A/C System: Combustibility
WARNING: This page is about a different car, the 2010 Volkswagen Passat and 2009 Volkswagen Passat. However, it is still accessible from the selected car via links, so may be relevant.
Refrigerant is non-flammable. It actually has a fire resistant or fire extinguishing effect. Refrigerant decomposes when exposed to flames or red-hot surfaces. UV light (occurring for example during electric welding) also causes refrigerant decomposition. The resultant decomposition products are toxic and are not to be inhaled. However, irritation of the mucous membranes provides an adequate and timely warning.