The application of RNA interference (RNAi) to produce genetically engineered crops with improved agronomic, nutritional, industrial, and food-processing traits is becoming increasingly common. As new products approach commercialization, it is timely to consider whether the approach currently applied to the environmental risk assessment (ERA) of genetically engineered crops expressing novel proteins remains appropriate for the ERA of genetically engineered plants utilizing RNAi approaches. This question was the subject of the conference “Problem Formulation for the Environmental Risk Assessment of RNAi Plants” convened by the Center for Environmental Risk Assessment (CERA), ILSI Research Foundation June 1-3, 2011. The objectives of the conference were:

1. To share information about current applications of RNAi for genetically engineered plants;
2. To use case studies to explore whether problem formulation for RNAi plants leads to new or additional risk hypotheses when compared with non-RNAi plants expressing similar traits, or if new risk assessment methodologies are necessary.

This report summarizes the proceedings of the conference, including presentations, case studies, a summary of discussions, and the points of consensus agreed by the participants.