Skepic you do know that most soldiers today have CBRN on hand as a leftover procedure from the cold war incase of nuclear attack on the front?  I easily can see your agent defeating the suits (NBC suits were fairly dynamic in the cold war as each side made better chemical weapons) but they would be on hand for the simple reason that threats from NBC vectors do exist in more ways than just your one chemical.

With that in mind I would have to say better suits would exist on order but are more expensive, for the simple reason that WMD level chemical weapons can wipe out an entire army in five minutes flat.