The ubiquitous advisories and legislations against releasing A/C refrigerant into the atmosphere are well known - if you need to discharge R-134a or R-22 from your A/C system, have the gas evacuated by a professional.

What do the professionals do with the gas though? Is there some chemical process to help convert it into something less harmful for the environment? If so, I'd like to know the details.

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    Often they can recapture the refrigerant and then reuse it.
    – Cullub
    Jul 7, 2016 at 18:39
  • This discussion is very interesting since I have an old 1991 Corolla I am trying to get the R-12 taken out of. Some repair shops seem to speak out of both sides of their mouth--first they say, we can do a conversion and/or yes we can evacuate it but THEN if you ask 'Do you have a tank to store it?' then they say 'Actually no we can't do it.' So then is this a regulation that is basically not being followed by many repair shops? Especially given Steve Racer's statement that R-12 and R-134a should NOT be mixed, it sounds like venting R-12 to the atmosphere is fairly common? Feb 11, 2017 at 18:08

1 Answer 1


When I got my Refrigerant Handling Certification from MACS many years ago, we were sworn to use a proper recycling machine, which captured everything and filtered out air, oils, and moisture. The refrigerant could then be re-used for the same or different vehicle. This was the transitional time, and there was much concern of a cheap "retrofit" DIY job creating a mix of R-12 "Freon" and R134a, which no machine could deal with.

When such contaminated refrigerant mixes were discovered, the offending stuff was shipped back to the manufacturer, or one of their agents, and destroyed - I know not by what manner - but I believe it was controlled incineration (Burning R-12 creates a sort of Mustard Gas) and that the process was very, very expensive. Most cases involved shipping and disposing of the "contaminated" recycling machine as well. I know many otherwise excellent and devout shops that illegally vented such systems, rather than incur a $10-$20k hazardous waste disposal incident. In truth, vacuuming for retrofit wasn't enough... there was always some residual chlorinated refrigerant stuck in the mineral oil, and the PAG oil wasn't sufficient viscosity to move it into solution.

Now with advent of R1234yf, this will eventually put me out of the A/C repair business. Whether it's flammable or not, as a shadetree independent I simply don't have the resources to buy yet another complete set of tools for dealing with the latest earth-friendly refrigerant.

  • How would a shop even know if they were facing a mix of R-12 and R134a?
    – dlu
    Jul 7, 2016 at 19:48
  • @dlu A gas sniffer will tell you what kind of gas(es) are in the system.
    – Ben
    Jul 7, 2016 at 20:12
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    Sounds like there's a serious investment in setting up to do A/C service…
    – dlu
    Jul 7, 2016 at 20:15
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    @dlu High side pressures went ludicrously high (~450+ psi). And there were these cross-threaded adapters that turned a threaded R-12 style fitting into a presslock R134a style.
    – SteveRacer
    Jul 7, 2016 at 20:16
  • @dlu Indeed. Instruments, tools and service equipment easily cost $thousands for a single tech.My instructor sold his HVAC business after 15 years partly due to the never-ending equipment hassles. It's a real turn-off for anyone interested in getting into HVAC, which provides job security for some but more headaches for everyone else. And recent changes focus not on the very real ozone depletion but, rather, global warming. IMO it's a real stretch to link any refrigerants to global warming. So what we've done, in essence, is sabotage climate control for little or no improvement to the climate. Nov 6, 2019 at 22:43

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