Approval and Promulgation of Implementation Plans and Designation of Areas for Air Quality Planning Purposes; Indiana; Redesignation of Vigo County 8-Hour Ozone Nonattainment Area to Attainment for Ozone, 70751-70761 [05-23221]

Agencies

• ENVIRONMENTAL PROTECTION AGENCY

[Federal Register Volume 70, Number 225 (Wednesday, November 23, 2005)]
[Proposed Rules]
[Pages 70751-70761]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 05-23221]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 52 and 81

[R05-OAR-2005-IN-0010; FRL-8001-5]


Approval and Promulgation of Implementation Plans and Designation 
of Areas for Air Quality Planning Purposes; Indiana; Redesignation of 
Vigo County 8-Hour Ozone Nonattainment Area to Attainment for Ozone

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: EPA is proposing to make a determination that the Vigo County 
ozone nonattainment area has attained the 8-hour ozone National Ambient 
Air Quality Standard (NAAQS). This proposed determination is based on 
three years of complete, quality-assured ambient air quality monitoring 
data for the 2002-2004 seasons that demonstrate that the 8-hour ozone 
NAAQS has been attained in the area.
    EPA is proposing to approve a request from the State of Indiana to 
redesignate Vigo County to attainment of the 8-hour ozone NAAQS. This 
request was submitted by the Indiana Department of Environmental 
Management (IDEM) on July 5, 2005 and supplemented on October 20, 2005 
and November 4, 2005. In proposing to approve this request, EPA is also 
proposing to approve the State's plan for maintaining the 8-hour ozone 
NAAQS in this area through 2015 as a revision to the Indiana State 
Implementation Plan (SIP). EPA is also finding adequate and is 
proposing to approve the State's 2015 Motor Vehicle Emission Budgets 
(MVEBs) for this area.

DATES: Comments must be received on or before December 23, 2005.

ADDRESSES: Submit comments, identified by Regional Material in EDocket 
(RME) ID No. R05-OAR-2005-IN-0010, by one of the following methods:
    1. Federal eRulemaking Portal: https://www.regulations.gov. Follow 
the on-line instructions for submitting comments.
    2. Agency Web site: https://docket.epa.gov/rmepub/. RME, EPA's 
electronic public docket and comments system, is EPA's preferred method 
for receiving comments. Once in the system, select ``quick search,'' 
then key in the appropriate RME Docket identification number. Follow 
the on-line instructions for submitting comments.
    3. E-mail: mooney.john@epa.gov.
    4. Fax: (312) 886-5824.
    5. Mail: You may send written comments to: John M. Mooney, Chief, 
Air Programs Branch Criteria Pollutant Section, (AR-18J), U.S. 
Environmental Protection Agency, Region 5, 77 West Jackson Boulevard, 
Chicago, Illinois 60604.
    6. Hand delivery: Deliver your comments to: John M. Mooney, Chief, 
Air Programs Branch Criteria Pollutant Section, (AR-18J), U.S. 
Environmental Protection Agency, Region 5, 77 West Jackson Boulevard, 
18th floor, Chicago, Illinois 60604. Such deliveries are only accepted 
during the Regional Office's normal hours of operation. The Regional 
Office's official hours of business are Monday through Friday, 8:30 
a.m. to 4:30 p.m. excluding Federal holidays.
    Instructions: Direct your comments to RME ID No. R05-OAR-2005-IN-
0010. EPA's policy is that all comments received will be included in 
the public docket without change, including any personal information 
provided and may be made available online at https://docket.epa.gov/
rmepub/, 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 RME, regulations.gov, 
or e-mail. The EPA RME Web site and the federal regulations.gov Web 
site are ``anonymous access'' systems, 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 RME or 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.
    Docket: All documents in the electronic docket are listed in the 
RME index at https://docket.epa.gov/rmepub/. Although listed in the 
index, some information is not publicly available, i.e., CBI or other 
information whose disclosure is restricted by statute. Certain other 
material, such as copyrighted material, is not placed on the Internet 
and will be publicly available only in hard copy form. Publicly 
available docket materials are available either electronically in RME 
or in hard copy at the Environmental Protection Agency, Region 5, Air 
and Radiation Division, 77 West Jackson Boulevard, Chicago, Illinois 
60604. We recommend that you telephone Steve Rosenthal, Environmental 
Engineer, at (312) 886-6052 before visiting the Region 5 office. This 
Facility is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, 
excluding Federal holidays.

FOR FURTHER INFORMATION CONTACT: Steve Rosenthal, Environmental 
Engineer, Criteria Pollutant Section, Air Programs Branch (AR-18J), 
U.S. Environmental Protection Agency, Region 5, 77 West Jackson 
Boulevard, Chicago, Illinois 60604, (312) 886-6052, 
rosenthal.steven@epa.gov.

SUPPLEMENTARY INFORMATION: Throughout this document whenever ``we,'' 
``us,'' or ``our'' is used, we mean EPA.

Table of Contents

I. What Actions Is EPA Proposing to Take?
II. What Is the Background for These Actions?
III. What Are the Criteria for Redesignation?
IV. Why Is EPA Proposing to Take These Actions?
V. What Would Be the Effect of These Actions?
VI. What Is EPA's Analysis of the Request?

[[Page 70752]]

    A. Attainment Determination and Redesignation
    B. Adequacy of Indiana's Motor Vehicle Emission Budgets (MVEBs)
VII. Proposed Actions
VIII. Statutory and Executive Order Reviews

I. What Actions Is EPA Proposing to Take?

    EPA is proposing to take several related actions. EPA is proposing 
to make a determination that the Vigo County, Indiana nonattainment 
area has attained the 8-hour ozone standard and that Vigo County has 
met the requirements for redesignation under section 107(d)(3)(E). EPA 
is thus proposing to approve the request to change the legal 
designation of the Vigo County area from nonattainment to attainment 
for the 8-hour ozone NAAQS. EPA is also proposing to approve Indiana's 
maintenance plan SIP revision for Vigo County (such approval being one 
of the CAA criteria for redesignation to attainment status). The 
maintenance plan is designed to keep Vigo County in attainment of the 
ozone NAAQS for the next 10 years. Additionally, EPA is announcing its 
action on the Adequacy Process for the newly-established 2015 MVEBs. 
The Adequacy comment period for the 2015 MVEBs began on July 12, 2005, 
with EPA's posting of the availability of this submittal on EPA's 
Adequacy Web site (at https://www.epa.gov/otaq/transp/conform/
adequacy.htm). The Adequacy comment period for these MVEBs ended on 
August 11, 2005. No requests for this submittal or adverse comments on 
this submittal were received during the Adequacy comment period. Please 
see the Adequacy Section of this rulemaking for further explanation on 
this process. Therefore, we are finding adequate and proposing to 
approve the State's 2015 MVEBs for transportation conformity purposes.

