[Environmental risk, health and justice: the protagonism of affected populations in the production of knowledge].

This article discusses the role of populations affected by environmental injustice situations in the production of knowledge about environmental health stemming from inequalities and discrimination in the distribution of risks and benefits of economic development. Special attention is given to the epistemological and political limits to producing knowledge and alternatives that enable advances in building more just and sustainable societies are highlighted. Based on a broader view of health, the limits of scientific approaches are called into question by acknowledging the importance of local knowledge are discussed, either to analyze environmental risks or their effects on health, including epidemiological studies. These limits are linked primarily to the concealment of conflicts and uncertainties, the lack of contextualization of exposure to risk and effects on health, as well as the difficulties of dialogue with the communities. The article also presents contributions and advances presented by environmental justice movements. The conclusion is that a constructivist, procedural and democratic perspective of confronting forms of knowledge and practices can guide the scientific production to benefit of environmental justice.