeaks, small amounts of chemical WMDs were found in Iraq and continued to surface for years after the 2003 US invasion.
The term,
"Weapon of Mass Destruction," is ambiguous. A molotov cocktail tossed into a crowded bar literally and categorically qualifies as a weapon of mass destruction. As does an ordinary fragmentation grenade or a high-capacity machine gun turned against an unarmed and trapped crowd.
As far as a chemical weapon is concerned, it can be considered a weapon of mass destruction if used to optimum effect. But not any moreso than a comparably lethal high-explosive or indendiary device. In keeping with the topic at hand, the chemical weapons found in Iraq, which were purchased from the U.S. as far back as the 1970s and 80s, are long past their shelf-life and are no longer useful.
The bottom line is the widely accepted meaning of a "WMD" is some sort of nuclear device, from a so-called "dirty bomb" to a full-scale thermonuclear bomb or artillery round. So the lingering rumors about chemical weapons being found in Iraq are nothing more than attempts to justify the illegal and immoral invasion of Iraq.