II. What Is the Background for These Actions?

    Ground-level ozone is not emitted directly by sources. Rather, 
emissions of nitrogen oxides (NOX) and volatile organic 
compounds (VOCs) react in the presence of sunlight to form ground-level 
ozone. NOX and VOCs are referred to as precursors of ozone.
    The CAA establishes a process for air quality management through 
the NAAQS. Vigo County was designated unclassifiable/attainment under 
the 1-hour ozone NAAQS, which was revoked on June 15, 2005. On July 18, 
1997, EPA promulgated a revised 8-hour ozone standard of 0.08 parts per 
million (ppm). This new standard is more stringent than the previous 1-
hour standard.
    On April 30, 2004 (69 FR 23857), EPA published a final rule 
designating and classifying areas under the 8-hour ozone NAAQS. These 
designations and classifications became effective June 15, 2004. The 
CAA required EPA to designate as nonattainment any area that was 
violating the 8-hour ozone NAAQS based on the three most recent years 
(2001-2003) of air quality data. The CAA contains two sets of 
provisions--subpart 1 and subpart 2--that address planning and control 
requirements for nonattainment areas. (Both are found in title I, part 
D.) Subpart 1 (which EPA refers to as ``basic'' nonattainment) contains 
general, less prescriptive, requirements for nonattainment areas for 
any pollutant--including ozone--governed by a NAAQS. Subpart 2 (which 
EPA refers to as ``classified'' nonattainment) provides more specific 
requirements for ozone nonattainment areas. Some ozone nonattainment 
areas are subject only to the provisions of subpart 1. Other ozone 
nonattainment areas are also subject to the provisions of subpart 2. 
Under EPA's 8-hour ozone implementation rule, signed on April 15, 2004, 
(69 FR 23951) an area was classified under subpart 2 based on its 8-
hour ozone design value (i.e., the 3-year average annual fourth-highest 
daily maximum 8-hour average ozone concentration), if it had a 1-hour 
design value at or above 0.121 ppm (the lowest 1-hour design value in 
Table 1 of subpart 2). All other areas are covered under subpart 1, 
based upon their 8-hour design values. Vigo County was designated as a 
subpart 1, 8-hour ozone nonattainment area by EPA on April 30, 2004, 
(69 FR 23857) based on air quality monitoring data from 2001-2003.
    Under EPA regulations at 40 CFR part 50, the 8-hour ozone standard 
is attained when the 3-year average of the annual fourth-highest daily 
maximum 8-hour average ozone concentrations is less than or equal to 
0.08 ppm (i.e., 0.084 ppm) when rounding is considered. 40 CFR 50.10 
and Appendix I. See 69 FR 23857 (April 30, 2004) for further 
information. The data completeness requirement is met when the average 
percent of days with valid ambient monitoring data is greater than 90%, 
and no single year has less than 75% data completeness as determined in 
Appendix I of Part 50.
    On July 5, 2005, Indiana requested that EPA redesignate Vigo County 
to attainment for the 8-hour ozone standard. This request was 
supplemented with submittals dated October 20, 2005 and November 4, 
2005. The redesignation request included three years of complete, 
quality-assured data for the period of 2002 through 2004, indicating 
the 8-hour NAAQS for ozone had been attained for Vigo County. Under the 
CAA, nonattainment areas may be redesignated to attainment if 
sufficient complete, quality-assured data are available for the 
Administrator to determine that the area has attained the standard and 
the area meets the other CAA redesignation requirements in section 
107(d)(3)(E).

III. What Are the Criteria for Redesignation?

    The CAA provides the requirements for redesignating a nonattainment 
area to attainment. Specifically, section 107(d)(3)(E) allows for 
redesignation providing that: (1) The Administrator determines that the 
area has attained the applicable NAAQS; (2) the Administrator has fully 
approved the applicable implementation plan for the area under section 
110(k); (3) the Administrator determines that the improvement in air 
quality is due to permanent and enforceable reductions in emissions 
resulting from implementation of the applicable SIP and applicable 
Federal air pollutant control regulations and other permanent and 
enforceable reductions; (4) the Administrator has fully approved a 
maintenance plan for the area as meeting the requirements of section 
175A; and (5) the state containing such area has met all requirements 
applicable to the area under section 110 and part D.
    EPA provided guidance on redesignation in the General Preamble for 
the Implementation of Title I of the CAA Amendments of 1990, on April 
16, 1992 (57 FR 13498), and supplemented this guidance on April 28, 
1992 (57 FR 18070). EPA has provided further guidance on processing 
redesignation requests in the following documents:
    ``Ozone and Carbon Monoxide Design Value Calculations'', Memorandum 
from William G. Laxton, Director Technical Support Division, June 18, 
1990;
    ``Maintenance Plans for Redesignation of Ozone and Carbon Monoxide 
Nonattainment Areas,'' Memorandum from G. T. Helms, Chief, Ozone/Carbon 
Monoxide Programs Branch, April 30, 1992;
    ``Contingency Measures for Ozone and Carbon Monoxide (CO) 
Redesignations,'' Memorandum from G. T. Helms, Chief, Ozone/Carbon 
Monoxide Programs Branch, June 1, 1992;
    ``Procedures for Processing Requests to Redesignate Areas to 
Attainment,''

[[Page 70753]]

Memorandum from John Calcagni, Director, Air Quality Management 
Division, September 4, 1992;
    ``State Implementation Plan (SIP) Actions Submitted in Response to 
Clean Air Act (ACT) Deadlines,'' Memorandum from John Calcagni, 
Director, Air Quality Management Division, October 28, 1992;
    ``Technical Support Documents (TSD's) for Redesignation Ozone and 
Carbon Monoxide (CO) Nonattainment Areas,'' Memorandum from G. T. 
Helms, Chief, Ozone/Carbon Monoxide Programs Branch, August 17, 1993;
    ``State Implementation Plan (SIP) Requirements for Areas Submitting 
Requests for Redesignation to Attainment of the Ozone and Carbon 
Monoxide (CO) National Ambient Air Quality Standards (NAAQS) On or 
After November 15, 1992,'' Memorandum from Michael H. Shapiro, Acting 
Assistant Administrator for Air and Radiation, September 17, 1993;
    ``Use of Actual Emissions in Maintenance Demonstrations for Ozone 
and CO Nonattainment Areas,'' Memorandum from D. Kent Berry, Acting 
Director, Air Quality Management Division, to Air Division Directors, 
Regions 1-10, dated November 30, 1993.
    ``Part D New Source Review (part D NSR) Requirements for Areas 
Requesting Redesignation to Attainment,'' Memorandum from Mary D. 
Nichols, Assistant Administrator for Air and Radiation, October 14, 
1994; and
    ``Reasonable Further Progress, Attainment Demonstration, and 
Related Requirements for Ozone Nonattainment Areas Meeting the Ozone 
National Ambient Air Quality Standard,'' Memorandum from John S. Seitz, 
Director, Office of Air Quality Planning and Standards, May 10, 1995.

