This paper examines normative and political aspects of the peer review, scientific consensus and public policy processes related to harmful algal blooms of Pfiesteria in estuarine waters of North Carolina and Maryland in the 1990s. After laying out a brief science and policy case history, the tension between the scientific consensus and public policy processes in this case is analyzed in terms of conflicts between scientific norms, public values and political expediency. The relationship between scientific consensus and public policy in general is then questioned in light of this case.