Propane and other dangerous chemicals like Ammonia have been used in industrial applications for many years .
But now they want to mainstream Propane use everywhere under the name R290 .
It requires specialized handling and tools just the kit to do solderless connectors is $8000.00
https://refrigeranthq.com/r-290-propane-refrigerant-info-fact-sheet/
This is being done to protect the environment which it is not
The old R12 and R 22 Freon's where perfectly safe but they claimed they created an Ozone hole in the atmosphere which was a total lie. The truth is when you do a deep dive into the issue was that R12 and 22 where about to loose their patent protection and any one could make it with out paying royalty's.
So they blamed Freon on the ozone whole and the rest is history . Owe by the way that's right scientists discovered the hole opens and closes in cycles.
So they started coming out with new more dangerous Freon's which used Benzene in there lubrication path and where not as efficient . in some cases they where even poisonous .With absolutely no proof R12 and 22 was dangerous to the environment .
Some installations now will require the use of fire protection sprinklers because of the danger.
another failure point and expense
Imagine a propane based system leaking into a restaurant that uses open flames .
But we do not have to
https://www.history.com/news/the-tragic-story-of-americas-deadliest-nightclub-fire
Remember the Coconut grove Night club fire that killed over 400 guests
It is now believed to have been fueled by the deadly flammable Methyl Chloride gas being used in the clubs conditioning system
So how long till they outlaw R290 and come up with anotherway to rip off the consumer