Document ID: EPA-HQ-ORD-2006-1009-0001
Agency: epa
Document Type: Notice
Title: Draft Toxicological Review of 2,2,4-Trimethylpentane: In Support of Summary Information on the Integrated Risk Information System (IRIS)
Posted Date: 2006-12-29T05:00Z

[Federal Register: December 29, 2006 (Volume 71, Number 250)]
[Notices]               
[Page 78434-78436]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr29de06-74]                         

-----------------------------------------------------------------------

ENVIRONMENTAL PROTECTION AGENCY

[FRL-8263-9; Docket ID No. EPA-HQ-ORD-2006-1009]

 
Draft Toxicological Review of 2,2,4-Trimethylpentane: In Support 
of Summary Information on the Integrated Risk Information System (IRIS)

AGENCY: Environmental Protection Agency (EPA).

[[Page 78435]]

ACTION: Notice of public comment period and external peer review panel 
meeting.

-----------------------------------------------------------------------

SUMMARY: The EPA is announcing a public comment period and an external 
peer review panel meeting to review the draft document titled, 
``Toxicological Review of 2,2,4-Trimethylpentane: In Support of Summary 
Information on the Integrated Risk Information System (IRIS)'' (NCEA-S-
2202), related to the human health assessment for 2,2,4-
trimethylpentane. The document was prepared by the National Center for 
Environmental Assessment (NCEA) within EPA's Office of Research and 
Development.
    EPA is releasing this draft document solely for the purpose of pre-
dissemination peer review under applicable information quality 
guidelines. This document has not been formally disseminated by EPA. It 
does not represent and should not be construed to represent any Agency 
policy or determination. EPA will consider any public comments 
submitted in accordance with this notice when revising the document.

DATES: The 45-day public comment period begins on December 29, 2006 and 
ends February 12, 2007. Technical comments should be in writing and 
must be received by EPA by February 12, 2007. The peer review panel 
meeting will be conducted on February 28, 2007, by teleconference and 
will begin at 1 p.m. and end at 4 pm. Members of the public may call 
into the teleconference meeting and are invited to provide oral 
statements at the commencement of the teleconference. (For more 
information refer to the instructions for registration provided in the 
ADDRESSES section of this notice.)

ADDRESSES: The external peer review panel meeting will be held by 
teleconference. Under an Interagency Agreement with EPA and the 
Department of Energy, the Oak Ridge Institute of Science and Education 
(ORISE) is organizing, convening, and conducting the peer review panel 
meeting. To obtain the teleconference call-in number and access code, 
register by February 14, 2007, by calling ORISE, P.O. Box 117, MS 17, 
Oak Ridge, TN 37831-0117, at (865) 576-2922 or (865) 241-3168 
(facsimile). Interested parties may also register on-line at: http://www.orau.gov/trimethylpentane.
 Public comments submitted to the EPA by 

February 12, 2007 will be provided to the external peer review panel 
prior to the teleconference meeting.
    The draft, ``Toxicological Review of 2,2,4-Trimethylpentane: In 
Support of Summary Information on the Integrated Risk Information 
System (IRIS)'' (NCEA-S-2202) is available primarily via the Internet 
on NCEA's home page under the Recent Additions menu at http://www.epa.gov/ncea.
 A limited number of paper copies are available by 

contacting the IRIS Hotline at (202) 566-1676, (202) 566-1749 
(facsimile), or hotline.iris@epa.gov. If you are requesting a paper 
copy, please provide your name, mailing address, the document title, 
and the EPA number of the requested publication. Copies are not 
available from ORISE.
    Technical comments may be submitted electronically via 
http://www.regulations.gov, by mail, by facsimile, or by hand delivery/

courier. Please follow the detailed instructions provided in the 
SUPPLEMENTARY INFORMATION section of this notice.

FOR FURTHER INFORMATION CONTACT: Questions regarding registration and 
logistics should be directed to Margaret Lyday, ORISE, P.O. Box 117, MS 
17, Oak Ridge, TN 37831-0117, at (865) 576-2922 or (865) 241-3168 
(facsimile), lydaym@orau.gov (email).
    If you have questions about the document, contact John Stanek, 
Chemical Manager, National Center for Environmental Assessment; 
telephone: (919) 541-1048; facsimile: (919) 541-0248; email: 
stanek.john@epa.gov.

