Air quality implementation plans; approval and promulgation; various States: Colorado,

[Federal Register: August 17, 2007 (Volume 72, Number 159)]

[Rules and Regulations]

[Page 46148-46157]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr17au07-9]

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R08-OAR-2007-0465; FRL-8453-5]

Approval and Promulgation of Air Quality Implementation Plans; State of Colorado; Revised Denver and Longmont Carbon Monoxide Maintenance Plans, and Approval of Related Revisions

AGENCY: Environmental Protection Agency (EPA).

ACTION: Direct final rule.

SUMMARY: EPA is taking direct final action approving a State Implementation Plan (SIP) revision submitted by the State of Colorado. On September 25, 2006, the Governor's designee submitted revised carbon monoxide (CO) maintenance plans for the Denver metropolitan and Longmont areas for the CO National Ambient Air Quality Standard (NAAQS). These revised maintenance plans address maintenance of the CO standard for a second ten-year period beyond redesignation, extends the horizon years, and contains revised transportation conformity budgets. In addition, Regulation No. 11, ``Motor Vehicle Emissions Inspection Program,'' and Regulation No. 13, ``Oxygenated Fuels Program,'' are removed from Denver's and Longmont's revised CO maintenance plans. EPA is approving Denver's and Longmont's revised CO maintenance plans, and the revised transportation conformity budgets. In addition, EPA is also approving the removal of Regulation No. 11 and Regulation No. 13 from Denver's and Longmont's revised CO maintenance plans. This action is being taken under section 110 of the Clean Air Act.

DATES: This direct final rule is effective on October 16, 2007 without further notice, unless EPA receives adverse comment by September 17, 2007. If adverse comment is received, EPA will publish a timely withdrawal of the direct final rule in the Federal Register informing the public that the rule will not take effect.

ADDRESSES: Submit your comments, identified by Docket Number EPA-R08- OAR-2007-0465, by one of the following methods:

http://www.regulations.gov. Follow the on-line

instructions for submitting comments.

E-mail: videtich.callie@epa.gov and fiedler.kerri@epa.gov.

Fax: (303) 312-6064 (please alert the individual listed in the FOR FURTHER INFORMATION CONTACT if you are faxing comments).

Mail: Callie A. Videtich, Director, Air and Radiation Program, Environmental Protection Agency (EPA), Region 8, Mailcode 8P- AR, 1595 Wynkoop Street, Denver, Colorado 80202-1129.

Hand Delivery: Callie A. Videtich, Director, Air and Radiation Program, Environmental Protection Agency (EPA), Region 8, Mailcode 8P-AR, 1595 Wynkoop Street, Denver, Colorado 80202-1129. Such deliveries are only accepted Monday through Friday, 8 a.m. to 4:30 p.m., excluding Federal holidays. Special arrangements should be made for deliveries of boxed information.

Instructions: Direct your comments to Docket ID No. EPA-R08-OAR- 2007-0465. EPA's policy is that all comments received will be included /

[[Page 46149]]

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.

For additional instructions on submitting comments, go to Section I. General Information of the SUPPLEMENTARY INFORMATION section of this document.

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 Air and Radiation

Program, Environmental Protection Agency (EPA), Region 8, 1595 Wynkoop Street, Denver, Colorado 80202-1129. EPA requests that if at all possible, you contact the individual listed in the FOR FURTHER INFORMATION CONTACT section to view the hard copy of the docket. You may view the hard copy of the docket Monday through Friday, 8 a.m. to 4 p.m., excluding Federal holidays.

FOR FURTHER INFORMATION CONTACT: Kerri Fiedler, Air and Radiation Program, Environmental Protection Agency (EPA), Region 8, Mailcode 8P- AR, 1595 Wynkoop Street, Denver, Colorado 80202-1129, phone (303) 312- 6493, and e-mail at: fiedler.kerri@epa.gov..

SUPPLEMENTARY INFORMATION:

Table of Contents

1. General Information II. What is the purpose of this action? III. What is the State's process to submit these materials to EPA? IV. EPA's Evaluation of Denver's and Longmont's Revised CO Maintenance Plans V. EPA's Evaluation of the Transportation Conformity Requirements VI. EPA's Evaluation of Regulation No. 11 Revisions VII. EPA's Evaluation of Regulation No. 13 Revisions VIII. Consideration of Section 110(l) of the Clean Air Act IX. Final Action X. Statutory and Executive Order Reviews

   Definitions

   For the purpose of this document, we are giving meaning to certain words or initials as follows:

   (i) The words or initials Act or CAA mean or refer to the Clean Air Act, unless the context indicates otherwise.

   (ii) The words EPA, we, us or our mean or refer to the United States Environmental Protection Agency.

   (iii) The initials NAAQS mean National Ambient Air Quality Standard.

   (iv) The initials SIP mean or refer to State Implementation Plan.

   (v) The word State means the State of Colorado, unless the context indicates otherwise.

1. General Information

   1. What Should I Consider as I Prepare My Comments for EPA?

   1. Submitting CBI. Do not submit this information to EPA through http://www.regulations.gov or e-mail. Clearly mark the part or all of

   the information that you claim to be CBI. For CBI information in a disk or CD ROM that you mail to EPA, mark the outside of the disk or CD ROM as CBI and then identify electronically within the disk or CD ROM the specific information that is claimed as CBI. In addition to one complete version of the comment that includes information claimed as CBI, a copy of the comment that does not contain the information claimed as CBI must be submitted for inclusion in the public docket. Information so marked will not be disclosed except in accordance with procedures set forth in 40 CFR part 2.

   2. Tips for Preparing Your Comments. When submitting comments, remember to:

   1. Identify the rulemaking by docket number and other identifying information (subject heading, Federal Register date and page number).

   2. Follow directions--The agency may ask you to respond to specific questions or organize comments by referencing a Code of Federal Regulations (CFR) part or section number.

   3. Explain why you agree or disagree; suggest alternatives and substitute language for your requested changes.

   4. Describe any assumptions and provide any technical information and/or data that you used.

   5. If you estimate potential costs or burdens, explain how you arrived at your estimate in sufficient detail to allow for it to be reproduced.

