[Federal Register Volume 59, Number 139 (Thursday, July 21, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-17556]


[[Page Unknown]]

[Federal Register: July 21, 1994]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 52 and 81

[M118-01-5767, M121-01-6241; AMS-FRL-5014-8]

 

Approval and Promulgation of Implementation Plans and Designation 
of Areas for Air Quality Planning Purposes: State of Michigan

AGENCY: Environmental Protection Agency (USEPA).

ACTION: Proposed rule.

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SUMMARY: The USEPA proposes to approve revisions to the Michigan State 
Implementation Plan (SIP) for attainment and maintenance of the 
National Ambient Air Quality Standard (NAAQS) for ozone. These 
revisions pertain to the Detroit-Ann Arbor moderate ozone nonattainment 
area which includes the following counties: Livingston, Macomb, Monroe, 
Oakland, Saint Clair, Washtenaw, and Wayne. The revisions being 
proposed for approval are the 1990 base year emission inventory, basic 
vehicle inspection and maintenance (I/M), and redesignation of the 
Detroit-Ann Arbor area to attainment for ozone and corresponding 175A 
maintenance plan.

DATES: Comments on these proposed actions must be received in writing 
by August 22, 1994 and will be considered before taking final action on 
these SIP revisions.

ADDRESSES: Written comments should be sent to Carlton T. Nash, Chief, 
Regulation Development Section, Air Toxics and Radiation Branch (AT-
18J), United States Environmental Protection Agency, Region 5, 77 West 
Jackson Boulevard, Chicago, Illinois, 60604. Copies of these SIP 
revisions and USEPA's analyses are available for inspection at the 
above address.

FOR FURTHER INFORMATION CONTACT: Jacqueline Nwia, Environmental 
Engineer, Regulation Development Section, Air Toxics and Radiation 
Branch (AT-18J), United States Environmental Protection Agency, Region 
5, 77 West Jackson Boulevard, Chicago, Illinois 60604, (312) 886-6081. 
Anyone wishing to come to Region 5 offices should contact Jacqueline 
Nwia first.

SUPPLEMENTARY INFORMATION: This document contains a number of 
submittals for which the USEPA is proposing action. For purposes of 
clarity, the following Table of Contents is provided as a guide for 
this action.

Table of Contents

A. 1990 Base Year Emission Inventory
    I. Background
    II. Review of the State Submittal
    III. Proposed Action
B. Inspection and Maintenance
    I. Background and Review Criteria
    II. Finding of USEPA Review
    III. Proposed Action
C. Redesignation
    I. Background
    II. Evaluation Criteria
    III. Review of State Submittal
    1. Attainment of the Ozone NAAQS
    2. Meeting Applicable Requirements of Section 110 and Part D
    (A) Section 110 Requirements
    (B) Part D Requirements
    (B1) Subpart 1 of Part D--Section 172(c) Provisions
    (B2) Subpart 1 of Part D--Section 176 Conformity Provisions
    (B3) Subpart 2 Requirements
    3. Fully Approved SIP Under Section 110(k) of the Act.
    4. Improvement in Air Quality Due to Permanent and Enforceable 
Measures.
    5. Fully Approved Maintenance Plan Under Section 175A.
    (A) Emissions Inventory--Base Year Inventory
    (B) Demonstration of Maintenance--Projected Inventories
    (C) Verification of Continued Attainment
    (D) Contingency Plan
    (E) Subsequent Maintenance Plan Revisions
    IV. Proposed Action
D. Procedural Background
E. Regulatory Process

A. Emissions Inventory

    The inventory was submitted by the State to satisfy certain Federal 
requirements for an approvable nonattainment area ozone SIP for the 
Detroit/Ann Arbor area in Michigan.
    A detailed analysis of Michigan's 1990 Base Year Emission Inventory 
SIP submittal is contained in the USEPA's technical support document 
(TSD), dated January 27, 1994 from Jeanette Marrero to the Docket, 
entitled ``TSD for Proposed Revision to Michigan's Ozone SIP for the 
1990 Base Year Emissions Inventory for Areas Designated Nonattainment 
for Ozone'' (Emission Inventory TSD), which is available from the 
Region 5 office listed above.

I. Background

    Under the Act, States have the responsibility to inventory 
emissions contributing to NAAQS nonattainment, to track these emissions 
over time, and to ensure that control strategies are being implemented 
that reduce emissions and move areas towards attainment. The Act 
requires ozone nonattainment areas designated as moderate, serious, 
severe, and extreme to submit a plan within 3 years of 1990 to reduce 
volatile organic compounds (VOC) emissions by 15 percent within 6 years 
after 1990. The baseline level of emissions, from which the 15 percent 
reduction is calculated, is determined by adjusting the base year 
inventory to exclude biogenic emissions and certain emission reductions 
not creditable towards the 15 percent. The 1990 base year emissions 
inventory is the primary inventory from which the periodic inventory, 
the reasonable further progress (RFP) projection inventory, and the 
modeling inventory are derived. Further information on these 
inventories and their purpose can be found in the ``Emission Inventory 
Requirements for Ozone SIP,'' USEPA, Office of Air Quality Planning and 
Standards (OAQPS), Research Triangle Park, North Carolina, March 1991. 
The base year inventory may also serve as part of statewide inventories 
for purposes of regional modeling in transport areas. The base year 
inventory plays an important role in modeling demonstrations for areas 
classified as moderate and above outside transport regions.
    The air quality planning requirements for marginal to extreme ozone 
nonattainment areas are set out in section 182(a)-(e) of title I of the 
Act. Further, the USEPA has issued a General Preamble describing 
USEPA's preliminary views on how USEPA intends to review SIP revisions 
submitted under title I of the Act, including requirements for the 
preparation of the 1990 base year inventory (57 FR 13502, April 16, 
1992 and 57 FR 18070, April 28, 1992). Because USEPA is describing its 
interpretations here only in broad terms, the reader should refer to 
the General Preamble for a more detailed discussion of the 
interpretations of title I advanced in this proposal and the supporting 
rationale. In this rulemaking action on the Michigan ozone base year 
emissions inventory, USEPA is proposing to apply its interpretations 
taking into consideration the specific factual issues presented. Thus, 
USEPA will consider any comments submitted within the comment period 
before taking final action on this proposal.
    Those States containing ozone nonattainment areas classified as 
marginal to extreme are required under section 182(a)(1) of the Act to 
submit a final, comprehensive, accurate, and current inventory of 
actual ozone season, weekday emissions from all sources within 2 years 
of enactment (November 15, 1992). This inventory is for calendar year 
1990 and is denoted as the base year inventory. It includes both 
anthropogenic and biogenic sources of volatile organic compounds (VOC), 
nitrogen oxides (NOX), and carbon monoxide (CO). The inventory is 
to address actual VOC, NOX, and CO emissions for the area during 
peak ozone season, which is generally comprised of the summer months. 
All stationary point and area sources, as well as highway mobile 
sources within the nonattainment area, are to be included in the 
compilation. Available guidance for preparing emission inventories is 
provided in the General Preamble (57 FR 13498, April 16, 1992).
    The inventory was submitted by the State to USEPA on January 5, 
1993 as a proposed revision to the SIP. The State of Michigan held a 
public hearing on August 2, 1993 to receive public comment on the 1990 
base year emission inventory for Detroit/Ann Arbor nonattainment areas 
and certified the hearing to the USEPA in a submittal on November 15, 
1993. Supplemental information was also submitted on November 29, 1993.
    The emission inventory was reviewed by USEPA to determine 
completeness shortly after its submittal, in accordance with the 
completeness criteria set out at 40 Code of Federal Regulations (CFR) 
part 51, appendix V, as amended by 57 FR 42216 (August 26, 1991). The 
submittal was found to be complete on March 16, 1993 with the exception 
of evidence of a public hearing. After receiving evidence of the public 
hearing, a letter from David Kee, Director, Air and Radiation Division, 
USEPA, Region 5, dated January 7, 1994 was sent to the Governor's 
designee indicating the completeness of the submittal and the next 
steps to be taken in the review process.

