Questions have been raised about the benefits and risks of oxygenated gasoline and reformulated gasoline ("oxyfuels"). This document highlights areas of information that would improve scientific understanding of the impacts of these fuels on the
environment and public health. It emphasizes the importance of obtaining data to support quantitative assessments of oxyfuels in comparison to conventional fuels. In addtion to providing some background information and outlining a general framework for comparative risk assessments of fuels, the document briefly summarizes currently available information and then focuses
on work that is now underway or planned and on data needs that remain to be filled. It is intended that this broad statement of information needs will facilitate the identification and prioritization of research and comparative assessment efforts on oxyfuels and conventional fuels.