Document ID: EPA-R08-OAR-2006-0163-0001
Agency: epa
Document Type: Proposed Rule
Title: Approval and Promulgation of Air Quality Implementation Plans; State of Montana; Missoula Carbon Monoxide Redesignation to Attainment, Designation of Areas for Air Quality Planning Purposes, and Approval of Related Revisions
Posted Date: 2007-04-25T04:00Z

[Federal Register: April 25, 2007 (Volume 72, Number 79)]
[Proposed Rules]               
[Page 20480-20488]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr25ap07-18]                         

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 52 and 81

[EPA-R08-OAR-2006-0163; FRL-8305-2]

 
Approval and Promulgation of Air Quality Implementation Plans; 
State of Montana; Missoula Carbon Monoxide Redesignation to Attainment, 
Designation of Areas for Air Quality Planning Purposes, and Approval of 
Related Revisions

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: EPA is proposing to approve State Implementation Plan (SIP) 
revisions submitted by the State of Montana. On May 27, 2005, the 
Governor of Montana submitted a request to redesignate the Missoula 
``moderate'' carbon monoxide (CO) nonattainment area to attainment for 
the CO National Ambient Air Quality Standard (NAAQS). The Governor also 
submitted a CO maintenance plan which includes transportation 
conformity motor vehicle emission budgets (MVEB) for 2000, 2010, and 
2020. In addition, EPA is proposing to approve CO periodic emission 
inventories for 1993 and 1996 for the Missoula nonattainment area that 
the State had previously submitted. This action is being taken under 
section 110 of the Clean Air Act.

DATES: Comments must be received on or before May 25, 2007.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R08-
OAR-2006-0163, 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.

[[Page 20481]]

--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-
2006-0163. 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.
 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, Environmental 
Protection Agency, Region 8, 1595 Wynkoop Street, Denver, Colorado 
80202-1129, phone (303) 312-6493, and e-mail at: fiedler.kerri@epa.gov.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. 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 the Missoula Redesignation Request and 
Maintenance Plan
V. EPA's Evaluation of the Transportation Conformity Requirements
VI. Consideration of Section 110(l) of the Clean Air Act
VII. Proposed Action
VIII. 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 Montana, unless the context 
indicates otherwise.

I. General Information

(a). 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.
    (b). Tips for Preparing Your Comments. When submitting comments, 
remember to:
    A. Identify the rulemaking by docket number and other identifying 
information (subject heading, Federal Register date and page number).
    B. 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.
    C. Explain why you agree or disagree; suggest alternatives and 
substitute language for your requested changes.
    D. Describe any assumptions and provide any technical information 
and/or data that you used.
    E. If you estimate potential costs or burdens, explain how you 
arrived at your estimate in sufficient detail to allow for it to be 
reproduced.
    F. Provide specific examples to illustrate your concerns, and 
suggest alternatives.
    G. Explain your views as clearly as possible, avoiding the use of 
profanity or personal threats.
    Make sure to submit your comments by the comment period deadline 
identified.

II. What is the purpose of this action?

    In this action, we are proposing approval of a change in the legal 
designation of the Missoula area from nonattainment for CO to 
attainment. We're proposing approval of the year 2000 attainment 
emission inventory and the maintenance plan that is designed to keep 
the area in attainment for CO for the next 13 years. We're also 
proposing approval of the transportation conformity motor vehicle 
emission budgets (MVEB) for 2000, 2010, and 2020, and we're proposing 
approval of the 1993 and 1996 CO periodic emission inventories.
    We originally designated Missoula as nonattainment for CO under the 
provisions of the 1977 CAA Amendments (see 43 FR 8962, March 3, 1978). 
On November 15, 1990, the Clean Air Act Amendments of 1990 were enacted 
(Pub. L. 101-549, 104 Stat. 2399, codified at 42 U.S.C. 7401-7671q). 
Under section 107(d)(1)(C) of the Clean Air Act (CAA), we designated 
the

[[Page 20482]]

Missoula area as nonattainment for CO because the area had been 
designated as nonattainment before November 15, 1990. Under section 186 
of the CAA, Missoula was classified as a ``moderate'' CO nonattainment 
area with a design value less than or equal to 12.7 parts per million 
(ppm), and was required to attain the CO NAAQS by December 31, 1995. 
See 56 FR 56694, November 6, 1991. Further information regarding this 
classification and the accompanying requirements are described in the 
``General Preamble for the Implementation of Title I of the Clean Air 
Act Amendments of 1990.'' See 57 FR 13498, April 16, 1992.
    Under the CAA, we can change designations if acceptable data are 
available and if certain other requirements are met. See CAA section 
107(d)(3)(D). Section 107(d)(3)(E) of the CAA provides that the 
Administrator may not promulgate a redesignation of a nonattainment 
area to attainment unless:
    (i) The Administrator determines that the area has attained the 
national ambient air quality standard;
    (ii) The Administrator has fully approved the applicable 
implementation plan for the area under CAA section 110(k);
    (iii) The Administrator determines that the improvement in air 
quality is due to permanent and enforceable reductions in emissions 
resulting from implementation of the applicable implementation plan and 
applicable Federal air pollutant control regulations and other 
permanent and enforceable reductions;
    (iv) The Administrator has fully approved a maintenance plan for 
the area as meeting the requirements of CAA section 175A; and,
    (v) The State containing such area has met all requirements 
applicable to the area under section 110 and part D of the CAA.
    Before we can approve the redesignation request, we must decide 
that all applicable SIP elements have been fully approved. Approval of 
the applicable SIP elements may occur simultaneously with our final 
approval of the redesignation request. That's why we are also proposing 
approval of the 1993 and 1996 CO periodic emission inventories and the 
year 2000 emission inventory.