II. Review of State Submittal

    When reviewing the final inventory, USEPA used the Level I, II, and 
III, ozone nonattainment inventory quality review checklists provided 
by the OAQPS to determine the acceptance and approvability of the final 
emission inventory.
    Level I is essentially the initial level of broad review that USEPA 
performs in order to determine if the inventory preparation guidance 
requirements found in the report ``Emission Inventory Requirements for 
Ozone SIPs'' (EPA-450/4-91-011) have been met. The Level II review 
addresses completeness, procedures and consistency for each of the four 
general source types in the inventory: stationary point and area 
sources, highway mobile sources, and non-highway mobile sources. The 
data quality is also evaluated. Detailed Level I and II review 
procedures can be found in the following document: ``Quality Review 
Guidelines for 1990 Base Year Emission Inventories,'' USEPA, OAQPS, 
Research Triangle Park, NC, July 27, 1992.
    Level III review procedures are specified in a memorandum from J. 
David Mobley, Chief, Emissions Inventory Branch, and G. T. Helms, 
Chief, Ozone/CO Programs Branch, to Air Branch Chiefs, Region I-X, 
``1990 Ozone/CO SIP Emission Inventory Level III Acceptance Criteria,'' 
October 7, 1992 and revised in a memorandum from John Seitz, Director, 
OAQPS, to Regional Air Division Directors, Region I-X, ``Emission 
Inventory Issues,'' June 24, 1993. The Level III review process is 
outlined here and consists of 10 points that the inventory must 
include. For a base year emission inventory to be acceptable it must 
pass all of the following acceptance criteria:
    1. An approved Inventory Preparation Plan (IPP) was provided and 
the Quality Assurance program contained in the IPP was performed and 
its implementation documented.
    2. Adequate documentation was provided that enabled the reviewer to 
determine the emission estimation procedures and the data sources used 
to develop the inventory.
    3. The point source inventory must be complete.
    4. Point source emissions must have been prepared or calculated 
according to the current USEPA guidance.
    5. The area source inventory must be complete.
    6. The area source emissions must have been prepared or calculated 
according to the current USEPA guidance.
    7. Biogenic emissions must have been prepared according to current 
USEPA guidance or another approved technique.
    8. The method (e.g., Highway Performance Monitoring System or a 
network transportation planning model) used to develop Vehicle Miles 
Traveled (VMT)\1\ estimates must follow USEPA guidance, which is 
detailed in the document, ``Procedures for Emission Inventory 
Preparation, volume IV: Mobile Sources,'' USEPA, Office of Mobile 
Sources and OAQPS, Ann Arbor, Michigan, and Research Triangle Park, 
North Carolina, December 1992. The VMT development methods were 
adequately described and documented in the inventory report.
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    \1\VMT is the number of miles traveled by vehicles of various 
types, preferably for each link of the highway system. The VMT is 
estimated using various models and/or methods.
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    9. The MOBILE model was correctly used to produce emission factors 
for each of the vehicle classes.
    10. Non-road mobile emissions were prepared according to current 
USEPA guidance for all of the source categories.
    The base year emission inventory will be approved if it passes 
Levels I, II, and III of the review process.
    The USEPA reviewed the State submittal using the Level I, II and 
III criteria noted above. These findings are discussed further in the 
Emission Inventory TSD.

III. Proposed Action

    The USEPA is proposing to fully approve the ozone emission 
inventory SIP submitted to USEPA for the Detroit/Ann Arbor area as 
meeting the section 182(a)(1) requirements of the Act for emission 
inventories. The State has submitted a complete inventory containing 
point, area, biogenic, on-road, and non-road mobile source data, and 
accompanying documentation. Emissions from these groupings of sources 
are presented in the following tables: 

                           Daily VOC Emissions From All Sources--Tons/Summer Weekday                            
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                                                                On-road      Non-road                           
                                       Point     Area source     mobile       mobile      Biogenic      Total   
     Ozone nonattainment area          source     emissions      source       source     emissions    emissions 
                                     emissions                 emissions    emissions                           
----------------------------------------------------------------------------------------------------------------
Detroit/Ann Arbor.................       167.08       252.27       327.00       531.03       113.90      1391.28
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                            Daily CO Emissions From All Sources--Tons/Summer Weekday                            
----------------------------------------------------------------------------------------------------------------
                                                                             On-road      Non-road              
                                                    Point     Area source     mobile       mobile       Total   
            Ozone nonattainment area                source     emissions      source       source     emissions 
                                                  emissions                 emissions    emissions              
----------------------------------------------------------------------------------------------------------------
Detroit/Ann Arbor..............................       146.28        45.22      3058.00       862.54      4112.04
----------------------------------------------------------------------------------------------------------------


                           Daily NOX Emissions From All Sources--Tons/Summer Weekday                            
----------------------------------------------------------------------------------------------------------------
                                                                             On-road      Non-road              
                                                    Point     Area source     mobile       mobile       Total   
            Ozone nonattainment area                source     emissions      source       source     emissions 
                                                  emissions                 emissions    emissions              
----------------------------------------------------------------------------------------------------------------
Detroit/Ann Arbor..............................       734.62        56.36       437.00       108.22      1336.20
----------------------------------------------------------------------------------------------------------------

    Detailed information on how each of the above source category 
groupings was determined is included in the Emission Inventory TSD.

B. Inspection and Maintenance

    A detailed analysis of the Michigan I/M SIP submittal is contained 
in the USEPA's TSD, dated February 1, 1994 from Brad Beeson to the 
Docket, entitled ``Technical Review of the Michigan SIP Submittal to 
Revise the I/M Program in Southeast Michigan'' (I/M TSD), which is 
available from the Region 5 office listed above.

