[Federal Register Volume 62, Number 36 (Monday, February 24, 1997)]
[Notices]
[Pages 8241-8242]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-4618]
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ENVIRONMENTAL PROTECTION AGENCY
[FRL-5693-9]
Peer-Review Workshop for Draft Dose-Response Modeling Chapter for
the Reassessment of Dioxin
AGENCY: U.S. Environmental Protection Agency.
ACTION: Notice of Peer-Review Workshop for Draft Dose-Response Modeling
Chapter of EPA's Health Assessment Document for Dioxin.
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SUMMARY: The U.S. Environmental Protection Agency (EPA) has scheduled a
peer-review workshop to be held on March 5, 1997, from 9:00 a.m. to
3:00 p.m. to review a revised draft of Chapter 8. Dose-Response
Modeling, which is part of the Health Assessment Document for 2,3,7,8-
Tetrachlorodibenzo-p-dioxin (TCDD) and Related Compounds. The health
assessment document is one component of the Agency's reassessment of
dioxin.
This revised chapter on dose-response was one of two chapters
referred back to the EPA for substantial revision after the Science
Advisory Board (SAB) review in May 1995. The public is invited to
attend the workshop, but seating will be limited and advance
reservations are suggested. Because time is limited for review of the
draft chapter prior to the peer-review workshop, written comments must
be provided to the Agency for 60 days subsequent to this notice. All
comments submitted within that time will be considered when the chapter
is revised for SAB review. At the workshop, a panel of scientific
experts from outside the Agency will review the draft dose-response
modeling chapter which, at this stage, is a work in progress and does
not represent Agency policy. Since the chapter evaluates only part of
the evidence supporting dioxin's overall toxic potential, no general
conclusions regarding the potential health effects or classification of
these compounds will be presented. This broader determination will be
based on the full weight-of-evidence and will be part of the risk
characterization component of the reassessment.
DATES: The peer-review workshop to review the draft dose-response
modeling chapter will be held March 5, 1997. Comments on the draft
chapter must be submitted in writing and be postmarked by April 25,
1997.
ADDRESSES: The meeting will be held at The Channel Inn Hotel, 650 Water
Street, SW, Washington, D.C. 20024. Members of the public wishing to
register to attend the meeting may phone Ms. Linda Tuxen at 202-260-
5949 between 10:00 a.m. and 6:00 p.m. Eastern Standard Time. During the
meeting some time will be designated for questions and comments from
the floor to encourage interactions among authors, peer-panel members,
and the other meeting attendees.
Members of the public may also submit written comments and other
materials relevant to the topic to: Ms. Linda Tuxen, National Center
for Environmental Assessment (8601), U.S. Environmental Protection
Agency, 401 M Street, S.W., Washington, DC 20460, Attention: Dioxin
Reassessment.
The draft chapter will be available on or about February 24, 1997.
To obtain a copy of the draft dose-response modeling chapter,
interested parties should contact the ORD Publications Center, U.S.
Environmental Protection Agency, 26 W. Martin Luther King Drive,
Cincinnati, OH 45268; telephone (513) 569-7562; fax (513) 569-7566.
Please provide your name, mailing address, and the chapter title and
EPA number as follows: Chapter 8. Dose-Response Modeling, EPA/600/P-92/
001C8.
The draft chapter also will be provided for inspection at the ORD
Public Information Shelf, EPA Headquarters Library, 401 M Street, S.W.,
Washington, DC 20460, between the hours of 10:00 a.m. and 4:00 p.m.,
Monday through Friday, except for Federal holidays, and at all of the
EPA Regional and Laboratory libraries.
FOR FURTHER INFORMATION CONTACT: To register for the workshop: Ms.
Linda Tuxen, National Center for Environmental Assessment (8601), U.S.
Environmental Protection Agency, 401 M Street, S.W., Washington, DC
20460; phone: 202-260-5949; fax: 202-401-2492; e-mail:
tuxen.linda@epamail.epa.gov.
For copies of the document: ORD Publications Center, CERI-FRN,
Office of Research and Development, U.S. Environmental Protection
Agency, 26 W. Martin Luther King Drive, Cincinnati, OH 45268; telephone
(513) 569-7562; fax (513) 569-7566.
For questions on the overall reassessment of dioxin: Dr. William
Farland, National Center for Environmental Assessment (8601), Office of
Research and Development, U.S. Environmental Protection Agency, 401 M
Street, S.W., Washington, DC 20460; telephone (202) 260-7315; fax (202)
401-2492; e-mail: farland.william@epamail.epa.gov.
SUPPLEMENTARY INFORMATION:
History of the Scientific Reassessment of Dioxin
As part of the SAB's May 1995 review of the draft Health Assessment
Document for 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and Related
Compounds, Chapter 8. Dose-Response Relationships, was identified as
one that may need substantial revision and further review. The SAB
commented that the chapter should be revised to better integrate human
and laboratory animal data, consider alternatives to the linear non-
threshold model, and clarify important
[[Page 8242]]
points. The purpose of this peer-review workshop is to review the
comments provided independently by the reviewers and to receive further
comment based on their discussion.
The EPA has undertaken this task in response to emerging scientific
knowledge of the biological, human health, and environmental effects of
dioxin. Significant advances have occurred in the scientific
understanding of mechanisms of dioxin toxicity, of the carcinogenic and
other adverse health effects of dioxin in people, of the pathways to
human exposure, and of the toxic effects of dioxin to the environment.
In 1985 and 1988, the Agency prepared assessments of the human
health risks from environmental exposures to dioxin. These assessments
were reviewed by the Agency's SAB. At the time of the 1988 risk
assessment, there was general agreement within the scientific community
that there could be a substantial improvement over the existing
response approach, but there was no consensus as to a more biologically
defensible methodology. The Agency was asked to explore the development
of such a method. The current reassessment activities are in part in
response to this request.
The EPA is making each phase of the current reassessment of dioxin
an open and participatory effort. It previously has convened two public
meetings (on November 15, 1991, and April 28, 1992) to inform the
public of the Agency's plans and activities, to hear and receive public
comments and reviews of the proposed plans for the reassessment, and
receive any current, scientifically relevant information.
The Agency convened two peer-review workshops to review draft
documents related to EPA's scientific reassessment of the health
effects of dioxin. The first workshop was held September 10 and 11,
1992, to review a draft exposure assessment titled, Estimating
Exposures to Dioxin-Like Compounds. The second workshop was held
September 22-25, 1992, to review eight chapters of a draft health
assessment document. The epidemiology chapter was also reviewed in
another workshop on September 8-9, 1993. It should be noted that
outside scientists have been heavily involved in the writing and peer
review of these draft documents. Drafts of the health and exposure
documents were made available for public review and comment in the fall
of 1994, both with a formal public comment period and at a number of
public meetings that were held around the country. The SAB reviewed the
documents in May 1995.
The purpose of the March 1997 peer-review workshop is to review the
draft of a revised and expanded dose-response modeling chapter. The
revised chapter evaluates the scientific quality and strength of the
dose-response modeling in the evaluation of toxic health effects, both
cancer and noncancer, from exposure to dioxin, with an emphasis on the
specific congener, 2,3,7,8-TCDD. A critical analysis of all available
data has been performed. It is hoped that the peer-review workshop will
provide a thoughtful and critical review of the dose-response portion
of the dioxin reassessment.
Dated: February 20, 1997.
William H. Farland,
Director, National Center for Environmental Assessment.
[FR Doc. 97-4618 Filed 2-21-97; 8:45 am]
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