Thanks for the links Don,

From the third link posted:

"The mission of Dugway is to test U.S. and Allied biological & chemical defense systems; perform Nuclear Biological Chemical survivable testing of defense material; provide support to chemical and biological weapons conventions; and Operate and maintain an installation to support test mission."

From the Second the map lists sites as either places where Chemical Activity takes place or as Chemical depots - that does not mean that these sites are being used to store the stuff for offensive purposes.

The Umatilla site mentioned in your first link has incinerators and is mentioned in the second as a site for storage and disposal.

The UK used the MOD site at Portendown for its chemical and bacteriological research - they had CB agents there - no weapons.

In late 60's and early 70's it was expected that Russia and the Warsaw Pact countries would sign up to the convention banning the use of such weapons - they didn't. UK had already given that undertaking and had destroyed whatever weapons it had. The US said they would stop weapons development, but would retain stockpiles until such time as they decayed or required controlled disposal.

Nothing you have shown me convinces me that the US or UK has any offensive weapons capability in terms of CB weapons. The weaponry of both countries and their strategic and tactical planning has no use for such unreliable weapons, used offensively they hinder more than help - NATO worked that out about forty years ago. For the US to suddenly revert to their use would be as much of a retrograde step as to issue their infantrymen with muzzleloading muskets.