Look, I know how bad both phosgene and Saddam are. I have no dispute with that. Here is the reality: you can make phosgene by overheating PVC plastics. It's easy. PVC is everywhere.
The only way to preclude phosgene being used as a chemical weapon is to monitor manufacturing and storage of the bulk materials and delivery systems. Preventing imports accomplishes very little.
In term of producing Phosgene from heating plastic, I think if this is the case we will have thousands of dead people everyday. The company I work for supply control elements to chemical firms that manufacture Phosgene and this was of the toughest applications we deal with because our control element must be designed to have zero leakage to the atmosphere because Phosgene is simply extremely deadly once it is inhaled.
"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."