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In the 1990's, some scientists proposed that certain chemicals might be disrupting the endocrine systems of humans and wildlife. A variety of chemicals have been found to disrupt the endocrine systems of animals in laboratory studies, and compelling evidence shows that endocrine systems of certain fish and wildlife have been affected by chemical contaminants, resulting in developmental and reproductive problems.


Based on this and other evidence, Congress passed the Food Quality Protection Act and the Safe Drinking Water Act (SDWA) Amendments in 1996 requiring that EPA screen pesticide chemicals for their potential to produce effects similar to those produced by the female hormones (estrogen) in humans and giving EPA the authority to screen certain other chemicals and to include other endocrine effects. Based on recommendations from an Advisory Committee, EPA has expanded the EDSP to include male hormones (androgens) and the thyroid system, and to include effects on fish and wildlife.

This site provides information about EPA's approach toward and progress on screening chemicals for endocrine effects. If you are new to the topic of endocrine disruption you might want to read the EDSP Overview and EDSP Primer for more detailed information on the endocrine system and the EDSP.

Tier 1 Screening Results for 52 Chemicals

On July 30, 2015, EPA released its reviews of the Tier 1 screening assay results for the first 52 pesticide chemicals (active and inert ingredients) in the Endocrine Disruptor Screening Program (EDSP). This is an important step in a multi-step process to protect public health and the environment by ensuring that exposure to chemicals does not result in adverse effects that can occur from the disruption of hormones. The Tier 1 screening data are the best way to determine whether a chemical has the potential to interact with the endocrine system and requires more thorough testing.

EDSP Announces Use of Cutting-Edge Technology for Endocrine Disruptor Screening

On June 18, 2015, EPA announced a plan for incorporating validated high throughput assays and a computational model into the Endocrine Disruptor Screening Program (EDSP) to screen chemicals for their ability to interact with the endocrine system. This proposed new method would serve as an alternative for three of the eleven current assays in the EDSP Tier 1 screening battery (estrogen receptor binding, estrogen receptor transactivation, uterotrophic). EPA has partial screening results for over 1,800 chemicals that have been evaluated using high throughput assays and a computational model for the estrogen receptor pathway. In the future, EPA plans to develop alternative screening methods for the remaining eight Tier 1 assays using further advancements in high throughput assays and computational models. Use of these alternative methods will accelerate the pace of screening, decrease costs, and reduce animal testing. In addition, this approach advances the goal of providing sensitive, specific, quantitative, and efficient screening using alternative test methods to some assays in the Tier 1 battery to protect human health and the environment.

List of EDSP Universe of Chemicals

Developed in response to recommendations from the Office of Inspector General, The EDSP Universe of Chemicals and General Validation Principles (17 pp, 198K, About PDF) document provides background on the universe of chemicals for endocrine disruptor screening and testing and an overview of the general validation principles that will be used to evaluate computational toxicological methods for chemical prioritization.

In November 2012, EPA released the List of EDSP Universe of Chemicals (177 pp, 2.54M, About PDF). This document is updated as new information becomes available. The List of the EDSP Universe of Chemicals contains approximately 10,000 chemicals as defined under FFDCA and SDWA 1996 amendments, although not all of the chemicals are expected to undergo EDSP Tier 1 screening. The agency plans to prioritize these chemicals for screening by considering physical chemical properties, exposure, and an effect-based approach using advanced computational toxicological methods. These methods and tools will be evaluated using OECD validation principles for their utilization in chemical prioritization. This topic was the focus of a January 29-31, 2013, FIFRA Science Advisory Panel meeting.

Initial List of Chemicals for Screening

EPA announced the initial list of chemicals to be screened for their potential effects on the endocrine system (or Tier I testing) on April 15, 2009, and the first test orders were issued on October 29, 2009. Test orders are requests for data. Now that screening is underway, EPA is reviewing test order responses and making available the status or test order responses (PDF) (53 pp, 555K, About PDF) and/or any decisions regarding testing requirements.

EPA will use a two-tiered screening and testing process: Through Tier 1, EPA hopes to identify chemicals that have the potential to interact with the endocrine system. Through Tier 2, EPA will determine the endocrine-related effects caused by each chemical and obtain information about effects at various doses.

Endocrine disruptor screening is currently proceeding on three fronts: 1) developing and validating Tier 2 tests; 2) selecting chemicals for screening and testing; and 3) implementing the policies and procedures the Agency will use to require screening.

Second List of Chemicals for Screening

In November 2010, EPA developed a second list of chemicals for screening and draft policies and procedures for the Agency's use to require testing of chemicals for Tier 1 screening. On June 14, 2013, EPA issued a revised second list of chemicals and revised policies and procedures for screening SDWA chemicals, including the statutory requirements associated with and format of the test orders, as well as EPA's procedures for fair and equitable sharing of test costs and data confidentiality.

As of May 22, 2014, EPA has removed hydrazine and hydrochlorofluorocarbon (HCFC-22) from the Second List of Chemicals for Screening (PDF) (5 pp, 90K, About PDF) to allow for further consideration of their physical/chemical properties and/or occurrence in regards to whether these substances are appropriate candidates for testing in the EDSP under Safe Drinking Water Act authority at this time. The U.S. Court of Appeals for the Third Circuit granted EPA’s motion for voluntary partial vacatur and remand regarding these two chemicals.


Agrobacterium Radiobacter

EPA issued an order exempting the microbial pesticides Agrobacterium radiobacter (A. radiobacter) strains K84 and K1026 from the screening and testing requirements of the EDSP. EPA considered all the available scientific evidence and determined these specific microbial pesticides are not anticipated to produce any effects on the estrogen, androgen or thyroid hormone systems. The FFDCA authorizes the EPA to exempt biologic substances or other substances from EDSP requirements if they are not anticipated to produce an endocrine effect. See the administrative order exempting A. radiobacter under Docket ID. No. EPA-HQ-OPP-2009-0878-0009.

EDSP Comprehensive Management Plan

The EDSP Comprehensive Management Plan was developed by the EPA to provide strategic guidance to the EPA staff and managers participating in the internal activities associated with EDSP. The plan describes the technical review processes that will be used in implementing this program and how the agency intends to factor technology advancements into the program. The plan is flexible to allow opportunities to streamline and promote efficient processes. This EDSP Comprehensive Management Plan was developed as an internal EPA document, however, it is being made publicly available consistent with the EPA's transparency objectives. The agency anticipates that this management plan will be a living document and will be evaluated for revision on an annual basis.

Additional Information

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