the company replies
I emailed the company with many of the concerns expressed in this thread; here is their response, which includes the acknowledgement that it contains propane:
"It is not corrosive nor does it turn acidic in the presence of moisture. The autoignition temp is much, much higher than that of 134a which goes in every newer car. The autoignition temp is 1,585F. At that temp, the tires would liquefy, the seats would catch fire, the metal would start to melt, and the
driver himself/herself would burst into flame as well. All of that would happen long before the refrigerant started top burn. In that scenario of well over 1000F, I would worry about the gas tank wouldn't you.
Yes there is propane in it. That is one reason it is so darn effient. Hydrocarbon refrigerants were first envisioned by Albert Einstein and he tried to patent three different types all involving hydrocarbons.
134a on the other hand will kill you if you inhale it at more than 4% concentration. Additionally, Coke, Fosters Brewing and Unilever (worlds largest icecream maker) have all made announcements regarding their intentions to use hydrocarbons instead of 134a or Freon. In Germany 100% of all new refrigerators use pure propane as the refrigerant. There has never been a hydrocarbon refrigerant fire ever, in over 20 million user years.