III. 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 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 Missoula City-County Air Pollution Control Board (MCCAPCB) held 
a public hearing for the Missoula CO redesignation request and the 
maintenance plan on November 18, 2004. The MCCAPCB adopted the Missoula 
CO redesignation request and maintenance plan on March 7, 2005. The 
Missoula CO redesignation request and maintenance plan were then 
forwarded to the Montana Department of Environmental Quality (MDEQ) for 
the State to conduct its public hearing. The MDEQ held a public hearing 
for the Missoula CO redesignation request and the maintenance plan on 
April 22, 2005 after which the SIP materials were forwarded to the 
Governor for his submittal to EPA. These SIP revision materials were 
submitted by the Governor to us on May 27, 2005.
    We have evaluated the Governor's submittal and have concluded that 
the State met the requirements for reasonable notice and public hearing 
under section 110(a)(2) of the CAA. By operation of law, under section 
110(k)(1)(B) of the CAA, the Governor's May 27, 2005, submittal became 
complete on November 27, 2005.

IV. EPA's Evaluation of the Missoula Redesignation Request and 
Maintenance Plan

    Under the CAA, we can change designations of areas if acceptable 
data are available and if certain other requirements are met. See CAA 
section 107(d)(3)(D). We have reviewed the Missoula area's 
redesignation request and maintenance plan (section 2.0) and believe 
that approval of the request is warranted, consistent with the 
requirements of CAA section 107(d)(3)(E) as presented in our section II 
above.
    As we noted above, before we can approve the redesignation request, 
we must decide that all applicable SIP elements have been fully 
approved. Approval of the applicable SIP elements may occur 
simultaneously with final approval of the redesignation request. That's 
why we are also proposing to approve the 1993 and 1996 periodic 
emission inventories and the year 2000 attainment inventory (to also 
suffice as the 1999 periodic emission inventory.) The following are 
descriptions of how the section 107(d)(3)(E) requirements are being 
addressed.

(a) Redesignation Criterion: The Area Must Have Attained the Carbon 
Monoxide (CO) NAAQS

    Section 107(d)(3)(E)(i) of the CAA states that for an area to be 
redesignated to attainment, the Administrator must determine that the 
area has attained the applicable NAAQS. As described in 40 CFR 50.8, 
the national primary ambient air quality standards for carbon monoxide 
are 9 parts per million (10 milligrams per cubic meter) for an 8-hour 
average concentration not to be exceeded more than once per year, and 
35 parts per million (40 milligrams per cubic meter) for a 1-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.
    Attainment of the CO standards is not a momentary phenomenon based 
on short-term data. Instead, we consider an area to be in attainment if 
each of the CO ambient air quality monitors in the area doesn't have 
more than one exceedance of the relevant CO standard over a one-year 
period. See 40 CFR 50.8 and 40 CFR 50, Appendix C. If any monitor in 
the area's CO monitoring network records more than one exceedance of 
the relevant CO standard during a one-year calendar period, then the 
area is in violation of the CO NAAQS. In addition, our interpretation 
of the CAA and EPA national policy \1\ has been that an area seeking 
redesignation to attainment must show attainment of the CO NAAQS for at 
least a continuous two-year calendar period. In addition, the area must 
also continue to show attainment through the date that we promulgate 
the redesignation in the Federal Register.
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    \1\ Refer to EPA's September 4, 1992, John Calcagni policy 
memorandum entitled ``Procedures for Processing Requests to 
Redesignate Areas to Attainment.''
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    Montana's CO redesignation request for the Missoula area is based 
on an analysis of quality assured ambient air quality monitoring data 
that are relevant to the redesignation request. As presented in section 
2.1.1 of the maintenance plan, ambient air quality monitoring data for 
consecutive calendar years 2000 through 2003 show a measured exceedance 
rate of the CO NAAQS of 1.0 or less per year, per monitor, in the 
Missoula nonattainment area. Further, we have reviewed ambient air 
quality data from 2004 through December 2006 and the

[[Page 20483]]

Missoula area continues to show attainment of the CO NAAQS. All of 
these data were collected and analyzed as required by EPA (see 40 CFR 
50.8 and 40 CFR 50, Appendix C) and have been archived by the State in 
our Air Quality System (AQS) national database. Therefore, we believe 
the Missoula area has met the first component for redesignation: 
demonstration of attainment of the CO NAAQS. We note that the State has 
also committed, in the maintenance plan, to continue the necessary 
operation of the CO monitor in compliance with all applicable Federal 
regulations and guidelines.