   6. Provide specific examples to illustrate your concerns, and suggest alternatives.

   7. Explain your views as clearly as possible, avoiding the use of profanity or personal threats.

   8. Make sure to submit your comments by the comment period deadline identified.

2. What is the purpose of this action?

   In this action, we are approving revised maintenance plans for the Denver and Longmont CO attainment/maintenance areas, that are designed to keep the areas in attainment for CO for a second ten-year period beyond redesignation. In addition, we are approving revised transportation conformity motor vehicle emissions budgets (MVEBs), and the removal of Regulation No. 11, ``Motor Vehicle Emissions Inspection Program,'' and Regulation No. 13, ``Oxygenated Fuels Program,'' from Denver's and Longmont's revised CO maintenance plans.

   We approved the original CO redesignation to attainment and maintenance plan for the Denver area on December 14, 2001 (see 66 FR 64751), and a revised CO maintenance plan for the Denver area on September 16, 2004 (see 69 FR 55752). The State has made the following changes: (1) Revised and updated the mobile source CO emissions with MOBILE6.2, based on the pending removal of Regulation No. 11, the inspection and maintenance (I/M) program, and Regulation No. 13, the oxygenated fuels program; (2) updated the transportation projections and stationary source inventories; (3) revised the MVEBs including applying a selected amount of the available safety margin to the transportation conformity MVEBs; and, (4) extended the horizon

   [[Page 46150]]

   year to 2021. We have determined that these changes are approvable as further described below.

   We approved the original CO redesignation to attainment and maintenance plan for the Longmont area on September 24, 1999 (see 64 FR 51694), and a revised CO maintenance plan for the Longmont area on September 30, 2004 (see 69 FR 58264). The State has made the following changes: (1) Revised and updated the mobile source CO emissions with MOBILE6.2, based on the pending removal of the I/M and oxygenated fuels programs; (2) updated the transportation projections and stationary source inventories; (3) revised the MVEBs including applying a selected amount of the available safety margin to the transportation conformity MVEBs; and, (4) extended the horizon year to 2020. We have determined that these changes are approvable as further described below.

3. What is the State's process to submit these materials to EPA?

   Section 110(k) of the CAA addresses our actions on submissions of revisions to a State Implementation Plan (SIP). The CAA requires States to observe certain procedural requirements in developing SIP revisions for submittal to us. Section 110(a)(2) of the CAA requires that each SIP revision be adopted after reasonable notice and public hearing. This must occur prior to the revision being submitted by a State to us.

   The Colorado Air Quality Control Commission (AQCC) held a public hearing for the revised Denver and Longmont carbon monoxide (CO) maintenance plans, Regulation No. 11 and Regulation No. 13 on December 15, 2005. The AQCC adopted the revised CO maintenance plans and removal of Regulation No. 11 and Regulation No. 13 from Denver's and Longmont's revised CO maintenance plans directly after the hearing. This SIP revision became State effective on March 2, 2006, and was submitted by the Governor's designee to us on September 25, 2006.

   We have evaluated the revised maintenance plans and have determined that the State met the requirements for reasonable notice and public hearing under section 110(a)(2) of the CAA. As required by section 110(k)(1)(B) of the CAA, we reviewed these SIP materials for conformance with the completeness criteria in 40 CFR part 51, Appendix V and determined that the submittal was administratively and technically complete. Our completeness determination was sent on February 21, 2007, through a letter from Robert E. Roberts, Regional Administrator, to Governor Bill Ritter.

4. EPA's evaluation of Denver's and Longmont's Revised CO Maintenance Plans

   EPA has reviewed the State's revised CO maintenance plans for the Denver and Longmont attainment/maintenance areas and believes that approval is warranted. The following are the key aspects of these revisions along with our evaluation of each:

   (a) The State has revised the Denver and Longmont CO maintenance plans and has provided air quality data that show continuous attainment of the CO NAAQS.

   As described in 40 CFR 50.8, the national primary ambient air quality standard for carbon monoxide is 9 parts per million (10 milligrams per cubic meter) for an 8-hour average concentration not to be exceeded more than once per year. 40 CFR 50.8 continues by stating that the levels of CO in the ambient air shall be measured by a reference method based on 40 CFR part 50, Appendix C and designated in accordance with 40 CFR part 53 or an equivalent method designated in accordance with 40 CFR part 53. The original Denver CO maintenance plan, approved by EPA on December 14, 2001, relied on ambient air quality data from 1996 through 1999. The previously revised Denver CO maintenance plan, approved by EPA on September 16, 2004, relied on ambient air quality data from 2000 through 2002. This revised Denver CO maintenance plan submitted September 25, 2006, relies on ambient air quality data from 2002 through 2004. Further, we have reviewed ambient air quality data from 2005 and 2006 and the Denver area shows continuous attainment of the CO NAAQS from 2000 to present.

   The original Longmont CO maintenance plan, approved by EPA on September 24, 1999, relied on ambient air quality data from 1989 through 1996. The previously revised Longmont CO maintenance plan, approved by EPA on September 30, 2004, relied on ambient air quality data from 1993 through 2003. This revised Longmont CO maintenance plan submitted September 25, 2006, relies on ambient air quality data from 1999 through 2004. Further, we have reviewed ambient air quality data from 2005 and 2006 and the Longmont area shows continuous attainment of the CO NAAQS from 1993 to present. All the above-referenced air quality data are archived in our Aerometric Information and Retrieval System (AIRS).

   (b) Using the MOBILE6.2 emission factor model, the State updated the attainment year, projected years and the maintenance year emission inventories.

   (1) The State updated the attainment year (2001), projected years (2009, 2010, 2013, 2015, 2020) and the maintenance year (2021) emission inventories for Denver's revised CO maintenance plan.

   Denver's revised CO maintenance plan submitted on September 25, 2006, included comprehensive inventories of CO emissions for the Denver area. These inventories include emissions from stationary point sources, area sources, non-road mobile sources, and on-road mobile sources. More detailed descriptions of the 2001 attainment year inventory, the revised 2013 projected inventory, the new 2009, 2010, 2015, and 2020 projected inventories, and the 2021 maintenance year projected inventory are documented in the revised maintenance plan in section C, ``Emission Inventories'' and in the State's Technical Support Document (TSD). The State's submittal contains emission inventory information that was prepared in accordance with EPA guidance. Summary emission figures from the 2001 attainment year and the projected years are provided in Table IV-1 below.

