The “HFCs” (primarily used as refrigerant gases) were used because of their non-flammable characteristics. They were a replacement for either ammonia or very light (ethane, propane and butane) hydrocarbon gases. Ammonia is a very irritating, and in fact poisonous, gas, which is to some degree flammable, which has very good compressibility and heat transfer properties, but when it leaks, causes all kinds of mischief to human breathing apparatus. The light fractions of liquified petroleum gases are also highly compressible, and like ammonia, can effect a huge amount of heat transfer, but if a leak develops, a very dangerous concentration of highly combustible oxygen-hydrocarbon mixture needs only the least of sparks to ignite with a devastatingly hot flame, a near-explosion.
HFC gases are simply unable to ignite. A sufficiently high temperature, to be sure, could cause the elements that make up the compounds to separate, but that much heat has a lot of other destructive properties, making any chance of combustion highly unlikely, and not a sustainable reaction at all.
Even a massive atmospheric leak of HFC is unlikely to be a long-continuing problem, as the molecular weight is quite high, and it would stratify at the lowest point, not rising very far into the atmosphere. HFC gases are singularly unreactive, and would decompose very slowly, if at all. Perhaps most likely is that the gaseous form would be adsorbed onto clay particles, and rendered harmless.
The capabilities of these molecules to absorb heat and give up that heat energy, which gives them such value as a refrigerant, may trap some heat for a short while, but when the conditions are reversed, it all comes to a zero-sum, as much as is absorbed is given back to the environment. These compounds do NOT concentrate heat energy, they only transfer it from one point to another.
Most of these highly paid “consultants” do not have a very good grasp of either physics or chemistry.
The most important “greenhouse gas” of them all? Water vapor. Vastly more important all by itself than all the other “greenhouse gases” put together.