(b) Redesignation Criterion: The Area Must Have Met All Applicable 
Requirements Under Section 110 and Part D of the CAA and Title II of 
the CAA

    To be redesignated to attainment, section 107(d)(3)(E)(v) requires 
that an area must meet all applicable requirements under section 110 
and part D of the CAA. We interpret section 107(d)(3)(E)(v) to mean 
that for a redesignation to be approved by us, the State must meet all 
requirements that applied to the subject area prior to or at the time 
of the submission of a complete redesignation request. In our 
evaluation of a redesignation request, we don't need to consider other 
requirements of the CAA that became due after the date of the 
submission of a complete redesignation request.
1. CAA Section 110 Requirements
    On January 10, 1980, we approved revisions to Montana's SIP as 
meeting the requirements of section 110(a)(2) of the CAA (see 45 FR 
2034). Although section 110 of the CAA was amended in 1990, most of the 
changes were not substantial. Thus, we have determined that the SIP 
revisions approved in 1980 continue to satisfy the requirements of 
section 110(a)(2). In addition, we have analyzed the SIP elements we 
are approving as part of this action, and we have determined they 
comply with the relevant requirements of section 110(a)(2).
2. Part D Requirements
    Before the Missoula ``moderate'' CO nonattainment area may be 
redesignated to attainment, the State must have fulfilled the 
applicable requirements of part D. Under part D, an area's 
classification indicates the requirements to which it will be subject. 
Subpart 1 of part D sets forth the basic nonattainment requirements 
applicable to all nonattainment areas, whether classified or 
nonclassifiable. Subpart 3 of part D contains specific provisions for 
``moderate'' CO nonattainment areas.
    The relevant subpart 1 requirements are contained in sections 
172(c) and 176. Our General Preamble (see 57 FR 13529, 13533, April 16, 
1992) provides EPA's interpretations of the CAA requirements for 
``moderate'' CO areas. The General Preamble (see 57 FR 13530, et seq.) 
provides that the applicable requirements of CAA section 172 are 
172(c)(3) (emissions inventory), 172(c)(5) (new source review 
permitting program), 172(c)(7) (the section 110(a)(2) air quality 
monitoring requirements), and 172(c)(9) (contingency measures). It is 
also worth noting that we interpreted the requirements of sections 
172(c)(2) (reasonable further progress--RFP) and 172(c)(6) (other 
measures) as being irrelevant to a redesignation request because they 
only have meaning for an area that is not attaining the standard. See 
EPA's September 4, 1992, memorandum entitled, ``Procedures for 
Processing Requests to Redesignate Areas to Attainment'', and the 
General Preamble, 57 FR at 13564, dated April 16, 1992. Finally, the 
State has not sought to exercise the options that would trigger 
sections 172(c)(4) (identification of certain emissions increases) and 
172(c)(8) (equivalent techniques). Thus, these provisions are also not 
relevant to this redesignation request.
    The relevant subpart 3 provisions were created when the CAA was 
amended on November 15, 1990 and appear in section 187 of the CAA. The 
new CAA requirements for a CO nonattainment area, classified as 
``moderate'' with a design value of 12.7 ppm or less, that are 
applicable to Missoula are a 1990 base year inventory (CAA section 
187(a)(1)), contingency provisions (CAA section 187(a)(3)), and 
periodic emission inventories (CAA section 187(a)(5)).
    A. Relevant CAA subpart 1 requirements.
    1. Emissions Inventory. For the CAA section 172(c)(3) emissions 
inventory requirement, the State submitted a 1990 base year CO 
emissions inventory for the Missoula area on July 18, 1995 which met 
the requirements of section 172(c)(3) of the CAA. We approved this 
inventory on December 15, 1997 (62 FR 65613).
    2. New Source Review (NSR) and Prevention of Significant 
Deterioration (PSD). For the CAA section 172(c)(5) New Source Review 
(NSR) requirements, the CAA requires all nonattainment areas to meet 
several requirements regarding NSR, including provisions to ensure that 
increased emissions will not result from any new or modified stationary 
major sources and a general offset rule. The State of Montana has a 
fully-approved NSR program (60 FR 36715, July 18, 1995.) The State also 
has a fully approved PSD program (60 FR 36715, July 18, 1995) that will 
apply, instead of nonattainment NSR, if we approve the redesignation to 
attainment.
    3. Air Quality Monitoring Requirements. For the CAA section 
172(c)(7) provisions (compliance with the CAA section 110(a)(2) Air 
Quality Monitoring Requirements), our interpretations are presented in 
the General Preamble (57 FR 13535). CO nonattainment areas are to meet 
the ``applicable'' air quality monitoring requirements of section 
110(a)(2) of the CAA. We have determined that the Missoula area has met 
the applicable air quality monitoring requirements of section 110(a)(2) 
of the CAA. See our descriptions in section IV.A above.
    4. Contingency Measures. Section 172(c)(9) of the CAA requires the 
submittal of contingency measures to be implemented in the event that 
an area fails to make reasonable further progress or to attain the 
NAAQS by the date applicable (which for a CO nonattainment area, with a 
design value of less than 12.7 ppm, was December 31, 1995.) To meet 
this requirement the State submitted a contingency measure, involving 
residential woodburning devices, on March 2, 1994. We approved this CO 
contingency measure on December 13, 1994 (59 FR 64133).
    5. Conformity. Section 176 of the CAA contains requirements related 
to conformity. Although EPA's regulations (see 40 CFR 51.390) require 
that states adopt transportation conformity provisions in their SIPs 
for areas designated nonattainment or subject to an EPA-approved 
maintenance plan, we have decided that a transportation conformity SIP 
is not an applicable requirement for purposes of evaluating a 
redesignation request under section 107(d) of the CAA. This decision is 
reflected in EPA's 1996 approval of the Boston carbon monoxide 
redesignation. (See 61 FR 2918, January 30, 1996.)
    B. Relevant CAA subpart 3 requirements.
    1. Emissions Inventory. For the CAA section 187(a)(1) emissions 
inventory requirement, the State submitted a 1990 base year CO 
emissions inventory for the Missoula area on July 18, 1995 which met 
the requirements of section 187(a)(1) of the CAA. We approved this 
inventory on December 15, 1997 (62 FR 65613).
    2. Periodic emission inventories. For the CAA section 187(a)(5) 
periodic

