The paper, which reports the findings of a case study of an environmental dispute, focuses on the role of the key players and the way in which they interacted with the underlying science. A model is proposed that lays out some of the dimensions of the complexity of public involvement, of the understandings of the science pertinent to such socio-scientific issues, and of the way knowledge of science is represented and disseminated in such issues. The analysis focuses on the value of local knowledge in framing and engaging with the issue, on the distinction between generative and evaluative engagement, and on the type of knowledge that proved central for engagement. The implications for science education and notions of scientific literacy are discussed.