with any product in an aerosol can there is a propellant. some propellants are simple like carbon dioxide for an air duster can. other propellants are designed like whipped cream with nitrous oxide. when a food manufacturer chooses a propellant it needs to not damage the food item. its safety and use is depending on you to read the label. look up the propellant, perhaps butane or others, on Wikipedia for the very specific answer you seek. some propellants are flammable and you must read the labels before using any aerosol. it may be just as easy to use a whipped butter or melt some cold butter in the microwave for easiest spreading on the frying pan. tip: if you are making grilled cheese, use the buttered bread to spread the butter on the pan.