[[Page 20484]]

emissions inventory requirement, the State submitted CO periodic 
emission inventories (PEI) for 1993 and 1996 on January 27, 2000. In 
addition, the State submitted a year 2000 CO emission inventory, on 
July 19, 2004, that qualifies for the 1999 PEI and is also the basis 
for the attainment year 2000 CO emission inventory that is part of the 
State's Missoula CO maintenance plan. We have reviewed these CO 
periodic emission inventories and have determined they contain 
comprehensive information with respect to point, area, non-road, and 
on-road mobile sources and were prepared in accordance with EPA 
guidance. We are proposing approval of the 1993 PEI, the 1996 PEI, and 
the year 2000 attainment inventory (for the 1999 PEI requirement) in 
conjunction with this action's proposed approval of the Missoula CO 
redesignation to attainment and maintenance plan.
    3. CAA Title II requirements. The relevant CAA Title II requirement 
is contained in section 211(m)(1) which requires the implementation of 
an oxygenated fuels program for CO areas with a design value of 9.5 ppm 
or greater.
    A. Title II, Part A of the CAA: Oxygenated fuels program (CAA 
section 211(m)(1)).
    Section 211(m)(1) of the CAA requires the submittal of a SIP 
revision to implement an oxygenated fuels program for CO nonattainment 
areas with a design value of 9.5 ppm or greater. To address this 
requirement, the State submitted a SIP revision on November 6, 1992 for 
the implementation of an oxygenated fuels program in Missoula County. 
EPA approved this SIP revision on November 8, 1994 (see 59 FR 55585).

(c) Redesignation Criterion: The Area Must Have a Fully Approved SIP 
Under Section 110(k) of the CAA

    Section 107(d)(3)(E)(ii) of the CAA states that for an area to be 
redesignated to attainment, it must be determined that the 
Administrator has fully approved the applicable implementation plan for 
the area under section 110(k).
    As noted above, EPA previously approved SIP revisions based on the 
pre-1990 CAA as well as SIP revisions required under the 1990 
amendments to the CAA. In this action, EPA is proposing approval of the 
Missoula area's 1993 periodic CO emissions inventory, the 1996 periodic 
CO emissions inventory, and the 2000 CO emission inventory (as meeting 
the 1999 periodic emissions inventory requirement). Thus, with our 
final approval of these SIP revisions, we will have fully approved the 
Missoula area's CO element of the SIP under section 110(k) of the CAA.

(d) Redesignation Criterion: The Area Must Show That the Improvement in 
Air Quality Is Due to Permanent and Enforceable Emissions Reductions

