00-14853. Draft Dioxin Reassessment Documents; Toxicity Equivalence Factors (TEFs) for Dioxin and Related Compounds and Integrated Summary and Risk Characterization for 2,3,7,8-Tetrachlorodibenzo-p-Dioxin (TCDD) and Related Compounds

AGENCY:

Environmental Protection Agency

ACTION:

Notice of peer review workshop and public comment period.

SUMMARY:

The U.S. Environmental Protection Agency (EPA) is announcing that an EPA contractor will be organizing, convening, and conducting an external peer review workshop to review the external review draft documents entitled, Part II. Chapter 9: Toxicity Equivalence Factors (TEFs) for Dioxin and Related Compounds (hereafter, TEF chapter) and Part III. Integrated Summary and Risk Characterization for 2,3,7,8-Tetrachlorodibenzo-p-Dioxin (TCDD) and Related Compounds (hereafter, Integrated Summary and Risk Characterization). The EPA is also announcing an extended public comment period for these two draft documents. The peer review workshop will be organized, convened, and conducted by the Eastern Research Group, Inc. (ERG), an EPA contractor for this external scientific peer review. The documents were prepared by the EPA's Office of Research and Development (ORD) and with the involvement of other federal agencies, in particular the National Institutes of Health's National Institute of Environmental Health Sciences. EPA will consider the peer review advice and public comment submissions in revising these draft dioxin reassessment documents in preparation for an upcoming review by EPA's Science Advisory Board (SAB).

DATES:

The two-day peer review workshop will be held on Tuesday, July 25, 2000, 9 a.m. to 5:30 p.m. and Wednesday, July 26, 2000, 8:30 a.m. to 5:00 p.m. Members of the public may attend as observers, and there will be a limited time for comments from the public. The extended public comment period begins June 12, 2000, and concludes two weeks following the SAB's peer review meeting on the dioxin reassessment which is scheduled for October 2000. The specific date of that meeting has not been determined. EPA will announce in a subsequent Federal Register (FR) notice the formal closing date of the public comment period.

ADDRESSES:

The external peer review workshop will be held at the Holiday Inn Capital, 550 C Street, SW, Washington, DC 20024, Tel: [phone]. The Eastern Research Group, Inc. (ERG), an EPA contractor, is organizing, convening, and conducting the peer review workshop. To attend the workshop as an observer, please register by Monday, July 17, 2000, by calling ERG at Tel: [phone], or send a facsimile to: 781-674-2906. Space is limited, and registrations to attend will be accepted on a first-come, first-served basis. Time will be set aside each day to hear comments from observers. Individual comments will be limited to no more than 5 minutes per person, and the number of people giving oral comments will be limited by the time available. If you wish to make comments at the workshop, please sign up in advance by contacting ERG. Commenters will be scheduled on a first-come, first-served basis. Please reference the “EPA Dioxin Workshop” when contacting ERG or the hotel.

Document Availability: The primary distribution method for the external review drafts of the TEF chapter and Integrated Summary and Risk Characterization to the public will be via the Internet on ORD's National Center for Environmental Assessment (NCEA) website. These external review drafts are available at http://www.epa.gov/​ncea/​dioxin.htm. These documents can be viewed and downloaded from the Internet for review and comment. Background information is also available at the above-mentioned website. This information, provided as background only, consists of other exposure and health sections of the reassessment, specifically Part I: Estimating Exposure to Dioxin-Like Compounds (Volumes 2-4) and Part II: Health Assessment for 2,3,7,8-Tetrachlorodibenzo-p-Dioxin (TCDD) and Related Compounds (Chapters 1-8).

In addition, a Compact Disk-Read Only Memory (CD-ROM) containing the external review draft of the TEF chapter and the background information, is available from EPA's National Service Center for Environmental Publications (NSCEP) in Cincinnati, Ohio (telephone: [phone], or 513-489-8190; facsimile 513-489-8695). If you are requesting a copy of the CD-ROM, please provide your name, mailing address, and reference the “Dioxin CD” and Document number EPA/600/P-00/001Ab-Ae. The background documents are available only on CD-ROM and the Internet.