IV. Why Is EPA Proposing To Take These Actions?

    On July 5, 2005, Indiana requested redesignation of Vigo County to 
attainment for the 8-hour ozone standard. Indiana supplemented this 
request with submittals dated October 20, 2005 and November 4, 2005. 
EPA believes that the area has attained the standard and has met the 
requirements for redesignation set forth in section 107(d)(3)(E) of the 
CAA.

V. What Would Be the Effect of These Actions?

    Approval of the redesignation request and maintenance plan would 
change the official designation of the area for the 8-hour ozone NAAQS 
found at 40 CFR part 81. It would also incorporate into the Indiana SIP 
a plan for maintaining the 8-hour ozone NAAQS through 2015. The 
maintenance plan includes contingency measures to remedy future 
violations of the 8-hour NAAQS, and establishes MVEBs for the year 2015 
of 2.48 tons per day (tpd) VOC and 3.67 tpd NOX for Vigo 
County.

VI. What Is EPA's Analysis of the Request?

A. Attainment Determination and Redesignation

    EPA is proposing to making a determination that the Vigo County 
nonattainment area has attained the 8-hour ozone standard and that the 
area has met all other applicable section 107(d)(3)(E) redesignation 
criteria. The basis for EPA's determinations is as follows:
1. The Area Has Attained the 8-hour Ozone NAAQS (Section 
107(d)(3)(E)(i))
    EPA is proposing to make a determination that Vigo County has 
attained the 8-hour ozone NAAQS. For ozone, an area may be considered 
to be attaining the 8-hour ozone NAAQS if there are no violations, as 
determined in accordance with 40 CFR 50.10 and Appendix I, based on 
three complete, consecutive calendar years of quality-assured air 
quality monitoring data. To attain this standard, the 3-year average of 
the fourth-highest daily maximum 8-hour average ozone concentrations 
measured at each monitor within an area over each year must not exceed 
0.08 ppm. Based on the rounding convention described in 40 CFR Part 50, 
Appendix I, the standard is attained if the design value is 0.084 ppm 
or below. The data must be collected and quality-assured in accordance 
with 40 CFR part 58, and recorded in Aerometric Information Retrieval 
System (AIRS). The monitors generally should have remained at the same 
location for the duration of the monitoring period required for 
demonstrating attainment.
    IDEM submitted ozone monitoring data for the 2002 to 2004 ozone 
seasons. The State quality assures monitoring data in accordance with 
40 CFR 58.10 and the Indiana Quality Assurance Manual and records the 
data in the AIRS database, thus making the data publicly available. 
IDEM operates two ozone monitors in Vigo County: Terre Haute and 
Sandcut. The data for 2002-2004 have been quality assured and are 
recorded in AIRS. For the Terre Haute monitor, data completeness 
averaged 98%, 98%, and 100% in 2002, 2003 and 2004, respectively. For 
the Sandcut monitor, data completeness averaged 96%, 93% and 97% in 
2002, 2003 and 2004, respectively. The annual fourth highest 8-hour 
average ozone concentrations and the three-year average fourth-high 8-
hour average ozone concentrations are summarized in Table 1.

    Table 1.--Annual Fourth-High 8-Hour Average Ozone Concentration and Three-year Average Fourth-High 8-Hour
                              Average Ozone Concentrations in Vigo County, Indiana
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                                                                                                 3-year average
                              Site                                   Year      4th high 8-hour   for ending year
                                                                               average  (ppm)         (ppm)
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Terre Haute....................................................         2002             0.082                NA
Terre Haute....................................................         2003             0.066                NA
Terre Haute....................................................         2004             0.057             0.068
Sandcut........................................................         2002             0.099                NA
Sandcut........................................................         2003             0.080                NA
Sandcut........................................................         2004             0.072             0.084
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    It should be noted that preliminary 2005 monitoring data show that 
Vigo County continues to attain the 8-hour ozone standard.
    In addition, as discussed below with respect to the maintenance 
plan, IDEM has committed to continue monitoring in these areas in 
accordance with 40 CFR part 58. In summary, EPA believes that the data 
submitted by Indiana provide an adequate demonstration that Vigo County 
has attained the 8-hour ozone NAAQS. Therefore, we are

[[Page 70754]]

