"Chlorine gas is never produced when PVC burns, and while the possibility of producing phosgene from burning PVC has been suggested, following reports of minimal quantities produced in laboratory experiments, it has never been detected in large scale fire tests and it is not considered a significant product of PVC combustion."
Allow me to ruin your day, even more: I worked seven years as a project engineer in the PVC industry. We had to take special provisions to preclude exposure to phosgene (not to mention VCM). With the tons of PVC available in packaging alone, the Iraqis could have obtained enough to create weapons. The chlorinated hydrocarbons in PVC and pesticides in any country with industry and agricultural as significant as Iraq is sufficient to produce enough phosgene to do serious damage.