Ontario Minamata disease is a neurological syndrome caused by severe mercury poisoning. It occurred in the Canadian province of Ontario, in 1970, and severely affected two First Nation communities in Northwestern Ontario following consumption of local fish contaminated with mercury, and one First Nation in Southern Ontario due to illegal disposal of industrial chemical waste. The disease was named after the infamous case of severe mercury poisoning in the fishing community of Minamata, Japan, which became known as Minamata disease because it devastated only the residents of the community.