The U.S. Environmental Protection Agency Strategic Plan for Evaluating the Toxicity of Chemicals

Abstract

In the 2007 report Toxicity Testing in the 21st Century: A Vision and a Strategy, the U.S. National Academy of Sciences envisioned a major transition in toxicity testing from cumbersome, expensive, and lengthy in vivo testing with qualitative endpoints, to in vitro robotic high-throughput screening with mechanistic quantitative parameters. Recognizing the need for agencies to partner and collaborate to ensure global harmonization, standardization, quality control and information sharing, the U.S. Environmental Protection Agency is leading by example and has established an intra-agency Future of Toxicity Testing Workgroup (FTTW). This workgroup has produced an ambitious blueprint for incorporating this new scientific paradigm to change the way chemicals are screened and evaluated for toxicity. Four main components of this strategy are discussed, as follows: (1) the impact and benefits of various types of regulatory activities, (2) chemical screening and prioritization, (3) toxicity pathway-based risk assessment, and (4) institutional transition. The new paradigm is predicated on the discovery of molecular perturbation pathways at the in vitro level that predict adverse health effects from xenobiotics exposure, and then extrapolating those events to the tissue, organ, or whole organisms by computational models. Research on these pathways will be integrated and compiled using the latest technology with the cooperation of global agencies, industry, and other stakeholders. The net result will be that chemical toxicity screening will become more efficient and cost-effective, include real-world exposure assessments, and eliminate currently used uncertainty factors.

Acknowledgments

The U.S. Environmental Protection Agency through its Office of Research and Development funded and managed the research described, and this article has been subjected to agency review and approved for publication. Reference to commercial products or services does not constitute endorsement. We gratefully acknowledge the contributions of U.S. Environmental Protection Agency (U.S. EPA) Future of Toxicity Testing Workgroup members, including Marcia Bailey, Arden Calvert, Laurel Celeste, Vicki Dellarco, Scott Jenkins, Gregory Miller, Nicole Paquette, Santhini Ramasamy, and William Sette. We are also thankful for the contributions of Katherine Anitole, Hugh Barton, Norman Birchfield, Michael Brody, Rory Conolly, David Dix, Stephen Edwards, Andrew Geller, Karen Hamernik, Jean Holmes, Richard Judson, Thomas Knudsen, Julian Preston, Kathleen Raffaele, Ram Ramabhadran, James Samet, Patricia Schmieder, Banalata Sen, Imran Shah, Linda Sheldon, John Vandenberg, and Maurice Zeeman of U.S. EPA. We also thank the external peer reviewers of the original report, John R. Bucher, George Daston, Daniel Krewski, and Martin Stephens, for their comments and suggestions. D. Krewski is the Natural Sciences and Engineering Research Council of Canada Chair in Risk Science at the University of Ottawa.

Notes

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