Current headlines tell us there is a “war on science,” focused particularly keeping scientists of the Environmental Protection Agency (EPA) closely in check by those who want to contain federal environmental policies. But the history of science in the EPA tells a more complicated story of how science, in becoming central to the identity of federal bureaucracies, has long been evolving under a variety of pressures to maintain its status as a constitutive element of the agency’s legitimacy. In this CSPO Conversations breakfast seminar, David Demortain (INRA) will discuss his forthcoming book, The Science of Bureaucracy. Risk Decision-Making and the US Environmental Protection Agency. The EPA has shaped the science of risk-based decision-making since its inception. The agency, it appears, did not embrace science under the pressure of risk scientists and industry groups advocating “sound science”, or other such universal standard of rationality. On the contrary, it evolved various models of rational decision-making, drawing from the expertise of allied toxicologists, biostatisticians, economists, engineers and other specialists of decision-making. From “probabilistic cancer risk assessment” to “risk ranking”, in forgoing methods of “risk communication” and more recent integrated science assessments, it forged these techniques to respond to the successive contestations of its action and of environmental issues. The rise and fall of these techniques in the agency reflect the difficulty to govern the environment in the face of deep political fractures about the value of preserving it.