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Endocrine Disruptor Screening Program (EDSP); Announcing the Availability of a Draft for Weight-of-Evidence Guidance Document: Evaluating Results of EDSP Tier 1 Screening To Identify Candidate Chemicals for Tier 2 Testing

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Environmental Protection Agency (EPA).




EPA is announcing the availability for public review and comment of a draft guidance document titled, “Weight-of-Evidence Guidance Document: Evaluating Results of EDSP Tier 1 Screening to Identify Candidate Chemicals for Tier 2 Testing.” This action is in compliance with a directive from the House Appropriations Committee FY 2010 Report directing the EPA to develop and publish criteria by October 30, 2010, for evaluating results of Tier 1 screening and determining whether a chemical should undergo Tier 2 analysis. The purpose of the weight-of-evidence (WoE) document is to set forth some of the general principles, criteria, and considerations EPA generally believes to be relevant under a WoE approach for evaluating data submitted as part of EPA's two-tiered paradigm for screening and testing chemicals for endocrine activity (i.e., estrogen, androgen, and thyroid hormonal systems; E, A, and T) under the EDSP. This document provides a transparent scientific approach for broadly evaluating Tier 1 screening data to detect an interaction with E, A, and/or T hormonal systems and determine if additional Tier 2 testing is necessary.


Comments must be received on or before January 3, 2011.


Submit your comments, identified by docket identification (ID) number EPA-HQ-OPPT-2010-0877, by one of the following methods:

  • Federal eRulemaking Portal: Follow the on-line instructions for submitting comments.
  • Mail: Document Control Office (7407M), Office of Pollution Prevention and Toxics (OPPT), Environmental Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460-0001.Start Printed Page 67964

Hand Delivery: OPPT Document Control Office (DCO), EPA East Bldg., Rm. 6428, 1201 Constitution Ave., NW., Washington, DC. Attention: Docket ID Number EPA-HQ-OPPT-2010-0877. The DCO is open from 8 a.m. to 4 p.m., Monday through Friday, excluding legal holidays. The telephone number for the DCO is (202) 564-8930. Such deliveries are only accepted during the DCO's normal hours of operation, and special arrangements should be made for deliveries of boxed information.

Instructions: Direct your comments to docket ID number EPA-HQ-OPPT-2010-0877. EPA's policy is that all comments received will be included in the docket without change and may be made available on-line at, including any personal information provided, unless the comment includes information claimed to be Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Do not submit information that you consider to be CBI or otherwise protected through or e-mail. The Web site is an “anonymous access” system, which means EPA will not know your identity or contact information unless you provide it in the body of your comment. If you send an e-mail comment directly to EPA without going through, your e-mail address will be automatically captured and included as part of the comment that is placed in the docket and made available on the Internet. If you submit an electronic comment, EPA recommends that you include your name and other contact information in the body of your comment and with any disk or CD-ROM you submit. If EPA cannot read your comment due to technical difficulties and cannot contact you for clarification, EPA may not be able to consider your comment. Electronic files should avoid the use of special characters, any form of encryption, and be free of any defects or viruses.

Docket: All documents in the docket are listed in the docket index available at Although listed in the index, some information is not publicly available, e.g., CBI or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, will be publicly available only in hard copy. Publicly available docket materials are available electronically at, or, if only available in hard copy, at the OPPT Docket. The OPPT Docket is located in the EPA Docket Center (EPA/DC) at Rm. 3334, EPA West Bldg., 1301 Constitution Ave., NW., Washington, DC. The EPA/DC Public Reading Room hours of operation are 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The telephone number of the EPA/DC Public Reading Room is (202) 566-1744, and the telephone number for the OPPT Docket is (202) 566-0280. Docket visitors are required to show photographic identification, pass through a metal detector, and sign the EPA visitor log. All visitor bags are processed through an X-ray machine and subject to search. Visitors will be provided an EPA/DC badge that must be visible at all times in the building and returned upon departure.

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For technical information contact: Don Bergfelt, Office of Science Coordination and Policy (7203M), Environmental Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460-0001; telephone number: (202) 564-8472; e-mail address:

For general information contact: The TSCA-Hotline, ABVI-Goodwill, 422 South Clinton Ave., Rochester, NY 14620; telephone number: (202) 554-1404; e-mail address:

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I. General Information

A. Does this action apply to me?

This action is directed to the public in general. You may be potentially affected by this action if you produce, manufacture, use, consume, work with, or import industrial or pesticide chemicals. To determine whether you or your business may be affected by this action, you should carefully examine section 408(p) of the Federal Food, Drug, and Cosmetic Act (FDCA) (21 U.S.C. 346a(p)) and the Safe Drinking Water Act (42 U.S.C. 300j-17). Potentially affected entities may include, but are not limited to:

  • Chemical manufacturers, importers and processors (NAICS code 325), e.g., persons who manufacture, import, or process chemical substances.
  • Pesticide, fertilizer, and other agricultural chemical manufacturers (NAICS code 3253), e.g., persons who manufacture, import or process pesticide, fertilizer, and agricultural chemicals.
  • Scientific research and development services (NAICS code 5417), e.g., persons who conduct testing of chemical substances for endocrine effects.