proposing to find that Vigo County has attained the 8-hour ozone 
standard.
2. For Purposes of Redesignation the Area Has Met All Applicable 
Requirements Under Section 110 and Part D; and the Area Has a Fully 
Approved SIP Under Section 110(k) (Sections 107(d)(3)(E)(v) and 
107(d)(3)(E)(ii))
    We are proposing to determine Indiana has met all currently 
applicable SIP requirements for purposes of redesignation for Vigo 
County under Section 110 of the CAA (general SIP requirements). We are 
also proposing to determine that the Indiana SIP meets all SIP 
requirements currently applicable for purposes of redesignation under 
Part D of Title I of the CAA (requirements specific to Subpart 1 
nonattainment areas), in accordance with section 107(d)(3)(E)(v). In 
addition, we are proposing to determine that the Indiana SIP is fully 
approved with respect to all applicable requirements for purposes of 
redesignation, in accordance with section 107(d)(3)(E)(ii). In making 
these proposed determinations, we have ascertained what SIP 
requirements are applicable to the areas for purposes of redesignation. 
As discussed more fully below, SIPs must be fully approved only with 
respect to currently applicable requirements of the CAA.
    a. Vigo County has met all requirements applicable for purposes of 
redesignation under section 110 and part D of the CAA. The September 4, 
1992 Calcagni memorandum (see ``Procedures for Processing Requests to 
Redesignate Areas to Attainment,'' Memorandum from John Calcagni, 
Director, Air Quality Management Division, September 4, 1992) describes 
EPA's interpretation of section 107(d)(3)(E) of the CAA. Under this 
interpretation, to qualify for redesignation of an area to attainment, 
the state and the area must meet the relevant CAA requirements that 
come due prior to the state's submittal of a complete redesignation 
request for the area. See also the September 17, 1993 Michael Shapiro 
memorandum and 60 FR 12459, 12465-66 (Mar. 7, 1995) (redesignation of 
Detroit-Ann Arbor, Michigan to attainment of the 1-hour ozone NAAQS). 
Applicable requirements of the CAA that come due subsequent to the 
state's submittal of a complete request remain applicable until a 
redesignation to attainment is approved, but are not required as a 
prerequisite to redesignation. See section 175A(c) of the CAA. Sierra 
Club v. EPA, 375 F.3d 537 (7th Cir. 2004). See also 68 FR 25424, 25427 
(May 12, 2003) (redesignation of the St. Louis/East St. Louis area to 
attainment of the 1-hour ozone NAAQS).
    General SIP requirements. Section 110(a) of title I of the CAA 
contains the general requirements for a SIP. General SIP elements and 
requirements are delineated in section 110(a)(2). These requirements 
include, but are not limited to, the following: submittal of a SIP that 
has been adopted by the state after reasonable public notice and 
hearing; enforceable emission limitations and other control measures, 
means or techniques; provisions for establishment and operation of 
appropriate devices, methods, systems and procedures necessary to 
monitor ambient air quality; implementation of a source permit program; 
provisions for the implementation of part C, Prevention of Significant 
Deterioration (PSD) and part D, New Source Review (NSR) permit 
programs; criteria for stationary source emission control measures, 
monitoring, and reporting; provisions for air quality modeling; and 
provisions for public and local agency participation in planning and 
emission control rule development.
    Section 110(a)(2)(D) of the CAA requires that SIPs contain certain 
measures to prevent sources in a state from significantly contributing 
to air quality problems in another state. To implement this provision, 
EPA has required certain states to establish programs to address 
transport of air pollutants (NOX SIP Call,\1\ Clean Air 
Interstate Rule (CAIR)(70 FR 25162)). However, the section 110(a)(2)(D) 
requirements for a state are not linked with a particular nonattainment 
area's designation and classification. EPA believes that the 
requirements linked with a particular nonattainment area's designation 
and classification are the relevant measures to evaluate in reviewing a 
redesignation request. The transport SIP submittal requirements, where 
applicable, continue to apply to a state regardless of the designation 
of any one particular area in the state.
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    \1\ On October 27, 1998 (63 FR 57356), EPA issued a 
NOX SIP call, requiring the District of Columbia and 22 
states, including Indiana, to reduce their statewide emissions of 
NOX in order to reduce the transport of ozone and ozone. 
In compliance with EPA's NOX SIP call, IDEM has developed 
rules governing the control of NOX emissions from 
Electric Generating Units (EGUs), major non-EGU industrial boilers, 
and major cement kilns. EPA approved Indiana's rules as fulfilling 
Phase I of the NOX SIP Call on November 8, 2001 (66 FR 
56465). On December 11, 2003 (68 FR 69025) EPA approved revisions to 
these rules.
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    We believe that these requirements should not be construed to be 
applicable requirements for purposes of redesignation. Further, we 
believe that the other section 110 elements described above that are 
not connected with nonattainment plan submissions and not linked with 
an area's attainment status are also not applicable requirements for 
purposes of redesignation. A state remains subject to these 
requirements after an area is redesignated to attainment. We conclude 
that only the section 110 and part D requirements which are linked with 
a particular area's designation and classification are the relevant 
measures in evaluating a redesignation request. This approach is 
consistent with EPA's existing policy on applicability of conformity 
and oxygenated fuels requirements for redesignation purposes, as well 
as with section 184 ozone transport requirements. See Reading, 
Pennsylvania, proposed and final rulemakings (61 FR 53174-53176, 
October 10, 1996), (62 FR 24826, May 7, 1997); Cleveland-Akron-Lorain, 
Ohio, final rulemaking (61 FR 20458, May 7, 1996); and Tampa, Florida, 
final rulemaking (60 FR 62748, December 7, 1995). See also the 
discussion on this issue in the Cincinnati ozone redesignation (65 FR 
37890, June 19, 2000), and in the Pittsburgh ozone redesignation (66 FR 
50399, October 19, 2001).
    We believe that section 110 elements not linked to the area's 
nonattainment status are not applicable for purposes of redesignation. 
Any section 110 requirements that are linked to the part D requirements 
for 8-hour ozone nonattainment areas are not yet due, since, as 
explained below, no part D requirements applicable for purposes of 
redesignation under the 8-hour standard became due prior to submission 
of the redesignation requests. Therefore, as discussed above, for 
purposes of redesignation, they are not considered applicable 
requirements.
    Part D Requirements. EPA has determined that the Indiana SIP meets 
applicable SIP requirements under part D of the CAA since no 
requirements applicable for purposes of redesignation became due for 
the 8-hour ozone standard prior to submission of the Vigo County 
redesignation request. Under part D, an area's classification 
determines the requirements to which it will be subject. Subpart 1 of 
part D, found in sections 172-176 of the CAA, sets forth the basic 
nonattainment requirements applicable to all nonattainment areas. 
Section 182 of the CAA, found in subpart 2 of part D, establishes 
additional specific requirements depending on the area's nonattainment 
classification. Vigo County was classified as subpart 1 nonattainment 
area, and therefore subpart 2 requirements do not apply.

[[Page 70755]]