I. Background and Review Criteria

    The Act requires States to make changes to improve existing I/M 
programs or implement new ones. Section 182(a)(2)(B)(i) requires States 
to submit SIP revisions for any ozone nonattainment area which has been 
classified as marginal, pursuant to section 181(a) of the Act, with an 
existing I/M program that was part of a SIP prior to enactment of the 
Act, or any area that was required by the Clean Air Act, as amended in 
1977 (1977 Act) to have an I/M program, to bring the program up to the 
level required in pre-1990 USEPA guidance, or to what had been 
committed to previously in the SIP, whichever was more stringent. Areas 
classified as moderate and worse ozone nonattainment areas were also 
subject to this requirement to improve programs to this level.
    On November 15, 1993 the Michigan Department of Natural Resources 
(MDNR) submitted to the USEPA a revision to the Michigan SIP which was 
intended to address the requirements for an I/M program in the Detroit-
Ann Arbor area. The revision included legislation which was signed into 
law by Governor Engler on November 13, 1993.2
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    \2\In addition to legislation revising the I/M program in the 
Detroit-Ann Arbor area, the State also submitted adopted legislation 
establishing an I/M program on the west side of the State. For 
reasons of clarity, however, that program will be the subject of a 
future Federal Register notice. Today's rulemaking only addresses 
the State's submittal related to the program in the Detroit-Ann 
Arbor area.
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    At the same time as this legislation was being developed, the MDNR 
was also in the process of developing a redesignation request from 
nonattainment to attainment for the Detroit-Ann Arbor moderate ozone 
nonattainment area.
    Section 107(d)(3)(E) of the Act states that an area can be 
redesignated to attainment if certain conditions are met. One of these 
conditions is that the USEPA has fully approved the applicable 
implementation plan under section 110(k) and that the State has met all 
applicable requirements of section 110 and part D. The USEPA's current 
approvability criteria for I/M in part require fully adopted rules for 
all aspects of the proposed SIP revision. In addition, all SIPs 
submitted must be subject to public hearing before they can be 
approved.
    On November 5, 1992 (57 FR 52950), the USEPA published a final rule 
(I/M Rule) establishing I/M requirements pursuant to section 182. On 
June 28, 1994 the USEPA published a proposal to amend requirements 
pertaining to SIP submissions for areas required to implement a basic 
I/M program that submit, and otherwise qualify for approval of, a 
redesignation request (``Proposed I/M Redesignation Rule''). The 
authority for that amendment is discussed in that proposal.
    The I/M Redesignation Rule proposes to allow areas that have 
requested redesignation to attainment, and are otherwise eligible to 
obtain approval of the request, to defer adoption and implementation of 
otherwise applicable requirements established in the originally 
promulgated I/M rule. For such areas, the USEPA does not believe it is 
necessary to revise or adopt new regulations which are not essential 
for clean air, and which would not be implemented after redesignation 
occurred because they are not necessary for maintenance. The proposed 
rule applies only to areas that by virtue of their air quality 
classification are required to implement a basic I/M program and that 
submit and obtain approval of a redesignation request.
    For such areas, the I/M Redesignation Rule proposes that the I/M 
component of the I/M SIP contain the following four criteria:
    (1) Legislative authority for basic I/M meeting all the 
requirements of subpart S such that implementing regulations can be 
adopted without any further legislative action,
    (2) A provision in the SIP providing that basic I/M be placed in 
the contingency measures portion of the maintenance plan upon 
redesignation,
    (3) a contingency measure consisting of a commitment by the 
Governor or his/her designee to adopt regulations to implement the I/M 
program in response to a specified triggering event, and
    (4) a commitment that includes an enforceable schedule for the 
adoption and implementation of a basic I/M program including 
appropriate milestones in the event the contingency measure is 
triggered.
    In this rulemaking, the USEPA is considering Michigan's I/M 
submittal based on the proposed I/M requirements for areas otherwise 
eligible for redesignation. If the State's redesignation request is not 
otherwise eligible for approval at the time the USEPA takes final 
action on it, or if the proposed I/M requirements for redesignation are 
not codified, Michigan's submittal will be judged by the current I/M 
approvability criteria as detailed in the USEPA's final I/M rule 
promulgated on November 5, 1992.
    As discussed in the Proposed I/M Redesignation Rule, while the 
USEPA considers the redesignation request, the State continues to be 
required to meet all the current SIP submission requirements including 
fully adopted rules and specific implementation deadlines as required 
under 40 CFR Sec. 51.372 of the I/M Rule. If the State does not comply 
with these requirements, it could be subject to sanctions pursuant to 
section 179. If the redesignation request is approved, any sanctions 
already imposed or any sanctions clock already triggered would be 
terminated.

II. Finding of USEPA Review

    On November 15, 1993 the State submitted a redesignation request 
including I/M as a contingency measure for the Detroit-Ann Arbor area 
to the USEPA.
    Using the proposed I/M Redesignation Rule criteria for areas 
redesignating from nonattainment to attainment, Michigan's I/M SIP 
submittal for the Detroit-Ann Arbor area is acceptable. The State held 
public hearings on the State's submittal February 14, 1994 in Detroit, 
Michigan.
    With respect to the first element of the four criteria, the 
proposed I/M Redesignation Rule requires ``legislative authority for 
basic I/M such that implementing regulations can be adopted without any 
further legislative action.'' The legislation adopted by Michigan as a 
whole includes all the essential elements of a satisfactory basic I/M 
program. The essential elements include:
     Describing the network type (``test and repair'').3
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    \3\The parenthetical information refers to the specifics in the 
Detroit-Ann Arbor, Michigan legislation.
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     Listing of geographic coverage of program (Wayne, Oakland, 
Macomb, and possibly Washtenaw if redesignated, or Wayne, Oakland, 
Macomb, Washtenaw, St. Clair, Livingston, and Monroe if not 
redesignated).
     Specifying the test type and procedure (idle test with BAR 
90 equipment).
     Listing of other applicable testing procedures (visual 
tampering inspection).
     Defining subject vehicle population (1975 and later).
     Specifying testing frequency (every 12 months).
     Granting authority to a State agency to develop necessary 
rules (MDNR).
     Establishing the enforceable obligation in the rule 
(persons shall not drive a motor vehicle without a valid emissions 
certificate of compliance or waiver).
    In addition to defining the elements essential to the definition of 
an I/M program, the legislation grants the authority to MDNR to develop 
the rest of the language necessary to make the program complete, 
including technical and administrative details. No further legislative 
action is necessary to authorize or implement the program.
    In the event of redesignation, the USEPA believes that the States's 
approach to implement I/M in the counties of Wayne, Oakland, Macomb, 
and Washtenaw counties is acceptable and meets the population 
requirements (geographic coverage) specified in the I/M rule (40 CFR 
51.350).
    Because the State has authorized and provided the essentials of an 
I/M program in its adopted legislation, the first element of the 
criteria proposed in the I/M Redesignation Rule is satisfied.
    The second element of the I/M Redesignation Rule proposes to 
require ``a provision in the SIP providing that basic I/M be placed in 
the contingency measures portion of the maintenance plan upon 
redesignation.'' This requirement is satisfied by the provision of 
section 8(2)(a) which requires a basic I/M program to be implemented as 
a contingency measure.
    The third and fourth elements of the proposed I/M Redesignation 
Rule require an enforceable schedule and commitment by the Governor or 
his/her designee for the adoption and implementation of a basic I/M 
program upon a specified, appropriate triggering event. These elements 
are satisfied based on language submitted to the USEPA on November 15, 
1993 under separate cover, within the State's redesignation 
application. Section 6.8.3 of the State's Southeast Michigan 
Redesignation TSD states ``implementation of the contingency measure[s] 
will be completed in a time-frame consistent with schedules of 
implementation required for SIPs under title I of the Act and 
corresponding regulations.'' This commitment was submitted to the USEPA 
on November 15, 1993 under the signature of Roland Harmes, the 
Governor's designee. The USEPA assumes that the effective date of the 
basic I/M legislation as a contingency measure is the date that the 
State determines that a basic I/M program is necessary, as shown by the 
urban airshed model (UAM), to correct a violation of the ozone NAAQS. 
The USEPA further assumes that the basic I/M program will be 
implemented in the Detroit-Ann Arbor area as a contingency measure 1 
year from the effective date of the legislation as stipulated in the I/
M rule 40 CFR 51.373(b).4
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    \4\Title 40 CFR 51.373(b) specifies the implementation of a 
basic I/M program within 1 year of obtaining legal authority.
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    While the USEPA is proposing approval of the State's I/M submittal 
based on the criteria proposed in the I/M Redesignation Rule, if the 
State's redesignation request is not approved, or if the alternative 
approval criteria applicable to redesignation is not codified as 
proposed, the State's submittal must be judged against the current I/M 
approvability criteria which require fully adopted rules for all 
aspects of the program, as detailed in USEPA's final I/M rule of 
promulgated on November 5, 1992. The State's submittal would then not 
be approvable because the submittal does not include detailed rules, 
including cut points, test procedures and standards, quality control 
procedures, waiver provisions, and program compliance and oversight.

III. Proposed Action

    Because the State's submittal meets the I/M approvability criteria 
for areas redesignating from nonattainment to attainment, USEPA is 
proposing to approve the I/M plan for the Detroit-Ann Arbor area that 
was submitted as a revision to the Michigan SIP. Alternatively, USEPA 
is proposing to disapprove the State's I/M SIP for the Detroit-Ann 
Arbor area if the State's redesignation request is ultimately not 
approved or if the I/M Redesignation Rule is not codified as proposed 
in USEPA's I/M rule before the USEPA finalizes its approval of the 
redesignation.

