[Federal Register Volume 73, Number 227 (Monday, November 24, 2008)]
[Notices]
[Pages 70999-71000]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E8-27853]


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ENVIRONMENTAL PROTECTION AGENCY

[FRL-8744-2; Docket ID No. EPA-HQ-ORD-2008-0789]


Literature Search for 2,3,7,8-Tetrachlorodibenzo-p-Dioxin (TCDD) 
Dose-Response Studies for Use in an Upcoming Expert Panel Workshop

AGENCY: Environmental Protection Agency.

ACTION: Notice; availability of a literature search, public review 
period, and request for information.

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SUMMARY: The U.S. Environmental Protection Agency (EPA) is announcing a 
45-day public review and request for additional information on 
available peer-reviewed literature for 2,3,7,8-tetrachlorodibenzo-p-
dioxin (TCDD) dose-response for use in human health risk assessment. An 
initial literature search was conducted by EPA through an Interagency 
Agreement with the Department of Energy's Argonne National Laboratory. 
Results of this preliminary search are available via the dioxin Web 
site http://www.epa.gov/ncea/dioxin. The public is invited to review 
the preliminary literature search results and submit any additional 
information, specifically peer-reviewed TCDD dose-response studies, to 
EPA that are not already identified in the literature search. Please 
submit any information in accordance with the instructions provided 
below. It is requested that the full publication be provided to EPA if 
possible. Results of this literature search will be used by scientists 
from EPA and other scientists from outside of EPA in the conduct of a 
scientific expert workshop, open to the public, to be held in 
Cincinnati, Ohio, on February 18-20, 2009. This workshop will be 
announced in a future Federal Register notice.
    This notice provides: (1) A link to the electronic list of recent 
literature search results for TCDD dose-response; and (2) instructions 
to the public for submitting additional scientific information 
pertinent to TCDD dose-response assessment to EPA that is not already 
identified in the literature search.

DATES: The 45-day public comment period begins November 24, 2008, and 
ends January 8, 2009.

ADDRESSES: Please submit relevant scientific information, identified by 
docket ID number EPA-HQ-ORD-2008-0789, online at http://www.regulations.gov (EPA's preferred method); by e-mail to 
[email protected]; by mail to the Office of Environmental Information 
(OEI) Docket (Mail Code: 2822T), U.S. Environmental Protection Agency, 
1200 Pennsylvania Ave., NW., Washington, DC 20460-0001 or by hand 
delivery or courier to the EPA Docket Center, EPA West, Room 3334, 1301 
Constitution Ave., NW., Washington, DC, between 8:30 a.m. and 4:30 p.m. 
Monday through Friday, excluding legal holidays. Please see 
SUPPLEMENTARY INFORMATION below for detailed instructions.

FOR FURTHER INFORMATION CONTACT: For information and help on submitting 
scientific information, please contact the OEI Docket by e-mail 
([email protected]), by phone (202-566-1752), or by fax (202-566-
1753). For information and help on accessing the Literature Search for 
TCDD Dose-Response and for technical information, please contact Glenn 
E. Rice, National Center for Environmental Assessment (Mail Code: MSA-
110), Office of Research and Development, U.S. Environmental Protection 
Agency, Cincinnati, Ohio 45268; telephone: 513-569-7813; facsimile: 
513-487-2539; or e-mail: [email protected].

SUPPLEMENTARY INFORMATION: 

Background

    In 1991, EPA announced that it would conduct a scientific 
reassessment of the potential health risks of exposure to dioxin and 
related compounds. EPA's Science Advisory Board (SAB) first reviewed 
the draft dioxin reassessment in 1995, and the document was revised to 
address SAB comments. In 2000, the SAB reviewed the integrated summary, 
risk characterization, and other information on toxic equivalency of 
dioxin-like compounds. Reports of the findings and recommendations of 
these SAB reviews are available on the SAB Web site at http://www.epa.gov/sab (see reports EPA-SAB-EC-95-021 and EPA-SAB-EC-01-006).
    In 2003, EPA produced an external review draft of the multi-year 
comprehensive reassessment of dioxin exposure and human health effects 
(http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=87843). This draft 
dioxin reassessment document, titled Exposure and Human Health 
Reassessment of 2,3,7,8-Tetrachlorodibenzo-p-Dioxin (TCDD) and Related 
Compounds, consisted of three parts: (1) A scientific review of 
information relating to sources and exposures to TCDD and other dioxins 
in the environment; (2) detailed reviews of scientific information on 
the health effects of TCDD, other dioxins, and dioxin-like compounds; 
and (3) an integrated summary and risk

