Here we go again. I don't go against HC-12a (duracool) because it is flamable. I am against it for a couple of reasons. Mainly a compressor manufacturer will void the warranty, if it is used, and it is not "legal" for a retrofit. R-134a is NOT being outlawed. It is just not legal to use in new vehicles. Just because something will work, doesn't mean it can be used. You can put alcohol in your radiator as antifreeze, but would you?