C. Redesignation

    Under the Act, nonattainment areas can be redesignated to 
attainment if sufficient data are available to warrant such changes and 
the area satisfies other criteria contained in section 107(d)(3) of the 
Act. On November 12, 1993 the State submitted a redesignation request 
and section 175A maintenance plan. If approved, the section 175A 
maintenance plan would become a federally enforceable part of the SIP 
for the Detroit-Ann Arbor area.
    A detailed analysis of the Michigan Redesignation Request and 
section 175A Maintenance Plan SIP submittal for the Detroit-Ann Arbor 
area is contained in the USEPA's TSD, dated February 24, 1994 from 
Jacqueline Nwia to the Docket, entitled ``TSD for the Request to 
Redesignate the Detroit/Ann Arbor, Michigan Moderate Nonattainment Area 
to Attainment for Ozone and the Proposed Revision to the Michigan Ozone 
SIP for a 175A Maintenance Plan'' and ``Amendments to the February 24, 
1994 TSD for the Request to Redesignate the Detroit/Ann Arbor, Michigan 
Moderate Nonattainment Area to Attainment for Ozone and the Proposed 
Revision to the Michigan Ozone SIP for a 175A Maintenance Plan,'' dated 
June 21, 1994 (Redesignation/Maintenance Plan TSD), which are available 
from the Region 5 office listed above.

I. Background

    The 1977 Act required areas that were designated nonattainment 
based on a failure to meet the ozone NAAQS, to develop SIPs with 
sufficient control measures to expeditiously attain and maintain the 
standard. The Detroit-Ann Arbor area was designated under section 107 
of the 1977 Act as nonattainment with respect to the ozone NAAQS (43 FR 
8962, March 3, 1978 and 43 FR 45993, October 5, 1978).
    After enactment of the amended Act on November 15, 1990 the 
nonattainment designation of the Detroit-Ann Arbor area continued by 
operation of law according to section 107(d)(1)(C)(i) of the Act; 
furthermore, it was classified by operation of law as moderate for 
ozone pursuant to section 181(a)(1) (56 FR 56694, November 6, 1991 and 
57 FR 56762, November 30, 1992), codified at 40 CFR 81.323.
    The Detroit-Ann Arbor area more recently has ambient monitoring 
data that show no violations of the ozone NAAQS, during the period from 
1991 through 1993. The area, therefore, became eligible for 
redesignation from nonattainment to attainment consistent with the 
amended Act, and to ensure continued attainment of the ozone standard, 
Michigan also submitted an ozone maintenance SIP for the Detroit-Ann 
Arbor on November 12, 1993. On November 12, 1993 Michigan requested 
redesignation of the area to attainment with respect to the ozone 
NAAQS. On October 22, 1993 Michigan held a public hearing on the 
maintenance plan component of the redesignation request.

II. Evaluation Criteria

    The 1990 Amendments revised section 107(d)(3)(E) to provide five 
specific requirements that an area must meet in order to be 
redesignated from nonattainment to attainment.
    1. The area must have attained the applicable NAAQS;
    2. The area has met all relevant requirements under section 110 and 
part D of the Act;
    3. The area has a fully approved SIP under section 110(k) of the 
Act;
    4. The air quality improvement must be permanent and enforceable;
    5. The area must have a fully approved maintenance plan pursuant to 
section 175A of the Act.

III. Review of State Submittal

    The Michigan redesignation request for the Detroit-Ann Arbor area 
will meet the five requirements of section 107(d)(3)(E), noted above, 
if the VOC RACT ``fix-up,''5 and ``catch-up,''6 and major 
non-CTG submittals7, the 1990 base year emission inventory, basic 
I/M, and the section 182(f) NOX exemption petition are also fully 
approved by the USEPA.8 Because the maintenance plan is a critical 
element of the redesignation request, USEPA will discuss its evaluation 
of the maintenance plan under its analysis of the redesignation 
request. USEPA's Redesignation/Maintenance Plan TSD contains a more in-
depth analysis of the submittal with respect to certain of these 
evaluation criteria.
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    \5\Section 182(b)(2) of the Act requires that moderate and above 
ozone nonattainment areas adopt RACT rules for three types of 
sources or source categories, i.e. RACT for source categories 
covered by the CTGs and for major sources that are not subject to a 
CTG, regardless of time of nonattainment designation.
    \6\Section 182(a)(2)(A) of the Act requires that ozone 
nonattainment areas submit rules and corrections to existing VOC 
rules that were required under the section 172(b)(3) RACT provision 
of the pre-amended Act (and related guidance).
    \7\Rules for major non-CTG sources are a requirement under the 
Section 182(b)(2) catch-ups.
    \8\The emission statement program was fully approved in a final 
rulemaking action on March 8, 1994 (59 FR 10752).
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1. Attainment of the ozone NAAQS
    The Michigan request is based on an analysis of quality-assured 
ozone air quality data which is relevant to the maintenance plan and to 
the redesignation request. Ambient air ozone monitoring data for 
calendar year 1991 through calendar year 19939 show an expected 
exceedance rate for the ozone standard of less than 1.0 per year of the 
ozone NAAQS in the Detroit-Ann Arbor area (40 CFR 50.9 and appendix H). 
Because the Detroit-Ann Arbor area has complete quality-assured data 
showing no violations of the standard over the most recent consecutive 
three calendar year period, the Detroit-Ann Arbor area has met the 
first statutory criterion of attainment of the ozone NAAQS. The State 
committed to continue monitoring in this area in accordance with 40 CFR 
part 58. (If, however, complete quality assured data shows violations 
of the ozone NAAQS before the final USEPA action on this redesignation, 
the USEPA proposes that it disapprove the redesignation request.)
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    \9\The redesignation request documentation presents 1990-1992 
ambient air quality monitoring data demonstrating that the Detroit-
Ann Arbor area attained the ozone NAAQS. In order to submit the 
redesignation request before November 15, 1993, Michigan prepared 
most of this documentation during the 1993 ozone season, when the 
1993 ozone data was not available. However, the USEPA reviewed the 
ambient monitoring data for 1993 contained in AIRS which 
demonstrates that the area continues to attain the ozone NAAQS.
---------------------------------------------------------------------------

