As products of the "new biotechnology," genetically modified organisms have provoked a wide-ranging risk debate on potential harm, especially from herbicide-tolerant crops. In response to this legitimacy problem, the European Community adopted precautionary legislation, which left open the definition of environmental harm. When the U.K. proposed Europe-wide market approval of a herbicide-tolerant oilseed rape, the proposal encountered dissent from some countries and environmentalist groups. Further debate on normative judgments became necessary to implement the precaution ary legislation. In dispute were several (...) regulatory boundaries—of administrative re sponsibility, causality, acceptability, and evidence. The boundary disputes expressed divergentframings of biotechnological risk, each with its implicit model of the socionatu ral order. In this way, the disputes can illuminate the sorts of risk framings that have already become embedded and standardized in other regulatory sectors. (shrink)