This listing is not intended to be exhaustive, but rather provides a guide for readers regarding entities likely to be affected by this action. Other types of entities not listed in this unit could also be affected. The North American Industrial Classification System (NAICS) codes have been provided to assist you and others in determining whether this action might apply to certain entities. If you have any questions regarding the applicability of this action to a particular entity, consult the technical person listed under FOR FURTHER INFORMATION CONTACT.

B. What should I consider as I prepare my comments for EPA?

1. Submitting CBI . Do not submit this information to EPA through or e-mail. Clearly mark the part or all of the information that you claim to be CBI. For CBI information in a disk or CD-ROM that you mail to EPA, mark the outside of the disk or CD-ROM as CBI and then identify electronically within the disk or CD-ROM the specific information that is claimed as CBI. In addition to one complete version of the comment that includes information claimed as CBI, a copy of the comment that does not contain the information claimed as CBI must be submitted for inclusion in the public docket. Information so marked will not be disclosed except in accordance with procedures set forth in 40 CFR part 2.

2. Tips for preparing your comments. When submitting comments, remember to:

i. Identify the document by docket ID number and other identifying information (subject heading, Federal Register date and page number).

ii. Follow directions. The Agency may ask you to respond to specific questions or organize comments by referencing a Code of Federal Regulations (CFR) part or section number.

iii. Explain why you agree or disagree; suggest alternatives and substitute language for your requested changes.

iv. Describe any assumptions and provide any technical information and/or data that you used.

v. If you estimate potential costs or burdens, explain how you arrived at your estimate in sufficient detail to allow for it to be reproduced.

vi. Provide specific examples to illustrate your concerns and suggest alternatives.

vii. Explain your views as clearly as possible, avoiding the use of profanity or personal threats.

viii. Make sure to submit your comments by the comment period deadline identified.Start Printed Page 67965

II. Background

A. What action is the agency taking?

EPA is announcing the availability of a draft guidance document titled, “Weight-of-Evidence Guidance Document: Evaluating Results of EDSP Tier 1 Screening to Identify Candidate Chemicals for Tier 2 Testing.” This document invites the public to review and comment on the guidance document, which is available electronically at ( using docket ID number EPA-HQ-OPPT-2010-0877 and the EDSP Web site​endo.

This document was prepared to provide a transparent, scientific approach to set forth some general principles, criteria, and considerations EPA generally believes to be relevant using a WoE approach to evaluate data submitted as part of EPA's EDSP involving a battery of validated Tier 1 screening assays as described in a notice published in the Federal Register issue of October 21, 2009 (74 FR 54415) (FRL-8432-6). The criteria discussed in this document are based, in part, on EPA's experience in developing and applying risk assessment guidelines involving cancer, reproductive and developmental toxicity, and ecological toxicity. Important considerations include the use of expert judgment formed through the scientific process, current understanding of endocrine mechanisms of toxicity, and knowledge of other fields of toxicology (e.g., developmental, reproductive, neurological and immunological toxicology, and toxicokinetics). Principles articulated in this document are equally applicable to a WoE evaluation of data from individual assays with multiple endpoints, as well as across the whole suite of assays in the EDSP Tier 1 screening battery. In addition, these principles would be generally applicable to the review of other scientifically relevant information (OSRI) submitted in response to test orders that request OSRI to be considered in lieu of designated screening assays in the Tier 1 battery.

In general, the EDSP is a two-tiered paradigm for screening and testing chemicals with the potential to interact with the endocrine system. Tier 1 screening consists of a battery of complementary in vitro and short term in vivo assays designed to maximize sensitivity for detecting interactions with the E, A, and/or T hormonal systems; whereas, Tier 2 testing consists of a group of individual in vivo tests designed to include males and females with an intact hypothalamic-pituitary-gonadal axis, multiple pathways of exposure and life-stages, and various taxa to further identify and characterize chemical-induced interactions with E, A, and/or T for risk assessment. The diversity in endocrine endpoints within and among the Tier 1 screening assays is expected to provide corroborating information and support a WoE evaluation to yield a decision as to whether or not the chemical indentified in Tier 1 requires additional testing in Tier 2.

B. What is the agency's authority for taking this action?

Section 408(p) of FFDCA requires EPA to “develop a screening program, using appropriate validated test systems and other scientifically relevant information, to determine whether certain substances may have an effect in humans that is similar to an effect produced by a naturally occurring estrogen, or such other endocrine effect as [EPA] may designate.” (21 U.S.C. 346a(p)). The statute generally requires EPA to “provide for the testing of all pesticide chemicals.” (21 U.S.C. 346a(p)(3)). “Pesticide chemical” is defined as “any substance that is a pesticide within the meaning of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), including all active and inert ingredients of such pesticide.” (21 U.S.C. 321(q)(1)).

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List of Subjects

  • Environmental protection
  • Endocrine disruptors
  • Screening assays
  • Weight-of-evidence
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Dated: October 27, 2010.

Stephen A. Owens,

Assistant Administrator, Office of Chemical Safety and Pollution Prevention.

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[FR Doc. 2010-27897 Filed 11-3-10; 8:45 am]