    Part D, Subpart 1 applicable SIP requirements. For purposes of 
evaluating this redesignation request, the applicable part D, subpart 1 
SIP requirements for Vigo County are contained in sections 172(c)(1)-
(9). A thorough discussion of the requirements contained in section 172 
can be found in the General Preamble for Implementation of Title I (57 
FR 13498, April 16, 1992).
    No requirements applicable for purposes of redesignation under part 
D became due prior to submission of the redesignation request, and, 
therefore, none is applicable to the area for purposes of 
redesignation. Since the State of Indiana has submitted a complete 
ozone redesignation request for Vigo County prior to the deadline for 
any submissions required for purposes of redesignation, we have 
determined that these requirements do not apply to the Vigo County area 
for purposes of redesignation.
    Furthermore, EPA has determined that areas being redesignated need 
not comply with the requirement that a NSR program be approved prior to 
redesignation, provided that the area demonstrates maintenance of the 
standard without part D NSR, since PSD requirements will apply after 
redesignation. A more detailed rationale for this view is described in 
a memorandum from Mary Nichols, Assistant Administrator for Air and 
Radiation, dated October 14, 1994, entitled, ``Part D New Source Review 
Requirements for Areas Requesting Redesignation to Attainment.'' 
Indiana has demonstrated that the area will be able to maintain the 
standard without part D NSR in effect, and therefore, EPA concludes 
that the State need not have a fully approved part D NSR program prior 
to approval of the redesignation request. The State's PSD program will 
become effective in Vigo County upon redesignation to attainment. See 
rulemakings for Detroit, Michigan (60 FR 12467-12468, March 7, 1995); 
Cleveland-Akron-Lorain, Ohio (61 FR 20458, 20469-20470, May 7, 1996); 
Louisville, Kentucky (66 FR 53665, October 23, 2001); and Grand Rapids, 
Michigan (61 FR 31834-31837, June 21, 1996).
    Section 176 conformity requirements. Section 176(c) of the CAA 
requires states to establish criteria and procedures to ensure that 
Federally-supported or funded activities, including highway projects, 
conform to the air quality planning goals in the applicable SIPs. The 
requirement to determine conformity applies to transportation plans, 
programs and projects developed, funded or approved under Title 23 
U.S.C. and the Federal Transit Act (transportation conformity) as well 
as to all other Federally-supported or funded projects (general 
conformity). State conformity revisions must be consistent with Federal 
conformity regulations relating to consultation, enforcement and 
enforceability that the CAA required the EPA to promulgate.
    EPA approved Indiana's general conformity SIP on January 14, 1998 
(63 FR 2146). Indiana does not have a Federally approved transportation 
conformity SIP. However, conformity analyses are performed pursuant to 
EPA's Federal conformity rules. Indiana has submitted on-highway motor 
vehicle budgets for Vigo County of 2.84 tpd of VOC and 3.67 tpd of 
NOX, based on the area's 2015 level of emissions. Vigo 
County must use the motor vehicle emissions budgets from the 
maintenance plan in any conformity determination that is effective on 
or after the effective date of the maintenance plan approval.
    EPA believes that it is reasonable to interpret the conformity SIP 
requirements as not applying for purposes of evaluating the 
redesignation request under section 107(d) for two reasons. First, the 
requirement to submit SIP revisions to comply with the conformity 
provisions of the CAA continues to apply to areas after redesignation 
to attainment since such areas would be subject to a section 175A 
maintenance plan. Second, EPA's Federal conformity rules require the 
performance of conformity analyses in the absence of Federally-approved 
state rules. Therefore, because areas are subject to the conformity 
requirements regardless of whether they are redesignated to attainment 
and must implement conformity under Federal rules if state rules are 
not yet approved, EPA believes it is reasonable to view these 
requirements as not applying for purposes of evaluating a redesignation 
request. See Wall v. EPA, 265 F.3d 426 (6th Cir. 2001), upholding this 
interpretation. See also 60 FR 62748 (Dec. 7, 1995) (Tampa, Florida). 
Thus, the area has satisfied all applicable requirements under section 
110 and part D of the CAA.
    b. For purposes of redesignation Vigo County has a fully approved 
applicable SIP under section 110(k) of the CAA. EPA has fully approved 
the Indiana SIP for Vigo County under section 110(k) of the CAA for all 
requirements applicable for purposes of redesignation. EPA may rely on 
prior SIP approvals in approving a redesignation request (See the 
September 4, 1992 John Calcagni memorandum, page 3, Southwestern 
Pennsylvania Growth Alliance v. Browner, 144 F.3d 984, 989-990 (6th 
Cir. 1998), Wall v. EPA, 265 F.3d 426 (6th Cir. 2001)) plus any 
additional measures it may approve in conjunction with a redesignation 
action. See 68 FR 25426 (May 12, 2003). Since the passage of the CAA of 
1970, Indiana has adopted and submitted, and EPA has fully approved, 
provisions addressing the various required SIP elements applicable to 
Vigo County under the 1-hour ozone standard. No Vigo County area SIP 
provisions are currently disapproved, conditionally approved, or 
partially approved. As indicated above, EPA believes that the section 
110 elements not connected with nonattainment plan submissions and not 
linked to the area's nonattainment status are not applicable 
requirements for purposes of redesignation. EPA also believes that 
since the part D requirements applicable for purposes of redesignation 
did not become due prior to submission of the redesignation request, 
they also are, therefore, not applicable requirements for purposes of 
redesignation.
3. The Improvement in Air Quality Is Due to Permanent and Enforceable 
Reductions in Emissions Resulting From Implementation of the SIP and 
Applicable Federal Air Pollution Control Regulations and Other 
Permanent and Enforceable Reductions (Section 107(d)(3)(E)(iii))
    EPA believes that Indiana has demonstrated that the observed air 
quality improvement in Vigo County is due to permanent and enforceable 
reductions in emissions resulting from implementation of the SIP, 
Federal measures, and other State-adopted measures.
    In making this demonstration, the State has calculated the change 
in emissions between 1999 and 2004, one of the years Vigo County 
monitored attainment. The reduction in emissions and the corresponding 
improvement in air quality over this time period can be attributed to a 
number of regulatory control measures that Indiana has implemented in 
recent years.
    a. Permanent and enforceable controls implemented. The following is 
a discussion of permanent and enforceable measures that have been 
implemented in the area:
    Reasonably Available Control Technology (RACT). Vigo County was not 
previously required to be covered by RACT regulations for existing 
sources under the CAA. However, Indiana has implemented statewide RACT 
controls through the following regulations:


[[Page 70756]]


326-IAC 8-2 Surface Coating Emission Limitations;
326-IAC 8-3 Organic Solvent Degreasing Operations;
326-IAC 8-4 Petroleum Sources;
326-IAC 8-5 Miscellaneous Operations; and
326-IAC 8-6 Organic Solvent Emission Limitations.

    NOX rules. In compliance with EPA's NOX SIP 
call, Indiana developed rules to control NOX emissions from 
Electric Generating Units (EGUs), major non-EGU industrial boilers, and 
major cement kilns. These rules required sources to begin reducing 
NOX emissions in 2004, with emission reductions increasing 
to 31 percent statewide by 2007. It should be noted that statewide 
NOX emissions actually began to decline in 2002 as sources 
phased in emission controls needed to comply with the State's 
NOX emission control regulations. From 2004 on, 
NOX emissions from EGUs are capped at a statewide total well 
below pre-2002 levels. It should be noted that NOX emissions 
are expected to further decline as the State meets the requirements of 
EPA's Phase II NOX SIP call (69 FR 21604).
    Federal Emission Control Measures. Reductions in VOC and 
NOX emissions have occurred statewide as a result of Federal 
emission control measures, with additional emission reductions expected 
to occur in the future as additional emission controls are implemented. 
Federal emission control measures have included: the National Low 
Emission Vehicle (NLEV) program, Tier 2 emission standards for 
vehicles, gasoline sulfur limits, and heavy-duty diesel engine 
standards. In addition, in 2004, EPA issued the Clean Air Non-road 
Diesel Rule (69 FR 38958). This rule will reduce off-road diesel 
emissions through 2010, with emission reductions starting in 2008.
    Indiana commits to maintain the implemented emission control 
measures after redesignation of Vigo County to attainment of the 8-hour 
ozone NAAQS. Any revisions to emission control regulations and emission 
limits will be submitted to the EPA for approval as SIP revisions.
    b. Emission reductions. Indiana is using 1999 for the nonattainment 
year inventory, emissions from which are used to compare to the 2004 
attainment year inventory to demonstrate that emission reductions (from 
1999 to 2004) have contributed to the improvement in air quality. 
Emissions estimates were taken directly from the National Emissions 
Inventory (NEI), with the following exception. Point source emissions 
information was compiled from IDEM's 1999 annual emissions statement 
database.
    For comparison, IDEM developed an inventory for 2004, one of the 
years the area monitored attainment of the 8-hour NAAQS. The point 
source sector information was compiled from IDEM's 2004 annual 
emissions statement database and the 2004 EPA Air Markets acid rain 
database. The area source sector information was taken from the Indiana 
2002 periodic inventory submitted to EPA. These projections were made 
from the U.S. Department of Commerce Bureau of Economic Analysis growth 
factors with some updated local information. The nonroad sector 
emission estimates were developed using NONROAD with the following 
modifications. Emissions were estimated for two nonroad categories not 
included in NONROAD, commercial marine vessels and railroads. 
Recreational motorboat population and spatial surrogates (used to 
assign emissions to each county) were updated. The populations for the 
construction equipment category were reviewed and updated based upon 
surveys completed in the Midwest and the temporal allocation for 
agricultural sources was also updated. The onroad sector emissions were 
calculated using MOBILE 6.2.
    Based on the inventories described above, Indiana's submittal 
documents changes in VOC and NOX emissions from 1999 to 2004 
for Vigo County. Indiana also documented the change in emissions for 
the surrounding Western Indiana Counties of Clay, Parke, Sullivan and 
Vermillion. Emissions data are shown in Tables 2 and 3 below.

