[Federal Register Volume 59, Number 176 (Tuesday, September 13, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-22442]
[[Page Unknown]]
[Federal Register: September 13, 1994]
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ENVIRONMENTAL PROTECTION AGENCY
[FRL-5070-7]
Reassessment of 2,3,7,8-Tetrachlorodibenzo-p-dioxin (2,3,7,8-
TCDD, dioxin)
AGENCY: Environmental Protection Agency (EPA).
ACTION: As part of the Agency's reassessment of 2,3,7,8-
tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD, hereinafter referred to as
simply dioxin), two External Review Draft documents are being made
available for a 120-day public review and comment period.
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SUMMARY: This notice announces the availability of two External Review
Draft documents for public review and comment:
1. Health Assessment Document for 2,3,7,8-Tetrachlorodibenzo-p-dioxin
(TCDD) and Related Compounds (EPA/600/BP-92/001a-c)
2. Estimating Exposure to Dioxin-Like Compounds (EPA/600/6-88/005Ca-c)
During the public comment period, public comment meetings will be
convened to take formal comments on the draft documents. These meetings
are being planned for the first two weeks of December at five
locations: Washington, DC; New York, NY/New Jersey; Chicago, IL;
Dallas, TX; and San Francisco, CA. Detailed information will be
provided in a future Federal Register notice.
The draft documents also will be reviewed at a Science Advisory
Board meeting to be held after the public comment period has ended,
early next year. Information about this meeting will be published in a
future Federal Register notice.
DATES: The draft documents will be made available on September 13,
1994. Comments must be postmarked by January 13, 1994.
ADDRESSES:
Requesting Documents
Due to the large size of both draft documents (each is over 1,000
pages in length), the documents will be available as follows:
Health Assessment Document for 2,3,7,8-Tetrachlorodibenzo-p-dioxin
(TCDD) and Related Compounds, EPA/600/BP-92/001a, 001b, 001c. (Note:
The full document is 3 volumes and approx. 1,100 pages.)
or
Risk Characterization Chapter, EPA/600/BP-92/001c. (Note: This third
volume of the 3-volume set integrates health and exposure information
on dioxin and related compounds; approx. 100 pages.)
and/or
Estimating Exposure to Dioxin-Like Compounds, EPA/600/6-88/005Ca, Cb,
Cc. (Note: The full document is 3 volumes and approx. 1,300 pages.)
or
Executive Summary Chapter of the Exposure Document, EPA/600/6-88/005Ca.
(Note: This first volume of the 3-volume set summarizes the exposure
information; approx. 100 pages.)
To obtain a paper copy of these draft documents, interested parties
should contact the ORD Publications Center, CERI-FRN, 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, document title, and EPA
number.
Please note that the two summary volumes also will be made
available as WordPerfect 5.1 files on 3\1/2\'' PC-DOS formatted disks.
Please request by document title and EPA number:
Risk Characterization Chapter (Vol. III-Health), EPA/600/BP-92/001ca
(disk)
Executive Summary Chapter (Vol. I-Exposure), EPA/600/6-88/005Caa (disk)
The draft documents 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 a.m. and 2 p.m., Monday
through Friday, except for Federal holidays, and at all of the EPA
Regional and Laboratory libraries.
Submitting Comments
All comments must be in writing. Commenters should submit three
copies of each comment, and if commenting on both documents--the health
assessment document and the exposure assessment--submit separate
comments rather than combined submissions.
For the health assessment document, send comments to: Dioxin Health
Assessment Comments, Technical Information Staff (8601), Office of
Health and Environmental Assessment, U.S. Environmental Protection
Agency, 401 M Street, S.W., Washington, DC 20460.
For the exposure assessment document, send comments to: Dioxin
Exposure Assessment Comments, Technical Information Staff (8601),
Office of Health and Environmental Assessment, U.S. Environmental
Protection Agency, 401 M Street, SW., Washington, DC 20460.
FOR FURTHER INFORMATION CONTACT:
For questions on the overall reassessment of dioxin or technical
questions on the health assessment document: William Farland, Office of
Health and Environmental Assessment (8601), Office of Research and
Development, U.S. Environmental Protection Agency, 401 M Street, SW.,
Washington, DC 20460; telephone (202) 260-7315; fax (202) 260-0393.
For technical questions on the exposure assessment: John Schaum,
Exposure Assessment Group (8603), Office of Health and Environmental
Assessment, U.S. Environmental Protection Agency, 401 M Street SW.,
Washington, DC 20460; telephone (202) 260-8909; fax 260-1722.
SUPPLEMENTARY INFORMATION:
The Scientific Reassessment of Dioxin
In April 1991, EPA announced that it would conduct a scientific
reassessment of the health risks of exposure to 2,3,7,8-
tetracholorodibenzo-p-dioxin (TCDD) and chemically similar compounds
collectively known as dioxin. 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. The reassessment is part of the
Agency's goals to improve the research and science base and to
incorporate improved research and science into EPA decisions.
