Niigata Minamata Disease: From 1965 to the Present—Voices That Remain Along the Agano River

Niigata Minamata Disease is a case of organic mercury poisoning that was officially confirmed in May 1965 in the lower reaches of the Agano River. Professors Tadao Tsubaki and Yoshiaki Ueki of Niigata University and their colleagues reported cases of mercury poisoning of unknown cause to Niigata Prefecture, and in June of that year, it was announced that there were seven patients, two of whom had died. Subsequently, the government issued an official statement in 1968 concluding that the cause was methylmercury compounds—a byproduct of the acetaldehyde manufacturing process at Showa Denko’s Kanose Plant—which had been discharged into the Agano River and accumulated in the human body through the consumption of fish and shellfish. The Agano River had long been deeply intertwined with the lives of local residents; fish from the river once sustained daily meals, and the river water was used for cooking and laundry. The mercury contamination not only damaged people’s health but also left deep scars on the custom of eating river fish, the fishing industry, and the bonds of trust within the local community. In 1967, patients filed a lawsuit against Showa Denko, and the plaintiffs prevailed in the first lawsuit in 1971. Litigation regarding certification and compensation continued thereafter, and the Niigata Minamata Disease case became more than just a medical issue—it evolved into a case that continues to raise questions about corporate responsibility, the government’s response, and the rights of victims of environmental pollution. Though the waters of the Agano River flow gently, its banks hold a long-standing memory—one that passes down the stories of the victims and serves as a reminder to prevent such pollution from ever happening again.