Endocrine Disruptor Screening Program
Universe of Chemicals and Validation Principles
November 2012 3 | Page
Later that year, the EPA published the EDSP Proposed Statement of Policy
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in which the agency stated
its concern about the endocrine disrupting potential of more than 87,000 chemical substances, including
pesticide chemicals (active and inert ingredients), commercial chemicals, cosmetics ingredients, food
additives, nutritional supplements and certain mixtures. The agency noted the impracticality of testing
87,000 chemicals. Furthermore, in order to ensure the EDSP screening and testing of these substances,
the authority would need to extend beyond FFDCA and SDWA and the effort would need to include
other federal agencies and departments. In recognition of the large volume of chemicals for potential
screening and the availability of new, advanced computational toxicological methods, the agency
announced the establishment of the National Center for Computational Toxicology (NCCT) to develop
high-throughput (HTP) assays for chemical prioritization and screening. The agency subsequently
proposed conducting HTP assays on approximately 15,000 chemicals captured in the EDSP universe of
chemicals domain (commercial chemicals produced in amounts greater than or equal to 10,000 pounds
per year and all pesticides).
In 1999, the EPA convened a joint meeting of the agency's Science Advisory Board (SAB) and Federal
Insecticide, Fungicide, and Rodenticide (FIFRA) Scientific Advisory Panel (SAP) to review the
proposed EDSP. By 1999, the agency concluded that the HTP and other computational toxicology tools
were not yet ready for regulatory implementation. The SAB/SAP concurred with this assessment and
expressed concerns regarding the ambitious scope of the 87,000 chemical universe for the EDSP.
Furthermore, the SAB/SAP advised that developing massive amounts of screening data, even on 15,000
chemicals, would not necessarily expedite the development of the appropriate underpinnings that the
agency needed before it proceeded with the screening of the large universe of chemicals anticipated to
be included in the EDSP. The panels recommended that the EPA not expand the set of agents beyond
those captured in FFDCA and SDWA until the agency developed or adopted validated systems and
provided clear decision criteria.
In September 2005, the agency published its approach for selecting chemicals for the initial round of
screening in the EDSP, effectively adopting the SAB/SAP's joint recommendations.
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In the approach,
chemicals were selected based on their relatively high potential for human exposure. The scope of the
first group included pesticide active ingredients and High Production Volume (HPV) chemicals used as
inert ingredients in pesticide formulations. This scope allowed the EPA "to focus its initial screening
efforts on a smaller and more manageable universe of chemicals that emphasizes the early attention to
the pesticide chemicals that Congress specifically mandated the EPA to test for possible endocrine
effects."
In the FY 2010 House Appropriations Committee Report,
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the committee directed the EPA to "publish
within one year of enactment a second list of no less than 100 chemicals for screening that includes
drinking water contaminants, such as halogenated organic chemicals, dioxins, flame retardants (PBDEs,
PCBs, PFCs), plastics (BPA), pharmaceuticals and personal care products." In response, on
November 17, 2010, the agency published a proposed second list of chemicals, including pesticides and
drinking water contaminants, for EDSP Tier 1 screening. The House committee also directed the EPA to
engage in a timely re-evaluation of the Tier 1 battery of assays, replacing outdated ones with updated,
more efficient screens that have been validated.
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63 Federal Register (FR) 71542-71568 (December 28, 1998), EDSP: Statement of Policy.
http://www.epa.gov/endo/pubs/122898frnotice.pdf
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70 FR 56449 56449 -56465 (September 27, 2005), EDSP; Chemical Selection Approach for Initial Round of Screening
https://federalregister.gov/a/05-19260
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U.S. Congress, House Appropriations Committee Report 111-180, pp. 105-106.
http://www.gpo.gov/fdsys/pkg/CRPT-111hrpt180/pdf/CRPT-111hrpt180.pdf