History
In 1985 and 1988, the Agency prepared assessments of the human
health risks from environmental exposures to dioxin. Also, in 1988, a
draft exposure document was prepared that presented procedures for
conducting site-specific exposure assessments to dioxin-like compounds.
These assessments were reviewed by the Agency's Science Advisory Board
(SAB). At the time of the 1988 assessments, there was general agreement
within the scientific community that there could be a substantial
improvement over the existing approach to analyzing dose response, 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 Agency's reassessment activities are in response to this
request.
Stages in the Reassessment Process That Have Been Completed
The EPA had endeavored to make each phase of the reassessment of
dioxin an open and participatory effort. On November 15, 1991, and
April 28, 1992, public meetings were held to discuss 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 the Fall of 1992, 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 future draft
Health Assessment Document for 2,3,7,8-Tetrachlorodibenzo-p-dioxin
(TCDD) and Related Compounds. Peer-reviewers were also asked to
identify issues to be incorporated into the risk characterization,
which was under development.
In the Fall of 1993, a third peer-review workshop was held on
September 7 and 8, to review a draft of the revised and expanded
Epidemiology and Human Data Chapter, which also would be part of the
future health assessment document. The revised chapter provided an
evaluation of the scientific quality and strength of the epidemiology
data 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.
Prior to each workshop, the draft documents or chapters were made
available in keeping with the Agency's continuing commitment to conduct
the reassessment of dioxin in an open and participatory manner, to keep
the public informed of its progress, and to encourage public
participation in the document development process. The public also was
invited to attend the workshops, to present oral comments, and/or to
submit written comments. At each workshop, a panel of scientific
experts from outside the Agency reviewed the draft documents and
provided valuable comments. It also should be noted that outside
scientists have been heavily involved throughout the developmental
process of writing and reviewing these draft documents. With this
notice, the External Review Drafts of both draft documents are being
released for a 120-day public review and comment period.
Current Stage of the Scientific Reassessment of Dioxin
The scientific reassessment of dioxin consists of five activities:
1. Update and revision of the health assessment document for dioxin.
2. Laboratory research in support of the dose-response model.
3. Development of a biologically based dose-response model for dioxin.
4. Update and revision of the dioxin exposure assessment document.
5. Research to characterize ecological risks in aquatic ecosystems.
The first four activities have resulted in two draft documents (the
health assessment document and exposure document) for 2,3,7,8-
tetrachlorodibenzo-p-dioxin (TCDD) and related compounds. These
companion documents, which form the basis for the Agency's reassessment
of dioxin, have been used in the development of the risk
characterization chapter that follows the health assessment (Chapter 9,
Volume III). The process for developing these documents consisted of
three phases which are outlined in later paragraphs.
The fifth activity, which is in progress at EPA's Environmental
Research Laboratory in Duluth, Minnesota, involves characterizing
ecological risks in aquatic ecosystems from exposure to dioxins.
Research efforts are focused on the study of organisms in aquatic food
webs to identify the effects of dioxin exposure that are likely to
result in significant population impacts. A report titled, Interim
Report on Data and Methods for the Assessment of 2,3,7,8-
Tetrachlorodibenzo-p-Dioxin (TCDD) Risks to Aquatic Organisms and
Associated Wildlife (EPA/600/R-93/055), was published in April 1993.
This report will serve as a background document for assessing dioxin-
related ecological risks. Ultimately, these data will support the
development of aquatic life criteria which will aid in the
implementation of the Clean Water Act.
As mentioned previously, completion of the health assessment and
exposure documents involves three phases: Phase 1 involved drafting
state-of-the-science chapters and a dose-response model for the health
assessment document, expanding the exposure document to address dioxin
related compounds, and conducting peer-review workshops by panels of
experts. This phase has been completed.
Phase 2, preparation of the risk characterization, began during the
September 1992 workshops with discussions by the peer-review panels and
formulation of points to be carried forward into the risk
characterization. Following the September 1993 workshop, this work was
completed and was incorporated as Chapter 9 (Volume III) of the draft
health assessment document. This phase has been completed.
Phase 3 is currently underway. It includes making External Review
Drafts of both the health assessment document and the exposure document
available for public review and comment.
Next Stages in the Reassessment Process
As described previously, public briefings will be held during the
first week of the public comment period to be followed by formal public
hearings in December 1994. After the close of the public comment
period, the Agency's Science Advisory Board (SAB) will review the draft
documents in public session (early 1995). Following SAB review, the
draft documents will be revised, comments and revisions will be
incorporated, and final documents will be issued.
Dated: August 30, 1994.
Carl R. Gerber,
Acting Assistant Administrator for Research and Development.
[FR Doc. 94-22442 Filed 9-12-94; 8:45 am]
BILLING CODE 6560-50-P-M
