For Release: September 9, 2019

EPA has developed an interim process to review synergy data for mixtures of pesticide active ingredients and potentially incorporate that information into our ecological risk estimates. The interim process will be available for public comment on or before October 24, 2019 on regulations.gov in docket EPA-HQ-OPP-2017-0433.

EPA generally evaluates pesticide ecological risks based on toxicity information from studies conducted with single active ingredients. This is based on best available evidence on pesticide interactions and the expectation that those interactions are rare. More recently, patent claims of synergy against target pests have raised questions and concerns about the adequacy of estimating risk of each individual active ingredient alone, especially for products mixed prior to application or products containing multiple active ingredients. Synergy occurs when the combined effect of two or more active ingredients are greater than the sum of the effects the chemicals would have individually. EPA hopes this process will close the gap between patent claims and our ecological risk assessments.

The specific feedback EPA is looking for is included in section IV of the Federal Register notice. Based on feedback and our analysis of the results of this process, EPA will determine whether synergy data supporting patents is useful for our ecological risk assessments and whether we should modify the interim process.