Tosoh Corp. engages in the manufacture and sale of basic chemicals, petrochemicals, fine chemicals, and specialty products. It operates through the following segments: Petrochemicals, Chlor-alkali, Specialty, Engineering, and Other. The Petrochemical segment offers olefins and polymers. The Chlor-alkali provides caustic soda, vinyl chloride monomer, polyvinyl chloride, high-performance polyurethane, organic chemicals, urethane raw materials, and cement. The Specialty segment handles inorganic or organic fine product, measurement and diagnostic products, electronic materials that include quartz glass and sputtering target. The Engineering segment deals with water treatment equipment and construction. The Other segment manages transportation and warehousing, inspection and analysis, and information processing businesses. The company was founded on February 11, 1935 and is headquartered in Tokyo, Japan.