               Table 2.--Comparison of 1999 and 2004 VOC and NOX Emissions for Vigo County (TPSD)
----------------------------------------------------------------------------------------------------------------
                                                       VOC                                   NOX
                                     ---------------------------------------------------------------------------
               Sector                                         Net change                            Net change
                                         1999       2004      (1999-2004)      1999       2004      (1999-2004)
----------------------------------------------------------------------------------------------------------------
Point...............................       7.36       4.84           -2.52      26.65      28.67            2.02
Area................................      14.18       6.48           -7.70       1.45       0.99           -0.46
Nonroad.............................       2.32       2.76            0.44       5.28       3.39           -1.89
Onroad..............................       8.30       6.22           -2.08      12.29       9.42           -2.87
                                     ------------
    Total...........................      32.16      20.30          -11.86      45.67      42.47           -3.20
----------------------------------------------------------------------------------------------------------------


           Table 3.--Comparison of 1999 and 2004 VOC and NOX Emissions for Surrounding Counties (TPSD)
----------------------------------------------------------------------------------------------------------------
                                                       VOC                                   NOX
                                     ---------------------------------------------------------------------------
               Sector                                         Net change                            Net change
                                         1999       2004      (1999-2004)      1999       2004      (1999-2004)
----------------------------------------------------------------------------------------------------------------
Point...............................       5.52       3.22           -2.30      82.39      62.90          -19.49
Area................................      19.18       6.76          -12.42       0.94       0.54           -0.40
Nonroad.............................       2.70       4.11            1.41       9.17       6.93           -2.24
Onroad..............................       7.20       6.12           -1.08       9.87      11.56            1.69
                                     ------------
    Total...........................      34.60      20.21          -14.39     102.37      81.93          -20.44
----------------------------------------------------------------------------------------------------------------

    Table 2 shows that Vigo County reduced NOX emissions by 
3.20 tpd and VOC emissions by 11.86 tpd between 1999 and 2004. Table 3 
shows emissions in the surrounding counties decreased by 14.39 tpd for 
VOC and 20.44 tpd for NOX.

[[Page 70757]]

    Based on the information summarized above, Indiana has adequately 
demonstrated that the improvement in air quality is due to permanent 
and enforceable emissions reductions.
4. The Area Has a Fully Approved Maintenance Plan Pursuant to Section 
175a of the CAA. (Section 107(d)(3)(E)(iv))
    In conjunction with its request to redesignate the Vigo County 
nonattainment area to attainment status, Indiana submitted a SIP 
revision to provide for the maintenance of the 8-hour ozone NAAQS in 
Vigo County for at least 10 years after redesignation.
    a. What is required in a maintenance plan? Section 175A of the CAA 
sets forth the required elements of a maintenance plan for areas 
seeking redesignation from nonattainment to attainment. Under section 
175A, the 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 redesignation, the 
State must submit a revised maintenance plan which demonstrates that 
attainment will continue to be maintained for ten years 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 implementation as EPA deems necessary to 
assure prompt correction of any future 8-hour ozone violations.
    The September 4, 1992 John Calcagni memorandum provides additional 
guidance on the content of a maintenance plan. An ozone maintenance 
plan should address the following items: The attainment VOC and 
NOX emissions inventories, a maintenance demonstration 
showing maintenance for the ten years of the maintenance period, a 
commitment to maintain the existing monitoring network, factors and 
procedures to be used for verification of continued attainment of the 
NAAQS, and a contingency plan to prevent or correct future violations 
of the NAAQS.
    b. Attainment Inventory. The State developed an inventory for 2004, 
one of the years the area monitored attainment of the 8-hour NAAQS. 
Inventory methodology is described in section 3 above. The attainment 
level of emissions is summarized along with the 2010 and 2015 projected 
emissions for Vigo County in Table 3 below.
    c. Demonstration of Maintenance. As part of the redesignation 
request, IDEM submitted revisions to the 8-hour ozone SIP to include a 
10-year maintenance plan as required by section 175A of the CAA. For 
Vigo County, this demonstration shows maintenance of the 8-hour ozone 
standard by assuring that current and future emissions of VOC and 
NOX remain at or below attainment year emission levels. A 
maintenance demonstration need not be based on modeling. See Wall v. 
EPA, 265 F.3d 426 (6th Cir. 2001), Sierra Club v. EPA, 375 F. 3d 537 
(7th Cir. 2004). See also 66 FR 53094, 53099-53100 (October 19, 2001), 
68 FR 25430-25432 (May 12, 2003).
    IDEM developed projected emissions inventories for 2010 and 2015. 
Onroad mobile source emissions were projected using Mobile 6.2 in 
accordance with ``Procedures for Preparing Emissions Projections,'' 
EPA-45/4-91-019. Emissions for the point, area and nonroad sectors were 
projected using growth and control files developed by the Midwest 
Regional Planning Organization. This method was used to ensure that the 
inventories used for redesignation are consistent with modeling 
performed in the future. These emission estimates are presented in 
Tables 4 and 5 below.

