The U.S. Environmental Protection Agency's Strategic Plan for Evaluating the Toxicity of Chemicals
Science and Technology Policy Council
To fulfill its mission to protect human health and the environment, EPA must evaluate the risks of adverse health effects resulting from exposure to chemicals in the environment. The traditional risk assessment approach relies heavily on data generated through the intentional dosing of experimental animals. While this approach has provided EPA with sound science to support regulatory decision making over the past several decades, EPA must address ever-increasing demands, including consideration of complex issues such as cumulative exposures, life-stage vulnerabilities, and genetic susceptibilities, not to mention the increasing number of chemicals and cost of toxicity testing. A new approach is proposed to address these demands, an approach based on the application of advances in molecular biology and computational sciences to transform toxicity testing and risk assessment practices.
EPA recently took the lead in commissioning the National Research Council (NRC) of the National Academies to develop a long-range vision for toxicity testing and risk assessment. Their 2007 report, Toxicity Testing in the 21st Century: a Vision and a Strategy, envisions a landmark transformation that focuses on identifying and evaluating "toxicity pathways," i.e., cellular response pathways responsible for adverse health effects when sufficiently perturbed by environmental agents under realistic exposure conditions.
To build upon the transformative changes advocated in the NRC document, while ensuring an internally coordinated and integrated approach, EPA established a cross-Agency workgroup under the auspices of its internal Science Policy Council. This workgroup produced The U.S. Environmental Protection Agency's Strategic Plan for Evaluating the Toxicity of Chemicals that provides a framework for EPA to comprehensively move forward to incorporate this new scientific paradigm into future toxicity testing and risk assessment practices.
This new paradigm has the potential to address increasingly complex issues that EPA faces in evaluating environmental contaminants for risks to human health and the environment. For example, it is expected to create more efficient and cost-effective means to screen and prioritize for further assessment the tens of thousands of chemicals that are already found in the environment. The new paradigm should facilitate evaluating the susceptibility of different life-stages and genetic variations in the population, understanding the mechanisms by which toxicity occurs, and considering the risks of concurrent, cumulative exposure to multiple and diverse chemicals, while at the same time significantly reducing reliance on animal testing for assessing human risk.
This Strategic Plan is centered on three interrelated components: (1) the use of toxicity pathways identification and use of this information in screening and prioritization of chemicals for further testing; (2) the use of toxicity pathways information in risk assessment; and (3) the institutional transition necessary to implement such practices across EPA. This Strategic Plan describes an ambitious and substantive improvement in the efficiency and effectiveness of the process by which environmental pollutants are evaluated for toxicity and risk.
External Peer Review Comments on the External Review Draft Strategic Plan for the Future of Toxicity Testing and Risk Assessment at the U.S. Environmental Protection Agency (PDF) (14 pp, 62KB,About PDF)EPA Response to External Peer Review Comments on the External Review Draft Strategic Plan for the Future of Toxicity Testing and Risk Assessment at the U.S. Environmental Protection Agency (PDF) (18 pp, 79 KB,About PDF)
Memorandum of Understanding on High Throughput Screening, Toxicity Pathway Profiling, and Biological Interpretation of Findings between EPA, the National Toxicology Program, and the NIH Chemical Genomics Center (2008)