METHANESULFONYL FLUORIDE is corrosive, toxic liquid. Vigorous reaction with water, steam, alkali. A dangerous storage hazard. On contact with moisture METHANESULFONYL FLUORIDE produces highly corrosive and toxic fumes of hydrogen fluoride gas. When heated to decomposition METHANESULFONYL FLUORIDE emits toxic fumes of fluoride, and oxides of sulfur [M. K.]. May react vigorously or explosively if mixed with diisopropyl ether or other ethers in the presence of trace amounts of metal salts [J. Haz. Mat., 1981, 4, 291].