I think freon could work but I need to look into it more. Do more research. I haven't heard of anyone ever ctb with freon so that might indicate it's a poor choice
My initial research since I 1st posted on this thread(the last 20-30 minutes in other words)is saying that this is a poor choice. Freon. There have been cases where it has resulted in death but they are very rare. Other gasses (helium, nitrogen, carbon gasses) would be much more effective. There are people who huff freon for a cheap thrill or high. Every once in a while someone dies from it. But not often.