Those Saddam WMDs that it turned out didn't really exist? Here's a long NYT report suggesting that the US government knew perfectly well that Al Muthanna, the manufacturing complex at the heart of Saddam's chemical weapons industry, did indeed contain stocks of deadly chemical materials, but wasn't particularly interested in sharing that information.
Al Muthanna is now controlled by Isis:
From 2004 to 2011, American and American-trained Iraqi troops repeatedly encountered, and on at least six occasions were wounded by, chemical weapons remaining from years earlier in Saddam Hussein’s rule.
In all, American troops secretly reported finding roughly 5,000 chemical warheads, shells or aviation bombs, according to interviews with dozens of participants, Iraqi and American officials, and heavily redacted intelligence documents obtained under the Freedom of Information Act.
The United States had gone to war declaring it must destroy an active weapons of mass destruction program. Instead, American troops gradually found and ultimately suffered from the remnants of long-abandoned programs, built in close collaboration with the West.
The New York Times found 17 American service members and seven Iraqi police officers who were exposed to nerve or mustard agents after 2003. American officials said that the actual tally of exposed troops was slightly higher, but that the government’s official count was classified.
The secrecy fit a pattern. Since the outset of the war, the scale of the United States’ encounters with chemical weapons in Iraq was neither publicly shared nor widely circulated within the military. These encounters carry worrisome implications now that the Islamic State, a Qaeda splinter group, controls much of the territory where the weapons were found.
The American government withheld word about its discoveries even from troops it sent into harm’s way and from military doctors. The government’s secrecy, victims and participants said, prevented troops in some of the war’s most dangerous jobs from receiving proper medical care and official recognition of their wounds.
Now those chemical weapons are very likely being used, once more, against the Kurds.
A useful summary at HuffPo.