fire-resistive, fire-resisting, fire-resistant adj. Not able to burn or able to burn only with difficulty. (Narrower terms: noncombustible (vs. combustible), incombustible)
... what I shall be," returned Joe, with sudden energy. "Since you are a paper expert I may be able to set you another task besides that of showing me the latest thing in fire-resisting liquids. Yes, I may want your services ... — Joe Strong The Boy Fire-Eater - The Most Dangerous Performance on Record • Vance Barnum