As part of the National Research Council (NRC) initiative on biotechnology, the Board on Biology will conduct a study for the Biotechnology Science Coordinating Committee (BSCC) of the Federal Coordinating Council for Science, Engineering and Technology to establish what properties of microorganisms and plants and the environments into which they will be introduced should be considered in determining levels of possible environmental risk. The proposed study is intended to provide guidance to both investigators and regulators in evaluating planned introductions of microorganisms and plants.