Approval and Promulgation of Air Quality Implementation Plans; Designation of Areas for Air Quality Planning Purposes; Arizona; Miami Sulfur Dioxide State Implementation Plan and Request for Redesignation to Attainment; Correction of Boundary of Miami Sulfur Dioxide Nonattainment Area

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Direct final rule.

SUMMARY:

EPA is taking direct final action under the Clean Air Act to approve the Miami Sulfur Dioxide Nonattainment Area State Implementation and Maintenance Plan as a revision to the Arizona state implementation plan. The Arizona Department of Environmental Quality developed this plan to maintain the sulfur dioxide national ambient air quality standards in the Miami (Gila County) area. The maintenance plan contains various elements, including contingency provisions that will be implemented if measured ambient concentrations of sulfur dioxide are above certain trigger levels. EPA is also approving the State of Arizona's request for redesignation of the Miami area from nonattainment to attainment for the sulfur dioxide standards. Lastly, EPA is correcting the boundary of the Miami sulfur dioxide nonattainment area to exclude a noncontiguous township that was erroneously included in the description of the area and to fix a transcription error in the listing of one of the other townships.

EPA is taking these actions consistent with provisions in the Clean Air Act that obligate the Agency to approve or disapprove submittals of revisions to state implementation plans and requests for redesignation. The intended effect is to redesignate the Miami, Arizona sulfur dioxide nonattainment area to attainment, provide for maintenance of the standard for the ten-year period following redesignation, and correct long-standing errors in the codified description of the area.

DATES:

This rule is effective on March 26, 2007 without further notice, unless EPA receives adverse comments by February 23, 2007. If we receive such comments, we will publish a timely withdrawal in the Federal Register to notify the public that this direct final rule will not take effect.

ADDRESSES:

Submit comments, identified by docket number EPA-R09-OAR-2006-0580, by one of the following methods:

1. Federal eRulemaking Portal: www.regulations.gov. Follow the on-line instructions.

2. E-mail: vagenas.ginger@epa.gov.

3. Mail or deliver: Ginger Vagenas (Air-2), U.S. Environmental Protection Agency Region IX, 75 Hawthorne Street, San Francisco, CA 94105-3901.

Instructions: All comments will be included in the public docket without change and may be made available online at www.regulations.gov,, including any personal information provided, unless the comment includes Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Information that you consider CBI or otherwise protected should be clearly identified as such and should not be submitted through the www.regulations.gov or e-mail. www.regulations.gov is an “anonymous access” system, and EPA will not know your identity or contact information unless you provide it in the body of your comment. If you send e-mail directly to EPA, your e-mail address will be automatically captured and included as part of the public comment. If EPA cannot read your comment due to technical difficulties and cannot contact you for clarification, EPA may not be able to consider your comment.

Docket: The index to the docket for this action is available electronically at www.regulations.gov and in hard copy at EPA Region IX, 75 Hawthorne Street, San Francisco, California. While all documents in the docket are listed in the index, some information may be publicly available only at the hard copy location (e.g., copyrighted material), and some may not be publicly available in either location (e.g., CBI). To inspect the hard copy materials, please schedule an appointment during normal business hours with the contact listed in the FOR FURTHER INFORMATION CONTACT section.

FOR FURTHER INFORMATION CONTACT:

Ginger Vagenas, Air Planning Office, (415) 972-3964 or by e-mail at vagenas.ginger@epa.gov.

SUPPLEMENTARY INFORMATION:

Elsewhere in this Federal Register, we are proposing approval and soliciting written comment on this action. Throughout this document, the words “we,” “us,” or “our” mean U.S. EPA.

Table of Contents

I. Summary of Today's Direct Final Action

II. Introduction

A. SO₂ NAAQS

B. State Implementation Plan

C. History of SO₂ Planning in Arizona

1. Development of the SO₂ SIP

2. Miami SO₂ Nonattainment Area

D. Sources of SO₂ Emissions in the Miami Area

III. CAA Requirements for Redesignation Requests and Maintenance Plans

IV. EPA's Evaluation of Redesignation Request and Maintenance Plan for the Miami, Arizona SO₂ Nonattainment Area

A. The Area Must Be Attaining the SO₂ NAAQS

B. The Area's Applicable Implementation Plan Must Be Fully Approved Under Section 110(k)

C. The Improvement in Air Quality Must Be Due to Permanent and Enforceable Reductions in Emissions

D. The Area Must Have Met All Applicable Requirements Under Section 110 and Part D

1. Section 110 Requirements

2. Part D Requirements

a. Section 172

b. Section 176

c. Subpart 5

E. The Area Must Have a Fully Approved Maintenance Plan

1. Attainment Inventory

2. Maintenance Demonstration

3. Monitoring Network

4. Verification of Continued Attainment

5. Contingency Plan

6. Subsequent Maintenance Plan Revisions

7. Conclusion

V. Boundary Correction

A. Background

B. Authority for Correcting Errors

C. Evaluation and Conclusion

VI. Public Comment and Final Action

VII. Statutory and Executive Order Review

I. Summary of Today's Direct Final Action

On June 26, 2002, the Arizona Department of Environmental Quality (``ADEQ'' or ``State'') submitted to EPA Region IX its Miami Sulfur Dioxide State Implementation and Maintenance Plan and its request for redesignation to attainment (``Miami SO<sub>2</sub> Maintenance Plan” or ``submittal”). The submittal summarizes the progress the State has made in attaining the sulfur dioxide (SO₂) national ambient air quality standards (NAAQS) in the Miami nonattainment area (Gila County, Arizona) (“Miami area”) and includes a plan to assure continued attainment of the SO₂ NAAQS for at least the next 10 years. The June 26, 2002 submittal also includes a request for redesignation of the boundary of the area and for redesignation of the status of the area, as amended, to “attainment” under section 107(d) of the Clean Air Act (“Act” or CAA). On June 30, 2004, ADEQ submitted certain replacement pages correcting errors in the June 26, 2002 submittal. On June 20, 2006, ADEQ submitted a letter withdrawing the boundary redesignation request and requesting EPA to address the boundary issue as an error correction under CAA section 110(k)(6) instead.

In today's direct final action, because we find that the Miami SO₂ Maintenance Plan meets the requirements for maintenance plans under section 175A of the Act and that the Miami area qualifies for redesignation under CAA section 107(d)(3)(E), we are approving the submittal (as amended by the submittals dated June 30, 2004 and June 20, 2006) as a revision to the Arizona SIP and redesignating the Miami area from nonattainment to attainment for the SO₂ NAAQS. Also, based on a review of the relevant State and EPA materials from the late 1970's, we are correcting errors under CAA section 110(k)(6) in the listing of the townships that comprise the Miami SO₂ nonattainment area to exclude a noncontiguous township and to fix a transcription error in one of the other townships so listed.

II. Introduction

The following section discusses the NAAQS for SO₂, CAA requirements for state implementation plans, SO₂ planning in Arizona generally and in the Miami area more specifically, and sources of emissions in the Miami area.

A. SO₂ NAAQS

The NAAQS for SO₂ consists of three standards: Two primary standards for the protection of public health and a secondary standard for protection of public welfare. The primary SO₂ standards address 24-hour average and annual average ambient SO₂ concentrations. The secondary standard addresses 3-hour average ambient SO₂ concentrations. The level of the annual SO₂ standard is 0.030 parts per million (ppm), which is equivalent to 80 micrograms per cubic meter (μg/m³), not to be exceeded in a calendar year. The level of the 24-hour standard is 0.14 ppm (365 μg/m³), not to be exceeded more than once per calendar year. The level of the secondary SO₂ standard is a 3-hour standard of 0.5 ppm (1,300 μg/m³), not to be exceeded more than once per calendar year. See 40 CFR 50.2-50.5.

