EPA Takes Strides to Strengthen Endocrine Disruptor Screening for Pesticides

The U.S. Environmental Protection Agency (EPA) on October 26, 2023, unveiled a comprehensive plan to improve the assessment of pesticides to quickly and effectively assess potential endocrine-disrupting effects in humans. This initiative will strengthen the Agency's ability to safeguard against such effects when making pesticide-related decisions under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) and to implement the Endocrine Disruptor Screening Program (EDSP) under Section 408(p) of the Federal Food, Drug, and Cosmetic Act (FFDCA).

Understanding Endocrine Systems and Disruptors

Endocrine systems, which regulate hormones in various living organisms, play a central role in processes ranging from development and reproduction to metabolism. Endocrine disruptors are chemicals that interfere with the natural functions of hormones. EPA established the EDSP in 1996 to evaluate how pesticides and other chemicals might affect the estrogen, androgen, and thyroid systems. However, challenges have hampered its effective implementation. EPA lacked efficient methods to rapidly test numerous chemicals for endocrine-disrupting effects and often did not provide clear explanations for collecting the necessary endocrine data.

The Path Forward

EPA's strategic plan involves using its FIFRA process to collect human health endocrine data to improve the efficiency of endocrine-related decision-making. The Agency will prioritize around 400 conventional pesticide active ingredients that are either being registered for the first time or are under registration review. In cases where existing data align with the findings of the FFDCA EDSP, EPA will use this information to expedite decisions and reduce the need for additional testing.

EPA is releasing a scientific paper to clarify which existing data can be used to support endocrine disruption findings. For 403 conventional pesticides, EPA has established sufficient estrogen and androgen data for 86 chemicals to make EDSP decisions regarding their potential effects on human systems. Additionally, 52 pesticide chemicals are now part of this plan, and EPA is communicating its final EDSP decisions regarding their potential effects on the human endocrine system.

Remaining Challenges

As the science on the human endocrine system, especially the thyroid, continues to evolve, EPA anticipates seeking scientific peer review in 2025 to assess advances and its current approach to thyroid assessments.

In the short term, EPA has identified 30 high-priority pesticides that require additional data on potential human estrogen and androgen effects. Preliminary data suggest that these pesticides may affect the endocrine system. The Agency is inviting the public to submit data or comments on these chemicals during a 60-day public comment period. To fill the remaining data gaps, EPA intends to issue FIFRA human health data requests for these pesticides in the spring of 2024. For a second group of 126 conventional pesticides with limited endocrine data, the Agency is seeking information to evaluate their endocrine data needs. Moreover, EPA will determine which of the 161 additional conventional pesticides will require updated endocrine data in the coming years during the registration review process.

The public comment period for this initiative opened on Friday October 27, and stakeholders are encouraged to submit their contributions via Docket EPA-HQ-OPP-2023-0474 at www.regulations.gov.