   Table IV-1.--Summary of CO Emissions in Tons per Day for Denver

   2001 2009 2010 2013 2015 2020 2021

   Point Sources.................................... 15.3 18.1 18.5 19.8 20.4 22.9 23.3 Area Sources..................................... 74.1 80.5 81.2 83.4 84.9 88.7 89.4 Non-Road Mobile Sources.......................... 199.4 239.0 241.3 245.6 250.4 262.6 265.6 On-Road Mobile Sources........................... 1708.1 1476.8 1523.9 1429.2 1416.0 1362.7 1372.1

   [[Page 46151]]

   Total........................................ 1997.0 1814.5 1864.9 1778.1 1771.7 1736.9 1750.3

   Note: The significant figures in this table are used to show the small contribution of certain source categories. They are not intended to indicate a level of accuracy in the inventories. Totals may not add due to rounding.

   (2) The State updated the attainment year (1993), projected years (2009, 2010, 2015) and the maintenance year (2020) emission inventories for Longmont's revised CO maintenance plan.

   Longmont's revised CO maintenance plan submitted on September 25, 2006, included comprehensive inventories of CO emissions for the Longmont area. These inventories include emissions from stationary point sources, area sources, non-road mobile sources, and on-road mobile sources. More detailed descriptions of the 1993 attainment year inventory, the revised 2010, and 2015 projected inventories, the new 2009 projected inventory, and the 2020 maintenance year projected inventory are documented in the revised maintenance plan in section C, ``Emission Inventories and Maintenance Demonstration,'' and in the State's TSD. The State's submittal contains emission inventory information that was prepared in accordance with EPA guidance. Summary emission figures from the 1993 attainment year and the projected years are provided in Table IV-2 below.

   Table IV-2.--Summary of CO Emissions in Tons per Day for Longmont

   Source category

   1993

   2009

   2010

   2015

   2020

   Point........................................

   0.18

   0.053

   0.055

   0.059

   0.066 Area.........................................

   3.503

   2.948

   2.956

   3.0

   3.048 Non-Road Mobile..............................

   6.36

   5.983

   6.012

   5.829

   5.988 On-Road Mobile...............................

   43.255 39.952 40.452

   36.459 35.456

   Total....................................

   53.298 48.938 49.565

   45.348 44.558

   Note: The significant figures in this table are used to show the small contribution of certain source categories. They are not intended to indicate a level of accuracy in the inventories. Totals may not add due to rounding.

   The State's approach follows EPA guidance on projected emissions and we believe it is acceptable.\1\ Further information on these projected emissions may also be found in the State's TSD. The revised mobile source emissions show the largest change from the original and previously revised maintenance plans and this is primarily due to the removal of the vehicle inspection/maintenance (I/M) (Regulation No. 11) and oxygenated fuels (Regulation No. 13) programs, effective January 1, 2008. The phase-out of residual I/M program benefits is estimated in the 2009 and 2010 analysis years. January 1, 2009 will have half the benefit of a biennial I/M program and January 1, 2010 will have no residual benefit due to the I/M program. The MOBILE6.2 modeling information is contained in the State's TSD. Much of the modeling data, input-output files, fleet makeup, MOBILE6.2 input parameters, etc. are on a compact disc (CD), included with the docket for this action, and available from either EPA or the State. Other revisions to the mobile sources categories were due to revised vehicle miles traveled (VMT) estimates that were provided to the State from the Denver Regional Council of Governments (DRCOG) which is the metropolitan planning organization (MPO) for both the Denver and Longmont areas. The revised VMT were extracted from DRCOG's 2030 Regional Transportation Plan of January, 2005. In summary, the revised maintenance plans and State TSDs contain detailed emission inventory information, that was prepared in accordance with EPA guidance, and are acceptable to EPA.

   \1\ ``Use of Actual Emissions in Maintenance Demonstrations for Ozone and Carbon Monoxide (CO) Nonattainment Areas'', signed by D. Kent Berry, Acting Director, Air Quality Management Division, November 30, 1993.

   (c) The State revised the maintenance demonstration used in the original and previously revised maintenance plans. (1) Denver

   The original Denver CO redesignation maintenance plan, approved on December 14, 2001, was revised and approved by EPA on September 16, 2004. The State has revised and updated the maintenance plan for a second ten-year period beyond redesignation.

   The September 25, 2006 revised maintenance plan updated mobile source CO emissions with MOBILE6.2, based on the pending removal of Regulation No. 11, the vehicle I/M program and Regulation No. 13, the oxygenated fuels program (from the CO maintenance plan), and using the most recent planning assumptions for the Denver metropolitan area from DRCOG's 2030 Regional Transportation Plan (RTP). The modeling domain- wide vehicle miles traveled (VMT) are presented in section C.2.(a) of Denver's revised CO maintenance plan and Table IV-3 below.

   Table IV-3.--Estimated Daily VMT

   Year

   2001

   2005

   2015

   2020

   2030

   57,984,600 61,842,200 77,544,600 84,765,600 98,499,600

   [[Page 46152]]

   Section C.2.(b) of Denver's revised CO maintenance plan contains a discussion of the State's assessment of point source emissions. Point source inventories were updated including new sources permitted since the previously approved maintenance plan. The State indicates point sources have little or no impact on the maintenance demonstration, consistent with what EPA has approved in previous maintenance plans. We find the State's overall analysis of revised point source emissions acceptable.

   For the non-road and area source emissions, the State relied upon updated demographic information from DRCOG. Several of the non-road and area source emissions are dependent on demographic data as a surrogate emission factor. DRCOG demographics are presented below from section C.1 (Table 4) of Denver's revised CO maintenance plan and a further discussion is presented in the State's TSD.

   Table IV-4.--Demographics

   Year

   2001

   2005

   2015

   2020

   2030

   Population..................................... 2,304,700 2,454,300 2,853,200 3,099,300 3,591,600 Households..................................... 916,480 988,000 1,156,300 1,262,300 1,474,400 Employment..................................... 1,306,800 1,267,100 1,612,300 1,721,300 1,939,500

   We have concluded that the revised maintenance demonstration is approvable. (2) Longmont

   The original Longmont CO redesignation maintenance plan, approved on September 24, 1999, was revised and approved by EPA on September 30, 2004. The State has revised and updated the maintenance plan for a second ten-year period beyond redesignation.