B. State Implementation Plan

The CAA requires states to implement, maintain, and enforce ambient air quality equal to or better than the NAAQS. A state's strategies for implementing, maintaining, and enforcing the NAAQS are submitted to EPA for approval, and, once approved, become part of the State Implementation Plan (or SIP) for that State. SIPs are compilations of regulatory and non-regulatory elements adopted, submitted, and approved at different times to address various types of changes in circumstances, such as new or revised NAAQS or amendments to the CAA. SIPs include, among other things, the following: (1) An inventory of emission sources; (2) statutes and regulations adopted by the state legislature and executive agencies; (3) air quality analyses that include demonstrations that adequate controls are in place to meet the NAAQS; and (4) contingency measures to be undertaken if an area fails to attain the standard or make reasonable progress toward attainment by the required date. The state must make proposed changes to the SIP available for public review and comment through a public hearing, and must formally adopt the changes before submitting them to EPA for approval. Upon our approval, a SIP revision becomes federally enforceable.

C. History of SO₂ Planning in Arizona

1. Development of the SO₂ SIP

In the early 1970's, soon after the Clean Air Amendments of 1970 were passed, Arizona began developing air quality regulations that applied to all Arizona primary copper smelters, including the one operating in the Miami area. These regulations focused on establishing an air quality monitoring network in the areas surrounding the smelters and determining the allowable emission rates from the smelters so that the SO₂ NAAQS could be attained and maintained. Arizona submitted various SIP revisions during the 1970s to establish approvable emission limitations for the primary copper smelters operating in the state. On September 20, 1979, the State submitted its SIP revision to EPA which contained its multi-point rollback (MPR) technique to establish operating limitations on smelters. After EPA's proposed conditional approval on November 30, 1981 (46 FR 58098), Arizona made necessary changes which corrected identified deficiencies. EPA granted full approval of the MPR-based SIP submittal on January 14, 1983 (48 FR 1717), but was not able to grant full approval to the SO₂ SIPs for six smelter areas (including Miami) because they lacked a strategy for addressing fugitive sources of SO₂.

On November 1, 2004, EPA approved several revisions to the SO₂ SIP, including site-specific requirements, compliance and monitoring, and fugitive emissions standards for existing primary copper smelters. See 69 FR 63321. In that same notice, EPA promulgated a limited approval/limited disapproval of R18-2-Appendix 8, which sets out procedures for calculating sulfur emissions using a sulfur balance method. ADEQ subsequently corrected the identified deficiencies and EPA approved the new version of R18-2-Appendix 8 as a SIP revision on April 12, 2006. See 71 FR 18624. The effective date for our April 12, 2006 final approval is June 12, 2006.

2. Miami SO₂ Nonattainment Area

Originally, the air quality planning area we refer to as the Miami SO₂ nonattainment area was not separately defined but rather was included in a county-wide SO₂ nonattainment area (see 43 FR 8969, March 3, 1978). At the request of the state of Arizona, the boundaries were reduced to nine townships in and around the city of Miami (44 FR 21261, April 10, 1979). See also, 40 CFR 81.303. In addition, six adjacent townships were designated as “cannot be classified”. Section 107(d)(1)(C) of the 1990 Clean Air Act Amendments (CAAA) brought forward, by operation of law, the nonattainment designations for areas, such as the Miami SO₂ area, that continued to be designated as nonattainment at the time of enactment of the CAAA, i.e., areas that had not been redesignated to “attainment” prior to November 1990.

D. Sources of SO₂ Emissions in the Miami Area

The dominant source of SO₂ emissions in the Miami area is the Phelps-Dodge Miami primary copper smelter (“Miami smelter”). Combined stack and fugitive SO₂ emissions from the smelter are limited under the source-specific EPA-approved rule (i.e., R18-2-7-715) to 2,420 pounds per hour annual average, which amounts to approximately 10,368 tons per year based on 357 days of operation (set forth for the permit for this facility) or approximately 10,600 tons per year assuming 365 days per year of smelter operation. Between 1996 and 2000, the smelter's actual SO₂ emissions ranged from 5,737 tons per year to 7,819 tons per year and represented 97 to 99% of the total stationary source SO₂ emissions in the Miami nonattainment area. See tables 4.1, 4.3, and 5.2 of the Miami SO₂ Maintenance Plan. There are several other point sources of SO₂ in the Miami area, all of which are relatively minor: BHP Copper, Pinto Valley; BHP Copper, Miami East Unit; Carlota Copper Company Mine; and the Phelps-Dodge Miami Mine. Viewed collectively, these sources are permitted to emit a total of approximately 100 tons per year. Actual emissions, however, are generally less than 10 tons per year. SO₂ emissions from area and mobile sources are about 150 tons per year. See sections 4.1 and 4.3 of the Miami SO₂ Maintenance Plan and table 1, below.

III. CAA Requirements for Redesignation Requests and Maintenance Plans

As stated in the summary section of this rule, Arizona has requested that we redesignate the Miami SO₂ nonattainment area to attainment. Any redesignation from nonattainment to attainment requires EPA to determine whether the requirements of Clean Air Act section 107(d)(3)(E), have been met. These criteria are: (1) At the time of the redesignation, we must find that the area has attained the relevant NAAQS; (2) the State must have a fully approved SIP for the area; (3) we must determine that the improvements in air quality are due to permanent and enforceable reductions in emissions resulting from implementation of the SIP and applicable federal regulations and other permanent and enforceable reductions; (4) the state must have met all the nonattainment area requirements applicable to the area; and (5) we must have fully approved a maintenance plan for the area under CAA section 175A.

To evaluate the State's redesignation request for the Miami area, we relied upon the Clean Air Act itself, particularly section 110 and part D (of title I), EPA's NAAQS and SIP regulations in 40 CFR parts 50 and 51, and guidance set forth in “General Preamble for the Implementation of Title I of the Clean Air Act Amendments of 1990” (57 FR 13498, April 16, 1992), and in the following EPA guidance documents: “Procedures for Processing Requests to Redesignate Areas to Attainment,” dated September 4, 1992, from John Calcagni, (“Calcagni Memo”), “Attainment Determination Policy for Sulfur Dioxide Nonattainment Areas,” dated January 26, 1995, from Sally L. Shaver, (“Shaver Memo”), and “Part D New Source Review (part D NSR) Requirements for Areas Requesting Redesignation to Attainment,” dated October 14, 1994, from Mary D. Nichols (“Nichols Memo”).

IV. EPA's Evaluation of Redesignation Request and Maintenance Plan for the Miami, Arizona SO₂ Nonattainment Area

A. The Area Must Be Attaining the SO₂ NAAQS

Under CAA section 107(d)(3)(E)(i), in order for an area to be redesignated, we must determine that the area has attained the applicable NAAQS. The air quality data should be representative of the area of highest concentration and should be measured by monitors that remain at the same location for the duration of the monitoring period required for demonstrating attainment. The data should be collected and quality-assured in accordance with 40 CFR part 58 and recorded in EPA's Air Quality System database (AQS) to be available for public review. Under 40 CFR part 58, States certify data that is entered into AQS on an annual basis.

For the purposes of determining whether an area has attained the SO₂ NAAQS, we require no fewer than two consecutive years of “clean” data (i.e., no violations) as recorded in AQS. In addition, to qualify for attainment determination purposes, the annual average and second-highest 24-hour average concentrations must be based upon hourly data that are at least 75 percent complete in each calendar quarter. See 40 CFR 50.4.

