Abstract: The invention provides an efficient and reliable method for extinguishing fire of a chlorosilane compound, which is a notoriously dangerous inflammable material in respect of the difficulty of extinguishment of fire thereof, by sprinkling a specific porous inert silica based or silica-alumina based powder defined by the content of silica or overall content of silica and alumina as well as various parameters as a powdery material followed by spraying an aqueous solution of sodium chloride, potassium chloride or calcium chloride. The fire extinguishing efficiency can be further enhanced when the sprinkled powder is a blend of the above defined porous powder and a specific silica sand in a specific proportion. When the sprinkled powder is such a binary blend, considerably good results can be obtained even by omitting the step of spraying of the aqueous salt solution.

Abstract: The invention provides a rapid and reliable method for extinguishment of fire on a chlorosilane compound such as trichlorosilane which is hardly extinguishable once set on fire by any conventional fire-extinguishing methods. The inventive method comprises sprinkling an inert siliceous powder composed of porous particles of specified silica or silica-alumina content having a specified particle diameter, pore diameter and porosity over the surface of the burning chlorosilane compound. The efficiency of fire-extinguishment can further be enhanced when sprinkling of the porous siliceous powder is followed by spraying of water or a highly halogenated hydrocarbon compound, e.g., monobromo monochloromethane and carbon tetrachloride, over the siliceous powder.