Air Plan Approval; South Carolina; Interstate Transport (Prongs 1 and 2) for the 2010 1-Hour NO2

AGENCY:

Environmental Protection Agency.

ACTION:

Proposed rule.

SUMMARY:

The Environmental Protection Agency (EPA) is proposing to approve a revision to the South Carolina State Implementation Plan (SIP), submitted by the South Carolina Department of Health and Environmental Control (DHEC), on December 7, 2016, addressing the Clean Air Act (CAA) interstate transport (prongs 1 and 2) infrastructure SIP requirements for the 2010 1-hour Nitrogen Dioxide (NO₂) National Ambient Air Quality Standard (NAAQS). The CAA requires that each state adopt and submit a SIP for the implementation, maintenance, and enforcement of each NAAQS promulgated by EPA, commonly referred to as an “infrastructure SIP.” Specifically, EPA is proposing to approve South Carolina's December 7, 2016, SIP submission addressing prongs 1 and 2 to ensure that air emissions in the State do not significantly contribute to nonattainment or interfere with maintenance of the 2010 1-hour NO₂ NAAQS in any other state.

DATES:

Comments must be received on or before September 14, 2017.

ADDRESSES:

Submit your comments, identified by Docket ID No. EPA-R04-OAR-2017-0045 at http://www.regulations.gov. Follow the online instructions for submitting comments. Once submitted, comments cannot be edited or removed from Regulations.gov. EPA may publish any comment received to its public docket. Do not submit electronically any information you consider to be Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Multimedia submissions (audio, video, etc.) must be accompanied by a written comment. The written comment is considered the official comment and should include discussion of all points you wish to make. EPA will generally not consider comments or comment contents located outside of the primary submission (i.e., on the web, cloud, or other file sharing system). For additional submission methods, the full EPA public comment policy, information about CBI or multimedia submissions, and general guidance on making effective comments, please visit http://www2.epa.gov/dockets/commenting-epa-dockets.

FOR FURTHER INFORMATION CONTACT:

Andres Febres of the Air Regulatory Management Section, Air Planning and Implementation Branch, Air, Pesticides and Toxics Management Division, U.S. Environmental Protection Agency, Region 4, 61 Forsyth Street SW., Atlanta, Georgia 30303-8960. Mr. Febres can be reached by telephone at (404) 562-8966 or via electronic mail at febres-martinez.andres@epa.gov.

SUPPLEMENTARY INFORMATION:

I. Background

By statute, SIPs meeting the requirements of sections 110(a)(1) and (2) of the CAA are to be submitted by states within three years after promulgation of a new or revised NAAQS to provide for the implementation, maintenance, and enforcement of the new or revised NAAQS. EPA has historically referred to these SIP submissions made for the purpose of satisfying the requirements of sections 110(a)(1) and 110(a)(2) as “infrastructure SIP” submissions. Sections 110(a)(1) and (2) require states to address basic SIP elements such as requirements for monitoring, basic program requirements, and legal authority that are designed to assure attainment and maintenance of the newly established or revised NAAQS. More specifically, section 110(a)(1) provides the procedural and timing requirements for infrastructure SIPs. Section 110(a)(2) lists specific elements that states must meet for the infrastructure SIP requirements related to a newly established or revised NAAQS. The contents of an infrastructure SIP submission may vary depending upon the data and analytical tools available to the state, as well as the provisions already contained in the state's implementation plan at the time in which the state develops and submits the submission for a new or revised NAAQS.

Section 110(a)(2)(D) has two components: 110(a)(2)(D)(i) and 110(a)(2)(D)(ii). Section 110(a)(2)(D)(i) includes four distinct components, commonly referred to as “prongs,” that must be addressed in infrastructure SIP submissions. The first two prongs, which are codified in section 110(a)(2)(D)(i)(I), are provisions that prohibit any source or other type of emissions activity in one state from contributing significantly to nonattainment of the NAAQS in another state (prong 1) and from interfering with maintenance of the NAAQS in another state (prong 2). The third and fourth prongs, which are codified in section 110(a)(2)(D)(i)(II), are provisions that prohibit emissions activity in one state from interfering with measures required to prevent significant deterioration of air quality in another state (prong 3) and from interfering with measures to protect visibility in another state (prong 4). Section 110(a)(2)(D)(ii) requires SIPs to include provisions ensuring compliance with sections 115 and 126 of the Act, relating to interstate and international pollution abatement.