2. Meeting Applicable Requirements of Section 110 and Part D
    On May 6, 1980 (45 FR 29801) and February 7, 1985 (50 FR 5250), 
USEPA fully approved Michigan's SIP for the Detroit-Ann Arbor area as 
meeting the requirements of section 110(a)(2) and part D of the 1977 
Act with the exception that Michigan must meet the part D RACT 
requirements for the ozone SIP. The 1990 Act, however, modified section 
110(a)(2) and, under part D, revised section 172 and added new 
requirements for all nonattainment areas. Therefore, for purposes of 
redesignation, to satisfy the requirement that the SIP meet all 
applicable requirements under the 1990 Act, USEPA has reviewed the SIP 
to ensure that it contains all measures that were due under the amended 
1990 Act prior to or at the time Michigan submitted its redesignation 
request for the Detroit-Ann Arbor area. The USEPA interprets section 
107(d)(3)(E)(v) to mean that for a redesignation request to be 
approved, the State has met all requirements that applied to the 
subject area prior to or at the time of the submission of a complete 
redesignation request. Requirements of the Act that come due 
subsequently, continue to be applicable to the area at those later 
dates [see section 175A(c)] and, if the redesignation of the area is 
disapproved, the State remains obligated to fulfill those requirements.
    (A.) Section 110 Requirements. Although section 110 was amended by 
the Act, the Detroit-Ann Arbor area SIP meets the requirements of 
amended section 110(a)(2). A number of the requirements did not change 
in substance and, therefore, USEPA believes that the pre-amendment SIP 
met these requirements. As to those requirements that were amended (57 
FR 27936 and 23939, June 23, 1993) many are duplicative of other 
requirements of the Act. The USEPA has analyzed the SIP and determined 
that it is consistent with the requirements of amended section 
110(a)(2).
    (B.) Part D Requirements. Before the Detroit-Ann Arbor area may be 
redesignated to attainment, it 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, classified as well as nonclassifiable. Subpart 
2 of part D establishes additional requirements for nonattainment areas 
classified under table 1 of section 181(a). As described in the General 
Preamble for the Implementation of title 1, specific requirements of 
subpart 2 may override subpart 1's general provisions (57 FR 13501 
(April 16, 1992)). The Detroit-Ann Arbor area was classified as 
moderate (56 FR 56694, November 6, 1991), codified at 40 CFR 81.323. 
Therefore, in order to be redesignated to attainment, the State must 
meet the applicable requirements of subpart 1 of part D--specifically 
sections 172(c) and 176 as well as the applicable requirements of 
subpart 2 of part D.
    (B1.) Subpart 1 of Part D--Section 172(c) Provisions. Section 
172(c) sets forth general requirements applicable to all nonattainment 
areas. Under 172(b), the section 172(c) requirements are applicable as 
determined by the Administrator, but no later than 3 years after an 
area has been designated as nonattainment under the amended Act. The 
USEPA has not determined that these requirements are applicable to 
ozone nonattainment areas on or before November 12, 1993--the date the 
State submitted a complete redesignation request for the Detroit-Ann 
Arbor area. Therefore, the State was not required to meet these 
requirements for redesignation purposes. In addition, as discussed 
below, Michigan has either satisfied the section 172(c) requirements 
or, as is the case for several of them, they lose their continued force 
once an area has demonstrated attainment and maintenance of the ozone 
NAAQS.
    (1) RFP is defined as progress that a nonattainment area must make 
each year toward attainment of the ozone NAAQS. This requirement only 
has relevance during the time it takes an area to attain the NAAQS. 
Because the Detroit-Ann Arbor area has attained the ozone NAAQS, its 
SIP has already achieved the necessary RFP toward that goal.
    (2) In addition, because the Detroit-Ann Arbor has attained the 
ozone NAAQS and is no longer subject to an RFP requirement, the section 
172(c)(9) contingency measures are not applicable unless the 
redesignation request and maintenance plan are not finally approved. 
Such contingency measures must take effect if the area fails to meet an 
RFP milestone or fails to attain the ozone NAAQS; the Detroit-Ann Arbor 
area no longer has RFP milestones and has already attained the NAAQS. 
However, section 175A contingency measures still apply.
    (3) Similarly, once an area is redesignated to attainment, 
nonattainment new source review (NSR) requirements are not generally 
applicable. The area then becomes subject to prevention of significant 
deterioration (PSD) requirements instead of the NSR program (57 FR 
13564). The State has an acceptable program for review of new sources 
(45 FR 29790, May 6, 1980 and 47 FR 3765, February 7, 1985). The PSD 
program was delegated to the State of Michigan on September 10, 1979 
and amended on November 7, 1983 and September 26, 1988. Moreover, as 
discussed with respect to the NSR requirements of part D, the USEPA 
believes that the applicability of the part C PSD program to 
maintenance areas makes it unnecessary to require that an area have 
obtained full approval of the NSR revisions required by part D in order 
to be redesignated.
    (4) The 172(c)(3) requirement for an emissions inventory has been 
met by submission and proposed approval of the 1990 base year emission 
inventory required by section 182(a)(1).
    (5) No additional Reasonably Available Control Measures (RACM) 
controls beyond what may already be required in the SIP are necessary 
upon redesignation to attainment. The General Preamble (57 FR 13560, 
April 16, 1992) explains that section 172(c)(1) requires the plans for 
all nonattainment areas to provide for the implementation of all RACM 
as expeditiously as practicable. The EPA interprets this requirement to 
impose a duty on all nonattainment areas to consider all available 
control measures and to adopt and implement such measures as are 
reasonably available for implementation in the area as components of 
the areas attainment demonstration. Because attainment has been 
reached, no additional measures are needed to provide for attainment.
    (6) For purposes of redesignation, the Michigan SIP was reviewed to 
ensure that all requirements of section 110(a)(2), containing general 
SIP elements, under the Act were satisfied. Title 40 CFR 52.1172 
evidences that the Michigan SIP was approved under section 110 of the 
Act, and further that it satisfies all part D, title I (as amended in 
1977) requirements on May 6, 1980 (45 FR 29801) and February 7, 1985 
(50 FR 5250) with the exception that Michigan must meet the part D RACT 
requirements for the ozone SIP.
    (B2.) Subpart 1 of Part D--Section 176 Conformity Provisions. 
Section 176(c) of the Act requires States to revise their SIPs to 
establish criteria and procedures to ensure that Federal actions, 
before they are taken, conform to the air quality planning goals in the 
applicable State SIP. The requirement to determine conformity applies 
to transportation plans, programs and projects developed, funded or 
approved under title 23 U.S.C. or the Federal Transit Act 
(``transportation conformity''), as well as to all other Federal 
actions (``general conformity''). Section 176 further provides that the 
conformity revisions to be submitted by States must be consistent with 
Federal conformity regulations that the Act required the USEPA to 
promulgate. Congress provided for the State revisions to be submitted 
on year after the date for promulgation of the final USEPA conformity 
regulations. When that date passed without such promulgation, USEPA's 
General Preamble for the implementation of title I informed States that 
its conformity regulations would establish a submittal date [see 57 FR 
13498, 13557 (April 16, 1992)]. The USEPA promulgated final 
transportation conformity regulations on November 24, 1993 (58 FR 
62188) and general conformity regulations on November 30, 1993 (58 FR 
63214). These conformity rules require that States adopt both 
transportation and general conformity provisions in the SIP for areas 
designated nonattainment or subject to a maintenance plan approved 
under section 175A of the Act. Pursuant to section 51.396 of the 
transportation conformity rule and section 51.851 of the general 
conformity rule, the State of Michigan is required to submit a SIP 
revisions containing transportation and general conformity criteria and 
procedures consistent with those established in the Federal rule by 
November 25 and 30, 1994, respectively. Because the deadline for such 
submittals has not yet come due, it is not an applicable requirement, 
under section 107(d)(3)(E)(v), for approval of this redesignation 
request.
    (B3.) Subpart 2 Requirements. Detroit-Ann Arbor is a moderate ozone 
nonattainment area. Under subpart 2, as of the date the State submitted 
a complete redesignation request, it is required to have met the 
requirements of section 182(a)(1), (2), and (3), section 182(b)(2), and 
(4), and section 182(f). The State has submitted SIP revisions which 
have not yet been approved by the USEPA but must be in order to find 
that the State has met all the applicable requirements of the following 
sections of the Act: Section 182(a)(1) 1990 base year emission 
inventory, section 182(a)(2)(A) VOC RACT ``fix-ups,'' section 
182(a)(2)(B) I/M fix-ups, section 182(b)(2) (``catch-ups'') VOC RACT 
for each VOC source covered by a CTG issued between enactment of the 
Act and the attainment date (since the due date for these rules is 
November 15, 1994 which has not come due yet, it is not a requirement 
for approval of this redesignation request), all VOC sources covered by 
any CTG issued before the date of enactment of the Act, and all other 
major stationary sources of VOC located in the area, section 182(b)(4) 
basic I/M, and section 182(f) NOX requirements. Section 182(b)(3) 
Stage II vapor recovery was also an applicable requirement. However, 
the ``onboard rule''10 was published on April 6, 1994 and section 
202(a)(6) of the Act provides that once onboard rules are promulgated, 
Stage II vapor recovery will no longer be a requirement. In addition, 
Michigan's emission statement program SIP submitted to satisfy the 
section 182(a)(3)(B) requirement was fully approved in a final USEPA 
rulemaking on March 8, 1994 (59 FR 10752). The USEPA is proposing to 
approve this redesignation request notwithstanding the lack of fully-
approved provisions submitted in compliance with the NSR requirements 
of part D, section 182(b)(5) of the CAA. The USEPA believes, as 
suggested by the General Preamble at 57 FR 13564 (April 16, 1992), that 
the applicability of the part C PSD program to maintenance areas makes 
it unnecessary to require that an area have obtained full approval of 
NSR revisions required by part D in order to be redesignated. The USEPA 
believes that this interpretation of the Act is appropriate 
notwithstanding section 175A(d)'s requirements that the contingency 
provisions of a maintenance plan include a commitment on the part of 
the State to implement all measures, to control the relevant air 
pollutant, that were contained in the SIP prior to redesignation. The 
term ``measure'' is not defined in section 175A(d) and it appears that 
Congress utilized the terms ``measure'' or ``control measure'' 
differently in different provisions of the CAA that concern the PSD and 
NSR permitting programs.
---------------------------------------------------------------------------