The State of Arizona initiated ambient monitoring of SO₂ in the Miami area in 1970. In order to establish coverage sufficient to evaluate the ambient impact of smelter emissions, this initial effort was expanded. Eventually more than sixteen stationary monitoring sites were established, with as many as seven monitors operating concurrently. Historic ambient SO₂ monitoring site locations and periods of operation are provided in Table 3.1, and Figures 3.1 and 3.2 of the State's submittal.

Following the Miami smelter's compliance with stack emissions limits (using continuous control technology) as required under Arizona Administrative Code (AAC) R9-3-515, which was submitted and approved by EPA as a revision to the Arizona SIP in the 1980's (but since amended and re-codified as R18-2-7-715), the number of SO₂ monitors has decreased. Between 1990 and 1996, the number of monitors varied from three to four and several monitoring locations changed, but since 1997, the three presently-operating monitors have remained at their current locations: the Jones Ranch monitor along Cherry Flats Road, the Ridgeline monitor along Linden Street, and the Townsite monitor along Sullivan Street.

All three presently-operating monitors are located south of the smelter, but vary in distance and elevation relative to smelter sources. The Townsite monitor lies closest to the smelter and at the lowest elevation among the three sites while the Jones Ranch monitor lies furthest from the smelter but at the highest elevation. The Jones Ranch and Townsite monitors are operated by Phelps Dodge using Thermal Electron pulsed fluorescent (TECO) samplers, and the Ridgeline monitor is operated by ADEQ using a Thermo pulse fluorescence analyzer.

Table 2 below summarizes the SO₂ monitoring data collected at the various monitors operated by ADEQ (or, in the case of Jones Ranch, ADEQ or the smelter operator) from 1988 through 2005. ADEQ ended its monitoring at Jones Ranch in 1994, but the smelter operator continues to monitor SO₂ at that location. Table 3 below presents estimated annual SO₂ emissions from the smelter over the same time period.

Review of historic data supports identification of the Jones Ranch monitor as the monitoring location where the highest concentrations are recorded among the network of monitoring locations selected to measure the impact of smelter-related emissions on ambient air quality. We note that the Jones Ranch monitoring site was determined to be the “limiting site” for the purposes of establishing emissions limits for the smelter. ADEQ closed its monitoring site at Jones Ranch in 1994, and while Phelps-Dodge continues to operate an SO₂ monitor at that site, the data is not recorded in AQS. In 1995, ADEQ began monitoring at the Ridgeline site, and no exceedances have ever been recorded there.

Based on a review of the data from the Miami SO₂ Maintenance Plan as well as tables 2 and 3 presented above, we find that the Miami nonattainment area has attained the SO₂ NAAQS and thereby meets the first criterion for redesignation. Our conclusion is based on six basic interrelated facts:

• Ambient SO₂ concentrations in the Miami air quality planning area are determined by emissions from the Phelps-Dodge primary copper smelter and local meteorological and topographic characteristics, and all other SO₂ sources have essentially no effect on ambient levels in the planning area;

• The monitor at the Jones Ranch site records SO₂ concentrations that are representative of the highest ambient levels in the nonattainment area;
• There are two consecutive and complete years of “clean” data from the Jones Ranch monitor, i.e., the limiting site, as recorded in AQS (1988 and 1989);
• During the 1988-1989 period, maximum concentrations were approximately 60% of the 3-hour-average secondary NAAQS and approximately 50% of the 24-hour-average primary NAAQS, and the highest of the annual-average concentrations measured in the area during this period was approximately 30% of the corresponding primary NAAQS;
• While annual emissions from the smelter have varied from year to year, they have generally been no higher than 50% above those that occurred during the 1988-1989 period; and
• No SO₂ exceedances have been measured at any of the monitoring sites over the 1988 to 2005 period.

B. The Area's Applicable Implementation Plan Must Be Fully Approved Under CAA Section 110(k)

Under CAA section 107(d)(3)(E)(ii), the SIP for the Miami area must be fully approved under CAA section 110(k) of the Act. We examined the applicable SIP for Arizona and also looked at the disapprovals listed in 40 CFR 52.125 and have determined that no disapprovals listed remain relevant to the applicable SIP. Arizona has a fully approved SIP with respect to SO₂ in the Miami area.

C. The Improvement in Air Quality Must Be Due to Permanent and Enforceable Reductions in Emissions

CAA section 107(d)(3)(E)(iii) requires that EPA determine that the improvement in air quality is due to permanent and enforceable reductions in emissions resulting from implementation of the SIP and/or applicable federal measures. Figure 6.1 of the Miami SO₂ Maintenance Plan (as amended in ADEQ's submittal dated June 30, 2004) illustrates the significant decline in emissions from the Miami smelter since the 1970's in inverse proportion to the level of control over smelter emissions sources.

Control over the smelter's SO₂ emissions has been made permanent and enforceable through EPA approval of State rules limiting such emissions as a revision to the Arizona SIP (specifically, R18-2-715, R18-2-715.01, R18-2-715.02, and R18-2-Appendix 8) and through ADEQ's issuance of a title V permit for the Miami smelter. Arizona's primary copper smelter rules and ADEQ's title V permit contain enforceable emission limitations that cap emissions at a level that has been shown to be protective of the NAAQS. Any relaxation to the SIP-approved limits must be approved by EPA as a revision to the Arizona SIP, and EPA may not approve any such SIP revision without a demonstration that the relaxation in the limits would not interfere with attainment or maintenance of the NAAQS. See CAA section 110(l). Therefore, we find that the improvement in ambient SO₂ concentrations in the Miami, AZ area is due to permanent and enforceable reductions in emissions resulting from implementation of the SIP.

D. The Area Must Have Met All Applicable Requirements Under Section 110 and Part D

Under CAA section 107(d)(3)(E)(v), we must determine whether the State of Arizona has met all requirements under section 110 and under part D (of title I) of the CAA applicable to the Miami SO₂ nonattainment area.

1. Section 110 Requirements

CAA section 110 contains the general requirements for SIPs (enforceable emissions limits, ambient monitoring, permitting of new sources, adequate funding, etc.). EPA's guidance for implementing section 110 of the Act is discussed in the General Preamble to Title I (57 FR 13498, April 16, 1992). Over the years, we have approved Arizona's SIP as meeting these basic requirements. The SIP includes enforceable emission limitations; requires monitoring, compiling, and analyzing of ambient air quality data; requires preconstruction review of new major stationary sources and major modifications to existing ones; provides for adequate funding, staff, and associated resources necessary to implement its requirements; and requires stationary source emission monitoring and reporting.

2. Part D Requirements

Before an area can be redesignated to attainment, it must have fulfilled the applicable requirements under part D (of title I). For this area, the relevant requirements are found in subparts 1 and 5 of part D. Subpart 1 of part D specifies the basic requirements applicable to all nonattainment areas. Subpart 5 sets out additional provisions for areas designated nonattainment for SO₂. As discussed below, EPA finds that Arizona has met the requirements of subpart 1 of part D, specifically sections 172(c) and 176, and subpart 5 as applicable for the Miami SO₂ nonattainment area.

a. Section 172

CAA section 172 contains the general requirements for nonattainment SIPs. A thorough discussion of the requirements of 172(c) can be found in the General Preamble for the implementation of title I (57 FR 13498, April 16, 1992). Additional guidance can be found in the Calcagni memo.

