The world of so-called natural refrigerants, particularly hydrocarbons (HCs), has gotten a lot more interesting recently.
The U.S. Environmental Protection Agency (EPA) has given Significant New Alternatives Program (SNAP) approval to three HCs. The idea is to open the door for greater use of such refrigerants in the United States. The argument in favor of HCs is that they are said to be less potentially damaging to the environment than HCFCs and HFCs should they leak from a less than tight system.