Continuing Assistance to the National Institutes of Health on Preparation of Additional Risk Assessments for the Boston University NEIDL, Phase 3, the fifth in a series of reports about the proposed facility, provides further technical input on the scope and design of any additional studies that may be needed to assess the risks associated with the siting and operation of the NEIDL. This report presents comments and questions on a "90 percent", or penultimate, draft of the revised risk assessment. According to the report, the "90 percent" draft of the risk assessment is a substantial improvement over past documents reviewed. Additionally, the report makes recommendations to improve the version that is ultimately prepared for public comment.