EPA has interpreted the requirements of CAA sections 172(c)(2) (reasonable further progress—RFP), 172(c)(6) (other measures), and 172(c)(9) (contingency measures) as not relevant to a redesignation request because they only have meaning for an area that is not attaining the standard (see the General Preamble and the Calcagni Memo), and as discussed above in section IV.A. of this notice, we find that the Miami area is attaining the SO₂ standard. Furthermore, the State has not sought to exercise options that would trigger section 172(c)(4) (identification of certain emissions increases). Thus, this provision is also not relevant to this redesignation request. The other provisions under 172(c) are discussed below.

Reasonably available control measures. Under CAA section 172(c)(1), reasonably available control measures (RACM), which include requirements for reasonably available control technology (RACT), are required for existing sources in nonattainment areas. In 1983, we approved the State's submittal of Rule R9-3-315, a predecessor to the State's current smelter rules codified at Arizona Administrative Code (AAC) R18-2-715. See 48 FR 1717 (January 14, 1983). This rule limited stack emissions from primary copper smelters, including the smelter in the Miami area. We concluded, however, that the control strategy for SO₂ in Arizona's six SO₂ nonattainment areas was incomplete due to the failure to address fugitive emissions problems. See 48 FR 1717 (January 14, 1983) and 40 CFR 52.125(a)(1).

In 1998, 2003, and 2006, the State submitted amended rules (AAC R18-2-715 (sections F, G, and H), R18-2-715.01, R18-2-715.02, and R18-2-Appendix 8). These rules address both fugitive and stack emissions from smelters and, in approving the rules, we found that the amended rules met the RACT requirement under CAA sections 172(c)(1) and 191(b). See 69 FR 26789 at 26788 (May 14, 2004), 69 FR 63321 (November 2, 2004), and 71 FR 18624 at 18625 (April 12, 2006). Furthermore, because the area has attained the standard, no further demonstration that RACM has been implemented need be submitted by the State.

Emissions inventory. The emissions inventory requirement of section 172(c)(3) is satisfied by the maintenance plan inventory requirements. The maintenance plan inventory is evaluated below, in section IV.E.1.

NSR permit program. Section 172(c)(5) requires new source review (NSR) permits for the construction and operation of new and modified major stationary sources located in nonattainment areas. ADEQ is the agency responsible for implementing the nonattainment area NSR permit program in the Miami area. Under ADEQ's rules, all new major sources and modifications to existing major sources are subject to the NSR requirements of these rules.

We have not yet fully approved the ADEQ NSR rules. We have, however, determined that an area being redesignated from nonattainment to attainment does not need to have an approved NSR program prior to redesignation, provided that the area demonstrates maintenance of the standard without nonattainment NSR in effect. See memorandum from Mary Nichols dated October 14, 1994 (“Part D New Source Review (part D NSR) Requirements for Areas Requesting Redesignation to Attainment.”) We have determined that the maintenance demonstration for Miami does not rely on nonattainment NSR.

Prevention of significant deterioration (PSD) is the permitting program that applies in attainment areas. PSD was established to preserve air quality in areas that are meeting the NAAQS. The PSD program requires new, modified, or reconstructed stationary sources to undergo preconstruction review and to apply best available control technology. In addition, sources are required to review PSD increment consumption and undertake preconstruction modeling. ADEQ has an EPA-approved PSD permitting program (Arizona Air Pollution Rule R9-3-304) for all criteria pollutants except respirable particulate matter (PM¹⁰). See 48 FR 19878 (May 3, 1983). The federal PSD program for PM¹⁰ was delegated to the State on March 12, 1999. ADEQ's partially approved, partially delegated PSD program will apply automatically to new major sources or major modifications to existing sources of SO₂ in the Miami area once the area is redesignated to attainment.

Compliance with section 110(a)(2). Under section 172(c)(7), plan provisions submitted to satisfy part D must meet the applicable provisions of section 110(a)(2) of the CAA. As noted in section IV.B. above, the Miami portion of the Arizona SIP meets these requirements.

Equivalent techniques. Under section 172(c)(8), EPA may allow the use of equivalent modeling, emission inventory, and planning procedures, unless EPA determines that the proposed techniques are, in the aggregate, less effective than the methods specified by EPA. The Miami SO₂ Maintenance Plan relies on an equivalent modeling technique referred to as Multipoint Rollback (MPR). MPR was used to derive emissions limits for the Miami smelter that provide for attainment and maintenance of the SO₂ NAAQS. The State's rules containing MPR-derived emission limits for the Miami smelter were approved by EPA on January 14, 1983 (48 FR 1717) and amended versions of the rules were approved by EPA on November 1, 2004 (69 FR 63321).

b. Section 176

Section 176(c) of the CAA requires states to establish criteria and procedures to ensure that federally supported or funded projects conform to the air quality planning goals in the applicable 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 Laws (“transportation conformity”) as well as to all other federally supported or funded projects (“general conformity”). Because EPA does not consider SO₂ a transportation-related pollutant, only the requirements related to general conformity apply to the Miami SO₂ area. The State of Arizona adopted general conformity criteria and procedures as a revision to the Arizona SIP. EPA approved Arizona's general conformity SIP on April 23, 1999 (64 FR 19916). Thus, the requirements of CAA section 176 have been satisfied.

c. Subpart 5

Subpart 5 of part D contains additional provisions for areas designated nonattainment for SO₂. Under CAA section 191(b), States with existing nonattainment areas for the primary SO₂ NAAQS where those areas lack fully approved SIPs, including part D plans, must submit implementation plans meeting the requirements of subpart 1 of part D. As discussed in section IV.D.2.a of this notice, the State of Arizona has met the requirements of subpart 1 of part D for the Miami area. Under CAA section 192(b), such areas were required to meet the primary SO₂ NAAQS as expeditiously as possibly but no later than November 15, 1995. As discussed in section IV.A of this notice, the Miami SO₂ nonattainment area met the primary SO₂ standards well before the applicable attainment date of November 15, 1995 and has continued to attain since then.

E. The Area Must Have a Fully Approved Maintenance Plan

Section 107(d)(3)(E)(iv) of the Act makes EPA approval of a maintenance plan meeting the requirements of section 175A another prerequisite to redesignation. Under section 175A, a maintenance plan must provide for maintenance of the NAAQS for at least 10 years after redesignation, and include any additional control measures as may be necessary to ensure such maintenance. In addition, maintenance plans are to contain such contingency provisions as EPA deems necessary to assure the prompt correction of a violation of the NAAQS that occurs after redesignation. The contingency measures must include, at a minimum, a requirement that the state will implement all control measures contained in the nonattainment SIP prior to redesignation.

The Calcagni Memo contains EPA guidance on the contents of maintenance plans submitted for the purposes of meeting section 175A. Generally, such plans should address the following five topics: the attainment emissions inventory, maintenance demonstration, monitoring network, verification of continued attainment, and a contingency plan.

Lastly, under CAA section 175A(b), states are required to submit a subsequent maintenance plan eight years after redesignation providing for maintenance of the NAAQS for an additional 10-year period beyond the initial 10-year maintenance period.

1. Attainment Inventory

The Miami SO₂ Maintenance Plan includes an emissions inventory for point sources, area sources, and mobile sources for 1999 and 2000 as well as a projection of emissions to 2015. See table 4 below. As discussed in section IV.A of this notice, the Miami area has continued to attain the SO₂ NAAQS since at least 1990 and thus 1999 and 2000 are acceptable as the basis upon which to develop an “attainment emissions inventory” for the purposes of a maintenance plan.