    Section 107(d)(3)(E)(iii) of the CAA provides that for an area to 
be redesignated to attainment, the Administrator must determine that 
the improvement in air quality is due to permanent and enforceable 
reductions in emissions resulting from implementation of the applicable 
implementation plan, implementation of applicable Federal air pollutant 
control regulations, and other permanent and enforceable reductions.
    The CO emissions reductions for the Missoula area, that are further 
described in section 2.3 of the maintenance plan, were achieved 
primarily through an oxygenated fuels program, Federal Motor Vehicle 
Control Program, residential woodburning regulations, changes in the 
transportation infrastructure involving the reconstruction of the 
Brooks/South/Russell (B/S/R) intersection, and outdoor open burning 
regulations. These five control strategies are fully discussed in 
section 2.3 of the maintenance plan and are summarized below.
    1. Oxygenated Fuels. As described in section 2.3.2.1 of the 
maintenance plan, since November of 1992, all gasoline sold within the 
Missoula CO nonattainment area must have a minimum oxygen content of 
2.7% by weight from November 1st through the last day of February each 
year. The use of oxygenates in gasoline helps provide additional oxygen 
in the fuel for better combustion of the fuel in the engine and a 
decrease in tailpipe CO emissions.
    2. Federal Motor Vehicle Control Program (FMVCP). Section 2.3.2.2 
of the maintenance plan discusses the FMVCP which involves Federal 
provisions that require vehicle manufacturers to meet more stringent 
vehicle emission limitations for new vehicles in future years. These 
emission limitations are phased in (as a percentage of new vehicles 
manufactured) over a period of years. As new, lower emitting vehicles 
replace older, higher emitting vehicles (``fleet turnover''), emission 
reductions are realized for a particular area such as Missoula.
    3. Residential Woodburning. As described in section 2.3.2.3 of the 
maintenance plan, in order to reduce the amount of CO emissions from 
residential woodburning, Missoula adopted progressively more stringent 
solid fuel burning device regulations. Currently, the only new solid 
fuel burning devices permitted in Missoula are pellet stoves and the 
regulations also require that most woodstoves be removed at the time of 
sale of a property.
    4. Transportation Infrastructure. Section 2.3.2.4 of the 
maintenance plan describes the changes in transportation infrastructure 
that specifically address the B/S/R intersection. Violations of the CO 
NAAQS were occurring at the B/S/R intersection in the 1980s and an 
initial intersection reconstruction was completed in 1985. This effort 
involved restricting left turn lanes and adding right turn and 
departure lanes. The CO designation of nonattainment for Missoula in 
1991 was again tied to monitoring data near the B/S/R intersection. The 
final reconstruction project involved the realignment of South Avenue 
such that South Avenue no longer enters the intersection. This 
construction effort was scheduled to be completed by the end of 2005. 
The South Avenue realignment simplified the intersection, reducing the 
projected peak-hour delay from 120 seconds to 20 seconds, and also 
allowed for the synchronization of all traffic lights along Brooks 
Street from Reserve to Mount. This reduces congestion along the whole 
corridor.
    5. Outdoor Burning. Section 2.3.2.5 of the maintenance plan 
describes the provisions of Missoula's outdoor burning regulations. 
These regulations reduce the impact of outdoor burning, especially 
during December, January, and February, by requiring a permit for each 
burn, allowing only the burning of untreated lumber and natural 
vegetation, requiring burners to call the Outdoor Burning Hotline to 
confirm if any burning or air quality restrictions are in effect, 
establishing burning seasons to reduce the generation of smoke, and 
prohibiting outdoor burning during December, January, and February 
except for ceremonial bonfires, emergency burning, and essential 
wintertime burning.
    We have evaluated the various Local, State, and Federal control 
measures, the original 1990 base year CO emission inventory (62 FR 
65613, December 15, 1997), the 1993 periodic CO emission inventory, the 
1996 periodic CO emission inventory, and the 2000 attainment year CO 
inventory that was provided with the State's May 27, 2005 submittal and 
have concluded that the improvement in air quality in the Missoula 
nonattainment area has resulted from emission reductions that are 
permanent and enforceable.

[[Page 20485]]

(e) Redesignation Criterion: The Area Must Have a Fully Approved 
Maintenance Plan Under Section 175A of the CAA

    Section 107(d)(3)(E)(iv) of the CAA provides that for an area to be 
redesignated to attainment, the Administrator must have fully approved 
a maintenance plan for the area meeting the requirements of section 
175A of the CAA.
    Section 175A of the CAA sets forth the elements of a maintenance 
plan for areas seeking redesignation from nonattainment to attainment. 
The maintenance plan must demonstrate continued attainment of the 
applicable NAAQS for at least ten years after the Administrator 
approves a redesignation to attainment. Eight years after the 
promulgation of the redesignation, the State must submit a revised 
maintenance plan that demonstrates continued attainment for a 
subsequent ten-year period following the initial ten-year maintenance 
period. To address the possibility of future NAAQS violations, the 
maintenance plan must contain contingency measures, with a schedule for 
adoption and implementation, that are adequate to assure prompt 
correction of a violation. In addition, we issued further maintenance 
plan interpretations in the ``General Preamble for the Implementation 
of Title I of the Clean Air Act Amendments of 1990'' (57 FR 13498, 
April 16, 1992), ``General Preamble for the Implementation of Title I 
of the Clean Air Act Amendments of 1990; Supplemental'' (57 FR 18070, 
April 28, 1992), and the EPA guidance memorandum entitled ``Procedures 
for Processing Requests to Redesignate Areas to Attainment'' from John 
Calcagni, Director, Air Quality Management Division, Office of Air 
Quality and Planning Standards, to Regional Air Division Directors, 
dated September 4, 1992.
    In this Federal Register action, EPA is proposing approval of the 
maintenance plan for the Missoula nonattainment area because we have 
determined, as detailed below, that the State's maintenance plan meets 
the requirements of section 175A and is consistent with the documents 
referenced above. Our analysis of the pertinent maintenance plan 
requirements, with reference to the Governor's May 27, 2005, submittal, 
is provided as follows:
1. Emissions Inventories--Attainment Year and Projections
    EPA's interpretations of the CAA section 175A maintenance plan 
requirements are generally provided in the General Preamble (see 57 FR 
13498, April 16, 1992) and the September 4, 1992, Calcagni Memorandum 
referenced above. Under our interpretations, areas seeking to 
redesignate to attainment for CO may demonstrate future maintenance of 
the CO NAAQS either by showing that future CO emissions will be equal 
to or less than the attainment year emissions or by providing a 
modeling demonstration.
    The maintenance plan that the Governor submitted on May 27, 2005, 
includes comprehensive inventories of CO emissions for the Missoula 
area. These inventories include emissions from stationary point 
sources, area sources, non-road mobile sources, and on-road mobile 
sources. The maintenance plan uses a year 2000 attainment inventory and 
includes interim-year projections with a final maintenance year of 
2020. More detailed descriptions of the 2000 attainment year inventory 
and the projected inventories are documented in section 2.5.1, section 
2.5.2.2, and Appendix D of the maintenance plan. The State's submittal 
contains detailed emission inventory information that was prepared in 
accordance with EPA guidance. Summary emission figures from the 2000 
attainment year, the interim projected years, and the final maintenance 
year of 2020 are provided in Table IV-1 below.

