If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.


Endocrine Disruptors

EPA to rebuild endocrine disruptor program

US agency to request data on estrogen, androgen effects for 30 high-priority pesticides

by Britt E. Erickson
October 31, 2023


After decades with little progress, the US Environmental Protection Agency plans to revamp an effort to evaluate pesticides for potential effects on estrogen, androgen, and thyroid hormones. The move follows a late-2022 lawsuit from environmental and farmworker groups and a scathing 2021 report from the EPA’s Office of Inspector General over endocrine disruptor testing delays.

By the numbers


Pesticides under review for reregistration at the US Environmental Protection Agency.


Number with sufficient animal data to exclude from additional testing for estrogen and androgen effects.


Number deemed high-priority because they showed estrogen or androgen effects in high-throughput assays and computational modeling.


Number deemed low-priority because they showed no estrogen or androgen effects in high-throughput assays and computational modeling.


Number with no animal or high-throughput data on estrogen and androgen effects.

Source: US Environmental Protection Agency.

The EPA’s beleaguered Endocrine Disruptor Screening Program, created in 1998 to comply with changes to US food and drinking water laws, has been on hiatus with no “effective internal controls in place since 2015,” according to the 2021 report.

To get the program back on track, the EPA will request data from manufacturers for 30 pesticides that showed estrogen or androgen activity when agency scientists tested them with high-throughput assays and computational modeling, the agency announced on Oct. 26.

The 30 high-priority pesticides are part of a group of 403 pesticides that the EPA is reviewing for safety as part of a routine reregistration process that happens every 15 years.

Of the 403 pesticides, only 86 have data on estrogen and androgen activity in animals that is sufficient to exclude them from further testing, the EPA says. The agency deemed 161 of them to be low-priority for testing because they showed no estrogen or androgen activity using high-throughput assays and computational modeling. The EPA has yet to determine whether the remaining 126 pesticides, which have not been tested with the high-throughput modeling approach and for which the EPA does not have animal data, need additional testing.

“This plan is a major milestone in our efforts to ensure that pesticide decisions continue to protect human health,” Jake Li, the EPA’s deputy assistant administrator for pesticide programs, says in a statement. “Starting with our highest priority chemicals, EPA will communicate more transparently our endocrine findings for humans, pulling from existing data when possible, and requesting new data when necessary to evaluate potential estrogen, androgen, and thyroid effects.”

The pesticide industry, which has long pushed back against expensive, time-consuming animal tests for endocrine disruption, says it welcomes the opportunity to inform the EPA as it advances the endocrine disruptor program. “Each pesticide approved by EPA for use undergoes hundreds of tests to help ensure that the product will not have any unreasonable effect on human health or the environment,” CropLife America, a trade association, says in an emailed statement.

The EPA will accept public comments on the new strategy until Dec. 26.



This article has been sent to the following recipient:

Chemistry matters. Join us to get the news you need.