ADEQ developed the area and mobile source estimates shown in table 4 based on EPA's AIRData for Gila County. Point source estimates are based on ADEQ annual emissions inventory data. See section 4.0 and appendix B of the Miami SO₂ Maintenance Plan. Sulfur dioxide emissions from the Phelps-Dodge smelter copper smelter itself are based on continuous emission monitoring systems and the assumption that stack emissions represent 25 percent of the facility's total annual (i.e., stack plus fugitive) SO₂ emissions. The actual percentage of total facility emissions emanating from the stacks varies from year to year (e.g., from 19 percent to 33 percent over the 1996 to 2000 period) but the 25 percent assumption is a reasonable average annual value based on material balance calculation methods.

Based on our review of the submitted plan, we conclude that the emissions inventory is based on reasonable methods and assumptions and is comprehensive and accurate.

2. Maintenance Demonstration

EPA allows states to demonstrate maintenance of the NAAQS by either showing that future emissions of a pollutant or its precursors will not exceed the level of the attainment inventory, or by modeling to show that the future mix of sources and emission rates will not cause a violation of the NAAQS. In the case of the Miami nonattainment area, the demonstration of maintenance relies on both a projected emissions inventory for future years of 2005, 2010, and 2015 for sources in the Miami nonattainment area as well as SO₂ emission limits for the Miami smelter that were developed using a variant of Multipoint Rollback (MPR) modeling and intended to minimize the probability of an exceedance of the SO₂ NAAQS due to smelter emissions.

The inventory from the Miami SO₂ Maintenance Plan shows that about 98% of the total SO₂ emissions in the Miami nonattainment area are generated by the smelter. Projections for the Miami smelter itself anticipate a minor increase from those in 1999 [7,819 tons per year (tpy)] to 2005 and beyond (8,000 tpy). The remaining point sources in the nonattainment area have existing permits that limit their allowable emissions to less than 100 tpy. Projections for area and mobile sources (increasing from 149 tpy to 162 tpy) are based on anticipated moderate increases in population and the assumption that SO₂ emissions from such sources are proportionate to the population. Total projected actual emissions of point, area, and mobile sources are expected to remain relatively constant, with total SO₂ emissions projected to be less than 24 tons on a daily basis and approximately 8,200 tons on annual basis by 2015. This represents an increase of only about 2 percent from 1999 levels. Thus, throughout the maintenance period, the Miami smelter is expected to continue to be the overwhelming source of SO₂ emissions in the area.

The emissions projections for the smelter (from 7,819 tpy) in 1999 to 8,000 tpy in 2005 and beyond are based on the expectation that, through 2015, the copper industry will not expand. While the expectation of continued low price pressures on copper may well have been reasonable in 2002 when the maintenance plan was adopted, changes in the copper market in fact have occurred over the past several years raising the price for copper thereby leading to a reasonable expectation of higher production levels at the Miami smelter than anticipated in the Miami SO₂ Maintenance Plan.

Nonetheless, the demonstration of maintenance of the SO₂ NAAQS in the Miami area does not rely solely on the emissions projections, but also on the SO₂ emission limits established under SIP rule AAC R18-2-715 (approved by EPA in 2004 and, as amended, in 2006) and incorporated into the title V operating permit for the Phelps-Dodge Miami smelter. These limits cap stack emissions at 604 pounds per hour (lbs/hr) on an annual average basis and total facility (i.e., stacks plus fugitives) emissions at 2,420 lbs/hr on an annual basis. SIP rule AAC R18-2-715 also establishes a cumulative occurrence table that caps the number of occurrences of 3-hour average emissions above various levels with, for example, only two occurrences allowed per year of stack SO₂ emissions greater than 5,900 lbs/hr, 3-hour average. The total facility emissions cap (2,420 lbs/hr) corresponds to approximately 10,600 tpy assuming round-the-clock, year-round operation (the permit however cites 10,400 tpy based on 357 work days in a given year).

As explained below, ADEQ has demonstrated that the new limits are protective of the SO₂ NAAQS. In order to increase the smelter's emissions limits the State would have to submit a SIP revision that demonstrates that, consistent with CAA section 110(l), the revision does not interfere with maintenance of the SO₂ NAAQS. Therefore, the emission limits for the smelter, supported by the emissions inventory projections that show that the smelter will remain the overwhelming source of SO₂ emissions in the area for the foreseeable future, in essence provide the demonstration necessary to show that the Miami area will continue to attain the SO₂ standard indefinitely, and thereby comply with CAA section 175A(a), which requires maintenance plans to provide for maintenance of the NAAQS for at least 10 years after redesignation.

Given the link then between the SO₂ emission limits on the Phelps-Dodge Miami smelter and the demonstration of maintenance, the Miami SO₂ Maintenance Plan provides a detailed explanation of how the limits were derived and how they minimize the probability of exceedance of the SO₂ NAAQS due to smelter operations. See chapter 5 of the submitted plan. First, it is important to note that ADEQ used a variant of the Multipoint Rollback (MPR) method to derive these emissions limits. In brief, MPR uses the ratio of monitored concentrations to the NAAQS to determine how much to scale the smelter's existing hourly distribution of emission rates so that they meet the NAAQS. Unlike simple rollback, which yields a single maximum emission rate never to be exceeded, MPR yields limitations on the number of times per year that the facility may exceed each of a series of emission rates. In the resulting cumulative occurrence table, the larger the emissions rate, the fewer number of occurrences are allowed per year. The emission rates are chosen so that the full hourly distribution results in attainment of the NAAQS on a probabilistic basis. This approach has been approved by EPA for use with smelters because of their highly variable emission rates. ADEQ used a variant of MPR, as explained further below, to show that the new limits are protective of the NAAQS.

ADEQ derived the original emissions limits for the smelter in the late 1970's using MPR, and adopted the original smelter SO2 emissions rule in 1979. To derive new, enforceable limits on the smelter stacks, it was necessary to distinguish stack emissions from total emissions, which include fugitives (those emissions not vented through the stack). The new emissions limits were derived by apportioning the old facility-wide emission limits between the stack emissions and fugitive emissions. Using mass balance, the total amount of emissions can be calculated from the total mass of sulfur entering the plant in raw materials. Stack emissions are monitored, and account for about 25% of the total sulfur. The fugitive emissions were then determined by subtracting the monitored stack emissions from the calculated total emissions. Because the release height of the stack and fugitive emissions is similar, and their emissions are fairly well-mixed by the time they reach the monitor, the stack also accounts for 25% of the observed concentration at the monitor, on average. Thus, 25% of the existing facility-wide limits (2,420 lb/hr) are what the stack must be limited to (605 lb/hr; the SIP rule caps the emissions at 604 lb/hr, which is slightly more conservative) in order to meet the NAAQS.

This provides only an annual average emission rate. To derive MPR-style limits on allowed occurrences of various emission rates (i.e., a cumulative occurrence table), ADEQ used the shape of the current hourly emission distribution and scaled it to match the required annual average emission rate. Since the new average limit is 1.75 times the current average actual emissions (604 lb/hr limit vs. 345 lb/hr current average), the current distribution and occurrence emission levels were scaled up by this factor. The result is new occurrence limits consistent with the new average limit of 604 lb/hr, the level needed to meet the NAAQS based upon the 1979 MPR analysis and the 25% stack fraction.

However, scaling according to the 1979 limits assumes that the 1979 relationship between emissions and ambient concentrations has not changed. There have been substantial operational and emissions changes at the smelter since the 1979 average emission limit and occurrence table were derived, which could have altered the shape of the emissions curve. If the current distribution shape has a broader peak than the 1979 one, then there will be relatively more instances of high ambient impacts, and so scaling of the average will not guarantee NAAQS-protective limits on short-term emissions.

