The CIA's account of how U.S. authorities failed to realize
troops were exposed to chemical agents at Khamisiyah suggests incompetence more
than conspiracy. (You can read this report on the internet: "CIA
Report on Intelligence Related to Gulf War Illnesses")
The CIA had known about Khamisiyah as a possible chemical weapons site since
1986. Several intelligence warnings in February 1991 that Khamisiyah might
contain chemical weapons were not passed on to the commanders of the divisions
that subsequently destroyed the site in March, 1991. The CIA account claims
that its analysts were:
(1) Confused about the name Khamisiyah (confusing it
with Tall al Lham and An Nasiriyah)
(2) Uncertain of Khamisiyah's precise location.
(3) Unsure about which "shape" of Iraqi bunker contained chemical weapons.
In October, 1991, Khamisiyah was visited by United Nations inspectors (UNSCOM)
who found the site heavily contaminated with sarin. The Iraqis told UNSCOM
officials that they had not destroyed the site; Coalition forces had done it
some time after the ground war ended.
The Iraqi story gained credibility after UNSCOM found a box of U.S. explosives
at the site. This information was passed on to U.S. authorities, but the CIA
and DOD did not believe the story and were unable to confirm it. Subsequent
warnings by UNSCOM and others did not lead the CIA and DOD to connect
Khamisiyah with U. S. troops.
It wasn't until June, 1996 that DOD officially recognized that (1) the site
contained chemical weapons and, (2) US troops had blown it up in March, 1991.