    \10\The rule which was published by the USEPA on April 6, 1994 
requires a vehicle based (onboard) system for the control of vehicle 
refueling emissions. Gasoline vapors which are normally vented to 
the atmosphere, are captured in a carbon canister and stored for 
later use by the vehicle's engine.
---------------------------------------------------------------------------

    Compare section 110(a)(2)(A) and (C) with section 161. In light of 
this ambiguity in the use of the term ``measure,'' the USEPA believes 
that the term ``measure'' as used in section 175A(d) may be interpreted 
so as not to include NSR permitting programs. That this is an 
appropriate interpretation is further supported by USEPA's historical 
practice dating back even before the 1990 CAA, of not requiring 
redesignating areas to demonstrate through modeling or otherwise a 
justification for replacing the nonattainment NSR program with the PSD 
program once an area was redesignated. Rather the USEPA has 
historically allowed the NSR program to be automatically replaced by 
the PSD program upon redesignation. Michigan has presented an adequate 
demonstration that the State has met all the requirements applicable to 
the area under section 110 and part D. The final approval of this 
redesignation request is contingent on the final approval of the SIP 
submittals as noted above. These requirements, their applicability and 
status are discussed in more detail in the USEPA's Redesignation/
Maintenance Plan TSD.
3. Fully Approved SIP Under Section 110(k) of the Act
    In other sections of this action, USEPA is proposing approval of 
the 1990 base year emission inventory and basic I/M (meeting the 
criteria of the June 28, 1994 proposed I/M Redesignation Rule). The SIP 
submittals for satisfying the requirements for VOC RACT catch-ups, and 
fix-ups are being acted upon in a separate action. The 182(f) NOX 
exemption petition also is being acted upon in a separate action. Once 
USEPA fully approves these submittals, the State will have a fully 
approved SIP under section 110(k), which also meets the applicable 
requirements of section 110 and part D as discussed above.
4. Improvement in Air Quality Due to Permanent and Enforceable Measures
    Under the pre-amended Act, USEPA approved the Michigan SIP control 
strategy for the Detroit-Ann Arbor nonattainment area, satisfied that 
the rules and the emission reductions achieved as a result of those 
rules were enforceable. Furthermore, numerous Federal measures apply to 
the Detroit-Ann Arbor area. The State provided a detailed discussion of 
the development of the emission reductions of ozone precursors (VOC and 
NOX) from 1988-1993. The State attributed the improvement in air 
quality that led to attainment of the ozone NAAQS to the federally 
enforceable Federal Motor Vehicle Control Program (FMVCP) and lower 
Reid Vapor Pressure (RVP)11 control measures. The emission 
reductions achieved from 1988 through 1993 are 226 tons VOC (21 
percent) and 45 tons of NOX (3.4 percent) per day. In association 
with its emission inventory discussed below, the State demonstrated 
that point source VOC emissions were not artificially low due to local 
economic downturn. This was accomplished by setting all growth factors 
at a minimum value of 1.0 for 1990 and beyond. The USEPA finds that the 
combination of existing USEPA-approved SIP and Federal measures 
contribute to the permanence and enforceability of reduction in ambient 
ozone levels that have allowed the area to attain the NAAQS.
---------------------------------------------------------------------------

    \1\1VOC emission reductions, in part, resulted from RVP 
reductions from 11.0 psi in 1988 to 9.0 psi in 1993.
---------------------------------------------------------------------------

5. Fully Approved Maintenance Plan Under Section 175A
    Section 175A of the Act sets forth the elements of a maintenance 
plan for areas seeking redesignation from nonattainment to attainment. 
The plan must demonstrate continued attainment of the applicable NAAQS 
for at least 10 years after the Administrator approves a redesignation 
to attainment. Eight years after the redesignation, the State must 
submit a revised maintenance plan which demonstrates attainment for the 
10 years following the initial 10-year period. To provide for the 
possibility of future NAAQS violations, the maintenance plan must 
contain contingency measures, with a schedule for implementation, 
adequate to assure prompt correction of any air quality problems. 
Section 175A(d) requires that the contingency provisions include a 
requirement that the State will implement all control measures that 
were contained in the SIP prior to redesignation as an attainment area. 
In this action, USEPA is proposing approval of the State of Michigan's 
maintenance plan for the Detroit-Ann Arbor area because USEPA finds 
that Michigan's submittal meets the requirements of section 175A 
provided that the State's contingency measures that were required as 
SIP revisions prior to the submission of the redesignation request are 
fully approved. If USEPA determines after notice and comment that it 
should give final approval to the maintenance plan, the Detroit-Ann 
Arbor nonattainment area will have a fully approved maintenance plan in 
accordance with section 175A.
    (A) Emissions Inventory--Base Year Inventory. The State has 
adequately developed an attainment emission inventory for 1993 that 
identifies 790 tons of VOC and 1336 tons of NOx per day as the 
level of emissions in the area sufficient to attain the ozone NAAQS. 
The 1993 attainment inventory was based on the comprehensive 
inventories of VOC and NOX emissions from area, stationary, and 
mobile sources for 1990. Consistent with emission inventory guidance, 
the 1990 base year emission inventory represents 1990 average summer 
day actual emissions for the Detroit-Ann Arbor area. Since the 
projected 1993 emissions are lower than the actual 1990 emissions 
(providing a more stringent attainment inventory) and 1993 is the 
attainment year, it is appropriate to utilize projected 1993 emissions 
for the attainment year inventory. Furthermore, the 1990 base year 
emission inventory was prepared in accordance with USEPA guidance. 
USEPA's TSDs prepared for the 1990 base year emission inventory 
(Emission Inventory TSD) SIP revision and the redesignation request 
(Redesignation/Maintenance Plan TSD) contain more in-depth details 
regarding the emission inventories for the Detroit-Ann Arbor area.
    The 1990 base year emission inventory also served as the basis for 
calculations to demonstrate maintenance by projecting emissions forward 
to the years 1993, 1996, 2000, and 2005. Projections are based on 
growth factors extracted from the Southeast Michigan Council of 
Governments Regional Development Forecast (RDF). Supplemental 
information used in the development of emission projections include 
source-specific data for electric utilities, automobile manufacturing, 
aircraft, and gasoline marketing.
    Growth factors are derived from employment forecasts by two-digit 
Source Industrial Code by county. In addition, product output data was 
used to develop growth factors for motor vehicle manufacturing, and 
utilities. The area source growth factors used from RDF were based on 
population or housing data. Furthermore, all growth factors that were 
less than 1.0 were set equal to 1.0 for 1990 and beyond to offset any 
effects of negative growth possibly due to economic downturns.
    In developing the mobile source emission estimates, the MOBILE5a 
model was used. The significant input parameters for the MOBILE5a model 
are analyzed in detail in the Redesignation/Maintenance Plan TSD.
    The stationary source emission estimates (point and area) were 
developed using the geocoded emissions modeling and projections system 
(GEMAP). This emission projection model and supporting documentation 
were reviewed by Region 5 and the Emission Inventory Branch of the 
OAQPS during the developmental stages of the redesignation request and 
appear to be acceptable since GEMAP employs methodologies equivalent to 
the applicable USEPA guidance on emission projections (June 21, 1993 
letter to John Schroeder and August 3, 1993 Record of Conversation with 
OAQPS, RADIAN and Region 5).
    (B.) Demonstration of Maintenance--Projected Inventories. In order 
to demonstrate continued attainment, the State projected anthropogenic 
1990 actual emissions of VOC and NOX emissions to the years 1993, 
1996, 2000, and 2005. These emission estimates are presented in the 
tables below and demonstrate that the VOC and NOX emissions will 
remain below the attainment year emissions (1993). In fact, the 
emissions projections through the year 2005 show that emissions will be 
reduced from 1993 levels by 21 tons of VOC and 98 tons of NOX per 
day by 2005. These emission reductions are primarily the result of the 
implementation of FMVCP. It is noted that the emission projections are 
conservative since they do not account for emission reductions that 
will result from the anticipated implementation of other control 
measures and programs during this time period. 

