Various inorganic borates are known to be useful as fire retardants for materials such as wood, paper, cloth and organic polymers. For example, O'Shawnessy U.S. Pat. No. 3,897,387 describes the use of calcium or magnesium mineral borates as fire retardant agents for organic materials such as plastics, rubber and cellulosic material. Woods U.S. Pat. No. 3,816,307 described the use of Group I metal or ammonium borates having an average particle size of 0.1 and 25 microns as fire retardants for various plastic materials. Gouinlock U.S. Pat. No. 3,385,819 discloses the use of sodium tetraborate in combination with a polyhalogenated cyclopentadiene as a fire retardant for polymeric compositions. Woods et al U.S. Pat. No. 3,718,615 describes the use of a specific hydrated zinc borate as a fire retardant for halogen containing polymers. According to Schwarez et al. U.S. Pat. No. 3,560,441, halogenated polymers can be flame retarded by use of a glass formed by heating antimony trioxide with various inorganic materials including sodium borates. Japanese Patent Disclosure No. 1977-37947 describes preparation of a filler for fire resistant building materials by reacting sulfuric acid with borax in the presence of a porous inorganic refractory aggregate such as perlite. The resultant product is a refractory aggregate impregnated with a mixture of sodium sulfate and boric acid which can be used as a fire resistant filler for incorporating in polyurethane. Other patents such as Draganov U.S. Pat. No. 3,983,040, Blasius U.S. Pat. No. 4,156,654, Christianson et al. U.S. Pat. No. 4,172,804 and Quinto U.S. Pat. No. 4,173,666 describe the reaction of metal borates such as borax or the borate ores with sulfuric acid to form a granular composition for use as a fire retardant for cellulosic materials, especially insulation made from waste newspapers.