[[Page 71000]]

characterization for TCDD and related compounds.
    In 2004, EPA asked the National Research Council of the National 
Academy of Sciences (NAS) to review the 2003 dioxin reassessment 
document. The NAS was charged with reviewing ``EPA's modeling 
assumptions (including those associated with dose-response curve and 
points-of-departure dose ranges and associated likelihood estimates 
identified for human health outcomes); EPA's quantitative uncertainty 
analysis; and EPA's selection of studies as a basis for its assessments 
and gaps in scientific knowledge.'' The NAS was also charged with 
addressing two points of controversy: (1) The scientific evidence for 
classifying dioxin as a human carcinogen; and (2) the validity of the 
nonthreshold, low-dose, linear dose-response model and the cancer slope 
factor calculated through the use of this model. In addition, EPA asked 
the NAS to comment on the usefulness of toxic equivalency factors 
(TEFs) and uncertainties associated with their use in risk assessment, 
as well as the uncertainty associated with EPA's approach to analysis 
of food sampling and human dietary intake data, taking into 
consideration the Institute of Medicine's report, Dioxin and Dioxin-
like Compounds in the Food Supply: Strategies to Decrease Exposure. In 
2006, the NAS published its review titled, Health Risks from Dioxin and 
Related Compounds: Evaluation of the EPA Reassessment. The NAS 
identified three areas that required substantial improvement to support 
a scientifically robust risk characterization. These three areas were: 
(1) Justification of approaches to dose-response modeling for cancer 
and non-cancer endpoints; (2) transparency and clarity in selection of 
key data sets for analysis; and (3) transparency, thoroughness, and 
clarity in quantitative uncertainty analysis. The NAS provided EPA with 
recommendations to address their key concerns. The full NAS report, 
including recommendations, is available at http://books.nap.edu/catalog.php?record_id=11688.
    EPA is now beginning to prepare a response to the NAS review of the 
2003 draft dioxin reassessment, and the development of this preliminary 
Literature Search for TCDD Dose-Response is one of the first steps in 
this process. EPA's response to the NAS review of the 2003 draft dioxin 
reassessment will focus on understanding human dose-response for TCDD, 
addressing both cancer and non-cancer endpoints. EPA's objective is to 
address the key findings of the NAS review regarding health effects 
associated with dioxin exposure, while maintaining transparency and 
openness throughout the process and providing opportunity for public 
participation and comment.
    To fully address the key concerns of the NAS, EPA will host a 
scientific expert panel workshop that will include scientists and 
experts from inside and outside of EPA. These experts will consider the 
literature on TCDD dose-response and discuss key scientific issues 
related to this subject area. The literature search results will be 
used by these expert panelists to provide EPA with a list of the key 
studies it should consider in its response to the NAS comments. This 
workshop will be announced in the Federal Register the near future.
    The quantitative assessment of dioxin health effects is important 
to EPA and other organizations with a high level of interest in the 
health risks associated with dioxin exposures. EPA plans to conduct its 
dioxin work in a transparent manner, with the active and open 
involvement of both stakeholders and the public. EPA is initiating the 
process by identifying and engaging with various groups with interest 
and expertise in dioxin health effects assessment. To provide for 
expert peer involvement and review, the SAB Staff Office has solicited 
nominations of nationally recognized scientists for consideration of 
membership on an SAB Panel to provide advice on EPA's reassessment of 
the health risks from dioxin and related compounds (73 FR 61114).
    The broad scope of dioxin science will likely require various 
workshops, consultations, and other discussions of the state of the 
science. EPA may solicit input and seek technical advice at various 
steps during its response to the NAS report. EPA commits to a general 
principle of keeping such discussions open and public, including the 
use of Federal Register notices in advance of conducting workshops and 
releasing interim drafts for review. EPA also has an internet site for 
posting progress reports and news, and for soliciting and sharing 
information on the latest developments in dioxin science (http://www.epa.gov/ncea/dioxin).

How To Submit Technical Input to the Docket (including via 
www.regulations.gov)

    Submit your input, identified by Docket ID No. EPA-HQ-ORD 2008-
0789, by one of the following methods:
     On-line: www.regulations.gov. Follow the on-line 
instructions for submitting input.
     E-mail: [email protected].
     Fax: 202-566-1753.
     Mail: Office of Environmental Information (OEI) Docket 
(Mail Code: 2822T), U.S. Environmental Protection Agency, 1200 
Pennsylvania Ave., NW., Washington, DC 20460. The phone number is 202-
566-1752.
     Hand Delivery: The OEI Docket is located in the EPA 
Headquarters Docket Center, Room 3334 EPA West Building, 1301 
Constitution Ave., NW., Washington, DC. The EPA Docket Center Public 
Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through 
Friday, excluding legal holidays. The telephone number for the Public 
Reading Room is 202-566-1744. Such deliveries are only accepted during 
the docket's normal hours of operation, and special arrangements should 
be made for deliveries of boxed information. If you provide information 
by mail or hand delivery, please submit three copies.
    Instructions: Direct your input to Docket ID No. EPA-HQ-ORD-2008-
0789. Please ensure that your information is submitted within the 
specified open period. Information received after the closing date will 
be marked ``late,'' and may only be considered if time permits. It is 
EPA's policy to include all information it receives in the public 
docket without change and to make this information available online at 
www.regulations.gov, including any personal information provided, 
unless the submission includes information claimed to be Confidential 
Business Information (CBI) or other information whose disclosure is 
restricted by statute. Do not submit information that you consider to 
be CBI or otherwise protected through www.regulations.gov or e-mail. 
The www.regulations.gov Web site is an ``anonymous access'' system, 
which means EPA will not know your identity or contact information 
unless you provide it in the body of your information. If you send an 
e-mail directly to EPA without going through www.regulations.gov, your 
e-mail address will be automatically captured and included as part of 
the input that is placed in the public docket and made available on the 
Internet.

     Dated: November 11, 2008.
Peter W. Preuss,
Director, National Center for Environmental Assessment.
[FR Doc. E8-27853 Filed 11-21-08; 8:45 am]
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