Japan Nitrogenous Fertilizer Company (Nichitsu/Chisso)

Japan Nitrogenous Fertilizer Company (日本窒素肥料株式会社), commonly known as Nichitsu, was a major Japanese chemical conglomerate founded by industrialist Noguchi Shitagau. It began with Sogi Electric, which Noguchi, an electrical engineer, set up in Kagoshima Prefecture in 1906; the firm used surplus hydroelectric power to make calcium carbide at Minamata in Kumamoto and in 1908 merged with Japan Carbide to become Nichitsu. It introduced the cyanamide process and later synthetic ammonia, opening a plant at Nobeoka, Miyazaki, in 1923, and grew into one of the "new zaibatsu".

The company aggressively expanded into colonial Korea in the late 1920s, where power and land were cheap. Backed by the Government-General of Korea, it developed hydroelectric power on the Pujon and Changjin rivers in the north and in 1927 founded Chōsen Nitrogenous Fertilizer, establishing the massive Hungnam chemical complex that became the largest industrial facility on the Korean Peninsula, later adding explosives, oils and fats and light-metal plants. Nichitsu also took part in the Sup'ung Dam on the Yalu, which began generating in the early 1940s. According to this site's earlier text, the company controlled 12 hydroelectric power stations and employed 45,000 workers at Hungnam alone.

In wartime the Hungnam plants produced ammonium sulphate, explosives feedstocks and aviation-fuel-related products for the military. The workforce was largely Korean, with marked ethnic discrimination in pay and rank, and a camp for Allied prisoners of war was located at Hungnam. Noguchi died in 1944. After Japan's defeat in 1945, Nichitsu lost all its Korean and other overseas assets; Hungnam was taken over by Soviet forces and then by the North Korean state. In Japan the group was broken up under zaibatsu dissolution, giving rise to companies such as Asahi Kasei and Sekisui Chemical.

The Minamata plant was rebuilt and relaunched in 1950 as Shin Nihon Chisso Hiryō, renamed Chisso in 1965. Methylmercury formed in its acetaldehyde process had been discharged untreated into Minamata Bay from around 1932. In May 1956 Dr Hosokawa Hajime of the company hospital reported cases of an unexplained neurological illness to the public health office — the official recognition of Minamata disease — but the government did not attribute it to the factory's effluent until 1968. The company later became notorious as Chisso Corporation, responsible for the Minamata mercury poisoning disaster; burdened with compensation, it transferred its businesses to a subsidiary, JNC, in 2011 and became a holding company responsible for redress.