 On 26 September 1968, the government announced its official conclusion as to the cause of Niigata Minamata disease.The report said, although "the circumstances of the poisoning are extremely complex, and they are difficult to reproduce", the mercury had probably been discharged from the Kanose plant over a long period of time.However, the report did not rule out other causes and Showa Denko's president, Masao Yasunishi, insisted the company was not the cause of the outbreak.