In order to address this, ADEQ carried out a second step in the submittal that is more consistent with the MPR procedure, in that it incorporated the ambient effect of the current emissions distribution, rather than relying on the 1979 relationship. ADEQ used monitoring data from 1996-2000, and emissions during that same period. The new emission limits, though a decrease from the old limits, represent an increase over the current actual emissions, and so should be shown to be consistent with the NAAQS. ADEQ assumed the smelter operated at the higher emissions rate allowed in the new limits, and applied the fractional emissions increase to ambient 3-hour, 24-hour, and annual SO₂ concentrations. This uses the current relationship between emissions and ambient concentration to show that the scaled-up emissions allowed in the new limits are consistent with the NAAQS. The result of this “rollback” scaling is shown in figure 5.4 of the Miami SO₂ Maintenance Plan, and also in table 5 below.

With this second verification step, ADEQ used a procedure consistent with MPR, an EPA-approved method for smelter attainment demonstrations, to show that the new limits are protective of the NAAQS. We find that the protection of the NAAQS provided by the smelter's SO₂ emissions limits, considered in the context of emissions projections that show that the smelter will remain the overwhelming source of SO₂ emissions in the area for the foreseeable future, sufficient to demonstrate maintenance through the maintenance period and beyond.

3. Monitoring Network

Currently, there are three monitoring sites in the Miami nonattainment area: the Ridgeline monitor operated by ADEQ, and the Jones Ranch and Townsite monitors operated by Phelps-Dodge. ADEQ and Phelps-Dodge Miami commit to continue monitoring ambient SO₂ concentrations at their respective sites for at least 10 years following the approval of the Miami SO₂ Maintenance Plan. Phelps-Dodge has the option of shutting down the monitors if the smelter has not operated for more than 2 years but commits to resume monitoring at the two sites three months prior to restarting of smelting operations. In addition, ADEQ commits to discussing changes to monitor locations with EPA and indicates that all ambient monitoring data will continue to be quality-assured in accordance with the requirements of 40 CFR part 58, Ambient Air Quality Surveillance. See section 7.2 of the submitted plan. We find that the Miami SO₂ Maintenance Plan adequately provides for continued monitoring of SO₂ concentrations in the Miami area.

At the present time, only the SO₂ monitoring data collected at ADEQ's Ridgeline site is certified and entered into AQS. However, because the Jones Ranch site has historically measured the highest SO₂ concentrations in the area and because the data from Jones Ranch is used in connection with the contingency plan, EPA has requested that ADEQ commit to working with Phelps-Dodge to ensure that SO₂ monitoring data from the Jones Ranch site is entered into AQS. By letter to EPA dated October 18, 2006, ADEQ has agreed that entering SO₂ monitoring data from the Jones Ranch site into AQS is appropriate and has committed to working with Phelps-Dodge to accomplish this task no later than the first quarter of 2008. This commitment provides additional assurance that a suitable monitoring network will be maintained within the Miami area through the maintenance period and provides additional support for the contingency plan discussed below in section IV.E.5 of this action.

4. Verification of Continued Attainment

ADEQ intends to track the progress of the Miami SO₂ Maintenance Plan through implementation and enforcement of the monitoring, reporting, and certification procedures to which permitted sources are subject under AAC R18-2-306 and R18-2-309. As a permitted source, the Phelps-Dodge Miami smelter is subject to these State requirements. ADEQ also notes that it has authority pursuant to Arizona Revised Statutes section 49-101 to monitor and ensure source compliance with all applicable rules and permit conditions. See section 7.3 of the submitted plan. Lastly, we note that ADEQ is required under 40 CFR part 51, subpart A, to report emissions data for large stationary sources, such as the Phelps-Dodge Miami smelter, on an annual basis. Considered together, the submitted plan and relevant EPA regulations adequately provide for verification of continued attainment of the SO₂ NAAQS in the Miami area.

5. Contingency Plan

Section 175A(d) of the CAA requires that maintenance plans include contingency provisions to promptly correct any violation of the NAAQS that occurs after redesignation of the area. The Calcagni memo provides additional guidance, noting that, although a state is not required to have fully adopted contingency measures that will take effect without further action by the state in order for the maintenance plan to be approved, the maintenance plan should ensure that the contingency measures are adopted expediently once they are triggered. Specifically, the maintenance plan should clearly identify the measures to be adopted, include a schedule and procedure for adoption and implementation of the measures, and contain a specific time limit for action by the state. In addition, the state should identify specific indicators, or triggers, that will be used to determine when the contingency measures need to be implemented.

Because the Phelps-Dodge smelter is the overwhelming source of SO₂ emissions in the Miami area, the contingency plan contained in section 7.4 of the Miami SO₂ Maintenance Plan focuses on ambient impacts and emissions attributable to it. The contingency plan uses monitored ambient concentrations of SO₂ to trigger actions designed to ensure continued attainment of the SO₂ NAAQS. The trigger levels and associated notification procedures and associated actions are described below.

Notification Procedure: If either of the Phelps-Dodge monitors or the ADEQ-operated monitor record ambient 3-hour average SO₂ levels between 0.425 ppm and 0.5 ppm (i.e., levels greater than 85%, but less than 100%, of the secondary SO₂ NAAQS), the entity that operates the monitor is required to notify the other party. A second occurrence in a calendar year of ambient concentrations between 0.425 ppm and 0.5 ppm, or an exceedance of the secondary NAAQS is defined as the protective trigger level (PTL). The response required by a triggering of the PTL is divided into two action levels.

First Action Level: If the PTL is tripped, Phelps-Dodge must undertake a series of inspections and a full calibration check of the ambient SO₂ analyzers and recording systems in order to validate the data. If the data are determined to be valid, Phelps-Dodge must perform any needed repairs or corrective actions and implement specified preventive measures. The source must also submit a report to ADEQ by the close of the second business day following an exceedance in which it describes the nature of the event, any corrective actions taken to resolve the event, and recommendations for future corrective actions to avoid recurrence of such an event.

Second Action Level: If the source is unable to correct the triggering of the PTL by implementing the actions required under the first action level, Phelps-Dodge must undertake an analysis to identify additional control measures needed to ensure maintenance of the NAAQS. Phelps-Dodge is required to submit recommendations to ADEQ within 30 business days following the triggering of the PTL. Using all available data, ADEQ will determine the cause and appropriate resolution of the event, and will require the adoption and implementation of additional control measures, as needed. ADEQ commits to initiating changes to the rules or to the permit as soon as possible.

Special Measure: A violation of the secondary NAAQS (i.e., a second exceedance in a calendar year) triggers the implementation of a special measure within 24 hours of the monitored violation that requires the source to reduce its operating rate by the same percentage as that by which the 3-hour standard was exceeded. These circumstances also require that the source comply with first action level requirements and, if necessary, second action level requirements. A second and higher concentration violation of the secondary NAAQS within the same calendar year requires that the operating rate be recalculated accordingly.

Upon review of the contingency plan in the Miami SO2 Maintenance Plan summarized above, we find that ADEQ has established a workable contingency plan, including trigger levels, notification procedures, and appropriate actions, for promptly correcting any violations of the SO2 NAAQS that occur after the redesignation of the Miami area to attainment and thereby satisfies the requirements of CAA section 175A(d).

6. Subsequent Maintenance Plan Revisions

As noted previously, CAA section 175A(b) requires states to submit a subsequent maintenance plan revision eight years after the redesignation request is approved by EPA. The subsequent maintenance plan is to provide for maintenance of the NAAQS for an additional 10 years following the first 10-year maintenance period. ADEQ has made a commitment to submit a subsequent maintenance plan to EPA eight years into the initial 10-year maintenance period (see page 53 of the submitted plan) and thereby satisfies CAA section 175A(b).