   This revised maintenance plan updated mobile source CO emissions with MOBILE6.2, based on the pending removal of Regulation No. 11 and Regulation No. 13 (from the CO maintenance plan), and using the latest transportation and demographic data from DRCOG. All emission source categories (point, area, non-road, and mobile) were updated using the latest version of applicable models (including MOBILE6.2), transportation data sets, emissions data, emission factors, population figures and other demographic information. As discussed above, the State prepared emission inventories for the years 1993, 2009, 2010, 2015 and 2020. The results of these calculations are presented in Table 3, ``1993-2020 Longmont CO Attainment Area Emissions (Tons per Day),'' on page 7 of the Longmont CO revised maintenance plan and are also summarized in our Table IV-2 above. Emissions for all future years are less than emissions for the 1993 attainment year. Therefore, maintenance of the CO NAAQS is demonstrated and is approvable. (d) Monitoring Network and Verification of Continued Attainment

   Continued attainment of the CO NAAQS in both the Denver and Longmont areas depend, in part, on the State's efforts to track indicators throughout the maintenance period. This requirement is met in section F, ``Monitoring Network/Verification of Continued Attainment'' of the revised Denver CO maintenance plan and section E, ``Monitoring Network/Verification of Continued Attainment'' of the revised Longmont CO maintenance plan. In these sections, the State commits to continue operating the CO monitors in both the Denver and Longmont areas, and to annually review the monitoring networks and make changes as appropriate.

   Also, in these sections, the State commits to track CO emissions from mobile sources (which are the largest component of the inventories) through the ongoing regional transportation planning process done by DRCOG. Since regular revisions to the transportation improvement programs are prepared every two years, and must go through a transportation conformity finding, the State will use this process to periodically review the Vehicle Miles Traveled (VMT) and mobile source emissions projections used in the revised maintenance plans. This regional transportation process is conducted by DRCOG in coordination with the Regional Air Quality Council (RAQC) (in Denver), the City of Longmont (in Longmont), the State's Air Pollution Control Division (APCD), the Colorado Air Quality Control Commission (AQCC), and EPA.

   Based on the above, we are approving these commitments as satisfying the relevant requirements[R3]from ``Procedures for Processing Requests to Redesignate Areas to Attainment,'' signed by John Calcagni, Director, Air Quality Management Division, September 4, 1992. We note that our final rulemaking approval renders the State's commitments federally enforceable. These commitments are also the same as those we approved in the original and the previously revised maintenance plans. (e) Contingency Plan

   Section 175A(d) of the CAA requires that a maintenance plan include contingency provisions. To meet this requirement, the State has identified appropriate contingency measures along with a schedule for the development and implementation of such measures.

   As stated in section G of the revised Denver CO maintenance plan and section F of the revised Longmont CO maintenance plan, the contingency measures for both the Denver and Longmont areas will be triggered by a violation of the CO NAAQS. (However, the maintenance plans note that an exceedance of the CO NAAQS may initiate a voluntary, local process by the RAQC (in Denver) or the City of Longmont (in Longmont), and APCD to identify and evaluate potential contingency measures.)

   The RAQC (in Denver) or the City of Longmont (in Longmont), in coordination with the APCD and AQCC, will initiate a subcommittee process to begin evaluating potential contingency measures no more than 60 days after being notified by the APCD that a violation of the CO NAAQS has occurred. The subcommittee will present recommendations within 120 days of notification and recommended contingency measures will be presented to the AQCC within 180 days of notification. The AQCC will then hold a public hearing to consider the recommended contingency measures, along with any other contingency measures that the AQCC believes may be appropriate to effectively address the violation of the CO NAAQS. The necessary contingency measures will be adopted and implemented within one year after the violation occurs.

   The potential contingency measures that are identified in section G.1 of Denver's revised CO maintenance plan and section F.3 of Longmont's revised CO maintenance plan include: (1) A

   [[Page 46153]]

   3.1% oxygenated fuels program from November 8 through February 7, with a 2.0% oxygen content required from November 1 through November 7, and (2) reinstatement of the enhanced I/M program in effect before January 10, 2000. Denver's revised CO maintenance plan also includes a third potential contingency measure: Transportation Control Measures (TCM) such as financial incentives for Ecopass, Auraria transit pass, and improved traffic signalization. Longmont's revised CO maintenance plan also includes a third potential contingency measure: Nonattainment New Source Review permitting requirements.

   Based on the above, we find that the contingency measures provided in Denver's and Longmont's revised CO maintenance plans are sufficient and meet the requirements of section 175A(d) of the CAA. We note the contingency measures and methodology to implement them are the same as those we approved in the original and previously revised maintenance plans. (f) Subsequent Maintenance Plan Revisions (1) Denver

   The previously approved maintenance plan addressed the period 2001 through 2013 and demonstrated, in accordance with section 175A(a) of the CAA, that the CO standard will be maintained for the initial ten- year period (through 2011). In accordance with section 175A(b), Colorado has submitted a revised maintenance plan eight years after our approval of the original redesignation. The purpose of this revised maintenance plan is to provide for maintenance of the CO standard for the additional ten years (through 2021) following the first ten-year period. (2) Longmont

   The previously approved maintenance plan addressed the period 1999 through 2009 and demonstrated, in accordance with section 175A(a) of the CAA, that the CO standard will be maintained for the initial ten- year period (through 2009). In accordance with section 175A(b), Colorado has submitted a revised maintenance plan eight years after our approval of the original redesignation. The purpose of this revised maintenance plan is to provide for maintenance of the CO standard for the additional ten years (through 2020) following the first ten-year period.

   Based on our review of the components of the revised Denver and Longmont CO maintenance plans, as discussed in items IV.(a) through IV.(f) above, we have concluded that the State has met the necessary requirements for us to fully approve the revised Denver and Longmont CO maintenance plans. It is important to note that neither the maintenance plans nor the control measures relied upon in these maintenance plans simply go away after the maintenance year (2021 for Denver, 2020 for Longmont). Both the maintenance plans and control measures relied upon in these maintenance plans will continue to be a part of Colorado's SIP unless we approve their removal. Both maintenance plans will remain in effect until they are revised and we approve the revision.

