They existed then, and still exist now. Plans were made for their use, both tactically and strategically. If you doubt it, look for books about chemical and biological weapons in your local library. You should find something that makes reference to development and testing. For policy, I don't have that many sources, but try the book "The Third World War," written by a former NATO general. Somewhere in there, you will find predictions, by a policy-maker for NATO, that chemical munitions would be used by NATO in a large-scale war.