[Federal Register Volume 65, Number 193 (Wednesday, October 4, 2000)]
[Notices]
[Pages 59186-59188]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-25473]


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ENVIRONMENTAL PROTECTION AGENCY

[FRL-6880-9]


Draft Dioxin Reassessment Documents; Dose-Response Modeling for 
2,3,7,8-TCDD, Toxic Equivalency 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 availability of draft documents for public review and 
comment and announcement of close of public comment period.

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SUMMARY: The U.S. Environmental Protection Agency (EPA) is announcing 
the availability of Science Advisory Board (SAB) review drafts of the 
Draft Dioxin Reassessment Documents, Chapter 8: Dose-Response Modeling 
for 2,3,7,8-TCDD, Chapter 9: Toxic Equivalency Factors (TEFs) for 
Dioxin and Related Compounds, and Part III: Integrated Summary and Risk 
Characterization for 2,3,7,8-Tetrachlorodibenzo-p-Dioxin (TCDD) and 
Related Compounds, for public review and comment. The documents were 
prepared by the EPA's Office of Research and Development (ORD) with the 
involvement of other federal agencies, in particular the National 
Institutes of Health's National Institute

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of Environmental Health Sciences. The Agency is also announcing the 
date for the close of the public comment period that began on June 12, 
2000.

DATES: In a June 12, 2000 Federal Register (65 FR 36898), the Agency 
announced the beginning of an extended public comment period, on both a 
previous version of these draft documents as well as those discussed in 
this Notice. It announced that the comment period began on June 12 and 
will be concluded two weeks following the SAB peer review meeting in 
the Fall. All public comments should be submitted by close of business 
on November 17, 2000. The SAB review meeting is scheduled for November 
1 and 2, 2000, and details related to that meeting will be announced in 
a separate FR notice.

Document Availability

    The primary distribution method for the three SAB review drafts of 
the dose-response modeling chapter (hereafter, Chapter 8), the TEF 
chapter (hereafter, Chapter 9) and Integrated Summary and Risk 
Characterization (hereafter, Part III) will be via the Internet on 
ORD's National Center for Environmental Assessment (NCEA) website. 
These SAB review drafts, in PDF format, are available at http://www.epa.gov/ncea/dioxin.htm. These documents can be reviewed and 
downloaded from the Internet. Background information is also available 
at the above-mentioned Internet site. This information, provided as 
background only, consists of other draft final 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 1-7). In addition, a Compact Disk-Read Only Memory (CD-ROM) 
containing the three SAB review drafts, the background information, and 
the draft final Database of Sources of Environmental Releases of 
Dioxin-Like Compounds in the United States, 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/
September 2000'' and document number EPA/600/P-00/001Bb-Be. The 
background documents are available only on CD-ROM and the Internet. A 
limited number of paper copies of draft Chapter 8, Chapter 9, and Part 
III will be available from NSCEP. To receive paper copies please 
provide your name, mailing address, and the document title and number, 
Part II. Chapter 8: Dose-Response Modeling for 2,3,7,8-TCDD, document 
number NCEA-I-0835; Part II. Chapter 9: Toxic Equivalency 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-00/001Bg.

Comment Submission

    Comments should be in writing and 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, N.W., 5th Floor, Washington, DC 20006; telephone: (202) 564-
3261; facsimile: (202) 565-0050. One unbound original with pages 
numbered consecutively, including attachments, and three copies should 
be submitted. An index is required for any attachments. Electronic 
comments may be emailed to: [email protected]. Commentors are 
requested to make clear that their comments pertain to the September 
2000 SAB review drafts.
    Please note that all technical comments received in response to 
this notice will be placed in a public record. 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 information contact the Technical 
Information Staff, NCEA-W (8623D), U.S. Environmental Protection 
Agency, 1200 Pennsylvania Avenue, N.W., Washington, DC 20460; 
telephone: 202-564-3261; facsimile: 202-565-0050; e-mail: 
[email protected].

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. 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.
    In September 1994, EPA released the external review drafts of the 
health effects and exposure documents. 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 (Chapter 8 and the Risk Characterization document) and 
development of an additional document that would focus on TEFs for 
dioxin and dioxin-like compounds. They also requested that the two 
redrafted documents and the new TEF chapter be submitted for 
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. However, the SAB's 
report stated that substantive further review of these sections by the 
SAB was not needed.
    On July 25 and 26, 2000, an external scientific peer-review meeting 
was held to review the new Chapter 9 and revised Part III. The third 
section of the reassessment on which the SAB recommended substantive 
revision, Chapter 8, underwent public comment and external peer review 
in March 1997. The July peer review meeting focused on the key science 
issues including: the characterization of cancer risk, how to 
extrapolate between animals and humans, non-cancer effects seen close 
to background exposures, and children's risk. A range of opinions 
regarding EPA's treatment of these issues in the draft chapters were 
expressed. Suggestions were made regarding improved presentation of 
these key science issues.
    After the July 25 and 26 external peer review meeting and 
subsequent receipt of the final meeting report, dated August 24, the 
documents were revised to address the comments of the scientific peer 
reviewers and the public comments received prior to September 25, the 
date the drafts were provided to the SAB review panel. The SAB will 
conduct its scientific peer review of draft Chapter 8, Chapter 9, and 
Part III on Wednesday and Thursday, November 1 and 2. The SAB review 
will be announced in a separate Federal Register notice. Following the 
SAB meeting, EPA will revise the draft reassessment documents to 
incorporate appropriate changes that have been indicated by the 
comments of Federal agencies, the public, and the SAB review panel. SAB 
approval is

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needed to produce a final EPA dioxin reassessment document.

    Dated: September 28, 2000.
Henry L. Longest II,
Deputy Assistant Administrator for Management, Office of Research and 
Development.
[FR Doc. 00-25473 Filed 10-3-00; 8:45 am]
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