             VOC Emission Inventory Summary (Tons Per Day)              
------------------------------------------------------------------------
                              1990     1993     1996     2000      2005 
------------------------------------------------------------------------
Point......................      153      154      155      156      157
Area.......................      377      382      390      402      416
Mobile.....................      326      254      234      214      196
                            --------------------------------------------
      Total................      856      790      779      772      769
------------------------------------------------------------------------


             NOX Emission Inventory Summary (Tons Per Day)              
------------------------------------------------------------------------
                              1990     1993     1996     2000      2005 
------------------------------------------------------------------------
Point......................      711      735      756      685      725
Area.......................      195      199      203      206      210
Mobile.....................      437      402      362      326      303
                            --------------------------------------------
      Total................    1,343    1,336    1,321    1,217    1,238
------------------------------------------------------------------------

    The emission projection methodologies used for the maintenance 
demonstration are the same as those used for the attainment inventory 
and discussed above.
    The emission projections show that the emissions are not expected 
to exceed the level of the base year 1993 inventory during the 10-year 
maintenance period. Further emission reductions that will occur during 
this maintenance demonstration that are not accounted for in the 
emission projections presented in the tables above such as title III 
maximum achievable control technology for air toxics, and onboard 
refueling vapor recovery. The projected emission inventories were 
prepared in accordance with USEPA guidance. Finally, USEPA's 
Redesignation/Maintenance Plan TSD contains more in-depth details 
regarding the projected emission inventories for the Detroit-Ann Arbor 
area.
    To demonstrate maintenance out to the year 2005 following 
redesignation, the State did not rely on certain SIP-approved measures. 
The State now requests that these measures (discussed below) be moved 
from the applicable SIP into the maintenance plan as contingency 
measures.
    The State has demonstrated maintenance without basic I/M, Stage I 
expansion12, Stage II and NOX RACT. The Act required a SIP 
submittal for these control measures prior to the submittal of the 
redesignation request, and consequently, they are required to be fully 
adopted and fully approved into the SIP prior to or at the time of full 
approval of the redesignation request. However, since the State has 
demonstrated attainment and maintenance without these programs these 
measures can be incorporated into the area's maintenance plan as 
contingency measures (see, e.g., September 17, 1993 Shapiro 
memorandum). The June 28, 1994 Proposed I/M Redesignation Rule proposes 
to allow basic I/M to be included as a contingency measure in the form 
of enabling legislation. Stage I must be fully adopted since it is a 
SIP element that was due prior to the submittal of the redesignation 
request. Stage II, however, does not have to be fully adopted. In fact, 
since the ``onboard rule'' was published on April 6, 1994 Stage II is 
no longer a requirement (section 202(a)(6) of the Act). However, if the 
State chooses to include this program as a contingency measure, 
enabling legislation would suffice. Michigan has chosen to retain Stage 
II as a contingency measure in the maintenance plan. Finally, the State 
submitted to USEPA a section 182(f) NOX exemption petition based 
on 1991-1993 ambient air quality data that demonstrates that the area 
is attaining the ozone NAAQS. The USEPA is currently taking action on 
this submittal. Since the Detroit-Ann Arbor area has demonstrated that 
it can maintain the standard without the implementation of these 
programs, USEPA proposes that the maintenance plan be approved with 
these elements as contingency measures. In addition, based on the 
maintenance demonstration, the USEPA plans to propose approval of the 
basic I/M enabling legislation (based on the June 28, 1994 proposed I/M 
Redesignation Rule), and the Stage I rule and 182(f) NOX exemption 
petition in a separate FR action.
---------------------------------------------------------------------------

    \1\2The expanded applicability of Stage I to county boundaries 
of each nonattainment area classified as moderate and above.
---------------------------------------------------------------------------

C. Verification of Continued Attainment

    Continued attainment of the ozone NAAQS in the Detroit-Ann Arbor 
area depends, in part, on the State's efforts toward tracking 
indicators of continued attainment during the maintenance period. The 
tracking plan for the Detroit-Ann Arbor area consists of two 
components; continued ambient ozone monitoring and inventory updates. 
To demonstrate ongoing compliance with the NAAQS, Michigan will 
continue to monitor ozone levels throughout the area. The State will 
also conduct periodic inventories for the redesignated area every 3 
years using the most recent emission factors, models and methodologies. 
The inventories will begin in 1996 with completion of the 1996 
inventory by July 1, 1998. Periodic inventories for 1999, 2002, and 
2005 will be completed with submittal to the USEPA on the first of 
October 2 years after the inventory year. The periodic inventory will 
consist of reviewing the assumptions of the maintenance demonstration 
such as VMT, population, employment, etc. If substantial changes are 
discovered, the State will reproject the emissions for the maintenance 
period.
    The contingency plan contains only one trigger, a monitored air 
quality violation of the ozone NAAQS, as defined in 40 CFR 50.9. The 
trigger date will be the date that the State certifies to the USEPA 
that the air quality data are quality assured and no later than 30 days 
after an ambient air quality violation is monitored.

