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ICCVAM Biennial Report 2018-2019

Biennial Progress Report 2018-2019 Interagency Coordinating Committee on the Validation of Alternative Methods

Evaluation of a Proposed Approach to Refine Inhalation Risk Assessment for Point of Contact Toxicity

EPA conducts human health risk assessments to evaluate the potential health effects of pesticides and toxic chemicals based on the use pattern or conditions of use. For evaluating effects via the inhalation route, data are required from subchronic inhalation toxicity studies using animals, usually rats. However, human and rat respiratory tracts differ to an extent that may affect the ability of animal test results to correctly predict effects in humans. It is also challenging to accurately establish a no-observed-adverse-effect concentration from animal studies. To that end, Syngenta Crop Protection proposed using a 3D in vitro inhalation toxicity model to derive a point of departure for inhalation toxicity for the fungicide chlorothalonil. The EPA Office of Pesticide Programs and Office of Pollution Prevention and Toxics provided feedback to Syngenta during development of the proposed approach. Results of the case study were evaluated by the Scientific Advisory Panel for the Federal Insecticide, Fungicide, and Rodenticide Act at their December 2018 meeting. The panel’s report, issued in April 2019, expresses support for the approach and makes recommendations for improvements. EPA has continued to work with Syngenta to address the panel’s recommendations.