Not that it matters, but HC-12a is actually nothing more than a registered trade/product mark of OZ Technology, Inc.
http://www.oztechnologyinc.com/hc12a.html
If you compare the MSDS for HC-12a or other 12a products, you'll see that they're essentially the same, with little variation. The drop in statement came from a Wikipedia entry that claims to be specifically about HC-12a, but speaks about automotive hydrocarbon refrigerants in general terms, thus I wouldn't place too much stock in the technical/specific accuracy of the Wikipedia entry. I was merely using it to reference hydrocarbon refrigerants in general, as opposed to being specifically about OZ Technology Inc's blend of 12a. Remember 12a blends aren't patented, so while only OZ can call their product 'HC-12a,' other 12a products could and probably do contain the exact same blend of hydrocarbons.