Through this proposed action, EPA is proposing to approve South Carolina's December 7, 2016, SIP submission addressing prong 1 and prong 2 requirements for the 2010 1-hour NO₂ NAAQS. All other applicable infrastructure SIP requirements for South Carolina for the 2010 1-hour NO₂ NAAQS have been addressed in separate rulemakings. See 80 FR 14019 (March 18, 2015), 81 FR 56512 (August 22, 2016), and 81 FR 63704 (September 16, 2016). A brief background regarding the 2010 1-hour NO₂ NAAQS is provided below.

On January 22, 2010, EPA established a new 1-hour primary NAAQS for NO₂ at a level of 100 parts per billion, based on a 3-year average of the 98th percentile of the yearly distribution of 1-hour daily maximum concentrations. See 75 FR 6474 (February 9, 2010). This NAAQS is designed to protect against exposure to the entire group of nitrogen oxides (NO_X). NO₂ is the component of greatest concern and is used as the indicator for the larger group of NO_X. Emissions that lead to the formation of NO₂ generally also lead to the formation of other NO_X. Therefore, control measures that reduce NO₂ can generally be expected to reduce population exposures to all gaseous NO_X which may have the co-benefit of reducing the formation of ozone and fine particles both of which pose significant public health threats.

States were required to submit infrastructure SIP submissions for the 2010 1-hour NO₂ NAAQS to EPA no later than January 22, 2013. For comprehensive information on 2010 1-hour NO₂ NAAQS, please refer to the Federal Register notice cited immediately above.

II. What is EPA's approach to the review of infrastructure SIP submissions?

The requirement for states to make a SIP submission of this type arises out of section 110(a)(1). Pursuant to section 110(a)(1), states must make SIP submissions “within 3 years (or such shorter period as the Administrator may prescribe) after the promulgation of a national primary ambient air quality standard (or any revision thereof),” and these SIP submissions are to provide for the “implementation, maintenance, and enforcement” of such NAAQS. The statute directly imposes on states the duty to make these SIP submissions, and the requirement to make the submissions is not conditioned upon EPA's taking any action other than promulgating a new or revised NAAQS. Section 110(a)(2) includes a list of specific elements that “each such plan” submission must address.

EPA has historically referred to these SIP submissions made for the purpose of satisfying the requirements of section 110(a)(1) and (2) as “infrastructure SIP” submissions. Although the term “infrastructure SIP” does not appear in the CAA, EPA uses the term to distinguish this particular type of SIP submission from submissions that are intended to satisfy other SIP requirements under the CAA, such as “nonattainment SIP” or “attainment plan SIP” submissions to address the nonattainment planning requirements of part D of Title I of the CAA, “regional haze SIP” submissions required by EPA rule to address the visibility protection requirements of section 169A of the CAA, and nonattainment new source review permit program submissions to address the permit requirements of CAA, Title I, part D.

Section 110(a)(1) addresses the timing and general requirements for infrastructure SIP submissions and section 110(a)(2) provides more details concerning the required contents of these submissions. The list of required elements provided in section 110(a)(2) contains a wide variety of disparate provisions, some of which pertain to required legal authority, some of which pertain to required substantive program provisions, and some of which pertain to requirements for both authority and substantive program provisions. EPA therefore believes that while the timing requirement in section 110(a)(1) is unambiguous, some of the other statutory provisions are ambiguous. In particular, EPA believes that the list of required elements for infrastructure SIP submissions provided in section 110(a)(2) contains ambiguities concerning what is required for inclusion in an infrastructure SIP submission.

The following examples of ambiguities illustrate the need for EPA to interpret some section 110(a)(1) and section 110(a)(2) requirements with respect to infrastructure SIP submissions for a given new or revised NAAQS. One example of ambiguity is that section 110(a)(2) requires that “each” SIP submission must meet the list of requirements therein, while EPA has long noted that this literal reading of the statute is internally inconsistent and would create a conflict with the nonattainment provisions in part D of Title I of the CAA, which specifically address nonattainment SIP requirements. Section 110(a)(2)(I) pertains to nonattainment SIP requirements and part D addresses when attainment plan SIP submissions to address nonattainment area requirements are due. For example, section 172(b) requires EPA to establish a schedule for submission of such plans for certain pollutants when the Administrator promulgates the designation of an area as nonattainment, and section 107(d)(1)(B) allows up to two years or in some cases three years, for such designations to be promulgated. This ambiguity illustrates that rather than apply all the stated requirements of section 110(a)(2) in a strict literal sense, EPA must determine which provisions of section 110(a)(2) are applicable for a particular infrastructure SIP submission.

