Read the EPA's official statement about all substitute refrigerants and see
the chart showing Freeze-12's makeup here:
http://www.epa.gov/spdpublc/title6/snap/macssubs.html

The EPA's official statements have to be read taking into account that they
are a large government organization that basically updates things very slowly
and really doesn't actually install these refrigerants themselves (only
evaluates them according to guidelines setup by other government employed
"experts").  You can take thier writings as gospel (which I don't) or try to
look for the spirit of what they are saying which works better.

I like Freeze-12 because it is much cheaper than R-12, works very well as
either a retrofit or a drop in replacement for R-12 (much better than the
R-134a retrofits I have done), and I really haven't seen any proof of the
much talked about, though never really tested idea that over time the mixed
refrigerant will cause the system's cooling capacity to degrade.  I mean if
you put R-12 in a system and is leaks out, over time the system's cooling
ability degrades too, so what is the real difference?

Also Freeze-12 is one of the few replacements that doesn't contain butane or
propane (no kaboom).

This is just my opinion.  Worth every penny you paid for it :)

Ken Wilford
http://www.vanagain.com
John 3:16
Phone: (856)-765-1583
Shop:   (856)-327-0027
Fax:     (856)-327-2242