7. Conclusion

ADEQ's Miami SO₂ Maintenance Plan adequately addresses the five basic topics that such plans should address, including attainment inventory, maintenance demonstration, monitoring network, verification of continued attainment, and contingency plan, and also provides for submittal of a subsequent maintenance plan. Therefore, we approve the Miami SO₂ Maintenance Plan as a revision to the Arizona SIP and thereby satisfy the related redesignation criterion of CAA section 107(d)(3)(E)(iv).

V. Boundary Correction

A. Background

Under section 107(d) of the Clean Air Act Amendments of 1977, each State was directed to submit to EPA a list identifying the NAAQS attainment status for all areas within the State. EPA was required under section 107(d)(2) of the 1977 Amended Act to promulgate the State lists, with any necessary modifications, within 60 days of their submittal. In 1978, in the absence of recommendations from the State of Arizona, EPA promulgated the original area designations for Arizona for each of the NAAQS. See 43 FR 8962 (March 3, 1978). EPA selected counties as the geographic basis for the original nonattainment area designations for SO₂ in Arizona and designated all of Gila County as a nonattainment area for the SO₂ NAAQS. See 43 FR 8962, at 8968.

On August 15, 1978, the State of Arizona submitted its area designations to EPA with the intent that EPA redesignate the original EPA-promulgated nonattainment areas to reflect the State's recommendations. The State's August 15, 1978 submittal included a background document prepared by the Arizona Department of Health Services and entitled, “Identification of Areas within Arizona that do or do not meet National Ambient Air Quality Standards (August 1, 1978)” (referred to herein as the “State's designations background report”). The State's designations background report identifies townships, or identifiable portions thereof, as the smallest geographic unit defining air quality planning areas in Arizona.

With respect to SO₂ in the Miami area, the State's designations background report includes a map showing a nonattainment area comprised by a total of nine townships: two townships in which the major source of SO₂ emissions in the area (i.e., the primary copper smelter) is located (T1N, R14E and T1N, R15E) and seven adjacent townships (or portions thereof) to the east, west, north and south. The State's map also shows six additional adjacent townships with the designation of “cannot be classified.”

In the State's designations background report, the State provided a specific list of townships defining the nonattainment and “cannot be classified” areas. However, the list of townships and the map illustrating the areas are not entirely consistent with one another. The State's list of townships for the Miami SO₂ nonattainment area includes, among others, the following townships moving west to east: T1N, R13E; T1N, R14E; T1N, R15E; and T1N, R16E. The township immediately east of T1N, R15E, however, is T1N, R151/2E not T1N, R16E, and thus the list inadvertently created a noncontiguous nonattainment area with a single township (T1N, R16E) isolated from the rest of the larger designated area. In contrast, the map submitted as part of the designations background report shows the nonattainment area boundary as a single contiguous area including both T1N, R151/2E and the western half of T1N, R16E. On April 10, 1979 (44 FR 21261), we approved the redesignation request by Arizona for the Miami SO₂ nonattainment area without modification and thereby codified the State's submitted list of townships (not the map) as the geographic definition for the Miami SO₂ nonattainment area thereby creating a noncontiguous nonattainment area (i.e., one township isolated from the rest of the townships comprising the nonattainment area). In its June 26, 2002 submittal of the Miami SO₂ Maintenance Plan and supplemental June 30, 2004 submittal, ADEQ requested that we redesignate the boundaries under CAA section 107(d)(3)(D) to create a single, contiguous planning area and to exclude tribal lands from the planning area. By letter dated June 26, 2006, however, ADEQ withdrew the boundary redesignation request as previously formulated but requested that EPA act to correct the boundary under section 110(k)(6) of the Act instead. As explained further below, we agree with ADEQ that a boundary correction is warranted, and we make the related corrections to the boundary in today's notice.

Also, while our April 10, 1979 final rule redesignating nonattainment areas in Arizona correctly listed T1S, R141/2E as one of the townships comprising the Miami SO₂ nonattainment area, the 1979 version of 40 CFR part 81 included a transcription error and listed this particular township as “T1S, R141/4E” instead of “T1S, R141/2E.” We are correcting the transcription error in this notice as well.

B. Authority for Correcting Errors

Section 110(k)(6) of the Clean Air Act, as amended in 1990, provides, “Whenever the Administrator determines that the Administrator's action approving, disapproving, or promulgating any plan or plan revision (or part thereof), area designation, redesignation, classification or reclassification was in error, the Administrator may in the same manner as the approval, disapproval, or promulgation revise such action as appropriate without requiring any further submission from the State. Such determination and the basis thereof shall be provided to the State and the public.”

We interpret this provision to authorize the Agency to make corrections to a promulgated regulation when it is shown to our satisfaction that (1) we clearly erred in failing to consider or in inappropriately considering information made available to EPA at the time of the promulgation, or the information made available at the time of promulgation is subsequently demonstrated to have been clearly inadequate, and (2) other information persuasively supports a change in the regulation. See 57 FR 56762, at 56763 (November 30, 1992).

In this instance, we have found clear error in our 1979 consideration of the State of Arizona's submitted recommendations for area redesignations and believe that correction of the error to be appropriate at this time in support of the State's submittal of a redesignation request and maintenance plan for the SO₂ NAAQS within the Miami air quality planning area.

C. Evaluation and Conclusion

Based on a comparison of the map submitted by the State in its 1978 designations background report that illustrates the nonattainment area with the accompanying list of townships defining the area, we find that the State erred by assuming that the township immediately east of T1N, R15E is T1N, R16E when it is actually T1N, R151/2E and by then including the former instead of the latter in the list of townships defining the nonattainment area. Whereas T1N, R151/2E lies immediately adjacent to one of the townships in which the major source of SO₂ emissions is located, T1N, R16E lies mostly within the San Carlos Indian Reservation, is more distant from the major source in the area, and has no known source of SO₂ emissions. EPA then erred in failing to discover this error in our 1979 consideration and approval of the State's recommended redesignation for the Miami SO₂ nonattainment area. By virtue of the State's designations background report submitted in August 15, 1978, EPA had the relevant information necessary to discover this error at the time of our April 10, 1979 final rule but failed to do so. The State has now requested redesignation of the Miami SO₂ nonattainment area to “attainment” and submitted a maintenance plan, which if approved as proposed herein, will begin the next phase (“maintenance”) of air quality planning in the Miami area.

We believe that correction of the error that resulted in the creation of a noncontiguous area would help provide a solid regulatory foundation for the maintenance phase of CAA planning in the Miami area by eliminating the noncontiguous portion of the otherwise contiguous Miami air quality planning area and by removing any uncertainties as to the area designation status and applicable requirements for township T1N, R16E. Furthermore, ADEQ's redesignation request and maintenance plan for the Miami area do not rely on any control measure within T1N, R16E to demonstrate attainment and maintenance of the SO₂ standard in the Miami area. We are therefore taking direct final action under CAA section 110(k)(6) to correct the designation for T1N, R16E and thereby remove it from the list of townships comprising the Miami SO₂ nonattainment area (which we are herein taking direct final action to redesignate to attainment). Specifically, we are correcting the error by revising the designation of T1N, R16E from “does not meet primary standards” to “cannot be classified” in the listing for Miami in the Arizona SO₂ table in 40 CFR 81.303. We are changing the designation of the township to “cannot be classified” for the SO₂ standard consistent with the State's 1978 approach for areas that, while in the general proximity of a recommended SO₂ nonattainment area, would be unlikely to experience violations of the standard because of the distance from the source and the terrain. For example, using this rationale, the State recommended, and we approved, “cannot be classified” designations for townships T2N, R16E and T1S, R16E.

