Europe, in general, is OC unfriendly. During my time in the Army I spent 7 months in Kosovo as a Military Policeman. Use of riot control agents (O.C.) required Presidential Authority. As a squad leader, I---No better yet my wet behing the ears M249 Gunner could, using his EXTENSIVE 4 months of experience and training, use deadly force.
So I the one civil disturbance we encountered when I needed to disperse a crowd I had to use riot batons or call and ask for permission through chain of command to use O.C.
Because OC is considered a chemical warfare agent in the same class as VX, sarin, etc. I don't remember which treaty it fell under or if the USA was a signator on same but because of our no first strike policy it was easier to use deadly rather than less than leathal means.