                                     Table 4.--Comparison of 2004-2015 VOC and NOX Emissions for Vigo County (TPSD)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                              VOC                                              NOX
                                                       -------------------------------------------------------------------------------------------------
                        Sector                                                             Net change                                       Net change
                                                           2004       2010       2015       2004-2015       2004       2010       2015       2004-2015
--------------------------------------------------------------------------------------------------------------------------------------------------------
Point.................................................       4.84       7.24       8.42            3.58      28.67      12.91      12.93          -15.74
Area..................................................       6.48       6.94       7.32            0.84       0.99       1.05       1.08            0.09
Nonroad...............................................       2.76       1.93       1.60           -1.16       3.39       2.01       1.53           -1.86
Onroad................................................       6.22       3.84       2.58           -3.64       9.42       5.76       3.34           -6.08
                                                       ------------
    Total.............................................      20.30      19.95      19.92           -0.38      42.47      21.73      18.88          -23.59
--------------------------------------------------------------------------------------------------------------------------------------------------------


                                 Table 5.--Comparison of 2004-2015 VOC and NOX Emissions for Surrounding Counties (TPSD)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                              VOC                                              NOX
                                                       -------------------------------------------------------------------------------------------------
                        Sector                                                             Net change                                       Net change
                                                           2004       2010       2015       2004-2015       2004       2010       2015       2004-2015
--------------------------------------------------------------------------------------------------------------------------------------------------------
Point.................................................       3.22       3.50       3.98            0.76      62.90      36.80      36.97          -25.93
Area..................................................       6.76       7.16       7.57            0.81       0.54       0.58       0.59            0.05
Nonroad...............................................       4.11       2.98       2.54           -1.57       6.93       3.60       2.98           -3.95
Onroad................................................       6.12       7.40       4.48           -1.64      11.56       4.31       3.09           -8.47
�������������������������������������������������������
--------------------------------------------------------------------------------------------------------------------------------------------------------

    The emission projections show that in Vigo County emissions are not 
expected to exceed the level of the 2004 attainment year inventory 
during the 10-year maintenance period. Vigo County VOC and 
NOX emissions are projected to decrease by 0.38 tpd and 
23.59 tpd, respectively. Surrounding County VOC and NOX 
emissions are projected to decrease by 1.64 tpd and 38.30 tpd, 
respectively.
    IDEM notes that, although ozone modeling is not required to support 
ozone redesignation requests, a significant amount of ozone modeling 
data exist that support the connection between emissions reductions and 
air quality improvement, including modeling data that support a 
demonstration of maintenance for Vigo County. IDEM notes that the 
available

[[Page 70758]]

modeling data demonstrate that Vigo is significantly impacted by ozone 
and ozone precursor transport and that NOX emission 
reductions are significantly beneficial for reducing 8-hour ozone 
concentrations in Vigo County. IDEM draws the conclusions discussed 
below from the various ozone modeling analyses that have addressed the 
Midwest.
    EPA modeling analyses for the Heavy Duty Engine rule. EPA conducted 
ozone modeling for Tier II vehicle and low-sulfur fuels to support the 
final rulemaking for the Heavy Duty Engine (HDE) and Vehicle Standards 
and Highway Diesel Fuel Rule. This modeling, in part, addressed ozone 
levels in Vigo County and the West Central Indiana Counties. A base 
year of 1996 was modeled, and the impacts of fuel changes and the 
NOX SIP call were addressed for high ozone episodes in 1995. 
The modeling supports the conclusion that the fuel improvements and the 
NOX SIP call result in significant ozone improvements (lower 
projected ozone concentrations) in Vigo County and in the West Central 
Indiana Counties. Using the modeling results to determine Relative 
Reduction Factors (RRFs)\2\ and, considering the 2001-2003 ozone design 
value at the Terre Haute ozone monitor (76 ppb) and at the Sandcut 
monitor (87) ppb, IDEM projected the 2007 ozone design value to be 66.1 
ppb and 80.4 ppb, at Terre Haute and Sandcut, respectively. Therefore, 
the NOX SIP call and the fuel modifications considered in 
the ozone modeling were found to significantly improve the ozone levels 
in Vigo County.
---------------------------------------------------------------------------

    \2\ Relative Reduction Factors are fractional changes in peak 
ozone concentrations projected to occur as the result of assumed 
changes in precursor emissions resulting from the implementation of 
emission control strategies. Relative Reduction Factors are derived 
through ozone modeling and are applied to monitored peak ozone 
concentrations to project post-control peak ozone levels.
---------------------------------------------------------------------------

    Lake Michigan Air Directors Consortium (LADCO) modeling analysis 
for the 8-hour ozone standard assessment. LADCO has performed ozone 
modeling to evaluate the effect of the NOX SIP call and Tier 
II/Low Sulfur Fuel Rule on 2007 ozone levels in the Lake Michigan area, 
which includes Vigo County and the West Central Indiana Counties. Like 
the EPA modeling discussed above, this modeling indicates that the 
2001-2003 ozone design values for the Vigo County monitoring sites 
would be reduced to below-standard levels in 2007 as the result of 
implementing the NOX SIP call and the Tier II/Low Sulfur 
Fuel Rule.
    EPA modeling analysis for the Clean Air Interstate Rule (CAIR). EPA 
conducted modeling in support of the CAIR rulemaking. The modeling was 
based on 1999-2003 design values. Future year modeling was conducted 
for Vigo County and future year design values for 2010 and 2015 were 
evaluated for attainment of the 8-hour ozone NAAQS. Results of the CAIR 
modeling show that Vigo County should continue to attain the 8-hour 
ozone NAAQS in 2010. With additional CAIR reductions in 2015, design 
values continue to decrease.
    As part of its maintenance plan, the State elected to include a 
``safety margin'' for the areas. A ``safety margin'' is the difference 
between the attainment level of emissions (from all sources) and the 
projected level of emissions (from all sources) in the maintenance plan 
which continues to demonstrate attainment of the standard. The 
attainment level of emissions is the level of emissions during one of 
the years in which the area met the NAAQS. For example, Vigo County 
attained the 8-hour ozone NAAQS during the 2002-2004 time period. 
Indiana uses 2004 as the attainment level of emissions for the area. 
The emissions from point, area, nonroad, and mobile sources in 2004 
equaled 20.30 tpd of VOC for Vigo County. Projected VOC emissions out 
to the year 2015 equaled 19.92 tpd of VOC. The SIP demonstrates that 
Vigo County will continue to maintain the standard with emissions at 
this level. The safety margin for VOC is calculated to be the 
difference between these amounts or, in this case, 0.38 tpd of VOC for 
2015. By this same method, 23.59 tpd (i.e., 42.47 tpd less 18.88 tpd) 
is the safety margin for NOX for 2015. The emissions are 
projected to maintain the area's air quality consistent with the NAAQS. 
The safety margin, or a portion thereof, can be allocated to any of the 
source categories, as long as the total attainment level of emissions 
is maintained.
    d. Monitoring Network. Indiana currently operates two ozone 
monitors in Vigo County. IDEM has committed to continue operating and 
maintaining an approved ozone monitor network in accordance with 40 CFR 
part 58.
    e. Verification of Continued Attainment. Continued attainment of 
the ozone NAAQS in Vigo County depends, in part, on the State's efforts 
toward tracking indicators of continued attainment during the 
maintenance period. The State's plan for verifying continued attainment 
of the 8-hour standard in Vigo County consists of plans to continue 
ambient ozone monitoring in accordance with the requirements of 40 CFR 
part 58. In addition, IDEM will periodically revise and review the VOC 
and NOX emissions inventories for Vigo County to ensure that 
emissions growth is not threatening the continued attainment of the 8-
hour ozone standard. Emissions inventories will be revised for 2005, 
2008, and 2011, as necessary to comply with the emissions inventory 
reporting requirements of the CAA. The updated emissions inventories 
will be compared to the 2004 emissions inventories to assess emission 
trends and assure continued attainment of the 8-hour ozone standard.
    f. Contingency Plan. The contingency plan provisions are designed 
to promptly correct or prevent a violation of the NAAQS that might 
occur after redesignation of an area to attainment. Section 175A of the 
CAA requires that a maintenance plan include such contingency measures 
as EPA deems necessary to assure that the State will promptly correct a 
violation of the NAAQS that might occur after redesignation. The 
maintenance plan should identify the contingency measures to be 
adopted, a schedule and procedure for adoption and implementation of 
the contingency measures, and a time limit for action by the state. The 
state should also identify specific indicators to be used to determine 
when the contingency measures need to be adopted and implemented. The 
maintenance plan must include a requirement that the state will 
implement all measures with respect to control of the pollutant(s) that 
were contained in the SIP before redesignation of the area to 
attainment. See section 175A(d) of the CAA.
    As required by section 175A of the CAA, Indiana has adopted a 
contingency plan for Vigo County to address a possible future ozone air 
quality problem. The contingency plan adopted by Indiana has two levels 
of responses, depending on whether a violation of the 8-hour ozone 
standard is only threatened (Warning Level) or has occurred or is 
imminent (Action Level).
    A Warning Level response will occur when an annual (1-year) fourth-
high monitored daily peak 8-hour ozone concentration of 88 ppb or 
higher is monitored in a single ozone season at any monitor within the 
ozone maintenance area. A Warning Level response will consist of 
Indiana performing a study to determine whether the high ozone 
concentration indicates a trend toward high ozone levels or whether 
emissions are increasing. If a trend toward higher ozone concentrations 
exists and is likely

