I have always been struck by the fact that the CWC entered into force less than a decade after the Iran-Iraq war ended. This 1988 CIA report seems pretty pessimistic about the convention:
It’s perfectly fair to describe the international response as “limited.” The document earlier notes the increased incentive for CW acquisition:
But such proliferation didn’t happen. Instead, no more countries used CW until Syria did. And most states are parties to the CWC.