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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

[Federal Register: June 12, 2000 (Volume 65, Number 113)]
[Notices]
[Page 36898-36900]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr12jn00-96]

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ENVIRONMENTAL PROTECTION AGENCY

[FRL-6714-9]


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.

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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: 202-
479-4000. 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: 781-674-7374, 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: 1-
800-490-9198, 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: 202-564-3261;
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

[[Page 36899]]

comments may be emailed to: dioxin.ncea@epa.gov.
    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: 781-674-7374; Fax: 781-674-
2906.
    For information on the public comment period, contact Linda C.
Tuxen, NCEA, telephone: 202-564-3332; facsimile: 202-565-0090; or
email: tuxen.linda@epa.gov. 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

[[Page 36900]]

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.
[FR Doc. 00-14853 Filed 6-9-00; 8:45 am]
BILLING CODE 6560-50-P

 
 

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