[[Page 70759]]

to continue, the emissions control measures necessary to reverse the 
trend will be determined taking into consideration ease and timing of 
implementation, as well as economic and social considerations. The 
study, including applicable recommended next steps, will be completed 
within 12 months from the close of the ozone season with the recorded 
high ozone concentration. If emission controls are needed to reverse 
the adverse ozone trend, the procedures for emission control selection 
under the Action Level response will be followed.
    An Action Level response will occur when a two-year average annual 
fourth-high monitored daily peak 8-hour ozone concentration of 85 ppb 
occurs at any monitor in the ozone maintenance area. A violation of the 
standard (a 3-year average of the annual fourth-highest daily maximum 
8-hour average ozone concentration of 85 ppb or greater) also triggers 
an Action Level response. In this situation, IDEM will determine the 
additional emission control measures needed to assure future attainment 
of the 8-hour ozone NAAQS. IDEM will focus on emission control measures 
that can be implemented in a short time, and selected emission control 
measures will be adopted and implemented within 18 months from the 
close of the ozone season with ozone monitoring data that prompted the 
Action Level Response. Adoption of any additional emission control 
measures will be subject to the necessary administrative and legal 
procedures, including publication of notices and the opportunity for 
public comment and response. If a new emission control measure is 
adopted by the State (independent of the ozone contingency needs) or is 
adopted at a Federal level and is scheduled for implementation in a 
time frame that will mitigate an ozone air quality problem, IDEM will 
determine whether this emission control measure is sufficient to 
address the ozone air quality problem. If IDEM determines that existing 
or soon-to-be-implemented emissions control measures should be adequate 
to correct the ozone standard violation problem, IDEM may determine 
that additional emission control measures at the State level may be 
unnecessary. Regardless, IDEM will submit to the EPA an analysis to 
demonstrate that proposed emission control measures are adequate to 
provide for future attainment of the 8-hour ozone NAAQS in a timely 
manner. EPA notes that it is construing this provision to require that 
any non-Federal control measure relied upon in lieu of a contingency 
measure be included in the State SIP or be submitted to EPA for 
approval into the SIP.
    Contingency measures contained in the maintenance plan are those 
emission controls or other measures that Indiana may choose to adopt 
and implement to correct possible air quality problems. These include, 
but are not limited to, the following:
    i. Lower Reid vapor pressure gasoline requirements;
    ii. Broader geographic applicability of existing emission control 
measures;
    iii. Tightened RACT requirements on existing sources covered by EPA 
Control Technique Guidelines (CTGs) issued in response to the 1990 CAA 
amendments;
    iv. Application of RACT to smaller existing sources;
    v. Vehicle Inspection and Maintenance (I/M);
    vi. One or more Transportation Control Measure (TCM) sufficient to 
achieve at least a 0.5 percent reduction in actual area wide VOC 
emissions, to be selected from the following:
    A. Trip reduction programs, including, but not limited to, 
employer-based transportation management plans, area wide rideshare 
programs, work schedule changes, and telecommuting;
    B. Transit improvements;
    C. Traffic flow improvements; and
    D. Other new or innovative transportation measures not yet in 
widespread use that affect State and local governments as deemed 
appropriate;
    vii. Alternative fuel and diesel retrofit programs for fleet 
vehicle operations;
    viii. Controls on consumer products consistent with those adopted 
elsewhere in the United States;
    ix. VOC or NOX emission offsets for new or modified 
major sources;
    x. VOC or NOX emission offsets for new or modified minor 
sources;
    xi. Increased ratio of emission offset required for new sources; 
and,
    xii. VOC or NOX emission controls on new minor sources 
(with VOC or NOX emissions less than 100 tons per year).
    g. Provisions for Future Updates of the Ozone Maintenance Plan. As 
required by section 175A(b) of the CAA, Indiana commits to submit to 
the EPA an update of the ozone maintenance plan eight years after 
redesignation of Vigo County to cover an additional 10-year period 
beyond the initial 10-year maintenance period.
    EPA has concluded that the maintenance plan adequately addresses 
the five basic components of a maintenance plan: attainment inventory, 
maintenance demonstration, monitoring network, verification of 
continued attainment, and a contingency plan. The maintenance plan SIP 
revision submitted by Indiana for Vigo County meets the requirements of 
section 175A of the CAA.

B. Adequacy of Indiana's Motor Vehicle Emissions Budgets (MVEBs)

1. How Are MVEBs Developed and What Are the MVEBs for Vigo County?
    Under the CAA, states are required to submit, at various times, 
control strategy SIP revisions and ozone maintenance plans for 
applicable areas (for ozone nonattainment areas and for areas seeking 
redesignations to attainment of the ozone standard). These emission 
control strategy SIP revisions (e.g., reasonable further progress SIP 
and attainment demonstration SIP revisions) and ozone maintenance plans 
create MVEBs based on onroad mobile source emissions for criteria 
pollutants and/or their precursors to address pollution from cars