Right,R 12 and 134a don't burn,but like any flourocarbon when heated like with a torch form Phosgene gas which when breathed in forms phosphoric acid which burns the lungs making them incapable of passing oxygen to the blood.This gas was used some during WW2 quite effectively.
I'm in the group that would rather have a little less cooling than a flammable compound in my AC. Although early in the history of refrigeration,methane was used as a refrigerant(talk about a bomb!) and our grandparents lived thru it only to prove that if your grandparents didn't have children,you probably won't either.
Ron