Review of U.S. EPA's ORD Staff Handbook for Developing IRIS Assessments

The U.S. Environmental Protection Agency's (EPA) Integrated Risk Information System (IRIS) program develops human health assessments that focus on hazard identification and dose-response analyses for chemicals in the environment. The ORD Staff Handbook for Developing IRIS Assessments (the handbook) provides guidance to scientists who perform the IRIS assessments in order to foster consistency in the assessments and enhance transparency about the IRIS assessment process. At the request of the EPA, this report reviews the procedures and considerations for operationalizing the principles of systematic reviews and the methods described in the handbook for determining the scope of the IRIS assessments, evidence integration, extrapolation techniques, dose-response analyses, and characterization of uncertainties. Table of Contents Front Matter Summary 1 Introduction 2 Overview of Organization and Content of the Handbook 3 Planning Assessments 4 Study Evaluation 5 Evidence Synthesis 6 Evidence Integration 7 Hazard Considerations and Study Selection for Deriving Toxicity Values References Appendix A: Committee Member Biosketches Appendix B: 2020 IRIS Handbook Organization and Contents and EPA Questions to the Committee Appendix C: Open Session Agendas