5. EPA's Evaluation of the Transportation Conformity Requirements

   One key provision of our conformity regulation requires a demonstration that emissions from the Long Range Transportation Plan and the Transportation Improvement Program are consistent with the emissions budgets in the SIP (40 CFR 93.118 and 93.124). The emissions budgets are defined as the level of mobile source emissions relied upon in the attainment or maintenance demonstration to maintain compliance with the NAAQS in the nonattainment or maintenance area. The rule's requirements and EPA's policy on emissions budgets are found in the preamble to the November 24, 1993, transportation conformity rule (58 FR 62193-62196) and in the sections of the rule referenced above. With respect to maintenance plans, our conformity regulation requires that motor vehicle emission budgets (MVEBs) must be established for the last year of the maintenance plan and may be established for any other years deemed appropriate (40 CFR 93.118).

   For transportation plan analysis years after the last year of the maintenance plan, a conformity determination must show that emissions are less than or equal to the maintenance plan's MVEBs for the last year of the implementation plan. EPA's conformity regulation (40 CFR 93.124) also allows the implementation plan to quantify explicitly the amount by which motor vehicle emissions could be higher while still demonstrating compliance with the maintenance requirement. The implementation plan can then allocate some, or all, of this additional safety margin to the emissions budgets for transportation conformity purposes. (1) Denver

   Section E.2 of the revised Denver CO maintenance plan describes the applicable transportation conformity requirements and updated MVEBs for the revised Denver CO maintenance plan. The State has established a MVEB for 2013 through 2020 and 2021 and beyond. Specifically, the CO MVEBs are defined as 1625 tons per day for 2013 through 2020, and 1600 tons per day for 2021 and beyond. As we explain more fully below, we view these as the budgets for 2013, and 2021 respectively.

   Under our conformity rules, a MVEB is established for a given year, not for a range of years. This is because the MVEB reflects the inventory value for motor vehicle emissions in a given year, plus, potentially, any safety margin in that year. (We explain the concept of safety margin more fully below.) It is not possible to specify the same MVEB for a range of years absent specific analysis supporting the derivation of that budget for each year in the range. As a practical matter, this is not usually important because our conformity rules also say that a MVEB for a particular year applies for conformity analyses of emissions in that year and all subsequent years before the next budget year. See 40 CFR 93.118(b)(1)(ii), ``Emissions in years for which no motor vehicle emissions budget(s) are specifically established must be less than or equal to the motor vehicle emissions budget(s) established for the most recent prior year.'' Therefore, the ``2013 through 2020'' and the ``2021 and beyond'' budgets were derived from, the 2013 and 2021 inventory values, respectively, for on-road vehicle emissions and available safety margin. Thus, we will refer to these as the 2013 and 2021 budgets in the remainder of this action.

   Section E. ``Carbon Monoxide Motor Vehicle Emissions Budget'' of the revised Denver CO maintenance plan describes the applicable transportation conformity requirements and updated MVEBs. The State has revised the 2013 MVEB, and established a new MVEB for the last year of the revised maintenance plan, 2021. Based on this, in order for a positive conformity determination to be made, transportation plan analyses for years between 2013 and 2020 must show that motor vehicle emissions will be less than or equal to the MVEB in 2013. In addition, transportation plan analyses for years after 2021 must show that motor vehicle emissions will be less than or equal to the MVEB in 2021. Our conformity regulation also allows the implementation plan (maintenance plan in this case) to quantify explicitly the

   [[Page 46154]]

   amount motor vehicle emissions that could be higher in 2013, while allowing a demonstration of maintenance of the NAAQS (40 CFR 93.124). This process is known as allocating all or a portion of the designated safety margin to the MVEB and is further described in 40 CFR 93.124 and below.

   In addition, our January 18, 2002 MOBILE6 policy states that `` * * * regardless of the technique used for attainment or maintenance demonstrations, a more rigorous assessment of the SIP's demonstration may be necessary if a State decides to reallocate possible excess emission reductions to the motor vehicle emissions budget safety factor.'' Since the State decided to allocate available excess emissions reductions in the revised maintenance plan to the 2013 and 2021 MVEBs, we required a ``more rigorous assessment'' in order to ensure that even with the allocation of safety margin to the 2013 and 2021 MVEBs, the revised maintenance plan would continue to demonstrate maintenance. The ``more rigorous assessment'' is described in section E.2 of the revised Denver CO maintenance plan, in the State's TSD, and below.

   In section E.2 of the revised Denver CO maintenance plan, the State revises the 2013 MVEB and establishes a MVEB for 2021 and these MVEBs are applicable to the boundaries of the Denver CO attainment/ maintenance area. The revised maintenance plan estimates the available safety margin using the EPA recommended ``more rigorous assessment'' methodology and allocates a portion of the available safety margin to the MVEBs in 2013 and 2021 as illustrated in Table V-2 below.

   Table V-2.--Derivation of the MVEBs for 2013 and 2021 and Allocation of the Safety Margin

   Budget years

   2013 2021

   Explanation

   2001 Total Attainment Inventory. 1997 1997 2001 attainment year inventory from all sources that established attainment level of emissions in the attainment/ maintenance area. Area and Point Source Emissions. 349 378 Total estimated emissions from point and area sources. Mobile Source Emissions......... 1429 1372 Estimated mobile source emissions based on MOBILE6.2 and State control strategies. Total Emission Inventory........ 1778 1750 Potential Safety Margin......... 219 247 Difference between the 2001 and 2013 and 2021 total emission inventories, respectively. Allowable Mobile Source

   1648 1619 Total mobile source Emissions.

   emissions that demonstrate maintenance of the CO NAAQS based on EPA's recommended ``more rigorous assessment''. Available Safety Margin......... 219 247 Difference between allowable mobile source emissions and estimated mobile source emissions which equals the available safety margin that may be allocated to the MVEB. Portion of the Safety Margin

   23 19 Portion of the available Reserved.

   safety margin that is reserved to account for point/area growth and other modeling uncertainties. Safety Margin allocated to the 196 228 Difference between MVEB.

   available safety margin and the reserved safety margin. 2013 and 2021 MVEBs............. 1625 1600 Total of estimated mobile source emissions and safety margin assigned to the budget, which establishes the MVEB for 2013 and 2021.

