The amended Toxic Substances Control Act (TSCA) has ushered in new developments in testing strategies. In March 2017, Andre E. Nel, Ph.D. (Division of NanoMedicine, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California (UCLA); California NanoSystems Institute, UCLA (CNSI)) and Timothy F. Malloy (CNSI; UCLA School of Law; UCLA Center on Environmental and Occupational Health) published Policy reforms to update chemical safety testing: TSCA reform empowers EPA to use modernized safety testing in the United States, in the Journal Science. This article discusses this new “paradigm” in testing, which it states relies “largely on nonanimal, alternative testing strategies (ATS), uses mechanism-based in vitro assays and in silico predictive tools for testing chemicals at considerably less cost.” There are technological and institutional challenges, however, that the article addresses, but the authors state they hope to provide a “cautious but hopeful assessment of this intersection of law and science.”
The article describes five iterative components that make up the elements of ATS: conceptual pathways; biomolecular events; screening and modeling; integrating evidence; and regulatory applications. These components work together to inform four types of regulatory decisions: “screening to identify chemicals and nanomaterials for more extensive testing and evaluation; ranking or prioritization for further action; qualitative or quantitative risk management in support of risk management; and comparative evaluation of the hazards and risks of different substances in support of safer design.”
Amended TSCA Section 4(h)(2) implements alternative testing methods to “promote the development and timely incorporation of new scientifically valid test methods and strategies that are not based on vertebrate animals,” and Section 4(h)(2)(A) directs EPA, by June 2018, to develop a strategic plan that will promote the development and implementation of alternative test methods and strategies to reduce, refine or replace vertebrate animal testing and provide information of equivalent or better scientific quality and relevance for assessing risks of injury to health or the environment of chemical substances or mixtures….”
The article states that while the amended statute seems to be only “procedural in nature” in terms of the implementation of ATS, as the statute compels EPA to facilitate development of ATS but does not obligate the agency to adopt it, two factors bode well for ATS implementation: (1) various EPA offices as well as its partner entities are “already engaged in bringing ATS into the regulatory context”; and (2) as amended TSCA mandates EPA to prioritize chemicals already in the marketplace for safety evaluations, by “specified enforceable deadlines,” which incentivizes the broader EPA chemical regulatory program to “adopt ATS for prioritization and subsequent risk evaluation of chemicals deemed high priority.” The article references EPA’s Office of Research and Development (ORD), the Office of Science Coordination and Policy (OSCP), the new chemical review program, and EPA’s partner entity the National Toxicology Program Interagency Center for the Evaluation of Alternative Toxicological Methods as those entities engaged in ATS implementation.