Frontmatter -- Acknowledgments -- Acknowledgment of Review Participants -- Preface -- Abbreviations -- Contents -- Public Summary -- Summary -- 1 Introduction -- 2 General Considerations of Uncertaintyand Variability, Selection of DoseMetric, and Dose-Response Modeling -- 3 Toxic Equivalency Factors -- 4 Exposure Assessment -- 5 Cancer -- 6 Noncancer End Points -- 7 Review of Risk Characterization -- 8 Conclusions and Recommendations -- References -- A Biographical Information onCommittee Members -- B EPA's 2005 Guidelines forCarcinogen Risk Assessment.