Following the publication of alarming news regarding the potential danger of using HFO-1234yf in Mobile Air Conditioning (MAC), an independent expert puts HFO-1234yf risks into perspective.
HFO-1234yf is indeed about 20,000 times less flammable than propane; it doesn’t ignite when in contact with a heated plate at 800 C, nor in a welding torch.
The release of HF produced by its incineration would be even lower than in the case of HFC-134a, used extensively up to now in millions of cars worldwide. If there would have been a real risk, then it would have already been identified with vehicles equipped with HFC-134a.
In addition, in the case of an auto fire, before HFO-1234yf would start burning, large quantities of toxic fumes would already have been emitted.
Source: (Après-vente-auto.com - In French)