"TeamCasa" wrote in message
...

R12 (Dichlorodifluoromethane) was on the list of chemicals banned by a
treaty in 1999. It had nothing to do with patents.


Actually DuPont's patent was running out in the early 90's They knew this
and lobbied to out law R12 and replace it with a more environmentally safe
refrigerant, one that they had the a new patent on. One that would not be
as detrimental to the ozone layer. Unfortunately the newer refrigerant is
more harmful to humans than the old R12. There was an ongoing article back
in the early 90's in the automotive trades magazines with details of how
this would unfold and it all happened as the articles indicated.