Rather than reclassifying township T1N, R151/2E as part of this redesignation action, we have decided to retain its current air quality planning status of “cannot be classified.” First, establishing township T1N, R151/2E as part of a future Miami maintenance area (and no longer as part of the “rest of state” area) could have unintended effects on SO₂ increment tracking under the State's prevention of significant deterioration permitting program. Second, no control measures in T1N, R151/2E have been relied upon for attainment or maintenance of the SO₂ standard in the Miami area. Third, including township T1N, R151/2E in the maintenance area would inappropriately subject projects in that township to certain CAA requirements, such as general conformity, that are intended only to apply within nonattainment areas and former nonattainment areas that have been redesignated to attainment. See CAA section 176(c)(5).

In addition to the correction described above, we are taking direct final action to correct the transcription error introduced first in the 1979 version of 40 CFR part 81 by replacing T1S, R141/4E with T1S, R141/2E in the list of townships comprising the Miami SO₂ air quality planning area.

VI. Public Comment and Final Action

As authorized under section 110(k)(3) of the Act, EPA is approving the Miami Sulfur Dioxide Nonattainment Area State Implementation and Maintenance Plan, as submitted by ADEQ on June 26, 2002, corrected by the submittal dated June 30, 2004, and amended by the submittal dated June 20, 2006, as a revision to the Arizona state implementation plan. In so doing, we find that the maintenance plan meets the requirements for such plans under CAA section 175A.

EPA is also approving the State of Arizona's request for redesignation of the Miami area from nonattainment to attainment for the SO₂ NAAQS based on our conclusion that all of the redesignation criteria in CAA section 107(d)(3)(E) have been satisfied. Specifically, we find that (1) the Miami area has attained the SO₂ NAAQS; (2) Arizona has a fully approved SIP for the Miami area; (3) the improvements in air quality in the Miami area are due to permanent and enforceable reductions in emissions resulting from implementation of EPA-approved smelter rules and title V permit conditions; (4) Arizona has met all of the nonattainment area requirements applicable to the Miami area; and (5) the State's submitted maintenance plan meets all relevant CAA requirements and is being approved in this notice.

Lastly, under CAA section 110(k)(6) and for the reasons stated above in section V of this notice, EPA is correcting the boundary of the Miami SO₂ nonattainment area to exclude a noncontiguous township that was erroneously included in the original description of the nonattainment area. Specifically, we are correcting the error by revising the designation of township T1N, R16E as listed in the Arizona SO₂ table in 40 CFR 81.303 from “does not meet primary standards” to “cannot be classified.” We are also correcting the erroneous transcription of one of the townships in the Miami SO₂ planning area in 40 CFR 81.303 by replacing “T1S, R141/4E” with “T1S, R141/2E.”

EPA is finalizing this action without proposing it in advance because the Agency views this action as noncontroversial and anticipates no adverse comments. However, in the Proposed Rules section of this Federal Register, we are simultaneously proposing approval of the same maintenance plan and request for redesignation and proposing the same corrections to the list of townships comprising the Miami, AZ SO₂ area. If we receive adverse comments by February 23, 2007, we will publish a timely withdrawal in the Federal Register to notify the public that the direct final approval will not take effect and we will address the comments in a subsequent final action based on the proposal. If we do not receive timely adverse comments, the direct final approval will be effective without further notice on March 26, 2007. This will approve the redesignation request and maintenance plan submitted by Arizona on June 26, 2002, as amended by submittals dated June 30, 2004 and June 20, 2006, and to revise the designation of township T1N, R16E as listed in the Arizona SO₂ table in 40 CFR 81.303 from “does not meet primary standards” to “cannot be classified” and replace the township incorrectly listed as “T1S, R141/4E” with “T1S, R141/2E”.

Please note that if EPA receives adverse comment on an amendment, paragraph, or section of this rule and if that provision may be severed from the remainder of the rule, EPA may adopt as final those provisions of the rule that are not the subject of an adverse comment.

VII. Statutory and Executive Order Review

Under Executive Order 12866 (58 FR 51735, October 4, 1993), this action is not a “significant regulatory action” and therefore is not subject to review by the Office of Management and Budget. For this reason, this action is also not subject to Executive Order 13211, “Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution, or Use” (66 FR 28355, May 22, 2001). This action merely approves a state plan and redesignation request as meeting Federal requirements and corrects a long-standing error in the boundary of an air quality planning area. It imposes no additional requirements beyond those imposed by state law. Accordingly, the Administrator certifies that this rule will not have a significant economic impact on a substantial number of small entities under the Regulatory Flexibility Act (5 U.S.C. 601 et seq.). Because this rule approves pre-existing requirements under state law and does not impose any additional enforceable duty beyond that required by state law, it does not contain any unfunded mandate or significantly or uniquely affect small governments, as described in the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4).

This rule also does not have tribal implications because it will not have a substantial direct effect on one or more Indian tribes, on the relationship between the Federal Government and Indian tribes, or on the distribution of power and responsibilities between the Federal Government and Indian tribes, as specified by Executive Order 13175 (65 FR 67249, November 9, 2000). Nonetheless, EPA has contacted the San Carlos Apache tribe to provide an opportunity to discuss the implications of exclusion of that portion of township T1N, R16E that lies within the reservation from the Miami SO₂ nonattainment area. In letters dated November 20, 2006 and December 12, 2006, EPA transmitted a fact sheet with background information on this issue and a map illustrating the air quality planning area boundary change.

This action also does not have Federalism implications because it does not have substantial direct effects on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government, as specified in Executive Order 13132 (64 FR 43255, August 10, 1999). This action merely approves a state plan and redesignation request implementing a Federal standard and corrects a long-standing error in the boundary of an air quality planning area. It does not alter the relationship or the distribution of power and responsibilities established in the Clean Air Act. This rule also is not subject to Executive Order 13045 “Protection of Children from Environmental Health Risks and Safety Risks” (62 FR 19885, April 23, 1997), because it is not economically significant.

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

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

Under section 307(b)(1) of the Clean Air Act, petitions for judicial review of this action must be filed in the United States Court of Appeals for the appropriate circuit by March 26, 2007. Filing a petition for reconsideration by the Administrator of this final rule does not affect the finality of this rule for the purposes of judicial review nor does it extend the time within which a petition for judicial review may be filed, and shall not postpone the effectiveness of such rule or action. This action may not be challenged later in proceedings to enforce its requirements. (See section 307(b)(2).)

List of Subjects

40 CFR Part 52

• Environmental protection
• Air pollution control
• Intergovernmental relations
• Reporting and recordkeeping requirements
• Sulfur oxides

40 CFR Part 81

• Environmental protection
• Air pollution control
• National parks
• Wilderness areas

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

Part 52, chapter I, title 40 of the Code of Federal Regulations is amended as follows:

PART 52—[AMENDED]

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

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

Subpart D—Arizona

2. Section 52.120 is amended by adding paragraph (c)(132) to read as follows:

Part 81, chapter I, title 40 of the Code of Federal Regulations is amended as follows:

PART 81—[AMENDED]

1. The authority citation for part 81 continues to read as follows:

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

Subpart C—[Amended]

2. In § 81.303, the table entitled “Arizona—SO ₂” is amended by revising the entry for Miami to read as follows: