Endocrine Disruption

Endocrine Disruptor Screening Program (EDSP) Overview

Program Overview

The Endocrine Disruptor Screening Program (EDSP) uses a two tiered approach to screen pesticides, chemicals, and environmental contaminants for their potential effect on estrogen, androgen and thyroid hormone systems. The EDSP is outlined in two Federal Register Notices published in 1998.

The EDSP is mandated to use validated methods for the screening and testing chemicals to identify potential endocrine disruptors, determine adverse effects, dose-response, assess risk and ultimately manage risk under current laws. These methods or assays allow EPA to identify and characterize the endocrine activity (specifically, estrogen, androgen and thyroid) of pesticides, commercial chemicals, and environmental contaminants.

Program History

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 (FQPA), which amended the Federal Food, Drug, and Cosmetic Act (FFDCA), and the Safe Drinking Water Act (SDWA) Amendments in 1996. FQPA requires that EPA screen pesticide chemicals for their potential to produce effects similar to those produced by the female hormones (estrogen) in humans and gives EPA the authority to screen certain other chemicals and to include other endocrine effects.

In October 1996, under the authority of the Federal Advisory Committee Act (FACA), EPA chartered a scientific advisory committee -- the Endocrine Disruptor Screening and Testing Advisory Committee (EDSTAC) -- to advise EPA on establishing a program to carry out Congress's directives. The EDSTAC committee members were charged with developing consensus-based recommendations for a scientifically defensible screening program that would provide EPA the necessary information to make regulatory decisions about the endocrine effects of chemicals. Over the course of two years, EDSTAC members thoroughly reviewed and discussed scientific information and sought the opinion of other experts and members of the public. EDSTAC's Final Report was presented to EPA in September 1998.

View the interactive EDSP timeline for an overview of program milestones.

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EDSP Approach

The EDSP uses a tiered approach for screening chemicals. Under the tiered approach:

  • Tier 1 screening data is used to identify substances that have the potential to interact with the endocrine system. Chemicals that go through Tier 1 screening and are found to exhibit the potential to interact with the estrogen, androgen, or thyroid hormone systems will proceed to Tier 2 for testing.
  • Tier 2 testing data identifies any adverse endocrine-related effects caused by the substance, and establish a quantitative relationship between the dose and that adverse effect. The results of Tier 2 testing will be combined with other hazard information and exposure assessment on a given chemical resulting in the risk assessment. Risk assessments are used to inform risk mitigation measures, as necessary, and regulatory decisions concerning chemicals.

As the EDSP screening and testing requirements mature into routine evaluations, the Agency intends to utilize the pesticide registration review process as the framework for managing its responsibilities regarding the endocrine screening of pesticides, and intends to eventually incorporate these requirements routinely into the pesticide registration review process.

While EPA has discretionary authority to issue, at any time, testing orders requiring manufacturers to conduct Tier 1 assays, the Agency plans to assess the performance of the Tier 1 battery based on the test data received for the initial list (List 1) of chemicals before beginning to routinely issue orders to test additional chemicals. If EDSP data exist at the time of a pesticide’s registration review, the Agency will consider the data when it makes its Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) (3)(c)(5) finding under registration review.

Key components of the EDSP include:

  1. Assay Validation
  2. Chemical Selection/Prioritization
  3. Policies and Procedures
  4. Use of High Throughput Screening and Computational Models

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Public Participation

EPA has involved the public, stakeholders, and has coordinated with international organizations in implementing EDSP. In October 1996, under the authority of the Federal Advisory Committee Act (FACA), EPA chartered a scientific advisory committee -- the Endocrine Disruptor Screening and Testing Advisory Committee (EDSTAC) -- to advise EPA on establishing a program to carry out Congress's directives.

After EDSTAC completed its work and disbanded in 1998, EPA organized a Standardization and Validation Task Force (SVTF) consisting of representation from a broad range of sectors, including federal agencies, agrichemical companies, commodity chemical companies, and environmental and public health organizations to coordinate and conduct the scientific and technical work necessary to validate the screens and tests recommended by the EDSTAC.

In 2001, SVTF was replaced by the Endocrine Disruptor Methods Validation Subcommittee (EDMVS), a subcommittee of an Advisory Council (NACEPT) established under the Federal Advisory Committee Act. As a charter member and co-chair of the Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM), EPA followed the interagency validation framework in the development and refinement of assays to reduce animal use, refine procedures involving animals to make them less stressful, and replace animals where scientifically appropriate.

In addition to the ICCVAM approach to assay validation in the United States, EPA considered the European approach by the European Center for the Validation of Alternative Methods (ECVAM), as well as the international approach by the Organization for Economic Co-operation and Development (OECD) since some screening assays involved a collaborative validation effort with OECD.

In 2004, the Endocrine Disruptor Methods Validation Advisory Committee (EDMVAC) was formed to replace EDMVS. The EDMVAC continued to function like EDMVS by providing advice and recommendations to EPA on scientific and technical aspects of the Tier 1 screens and Tier 2 assays being considered for the Endocrine Disruptor Screening Program.

In 2007, the EDMVAC was disbanded, and the functions of this advisory committee were taken over by the Federal Insecticide, Fungicide, and Rodenticide Act Science Advisory Panel (FIFRA SAP). The Panel provides scientific advice, information, and recommendations to the EPA Administrator on pesticides and pesticide related issues as to the impact on health and the environment of regulatory actions. The FIFRA SAP will continue to evaluate relevant scientific issues, protocols, data, and interpretations of the data for the assays during the validation process. 

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