Niigata Minamata Disease and Showa Denko

Niigata Minamata Disease is an organic mercury intoxication prevailed in the Agano River area in central part of Niigata Prefecture in 1950s and 1960s. Many patients have suffered from the disease until today, and some of them died of it in extreme agony. This disease was caused by methyl mercury from Kanose Factory of Showa Denko which produced acetaldehyde as its main product in terms of limestone based chemical technology. Discharged methyl mercury was stored and condensed in plankton, aquatic insects and fish of the river and was eaten by many people and made Niigata Minamata Disease patients. Some of them presented a case to Niigata District Court in 1967 and won the case in 1971. Niigata Minamata Disease has scarcely been of research topics in social science areas in spite of many studies in chemical and medical areas. This article may be a challenge in this tendency. Two research steps are taken in this research: one step is physical accounting approach for historical examination of Niigata Minamata Disease and its patients and the other step is external environmental accounting approach about disclosure of compensation in annual reports. Conclusions are: a) Patients had once spent normal lives but suffered from a disease of mercury intoxication. Their geographical distribution is so wide ranging from the mouth of the Agano River to the area of 60km upstream. There were no apologies to them and compensation was paid very late. b) Showa Denko has denied any involvement and responsibility on Niigata Minamata Disease. External statement of opinions was practiced by writing additional descriptions of “Case of Methyl Mercury Intoxication around the Agano River< in its annual reports. No cares were paid on minus product which comes with positive products in manufacturing processes but sales increase in terms of new technological innovation was consistently kept. c) Compensation was 26,886 yen million in total which was disclosed in sections of non operational actions or outside management policies: Section of Decrease of Deferred Profit Surplus, Statement of Surplus, and Section of Extraordinary Loss, Statement of Income, in response to changes of Financial Statements Regulation (cf. Appendix 2)