Also, a limited number of paper copies of only the draft TEF chapter and the Integrated Summary and Risk Characterization will be available from NSCEP. If you are requesting a paper copy of either the draft TEF chapter or draft Integrated Summary and Risk Characterization, please provide your name, mailing address, and the document title and number, Part II. Chapter 9: Toxicity Equivalence Factors (TEFs) for Dioxin and Related Compounds, Document number NCEA-I-0836; and/or Part III. Integrated Summary and Risk Characterization for 2,3,7,8-Tetrachlorodibenzo-p-Dioxin (TCDD) and Related Compounds, Document number EPA/600/P-00/001Ag. Copies of draft documents or background information are not available from ERG.

Comment Submission: Comments may be mailed to the Technical Information Staff (8623D), NCEA-W, U.S. Environmental Protection Agency, 1200 Pennsylvania Avenue, NW., Ariel Rios Building, Washington, DC 20460, or delivered to the Technical Information Staff at 808 17th Street, NW., 5th Floor, Washington, DC 20006; telephone: [phone]; facsimile: 202-565-0050. Comments should be in writing. Please submit one unbound original with pages numbered consecutively, and three copies of the comments. For attachments, provide an index, number pages consecutively with the comments, and submit an unbound original and three copies. Electronic comments may be emailed to: [e-mail].

Please note that all technical comments received in response to this notice will be placed in a public record. For that reason, commentors should not submit personal information (such as medical data or home address), Confidential Business Information, or information protected by copyright. Due to limited resources, acknowledgments will not be sent.

FOR FURTHER INFORMATION CONTACT:

For workshop information, registration, and logistics, contact ERG, 110 Hartwell Avenue, Lexington, Massachusetts, 02421-3136; Tel: [phone]; Fax: [phone].

For information on the public comment period, contact Linda C. Tuxen, NCEA, telephone: [phone]; facsimile: 202-565-0090; or email: [e-mail]. This is an extended public comment period that will continue until the SAB meeting in the Fall 2000. It is very important to note that, as the dioxin reassessment process continues, two versions of the draft sections will be put on the dioxin website. The external review drafts, the availability of which are announced in this FR notice, will be replaced by the SAB review drafts in early September. The public is requested to make clear in their submitted comments on which draft document they are commenting.

SUPPLEMENTARY INFORMATION:

In April 1991, EPA announced that it would conduct a scientific reassessment of the health risks of exposure to dioxin and dioxin-like compounds. Previous EPA dioxin assessment documents, one final and one draft, were completed in 1985 and 1988, respectively. EPA undertook the 1991 reassessment in light of significant advances in our scientific understanding of mechanisms of dioxin toxicity, significant new studies of dioxin's carcinogenic potential in humans and increased evidence of other adverse health effects. EPA has worked to make each phase of the dioxin reassessment an open and participatory process. These efforts have included the involvement of outside scientists as principal authors of several chapters, frequent public meetings to report progress and take public comment, and publication of early drafts for public comment and peer review. Early in the reassessment process, EPA held public meetings (1991 and 1992) to inform the public of the Agency's plans and activities for the reassessment, to hear and receive public comments and reviews of the proposed plans, and to receive any current, scientifically relevant information. In 1992 and 1993, the Agency convened three peer-review workshops to review early drafts of the reassessment chapters.

