In 1970, severe mercury poisoning, called Ontario Minamata disease, was discovered among Asubpeeschoseewagong First Nation and Wabaseemoong Independent Nations people, who lived near Dryden, Ontario. There was extensive mercury pollution caused by Dryden Chemicals Company’s waste water effluent in the Wabigoon-English River system. Because local fish were no longer safe to eat, the Ontario provincial government closed the commercial fisheries run by the First Nation people and ordered them to stop eating local fish. Previously it had made up the majority of their diet. In addition to the acute mercury poisoning in northwestern Ontario, Aamjiwnaang First Nation people near Sarnia, Ontario experienced a wide range of chemical effects, including severe mercury poisoning. They suffered low birth rates, skewed birth-gender ratio, and health effects among the population. This led to legislation and eventually the Indian Health Transfer Policy that provided a framework for the assumption of control of health services by First Nations people, and set forth a developmental approach to transfer centred on the concept of self-determination in health. Through this process, the decision to enter into transfer discussions with Health Canada rests with each community. Once involved in transfer, communities are able to take control of health programme responsibilities at a pace determined by their individual circumstances and health management capabilities.