The patents were running out and China was set to be the major producer; R-12 was the best gas for the type of refrigeration we commonly use as its safety level is unequaled.
Dupont was a happy camper but the madness reigned and now the hole comes and goes, just as it has all along.
Its chief replacement, HFC-134 was just made a GHG by Jackson, Browner et al this year and here we go again.
When did they get the patent? When was it set to expire?