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FEDERAL REGISTER
VOL. 59, No. 139
Proposed Rules

ENVIRONMENTAL PROTECTION AGENCY (EPA)

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

59 FR 37190

DATE: Thursday, July 21, 1994
ACTION: Proposed rule.

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 tothe 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) n1 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.

n1 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.

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 

Ozone            Point source    Area source     On-road mobile 
nonattainment    emissions       emissions       source 
area                                             emissions 

Detroit/Ann      167.08          252.27          327.00 
Arbor 

Ozone            Non-road        Biogenic        Total 
nonattainment    mobile source   emissions       emissions 
area             emissions 

Detroit/Ann      531.03          113.90          1391.28 
Arbor 



Daily CO Emissions From All Sources-Tons/Summer Weekday 

Ozone            Point source    Area source     On-road mobile 
nonattainment    emissions       emissions       source 
area                                             emissions 

Detroit/Ann      146.28          45.22           3058.00 
Arbor 

Ozone nonattainment  Non-road mobile       Total emissions 
area                 source emissions 

Detroit/Ann Arbor    862.54                4112.04 



Daily NOx Emissions From All Sources-Tons/Summer Weekday 

Ozone            Point source    Area source     On-road mobile 
nonattainment    emissions       emissions       source 
area                                             emissions 

Detroit/Ann      734.62          56.36           437.00 
Arbor 

Ozone nonattainment  Non-road mobile       Total emissions 
area                 source emissions 

Detroit/Ann Arbor    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. n2

n2 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.

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 | 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"). n3

n3 The parenthetical information refers to the specifics in the Detroit-Ann Arbor, Michigan legislation.

- 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). n4

n4 Title 40 CFR 51.373(b) specifies the implementation of a basic I/M program within 1 year of obtaining legal authority.

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," n5 and "catch-up," n6 and major non-CTG submittals n7 , the 1990 base year emission inventory, basic I/M, and the section 182(f) NOx exemption petition are also fully approved by the USEPA. n8 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.

n5 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.

n6 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).

n7 Rules for major non-CTG sources are a requirement under the Section 182(b)(2) catch-ups.

n8 The emission statement program was fully approved in a final rulemaking action on March 8, 1994 (59 FR 10752).

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 1993 n9 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.)

n9 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" n10 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.

n10 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) n11 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.

n11 VOC 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 

Point           153             154             155 
Area            377             382             390 
Mobile          326             254             234 

Total           856             790             779 

               2000            2005 

Point           156             157 
Area            402             416 
Mobile          214             196 

Total           772             769 



NOx Emission Inventory Summary (Tons Per Day) 

               1990            1993            1996 

Point           711             735             756 
Area            195             199             203 
Mobile          437             402             362 

Total           1,343           1,336           1,321 

               2000            2005 

Point           685             725 
Area            206             210 
Mobile          326             303 

Total           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 expansion n12 , 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.

n12 The 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]

BILLING CODE 6560-50-P


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