D. Contingency Plan

    The level of VOC and NOX emissions in the Detroit-Ann Arbor 
area will largely determine its ability to stay in compliance with the 
ozone NAAQS in the future. Despite best efforts to demonstrate 
continued compliance with the NAAQS, the ambient air pollutant 
concentrations may exceed or violate the NAAQS. Therefore, as required 
by section 175A of the Act, Michigan has provided contingency measures 
with a schedule for implementation in the event of a future ozone air 
quality problem. Contingency measures contained in the plan include 
basic I/M, NOX RACT, Stage I expansion, Stage II, RVP reduction to 
7.8 psi and intensified RACT for degreasing operations. In instances 
where the contingency measures must be actually adopted and 
implemented, the schedules specified for these SIPs in the Act and any 
corresponding regulations will be observed, with the exception of 
implementation of 7.8 RVP and intensified degreasing rules which will 
commence 12 months after the decision to employ these measures. Once 
the triggering event, a violation of the ozone NAAQS, is confirmed, the 
State will implement one or more appropriate contingency measure. 
Selection of the contingency measure(s) will be based on a technical 
analysis using UAM. The Governor will select the contingency measures 
within 6 months of a triggering event. The adoption and implementation 
schedules for the selected contingency measure(s) will be submitted to 
the USEPA with the UAM analysis. The USEPA understands, on the basis of 
the State's submission, that the adoption and implementation schedules 
specified in the Act and any corresponding regulations would be 
observed; therefore, the following schedules will be applicable for the 
contingency measures specified in the contingency plan:
     Basic I/M would be implemented as a contingency measure 1 
year from the effective date of the legislation, which would be the 
date of the decision to employ a basic I/M program to correct a 
violation of the ozone NAAQS. Part 40 CFR 51.373(b) stipulates 
implementation of basic I/M within 1 year of obtaining legal authority.
     NOX RACT rules would be submitted 2 years from date 
of the decision to employ NOx RACT as a contingency measure. The 
NOX RACT rules would be implemented 30.5 months from the date NOx 
RACT rules are submitted to the USEPA or 54.5 months from the date of 
the decision to employ NOX RACT as a contingency measure. This 
schedule is consistent with section 182(b)(2)(C) which is the schedule 
applicable to the adoption and implementation of NOX RACT as 
specified by section 182(f).
     Implementation of Stage I expansion to the entire seven 
county Detroit-Ann Arbor area (currently, Stage I is implemented in 
Wayne, Oakland and Macomb counties) would be in accordance with the 
schedule contained in Michigan's Stage I legislation (Senate Bill 726, 
section 9i). Gasoline dispensing facilities of any size constructed 
after November 15, 1990 must implement Stage I within 6 months of the 
decision to employ Stage I as a contingency measure. Existing 
facilities dispensing 100,000 gallons or more of gasoline a month must 
implement Stage I within 1 year and facilities dispensing less than 
100,000 gallons of gasoline a month must implement Stage I within 2 
years of the decision to employ Stage I as a contingency measure.
     Stage II would be implemented according to the same 
schedule set forth for Stage I, since they are contained in the same 
legislation (Senate Bill 726), but will only be implemented in the 
counties of Wayne, Oakland, Macomb and Washtenaw.
    Under separate cover, the State has submitted to the USEPA, as SIP 
revisions, fully adopted legislation allowing implementation of a basic 
I/M program, Stage I, and Stage II in the Detroit-Ann Arbor area. The 
legislation provide for implementation of these programs as contingency 
measures within areas redesignated to attainment for ozone.
    The USEPA's Redesignation/Maintenance Plan TSD provides a more 
detailed discussion of each contingency measure.
    The USEPA finds that the five contingency measures provided in the 
State submittal meet the requirements of section 175A(d) of the Act 
since they would promptly correct any violation of the ozone NAAQS.

E. Subsequent Maintenance Plan Revisions

    In accordance with section 175A(b) of the Act, the State has agreed 
to submit a revised maintenance SIP 8 years after the area is 
redesignated to attainment. Such revised SIP will provide for 
maintenance for an additional 10 years.

IV. Proposed Action

    The USEPA proposes to approve the Detroit-Ann Arbor ozone 
maintenance plan as a SIP revision meeting the requirements of section 
175A if there is full and final approval of the outstanding VOC RACT 
requirements previously discussed, 1990 base year emission inventory, 
basic I/M (meeting the criteria of the June 28, 1994 proposed I/M 
Redesignation Rule), and the section 182(f) NOX exemption 
petition. In addition, the USEPA is proposing approval of the 
redesignation request for the Detroit-Ann Arbor area, subject to final 
approval of the maintenance plan, because the State has demonstrated 
compliance with the requirements of section 107(d)(3)(E) for 
redesignation pending full approval of the SIP elements listed above. 
(In the alternative, if ambient air quality violations occur before 
USEPA takes final action on the proposed redesignation or if the USEPA 
does not fully approve any of the SIP revisions listed above, the USEPA 
proposes to disapprove this redesignation request.)
    Nothing in this action should be construed as permitting or 
allowing or establishing a precedent for any future request for 
revision to any SIP. Each request for revision to the SIP shall be 
considered separately in light of specific technical, economic, and 
environmental factors and in relation to relevant statutory and 
regulatory requirements.
    Ozone SIPs are designed to satisfy the requirements of part D of 
the Act and to provide for attainment and maintenance of the ozone 
NAAQS. This proposed redesignation should not be interpreted as 
authorizing the State to delete, alter, or rescind any of the VOC or 
NOX emission limitations and restrictions contained in the 
approved ozone SIP. Changes to ozone SIP VOC regulations rendering them 
less stringent than those contained in the USEPA approved plan cannot 
be made unless a revised plan for attainment and maintenance is 
submitted to and approved by USEPA. Unauthorized relaxations, 
deletions, and changes could result in both a finding of 
nonimplementation [section 173(b) of the Act] and in a SIP deficiency 
call made pursuant to section 110(a)(2)(H) of the Act.

D. Procedural Background

    This action has been classified as a Table 2 Action by the Regional 
Administrator under the procedures published in the Federal Register on 
January 19, 1989 (54 FR 2214-2225). A revision to the SIP processing 
review tables was approved by the Acting Assistant Administrator for 
Office of Air and Radiation on October 4, 1993 (Michael Shapiro's 
memorandum to Regional Administrators). A future action will inform the 
general public of these tables. On January 6, 1989, the Office of 
Management and Budget (OMB) waived Table 2 and 3 SIP revisions from the 
requirement of section 3 of Executive Order 12291 for a period of 2 
years (54 FR 2222). The USEPA has submitted a request for a permanent 
waiver for Table 2 and Table 3 SIP revisions. OMB has agreed to 
continue the waiver until such time as it rules on USEPA's request. 
This request continued in effect under Executive Order 12866 which 
superseded Executive order 12291 on September 30, 1993.

E. Regulatory Process

    Under the Regulatory Flexibility Act, 5 U.S.C. section 600 et seq., 
the USEPA must prepare a regulatory flexibility analysis assessing the 
impact of any proposed or final rule on small entities. 5 U.S.C. 
section 603 and 604. Alternatively, the USEPA may certify that the rule 
will not have a significant impact on a substantial number of small 
entities. Small entities include small businesses, small not-for-profit 
enterprises, and government entities with jurisdiction over populations 
of less than 50,000.
    The SIP approvals under section 110 and subchapter I, part D of the 
Act do not create any new requirements, but simply approve requirements 
that the State is already imposing. Therefore, because the Federal SIP 
approval does not impose any new requirements, I certify that it does 
not have a significant impact on any small entities affected. Moreover, 
due to the nature of the Federal-State relationship under the Act, 
preparation of a regulatory flexibility analysis would constitute 
Federal inquiry into the economic reasonableness of State action. The 
Act forbids USEPA to base its actions concerning SIP's on such grounds. 
Union Electric Co. v. U.S.E.P.A., 427 U.S. 246, 256-66 (S.Ct. 1976); 42 
U.S.C. section 7410(a)(2).
    Under section 307(b)(1) of the Act, petitions for judicial review 
of this action must be filed in the United States Court of Appeals for 
the appropriate circuit by September 19, 1994. Filing a petition for 
reconsideration by the Administrator of this rule does not affect the 
finality of this rule for the purposes of judicial review nor does it 
extend the time within which a petition for judicial review may be 
filed, and shall not postpone the effectiveness of such a rule. This 
action may not be challenged later in proceedings to enforce its 
requirements. (section 307(b)(2).)

List of Subjects

40 CFR Part 52

    Environmental protection, Air pollution control, Nitrogen oxides, 
Ozone, Volatile organic compounds, Hydrocarbons, Intergovernmental 
relations, Carbon monoxide, Motor vehicle pollution, Particulate 
matter, Reporting and record keeping requirements.

40 CFR Part 81

    Environmental protection, Air pollution control, National parks, 
Wilderness areas.

    Authority: 42 U.S.C. 7401-7671q.

    Dated: June 24, 1994.
David A. Ullrich,
Acting Regional Administrator.
[FR Doc. 94-17556 Filed 7-20-94; 8:45 am]
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