                           Table IV-1.--CO Emission Inventories for the Missoula Area
                                       [All figures in tons per day of CO]
----------------------------------------------------------------------------------------------------------------
                           Year                               2000       2005       2010       2015       2020
----------------------------------------------------------------------------------------------------------------
Point Sources............................................       0.30       0.33       0.37       0.41       0.46
Area Sources.............................................       6.62       6.37       6.10       5.88       5.69
Non-Road Mobile Sources..................................       5.06       5.73       6.14       6.52       7.01
On-Road Mobile Sources...................................      44.86      32.73      27.10      24.97      22.98
                                                          ------------------------------------------------------
    Total................................................      56.83      45.16      39.71      37.78      36.14
----------------------------------------------------------------------------------------------------------------

2. Demonstration of Maintenance--Projected Inventories and CAL3QHC 
Intersection Modeling
    As we presented above, total CO emissions were projected forward by 
the State for the years 2005, 2010, 2015, and 2020. We note the State's 
approach for developing the projected inventories follows EPA guidance 
on projected emissions and we believe they are acceptable.\2\ Further 
information regarding these CO emission inventories is also provided in 
section 2.5.2.2 and in Appendix D of the maintenance plan. The 
projected inventories show that CO emissions are not estimated to 
exceed the 2000 attainment level during the time period of 2000 through 
2020 and, therefore, the Missoula area has satisfactorily demonstrated 
maintenance.
    In addition to the emission inventory projections, the State also 
performed ``hot-spot'' modeling to evaluate predicted CO concentrations 
at the B/S/R intersection. This effort involved the CAL3QHC-R 
intersection model and considered meteorological data, relevant CO 
emission contributions from point, area, non-road, and on-road sources, 
and information specific to the B/S/R intersection such as traffic 
patterns and intersection geometry. Consistent with EPA guidance, the 
State modeled CO concentrations at 60 receptor sites around the 
intersection and at the location of the CO ambient air quality 
monitoring site at the B/S/R intersection. The years modeled were 2000, 
2005, 2010, and 2020. We note this modeling effort was consistent with 
our modeling guidance.
---------------------------------------------------------------------------

    \2\ ``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.
---------------------------------------------------------------------------

    The results of the State's modeling for 2000, 2005, 2010, and 2020 
are presented in section 2.5.2.1 and Appendix C of the maintenance plan 
and in Table IV-2 below.

[[Page 20486]]

     Table IV-2.--CAL3QHC-R Modeled CO Concentrations for the B/S/R
                              Intersection
                  [All values are in parts per million]
------------------------------------------------------------------------
                                 2000       2005       2010       2020
------------------------------------------------------------------------
First Maximum 8-hour CO            11.8        8.9        5.4        4.5
 Value......................
Second Maximum 8-hour CO           10.7        8.0        4.4        3.6
 Value......................
First Maximum 8-hour CO             7.0        5.4        3.2        2.5
 Value at the Monitor
 Location...................
Second Maximum 8-hour CO            6.7        5.1        2.9        2.4
 Value at the Monitor
 Location...................
------------------------------------------------------------------------