   As stated above, our January 18, 2002 MOBILE6 policy required a ``more rigorous assessment'' in order to ensure that even with the allocation of safety margin emissions to the MVEBs, the revised maintenance plan would continue to demonstrate maintenance. We determined that a ``more rigorous assessment'' for the revised Denver CO maintenance plan would be an intersection modeling analysis similar to that performed by the State for the original EPA-approved Denver CO maintenance plan and the previously revised EPA-approved Denver CO maintenance plan. The State's intersection analysis used a background CO concentration combined with CAL3QHC intersection (``hot spot'') modeling of the same six high-volume, high congestion intersections that were analyzed for the original and previously revised maintenance plan.

   The background CO concentration for each intersection used the second highest 8-hour maximum monitored value at a nearby CO ambient air quality monitor for the time period of 2000 through 2002. The CAL3QHC intersection modeling used 2013 and 2021 MOBILE6.2 mobile sources emissions and DRCOG projected traffic data. The background concentration and results from the CAL3QHC modeling were then combined for each intersection. If the resulting concentration was greater than 9 ppm (the CO NAAQS), the background concentration was reduced by the necessary percentage to bring the total intersection value below 9 ppm. Since it is assumed that background concentrations are influenced by regional emissions of CO, the State, in order to determine the allowable regional emissions, reduced the base regional emissions (1997 tons per day in 2001) by the same percentage it had to reduce the initial background concentration.

   The State modeled the six intersections based on the 2013 MVEB of 1625 tons per day and the 2021 MVEB of 1600 tons per day of CO. The results are shown in Table 13 on page 23, of the State's revised maintenance plan and are reproduced in Table V-3 below.

   Table V-3.--Intersection Modeling Results [In parts per million]

   2013 2021 Intersection

   Total Total ppm ppm

   28th & Arapahoe (Boulder)............................. 7.8 7.3 University & Belleview................................ 7.1 6.8 University & 1st Ave.................................. 7.5 7.1 Foothills & Arapahoe (Boulder)........................ 7.3 6.9 Wadsworth & Alameda................................... 6.5 6.0 20th & Broadway (CAMP)................................ 6.6 6.5

   The modeling results presented in the revised Denver CO maintenance plan and the State's TSD, and repeated in Table V-3 above, show that CO concentrations are not estimated to exceed the 9.0 ppm 8-hour average CO NAAQS for 2013 or 2021. We have concluded that the State has satisfactorily addressed the requirements of our January 18, 2002 MOBILE6 policy for a ``more rigorous assessment'' of MVEBs and has also demonstrated maintenance of the CO NAAQS while using a transportation conformity MVEB of 1625 tons per day

   [[Page 46155]]

   for 2013 and 1600 tons per day for 2021. Therefore, we are approving the transportation conformity MVEB of 1625 tons per day of CO, for the Denver attainment/maintenance area, for 2013 and 1600 tons per day of CO, for the Denver attainment/maintenance area, for 2021.

   Pursuant to Sec. 93.118(e)(4) of EPA's transportation conformity rule, as amended, EPA must determine the adequacy of submitted MVEBs. EPA reviewed the Denver CO 2021 budget for adequacy using the criteria in 40 CFR 93.118(e)(4), and determined that the 2021 budget was adequate for conformity purposes. EPA's adequacy determination was made in a letter to the State on May 3, 2007, and was announced in the Federal Register on June 13, 2007 (72 FR 32646). As a result of this adequacy finding, the 2021 budget took effect for conformity determinations in the Denver area on June 28, 2007. However, we are not bound by that determination in acting on the maintenance plan. (2) Longmont

   Section D, ``Transportation Conformity and Mobile Source Carbon Monoxide Emission Budgets,'' of the Longmont CO revised maintenance plan briefly describes the applicable transportation conformity requirements, provides MVEB calculations, identifies safety margin, and indicates that the City of Longmont and DRCOG elected to apply the identified safety margin to the MVEB for 2010 through 2014, 2015 through 2019, and 2020 and beyond. Specifically, the CO MVEBs are defined as 43 tons per day for 2010 through 2014, 43 tons per day for 2015 through 2019, and 43 tons per day for 2020 and beyond. As we explained more fully above in V.(1), ``Denver,'' we view these as the budgets for 2010, 2015, and 2020 respectively.

   For the revised Longmont CO maintenance plan, the safety margin is the difference between the attainment year (1993) total emissions and the projected future year's total emissions. Part, or all, of the safety margin may be added to projected mobile source CO emissions to arrive at a motor vehicle emissions budget to be used for transportation conformity purposes. The safety margins, less one ton per day, were added to projected mobile source CO emissions for 2010, 2015, and 2020. The derivation and determination of safety margins and motor vehicle emissions budgets for the Longmont CO maintenance plan is further illustrated in Table V-4 below and in section D of the revised maintenance plan.

   Table V-4.--Mobile Sources Emissions, Safety Margins, and Motor Vehicle Emissions Budgets In Tons of CO per Day (tpd)

   Mobile source Total

   Margin of Motor vehicle Year

   emissions emissions

   Math

   safety (tpd) emission (tpd)

   (tpd)

   budget (tpd)

   1993.......................... ........... 53.298 2010.......................... 40.452 49.565 53.298 - 49.565 =

   2.733

   43 3.733. 3.733 - 1 = 2.733..... 2.733 + 40.452 = 43.185. 2015.......................... 36.459 45.348 53.298 - 45.348 = 7.95

   6.95

   43 7.95 - 1 = 6.95....... 6.95 + 36.459 = 43.409 2020.......................... 35.456 44.558 53.298 - 44.558 = 8.74

   7.74

   43 8.74 - 1 = 7.74....... 7.74 + 35.456 = 43.196

   Our analysis indicates that the above figures are consistent with maintenance of the CO NAAQS throughout the maintenance period. Therefore, we are approving the 43 tons per day CO MVEB for 2010, 2015, and 2020 for the Longmont area.

