SUPPLEMENTARY INFORMATION:

I. Information About the Document

Section 108(a) of the Clean Air Act directs the Administrator to identify certain pollutants which “may reasonably be anticipated to endanger public health and welfare” and to issue air quality criteria for them. These air quality criteria are to “accurately reflect the latest scientific knowledge useful in indicating the kind and extent of all identifiable effects on public health or welfare which may be expected from the presence of [a] pollutant in the ambient air. * * * .” Under section 109 of the Act, EPA is then to establish national ambient air quality standards (NAAQS) for each pollutant for which EPA has issued criteria. Section 109(d) of the Act subsequently requires periodic review and, if appropriate, revision of existing air quality criteria to reflect advances in scientific knowledge on the effects of the pollutant on public health and welfare. EPA is also to revise the NAAQS, if appropriate, based on the revised air quality criteria.

Sulfur oxides are one of six principal (or “criteria”) pollutants for which EPA has established air quality criteria and NAAQS. EPA periodically reviews the scientific basis for these standards by preparing an Integrated Science Assessment (ISA) (formerly called an Air Quality Criteria Document). The ISA and supplementary annexes, in conjunction with additional technical and policy assessments, provide the scientific basis for EPA decisions on the adequacy of a current NAAQS and the appropriateness of new or revised standards. The Clean Air Scientific Advisory Committee (CASAC), an independent science advisory committee established pursuant to section 109 of the Clean Air Act and part of the EPA's Science Advisory Board (SAB), provides independent scientific advice on NAAQS matters, including advice on EPA's draft ISAs. ( printed page 55208)

On May 16, 2006 (71 FR 28023), EPA formally initiated its current review of the criteria for Sulfur Oxides, requesting the submission of recent scientific information on specified topics. A draft of EPA's “Integrated Plan for Review of the Primary National Ambient Air Quality Standard for Sulfur Dioxide” was made available in February 2007 for public comment and was discussed by the Clean Air Science Advisory Committee (CASAC) via a publicly accessible teleconference consultation on May 11, 2007 (72 FR 20336). The Plan is being finalized and will be made available on EPA's Web site ( http://www.epa.gov/​ttn/​naaqs/​standards/​so2/​s_​so2_​cr_​pd.html). In February 2007 (72 FR 6238), a workshop was held to discuss, with invited scientific experts, initial draft materials prepared in the development of the ISA and supplementary annexes for sulfur oxides.

The draft “Integrated Science Assessment for Sulfur Oxides Health Criteria; First External Review Draft” will be discussed by CASAC at a future public meeting; public comments that have been received prior to the public meeting will be provided to the CASAC review panel. A future Federal Register notice will inform the public of the exact date and time of that CASAC meeting.

II. How To Submit Information to the Docket

Submit your comments, identified by Docket ID No. EPA-HQ-ORD-2006-0260 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 by mail or hand delivery, please submit one unbound original with pages numbered consecutively, 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-2006-0260. Please ensure that your comments are submitted within the specified comment period. Comments 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 comments it receives in the public docket without change and to make the comments available online at http://www.regulations.gov, including any personal information provided, unless a 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.