You don't even have to have nefarious intentions. Chlorine gas is a perfectly normal industrial chemical, but simply dropping a few tanks over a trench system turns it into a chemical weapon.

Thus the quotes.

This is still pretty big, though. I imagine further legislation will be easier if the negotiators can say that legally nobody has any chemical weapons right now.

Of course, I'm sure there's facilities that could start making them in a hurry.

somewhere by secret services or criminal enterprises.

You say that as if they are two separate things.

Honestly I wouldn't be surprised if the big players have replaced chemical weapons with something just as horrible but more "smart" like micro-drones with explosive charges and facial recognition.

Hence the quotes.

it is not. Chemical weapons and radiation weapons are pretty different animals.