    As shown, the CAL3QHC-R model predicted an exceedance of the CO 
NAAQS in 2000 at a modeling receptor location near the intersection. We 
consider this to be a conservative estimate by the model. For 
comparison, for 2000 the model predicted first maximum 8-hour and 
second maximum 8-hour CO concentrations of 7.0 and 6.7 ppm, 
respectively, at the ambient air quality monitoring site. However, 
actual ambient air quality data from the monitor for 2000 were a first 
maximum 8-hour value of 3.9 ppm and second maximum 8-hour value of 3.3 
ppm (ref. section 2.1.1 and Figure 2-3 of the maintenance plan.)
    Based on the information provided in sections 2.5.2.1 and 2.5.2.2, 
the maintenance plan concludes that maintenance of the CO NAAQS is 
demonstrated. Specifically, the actual monitored values for 2000 
indicate no exceedances of the CO NAAQS for the Missoula area, the 
modeled CO values for 2005, 2010, and 2020 are less than the 8-hour CO 
NAAQS (9.0 ppm), and, as stated earlier in this action, predicted CO 
emissions for 2005, 2010, and 2020 are all less than the attainment 
year levels of 2000.
    We have reviewed the State's CAL3QHC-R modeling data and results 
and the attainment year and projected years CO emission inventory 
information, and have concluded that the State has satisfactorily 
demonstrated maintenance of the CO NAAQS through 2020.
3. Monitoring Network and Verification of Continued Attainment
    Continued attainment of the CO NAAQS in the Missoula area depends, 
in part, on the State's efforts to track indicators throughout the 
maintenance period. This requirement is met in section 2.5.3 of the 
Missoula CO maintenance plan. In section 2.5.3 the State commits to 
review mobile source emission inventory data and compare that 
information to the emission inventory data in the Missoula CO 
maintenance plan. In section 2.5.3 the State also commits to continue 
the operation of the CO monitor in the Missoula area, specifically at 
the B/S/R intersection, and to annually review this monitoring network 
and make changes as appropriate.
    Based on the above, we are approving these commitments as 
satisfying the relevant requirements and note that this approval will 
render the State's commitments federally enforceable.
4. 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 2.5.5 and 2.5.5.4 of the Missoula CO 
maintenance plan, the contingency measures for the Missoula area will 
be triggered by a violation of the CO NAAQS.
    Section 2.5.5.4 states that contingency measures contained in the 
Missoula City-County Air Pollution Control Plan will be implemented 
within 60 days of notification by the MDEQ and EPA that the area has 
violated the CO NAAQS. If those measures are not adequate, the Missoula 
City-County Air Pollution Control Board (MCCAPCB), in conjunction with 
the Air Quality Advisory Council (AQAC), will initiate a process to 
begin evaluating potential contingency measures. The Missoula City-
County Health Department (MCCHD) and the AQAC will present 
recommendations to the MCCAPCB within 180 days of notification. The 
MCCAPCB will then hold a public hearing to consider the contingency 
measures recommended, along with any other contingency measures that 
the MCCAPCB 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 of the MCCHD being notified of 
the CO NAAQS violation.
    The potential contingency measures that are identified in section 
2.5.5.1 of the Missoula CO maintenance plan include (a) expanding the 
2.7% oxygenated fuels program in Missoula County to months outside of 
the current program time frame of November 1st through the end of 
February, (b) further restricting woodstove burning, (c) increasing the 
oxygenated fuels content to 3.1% by weight, and (d) constructing 
transportation projects and implementing transportation control 
measures. A more complete description of the triggering mechanism and 
these contingency measures can be found in section 2.5.5 of the 
Missoula CO maintenance plan.
    Based on the above, we find that the contingency plan provided in 
the Missoula CO maintenance plan meets the requirements of section 
175A(d) of the CAA.
5. Subsequent Maintenance Plan Revisions
    In accordance with section 175A(b) of the CAA, the MCCHD and MDEQ 
have committed to submit a revised maintenance plan eight years after 
our approval of the redesignation. This provision for revising the 
maintenance plan is contained in section 2.5.7 of the Missoula CO 
maintenance plan.

V. EPA's Evaluation of the Transportation Conformity Requirements

    One key provision of our conformity regulation requires a 
demonstration that emissions from the transportation plan and 
Transportation Improvement Program are consistent with the emissions 
budget(s) in the SIP (40 CFR sections 93.118 and 93.124). The emissions 
budget is 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 62193-96) and in the sections of the rule referenced above.
    Section 2.5.6 of the Missoula CO maintenance plan defines the CO 
motor vehicle emissions budgets in the Missoula CO maintenance area as 
44.86 tons per day for 2005 through 2009, 43.22 tons per day for 2010 
through 2019, and 42.67 tons per day for 2020 and beyond. As we explain 
more fully below, we view these as the budgets for 2000, 2010, and 2020 
respectively.

[[Page 20487]]

    Under our conformity rules, a motor vehicle emissions budget is 
established for a given year, not for a range of years. This is because 
the motor vehicle emissions budget 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 motor vehicle 
emissions budget 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 motor vehicle emissions budget 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.'').
    The maintenance plan's ``2005 through 2009'' motor vehicle 
emissions budget in fact is derived directly from the year 2000 
inventory value for on-road vehicle emissions. It is apparent from the 
maintenance plan that MCCHD and MDEQ were not relying on 2005 inventory 
numbers to establish the ``2005 through 2009'' budget, and thus, it is 
not truly a 2005 budget. We assume the maintenance plan designates this 
as a 2005 to 2009 budget because the maintenance plan was adopted in 
2005, and the years 2000 through 2004 had already passed. However, 
because it was derived from 2000 values, the ``2005 through 2009'' 
budget is actually a 2000 budget, and we will refer to it as such in 
the remainder of this proposal. Consistent with our discussion above, 
the 2000 budget applies for conformity analyses of emissions in the 
year 2000 and all subsequent years before the next budget year; i.e., 
since the next budget year is 2010, the 2000 budget applies for 
analyses of years 2000 through 2009.
    Similarly, the ``2010 through 2019'' and ``2020 and beyond'' 
budgets were derived from, respectively, 2010 and 2020 inventory values 
for on-road vehicle emissions and available safety margin. Thus, we 
will refer to these as the 2010 and 2020 budgets in the remainder of 
this proposal.
    For the Missoula CO maintenance plan, the ``safety margin'' is the 
difference between the attainment year (2000) 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, and 2020. The 
derivation and determination of safety margins and motor vehicle 
emissions budgets for the Missoula CO maintenance plan is further 
illustrated in Table V-1 below and in section 2.5.6, Table 2-7 of the 
maintenance plan:

                  Table V-1.--Mobile Sources Emissions, Safety Margins, and Motor Vehicle Emissions Budgets in Tons of CO per Day (TPD)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                            Mobile sources       Total                                                                     Motor vehicle
                   Year                        emissions       emissions                        Math                         Margin of       emissions
                                                 (TPD)           (TPD)                                                     safety (TPD)    budget (TPD)
--------------------------------------------------------------------------------------------------------------------------------------------------------
2000......................................           44.86           56.83  ............................................             N/A           44.86
2010......................................           27.10           39.71  56.83-39.71 = 17.12.........................           16.12           43.22
                                                                            17.12-1 = 16.12.............................
                                                                            27.10+16.12 = 43.22.........................
2020......................................           22.98           36.14  56.83-36.14 = 20.69.........................           19.69          42.67
                                                                            20.69-1 = 19.69.............................
                                                                            22.98+19.69 = 42.67.........................
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: N/A = Not Applicable.

    Our analysis indicates that the above figures are consistent with 
maintenance of the CO NAAQS throughout the maintenance period. 
Therefore, we are approving the 44.86 tons per day budget for 2000, 
43.22 tons per day budget for 2010, and 42.67 tons per day budget for 
2020 for the Missoula area.
    Pursuant to section 93.118(e)(4) of EPA's transportation conformity 
rule, as amended, EPA must determine the adequacy of submitted mobile 
source emissions budgets. EPA reviewed the Missoula CO maintenance plan 
budgets for adequacy using the criteria in 40 CFR 93.118(e)(4), and 
determined that the budgets were adequate for conformity purposes. 
EPA's adequacy determination was made in a letter to the MDEQ on May 4, 
2006, and was announced in the Federal Register on June 1, 2006 (71 FR 
31181). As a result of this adequacy finding, the budgets took effect 
for conformity determinations in the Missoula area on June 16, 2006. 
However, we are not bound by that determination in acting on the 
maintenance plan.\3\
---------------------------------------------------------------------------

    \3\ In its adequacy determination, EPA listed and found adequate 
budgets for 2005, 2010, and 2021. The listed years should have been 
2000, 2010, and 2020, consistent with our discussion above. Assuming 
we do not change this proposal in response to public comment, the 
final approved budgets will be for years 2000, 2010, and 2020.
---------------------------------------------------------------------------

VI. 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. The Missoula CO maintenance plan will not interfere with 
attainment, reasonable further progress, or any other applicable 
requirement of the CAA.

VII. Proposed Action

    In this action, EPA is proposing approval of the request for 
redesignation from nonattainment to attainment for CO for the Missoula 
area, the Missoula area's maintenance plan, the 1993 PEI, the 1996 PEI, 
the year 2000 attainment inventory (which fulfills the 1999 PEI 
obligation), and the transportation conformity CO motor vehicle 
emission budgets of 44.86 tons per day for 2000, 43.22 tons per day for 
2010, and 42.67 tons per day for 2020.
    Submit your comments, identified by Docket ID No. EPA-R08-OAR-2006-
0163, by one of the methods identified above at the front of this 
proposed rule. In deciding on our final action, we will consider your 
comments if they are received before May 25, 2007. EPA will

[[Page 20488]]

address all public comments in a subsequent final rule based on this 
proposed rule. EPA will not institute a second comment period on this 
action. Any parties interested in commenting must do so at this time.

VIII. Statutory and Executive Order Reviews

    Under Executive Order 12866 (58 FR 51735, October 4, 1993), this 
proposed 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 
proposed action merely proposes to approve state law as meeting Federal 
requirements and imposes no additional requirements beyond those 
imposed by state law. Accordingly, the Administrator certifies that 
this proposed 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 proposes to approve 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 Unfunded Mandates Reform Act of 
1995 (Pub. L. 104-4).
    This proposed 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 a substantial 
direct effect 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 proposes to approve 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 
proposed 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 proposes to approve a state rule 
implementing a Federal standard.
    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 proposed 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.).

List of Subjects

40 CFR Part 52

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

40 CFR Part 81

    Air pollution control, National parks, Wilderness areas.

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

    Dated: April 17, 2007.
Kerrigan G. Clough,
Acting Regional Administrator, Region 8.
 [FR Doc. E7-7900 Filed 4-24-07; 8:45 am]

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