I thought I posted this, but can’t find it. I apologize if it is a duplicate.
If you want true science on R-12 do it yourself. Find a nice limestone rock, whatever size you can move. Take it to a swimming pool, hold it so the top of it is even with the water in the pool. Then, let go.
Does it bounce around up there destroying pool ions? No, it goes down, down, down, and when it hits the bottom it stays there. Check it very day for a year. Does it ever come back up? No, it went down and it stays there.
Specific gravity of limestone in water is only 2.5. Specific gravity of R-12 in “air” is 4.3 which is 72% higher sp.g. It goes down faster and stays harder. The real danger of R-12 was spelunkers were going to suffocate in deep caves where R-12 eventually ended up. [sarcasm]
Also, I don’t remember anyone ever claiming they actually found an R-12 molecule in the ionosphere. I wouldn’t believe them if they say they did, because the stuff is simply too heavy. And, it is incredibly inert, so it can’t form complex compounds and grow wings to it can fly away. Diffusion is simply mumbo-jumbo to confuse gullible people.
In the 90’s, estimates of cost to replace R-12 for the planet was estimated to run around one trillion dollars. That did not include increased energy costs for less efficient R-134A, forever. But, hey, the patent was expiring and du Pont needed something new at a higher price. They got it. Thanks for helping them, guys.
I worked in a large electronics plant. We had big ‘chambers’ we called them, each producing enough cooling to cook as many as 8 full sized houses, just to heat and cool electronics to make sure it would work at the wide temperatures military electronics experience. The compressors were gigantic and required special handling tools to move and install. They ran on 440V.
How many such chambers? I have no idea. If you told me several hundred, I would believe it. Not too many more, and not too many less. There was a lot of R-12 in those buildings.
The first time I saw a refrigeration guy open a system, the gas came hissing out. I freaked out. He laughed. And, eventually I realized he was correct. At no time could you smell it on the shop floor.
The small amounts of R-12 used in cars did not cause any problems to anyone or anything. The refrigeration guys knew when they soldered tubing on R-12 systems, they had to pump them out first, they were well aware of phosgene gas coming from R-12 with propane soldering torches. No, that’s wrong. Early in my time in that company, we did have a refrigeration worker get a dose of phosgene one day, so procedures were changed for more training.
It is extremely rare that a/c R-12 would hit over 1,000 degrees in a car wreck situation. If the system ruptures, the gas will soon enough hit the ground and move away.
All the people who worked with R-12 knew instantly that R-12 destroying the ionosphere was pure bunkum. But, with bullying they got it outlawed, the same bullying being used to try to ram non-existent global warming through. Enough already.
We used other types of freon, In one area, they had tanks of it, not R-12, in open tanks, with only a simply metal lid over the top for cleaning circuit boards. It smelled up the whole area, and made people feel sick. Our illustrious safety director told us the stuff would not harm you, if you took a bath in it. I called the number on the safety sheet, using my own phone card so they couldn’t ding me for unauthorized phone charges. I ended up talking to the CEO of the division which made the stuff. He did not ask my job title, fortunately. 
After he understood the issue, he said, “Our policy is when you can smell it, you are getting too much.”
I wrote up a report on my phone call and massively distributed it, including to the union officials. Someone came and told me a higher-up had said I was supposed to be working, not calling people on the phone. I said to tell him to come down and we could examine my official job description, which did include liaison with customers and vendors. He did not come down, and in a few days, the open tank was gone.
There is also no global warming. If you want to believe in both things, I guess you can, no matter how false they are. But, it is unlikely R-12 will be un-outlawed no matter what the truth is.