SUPPLEMENTARY INFORMATION: 

I. Information About the Document

    IRIS is a database that contains Agency scientific positions on 
potential adverse human health effects that may result from chronic (or 
lifetime) exposure to specific chemical substances found in the 
environment. The database (available on the Internet at http://www.epa.gov/iris
) contains qualitative and quantitative health effects 

information for more than 500 chemical substances that may be used to 
support the first two steps (hazard identification and dose-response 
evaluation) of the risk assessment process. When supported by available 
data, the database provides oral reference doses (RfDs) and inhalation 
reference concentrations (RfCs) for chronic health effects, and oral 
slope factors and inhalation unit risks for carcinogenic effects. 
Combined with specific exposure information, government and private 
entities use IRIS to help characterize public health risks of chemical 
substances in a site-specific situation and thereby support risk 
management decisions designed to protect public health.
    2,2,4-Trimethylpentane, also known as isooctane or 
isobutyltrimethylmethane, is a hydrocarbon used primarily in deriving 
high-octane fuels. It comprises about 10% of unleaded gasoline. 2,2,4-
Trimethylpentane is released into the environment through the 
manufacture, use, and disposal of products associated with the gasoline 
and petroleum industry. The current assessment posted on IRIS (1991) 
does not include an evaluation of the oral non-cancer or the cancer 
literature; for the inhalation RfC, a message indicates that the health 
effects data for 2,2,4-trimethylpentane were considered inadequate for 
the derivation of an inhalation RfC. A review of the more recent 
literature identified mechanistic studies, gavage studies, and 
toxicokinetic studies, the majority of which were designed to 
specifically address and characterize the involvement of 
alpha2u-globulin accumulation in the renal toxicity observed 
in the male rat. Little or no evaluation of other endpoints in tissues/
organs other than the kidney was reported. Therefore, the major issues 
discussed in the draft assessment are: (1) the association of TMP-
induced renal effects in male rats with alpha2u-globulin 
accumulation, and (2) the lack of studies with sufficient duration and 
dose-response information for any endpoint from which to derive 
reference values.

II. How to Submit Technical Comments to the Docket at 
http://www.regulations.gov

    Submit your comments, identified by Docket ID No. EPA-HQ-ORD-2006-
1009 by one of the following methods:
     http://www.regulations.gov: Follow the on-line 

instructions for submitting comments.
     E-mail: ORD.Docket@epa.gov.
     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, EPA West Building, Room 3334, 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 comments in writing, please submit one unbound 
original with pages numbered consecutively,

[[Page 78436]]

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.
    Instructions: Direct your comments to Docket ID No. EPA-HQ-ORD-
2006-1009. EPA's policy is that all comments received will be included 
in the public docket without change and may be made available online at 
http://www.regulations.gov, including any personal information 

provided, unless the comment 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 http://www.regulations.gov 

or e-mail. The http://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 comment. If you 
send an e-mail comment directly to EPA without going through 
http://www.regulations.gov, your e-mail address will be automatically captured 

and included as part of the comment that is placed in the public docket 
and made available on the Internet. If you submit an electronic 
comment, EPA recommends that you include your name and other contact 
information in the body of your comment and with any disk or CD-ROM you 
submit. If EPA cannot read your comment due to technical difficulties 
and cannot contact you for clarification, EPA may not be able to 
consider your comment. Electronic files should avoid the use of special 
characters, any form of encryption, and be free of any defects or 
viruses. For additional information about EPA's public docket visit the 
EPA Docket Center homepage at http://www.epa.gov/epahome/dockets.htm.

    Docket: All documents in the docket are listed in the 
http://www.regulations.gov index. Although listed in the index, some 

information is not publicly available, e.g., CBI or other information 
whose disclosure is restricted by statute. Certain other material, such 
as copyrighted material, will be publicly available only in hard copy. 
Publicly available docket materials are available either electronically 
in http://www.regulations.gov or in hard copy at the OEI Docket in the EPA 

Headquarters Docket Center.

    Dated: December 20, 2006.
George Alapas,
Deputy Director, National Center for Environmental Assessment.
[FR Doc. E6-22431 Filed 12-28-06; 8:45 am]

BILLING CODE 6560-50-P