The Canadian oil industry operates predominantly on First Nations treaty lands using in situ methods of bitumen extraction to feed an insatiable global appetite for oil, resulting in environmental contamination on an immense scale. The nature of this contamination of groundwater, plants, animals, and human health in northern Alberta remains contested. This industrial site has been extracting bitumen from a geographical area larger than 79,000 km2 since 1967, yet the scientific knowledge produced about the health and environmental effects of this industry in the last 49 years has been largely industry-sponsored and has not allocated epistemic space for Indigenous Traditional Knowledge about the consequences of industrial contamination for animals, plants, soil, waterways, and human health. Through an inquiry into the historical and present-day dynamics among actors engaged with knowledge production connecting landscape, human health, geology and oil extraction in Canada, this project examines the fluctuating ways that science relates to knowledge practices that challenge its otherwise stable norms and paradigms. How has the Canadian federal government managed its duty to protect people living on treaty lands from the risks posed by industry and environmental contamination? How have First Nations communities collaborated with toxicologists to render evidence of the harms that follow from environmental contamination into a form that will be recognized by federal government policymakers? What are the epistemic consequences of such collaborations that aim to preserve the autonomy of multiple knowledges? Can such projects enact a democratic collaboration in which neither distinct form of knowledge is appropriated or assimilated? This project examines the generative possibilities of methodologies for public participation in science that actively mobilize dissensus between incommensurable knowledges—rather than attempting to smooth over epistemic tensions—with the aim of developing new ways of producing evidence of harm in a political context in which extensive resources are being directed towards the silencing of such forms of evidence. -- Image caption: Gladys Scott and Margery Rowbotham testing oil and gas samples at the Alberta Research Council, January 13, 1959. Library and Archives of Canada, MIKAN 4365726.