   As described above, EPA must determine the adequacy of submitted MVEBs. EPA reviewed the Longmont CO 2020 budget for adequacy using the criteria in 40 CFR 93.118(e)(4), and determined that the 2020 budget was adequate for conformity purposes. EPA's adequacy determination was made in a letter to the State on May 3, 2007, and was announced in the Federal Register on June 13, 2007 (72 FR 32646). As a result of this adequacy finding, the 2020 budget took effect for conformity determinations in the Longmont area on June 28, 2007. However, we are not bound by that determination in acting on the maintenance plan.

6. EPA's Evaluation of the Regulation No. 11 Revisions

   Colorado's Regulation No. 11 is entitled, ``Motor Vehicle Emissions Inspection Program.'' In developing the revised Denver and Longmont CO maintenance plans, the State conducted a comprehensive reevaluation of mobile source control programs with MOBILE6.2 and the latest transportation sets from DRCOG's 2030 Regional Transportation Plan. Based on the results from the modeling demonstration in the State's TSD

   [R4] , Colorado's Regulation No. 11 can be removed from the revised Denver and Longmont CO maintenance plans effective December 31, 2007. These revised maintenance plans reflect the removal of Regulation No. 11 in that the mobile source CO emissions were calculated without the CO emissions reduction benefit of an inspection and maintenance (I/ M) program starting January 1, 2008 and continuing through 2021 for Denver and 2020 for Longmont. The phase-out of residual I/M program benefits is estimated in the 2009 and 2010 analysis years. January 1, 2009 will have half the benefit of a biennial I/M program and January 1, 2010 will have no residual benefit due to the I/M program. Even with the elimination of the I/M program from the revised Denver and Longmont CO maintenance plans beginning on January 1, 2008, the areas were still able to meet our requirements to demonstrate maintenance of the CO standard through 2021 for Denver and 2020 for Longmont.

   We note that the removal of the I/M program from Denver's revised CO maintenance plan does not mean the I/M program is eliminated. The State relies on the I/M program in Denver's 1-hour ozone maintenance plan and Denver's 8-hour ozone Early Action Compact (EAC). Therefore, the motor vehicle I/M program will remain intact in the Denver-metro area. We have

   [[Page 46156]]

   reviewed and are approving the removal of Regulation No. 11 from the revised Denver and Longmont CO maintenance plans.

   Additionally, we note that the State had made previous revisions to Regulation No. 11 regarding the repeal of the basic vehicle emissions inspection program in the Fort Collins and Greeley areas that were adopted by the Colorado AQCC on November 17, 2005, and submitted to us for approval by the Governor on August 8, 2006. We previously approved Fort Collins' and Greeley's revised CO maintenance plans which eliminated the Basic I/M program from the Federal SIP on July 22, 2003 and August 19, 2005, respectively (68 FR 43316 and 70 FR 48650). Without the CO emissions reduction benefit of a Basic I/M program, these areas were still able to meet our requirements to demonstrate maintenance of the CO standard. The August 8, 2006 submittal merely clarifies the geographical applicability in Part A.1 and Part A.IV. In addition, the August 8, 2006 submittal also eliminates the inspection requirement for vehicles that have not yet reached their fourth model year, registering in the I/M program area for the first time. This is consistent with the regulation and the mobile source modeling that the first four model years are exempt from the I/M program. We have reviewed and are approving Part A.1 and Part A.IV of Regulation No. 11 as submitted on August 8, 2006, to repeal the Basic Vehicle Emissions Inspection Program in the Fort Collins and Greeley areas.[R5] Please note we are not acting on other Regulation No. 11 revisions submitted on August 8, 2006 at this time. These other revisions are located in Part F and revise the emissions limits for motor vehicle exhaust, evaporative and visible emissions for light-duty and heavy- duty vehicles.

7. EPA's Evaluation of the Regulation No. 13 Revisions

   Colorado's Regulation No. 13 is entitled, ``Oxygenated Fuels Program.'' The purpose of this regulation is to reduce CO emissions from gasoline powered motor vehicles through the wintertime use of oxygenated gasoline. In developing the revised Denver and Longmont CO maintenance plans, the State conducted a comprehensive reevaluation of mobile source control programs with MOBILE6.2 and the latest transportation sets from DRCOG's 2030 Regional Transportation Plan. Based on the results from the modeling demonstration in the State's TSD[R6], Colorado's Regulation No. 13 can be removed from the revised Denver and Longmont CO maintenance plans effective December 31, 2007. These maintenance plans reflect the removal of Regulation No. 13 in that the mobile source CO emissions were calculated without the CO emissions reduction benefit of an oxygenated fuels program starting January 1, 2008 and continuing through 2021 for Denver and 2020 for Longmont. Even with the elimination of the oxygenated fuels program from the revised Denver and Longmont CO maintenance plans beginning on January 1, 2008, the areas were still able to meet our requirements to demonstrate maintenance of the CO standard through 2021 for Denver and 2020 for Longmont.

   Additionally, we note that the State had made previous revisions to Regulation No. 13 regarding methyl tert-butyl ether (MTBE) that were adopted by the Colorado AQCC on January 11, 2001, and submitted to us for approval by the Governor on July 31, 2002. With our approval of the removal of Regulation No. 13 from the revised Denver and Longmont CO maintenance plans, the oxygenated fuels program is not federally required and will no longer be federally applicable in any area. Regulation No. 13 will, however, remain as a state only regulation. Therefore, this July 31, 2002 submittal does not require further EPA action. We have reviewed and are approving the removal of Regulation No. 13 from the revised Denver and Longmont CO maintenance plans.

8. Consideration of Section 110(l) of the Clean Air Act

   Section 110(l) of the CAA states that a SIP revision cannot be approved if the revision would interfere with any applicable requirement concerning attainment and reasonable further progress towards attainment of a NAAQS or any other applicable requirement of the CAA. As stated above, the revised CO maintenance plans show continuous attainment of the CO NAQAQS since 2001 for Denver and 1993 for Longmont. The revised maintenance plans along with the removal of Regulation No. 11 and Regulation No. 13 will not interfere with attainment, reasonable further progress, or any other applicable requirement of the CAA.

9. Final Action

   In this action, EPA is approving the revised Denver and Longmont CO maintenance plans, that were submitted on September 25, 2006, and we are also approving the revised transportation conformity motor vehicle emission budgets for CO for the years 2013 and 2021 for Denver, and 2010, 2015, and 2020 for Longmont. Furthermore, we are approving the removal of Regulation No. 11 (I/M) and Regulation No. 13 (Oxygenated Fuels) from the revised Denver and Longmont CO maintenance plans.