In September 1994, EPA released the external review drafts of the health effects and exposure documents which amounted to over 2,200 pages. In late 1994 EPA took public comment and held numerous public meetings across the country on the drafts, followed by SAB review of the draft dioxin reassessment in May 1995. The SAB's report was received in the Fall of that year. In its report to the Agency, the SAB responded favorably to most portions of the reassessment, but recommended substantive revision of two key sections. The SAB recommended the revision of these two sections, Chapter 8: Dose-Response Modeling for 2,3,7,8-TCDD and the Risk Characterization document, and the development of an additional document that would focus on the toxicity equivalent factors (TEFs) for dioxin and dioxin-like compounds. In addition to these substantive recommendations, the SAB suggested that the redrafting process include broader participation of outside scientists from both the public and private sectors. They also requested that the two redrafted chapters and the new TEF chapter be submitted to independent external peer review, before being returned to the SAB for re-review. With respect to Chapters 1-7 of the health document and the full exposure reassessment document, the SAB accepted these sections. They suggested that the sections be updated to address public and SAB comments and to incorporate new scientific data, but the SAB's report stated that substantive further review of these sections by the SAB was not needed.

After receipt of the SAB's report, the Agency worked with over 40 individual stakeholders from the private and public sectors, representing environmental, industry, academic, state, and other public interest and public health communities, on the next steps and to gather input on possible approaches for conducting the revision process. The Agency has tried to keep these individuals apprised of reassessment activities at critical points in the revision process. The Agency expects that these individuals will be important avenues of public comment on the draft documents.

The final dioxin reassessment will consist of three parts. Part I: Estimating Exposure to Dioxin-Like Compounds focuses on sources, levels of dioxin-like compounds in environmental media, and human exposures. Part II: Health Assessment for 2,3,7,8-Tetrachlorodibenzo-p-Dioxin (TCDD) and Related Compounds includes information on critical human health end points, mode of action, pharmacokinetics, dose-response, and TEFs. There will be a total of nine chapters in Part II. Part III: Integrated Summary and Risk Characterization for 2,3,7,8-Tetrachlorodibenzo-p-Dioxin (TCDD) and Related Compounds is intended to be a stand-alone document. In this part, key findings pertinent to understanding the potential hazards and risks of dioxins are described and integrated, including a discussion of all important assumptions and uncertainties.

The two draft documents that are the subject of the independent scientific peer review meeting announced today are the new TEF chapter and the updated, revised, and reformatted Integrated Summary and Risk Characterization. The TEF chapter was developed as a result of a recommendation from the SAB to gather in one place the discussion and scientific information on the complex issue and use of TEFs for dioxin and dioxin-like compounds. The draft TEF chapter was developed by a team of experts and has undergone internal EPA review. The Integrated Summary and Risk Characterization, formerly identified as Chapter 9: Risk Characterization in the 1994 draft reassessment, was initially revised using a writing team process. The writing team was composed of approximately 12 leading scientific experts in fields related to dioxin exposure and health effects. These experts came from a wide range of public and private organizations, as well as academia. A preliminary revised draft was developed by a writing group and was reviewed by the 40 individual stakeholders. This preliminary draft was used as the framework for an extensively revised document developed by a small internal EPA writing group.

The third section of the reassessment on which the SAB recommended substantive revisions is Chapter 8: Dose-Response Modeling for 2,3,7,8-TCDD. The draft Chapter 8 underwent public comment and external peer review in March 1997. A writing team developed the draft final chapter based on the peer review and public comments and any relevant new scientific data in January 2000. Because this section has already undergone extensive review, we are not soliciting further comments. The next step for Chapter 8 is SAB review in the Fall 2000.

After the July 25 and 26 external peer review workshop, the TEF chapter and Integrated Summary and Risk Characterization will be revised to reflect the comments of the independent scientific peer reviewers, other Federal agencies, and the public. In the Fall, the SAB will conduct a scientific peer review of the TEF chapter, the dose-response modeling chapter, and the Integrated Summary and Risk Characterization. The SAB review will be anounced in the Federal Register. EPA expects to conclude the dioxin reassessment about six months from now, incorporating appropriate changes that have been indicated by the comments of Federal agencies, the public, the external peer reviewers, and the SAB review panel. Final SAB approval is needed to produce a final EPA dioxin reassessment document.

Dated: June 6, 2000.

Norine E. Noonan,

Assistant Administrator for Research and Development.