   EPA is publishing this rule without prior proposal because the Agency views this as a noncontroversial amendment and anticipates no adverse comments. However, in the ``Proposed Rules'' section of today's Federal Register publication, EPA is publishing a separate document that will serve as the proposal to approve the SIP revision if adverse comments are filed. This rule will be effective October 16, 2007 without further notice unless the Agency receives adverse comments by September 17, 2007. If the EPA receives adverse comments, EPA will publish a timely withdrawal in the Federal Register informing the public that the rule will not take effect. EPA will address all public comments in a subsequent final rule based on the proposed rule. The EPA will not institute a second comment period on this action. Any parties interested in commenting must do so at this time. Please note that if EPA receives adverse comment on an amendment, paragraph, or section of this rule and if that provision may be severed from the remainder of the rule, EPA may adopt as final those provisions of the rule that are not the subject of an adverse comment.

10. Statutory and Executive Order Reviews

    Under Executive Order 12866 (58 FR 51735, October 4, 1993), this action is not a ``significant regulatory action'' and therefore is not subject to review by the Office of Management and Budget. For this reason, this action is also not subject to Executive Order 13211, ``Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution, or Use'' (66 FR 28355, May 22, 2001). This action merely approves state law as meeting Federal requirements and imposes no additional requirements beyond those imposed by state law. Accordingly, the Administrator certifies that this rule will not have a significant economic impact on a substantial number of small entities under the Regulatory Flexibility Act (5 U.S.C. 601 et seq.). Because this rule approves pre-existing requirements under state law and does not impose any additional enforceable duty beyond that required by state law, it does not contain any unfunded mandate or significantly or uniquely affect small governments, as described in the

    [[Page 46157]]

    Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4).

    This rule also does not have tribal implications because it will not have a substantial direct effect on one or more Indian tribes, on the relationship between the Federal Government and Indian tribes, or on the distribution of power and responsibilities between the Federal Government and Indian tribes, as specified by Executive Order 13175 (65 FR 67249, November 9, 2000). This action also does not have Federalism implications because it does not have substantial direct effects on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government, as specified in Executive Order 13132 (64 FR 43255, August 10, 1999). This action merely approves a state rule implementing a Federal standard, and does not alter the relationship or the distribution of power and responsibilities established in the Clean Air Act. This rule also is not subject to Executive Order 13045 ``Protection of Children from Environmental Health Risks and Safety Risks'' (62 FR 19885, April 23, 1997), because it is not economically significant.

    In reviewing SIP submissions, EPA's role is to approve state choices, provided that they meet the criteria of the Clean Air Act. In this context, in the absence of a prior existing requirement for the State to use voluntary consensus standards (VCS), EPA has no authority to disapprove a SIP submission for failure to use VCS. It would thus be inconsistent with applicable law for EPA, when it reviews a SIP submission, to use VCS in place of a SIP submission that otherwise satisfies the provisions of the Clean Air Act. Thus, the requirements of section 12(d) of the National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 note) do not apply. This rule does not impose an information collection burden under the provisions of the Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.).

    The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the Small Business Regulatory Enforcement Fairness Act of 1996, generally provides that before a rule may take effect, the agency promulgating the rule must submit a rule report, which includes a copy of the rule, to each House of the Congress and to the Comptroller General of the United States. EPA will submit a report containing this rule and other required information to the U.S. Senate, the U.S. House of Representatives, and the Comptroller General of the United States prior to publication of the rule in the Federal Register. A major rule cannot take effect until 60 days after it is published in the Federal Register. This action is not a ``major rule'' as defined by 5 U.S.C. 804(2).

    Under section 307(b)(1) of the Clean Air Act, petitions for judicial review of this action must be filed in the United States Court of Appeals for the appropriate circuit by October 16, 2007. Filing a petition for reconsideration by the Administrator of this final rule does not affect the finality of this rule for the purposes of judicial review nor does it extend the time within which a petition for judicial review may be filed, and shall not postpone the effectiveness of such rule or action. This action may not be challenged later in proceedings to enforce its requirements. (See section 307(b)(2).)

    List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Carbon monoxide, Incorporation by reference, Intergovernmental relations, Reporting and recordkeeping requirements.

    Dated: July 31, 2007. Kerrigan G. Clough, Acting Regional Administrator, Region VIII.

    0 40 CFR part 52 is amended to read as follows:

    PART 52--[AMENDED]

    0 1. The authority citation for part 52 continues to read as follows:

    Authority: 42 U.S.C. 7401 et seq.

    Subpart G--Colorado

    0 2. Section 52.320 is amended by adding paragraph (c)(111) [R7]to read as follows:

    Sec. 52.320 Identification of plan.

    * * * * *

    (c) * * *

    (111) On August 8, 2006, the Governor of Colorado submitted SIP revisions to Colorado's Regulation No. 11 ``Motor Vehicle Emissions Inspection Program'' that repeals the basic vehicle emissions inspection program in the Fort Collins and Greeley areas.

    (i) Incorporation by reference.

    (A) Regulation No. 11 ``Motor Vehicle Emissions Inspection Program,'' 5CCR1001-13, Part A.1 and Part A.IV, as adopted on November 17, 2005, and effective January 30, 2006. 0 3. Section 52.349 is amended by adding paragraphs (m) and (n) to read as follows:

    Sec. 52.349 Control strategy: Carbon monoxide.

    * * * * *

    (m) Revisions to the Colorado State Implementation Plan, revised Carbon Monoxide Maintenance Plan for Denver, as adopted by the Colorado Air Quality Control Commission on December 15, 2005, State effective on March 2, 2006, and submitted by the Governor's designee on September 25, 2006.

    (n) Revisions to the Colorado State Implementation Plan, revised Carbon Monoxide Maintenance Plan for Longmont, as adopted by the Colorado Air Quality Control Commission on December 15, 2005, State effective on March 2, 2006, and submitted by the Governor's designee on September 25, 2006.

    [FR Doc. E7-16146 Filed 8-16-07; 8:45 am]

    BILLING CODE 6560-50-P