Another example of ambiguity within section 110(a)(1) and (2) with respect to infrastructure SIPs pertains to whether states must meet all of the infrastructure SIP requirements in a single SIP submission, and whether EPA must act upon such SIP submission in a single action. Although section 110(a)(1) directs states to submit “a plan” to meet these requirements, EPA interprets the CAA to allow states to make multiple SIP submissions separately addressing infrastructure SIP elements for the same NAAQS. If states elect to make such multiple SIP submissions to meet the infrastructure SIP requirements, EPA can elect to act on such submissions either individually or in a larger combined action. Similarly, EPA interprets the CAA to allow it to take action on the individual parts of one larger, comprehensive infrastructure SIP submission for a given NAAQS without concurrent action on the entire submission. For example, EPA has sometimes elected to act at different times on various elements and sub-elements of the same infrastructure SIP submission.

Ambiguities within section 110(a)(1) and (2) may also arise with respect to infrastructure SIP submission requirements for different NAAQS. Thus, EPA notes that not every element of section 110(a)(2) would be relevant, or as relevant, or relevant in the same way, for each new or revised NAAQS. The states' attendant infrastructure SIP submissions for each NAAQS therefore could be different. For example, the monitoring requirements that a state might need to meet in its infrastructure SIP submission for purposes of section 110(a)(2)(B) could be very different for different pollutants, because the content and scope of a state's infrastructure SIP submission to meet this element might be very different for an entirely new NAAQS than for a minor revision to an existing NAAQS.

EPA notes that interpretation of section 110(a)(2) is also necessary when EPA reviews other types of SIP submissions required under the CAA. Therefore, as with infrastructure SIP submissions, EPA also has to identify and interpret the relevant elements of section 110(a)(2) that logically apply to these other types of SIP submissions. For example, section 172(c)(7) requires attainment plan SIP submissions required by part D to meet the “applicable requirements” of section 110(a)(2); thus, attainment plan SIP submissions must meet the requirements of section 110(a)(2)(A) regarding enforceable emission limits and control measures and section 110(a)(2)(E)(i) regarding air agency resources and authority. By contrast, it is clear that attainment plan SIP submissions required by part D would not need to meet the portion of section 110(a)(2)(C) that pertains to the Prevention of Significant Deterioration (PSD) program required in part C of Title I of the CAA, because PSD does not apply to a pollutant for which an area is designated nonattainment and thus subject to part D planning requirements. As this example illustrates, each type of SIP submission may implicate some elements of section 110(a)(2) but not others.

Given the potential for ambiguity in some of the statutory language of section 110(a)(1) and section 110(a)(2), EPA believes that it is appropriate to interpret the ambiguous portions of section 110(a)(1) and section 110(a)(2) in the context of acting on a particular SIP submission. In other words, EPA assumes that Congress could not have intended that each and every SIP submission, regardless of the NAAQS in question or the history of SIP development for the relevant pollutant, would meet each of the requirements, or meet each of them in the same way. Therefore, EPA has adopted an approach under which it reviews infrastructure SIP submissions against the list of elements in section 110(a)(2), but only to the extent each element applies for that particular NAAQS.

Historically, EPA has elected to use guidance documents to make recommendations to states for infrastructure SIPs, in some cases conveying needed interpretations on newly arising issues and in some cases conveying interpretations that have already been developed and applied to individual SIP submissions for particular elements. EPA most recently issued guidance for infrastructure SIPs on September 13, 2013 (2013 Guidance). EPA developed this document to provide states with up-to-date guidance for infrastructure SIPs for any new or revised NAAQS. Within this guidance, EPA describes the duty of states to make infrastructure SIP submissions to meet basic structural SIP requirements within three years of promulgation of a new or revised NAAQS. EPA also made recommendations about many specific subsections of section 110(a)(2) that are relevant in the context of infrastructure SIP submissions. The guidance also discusses the substantively important issues that are germane to certain subsections of section 110(a)(2). EPA interprets section 110(a)(1) and (2) such that infrastructure SIP submissions need to address certain issues and need not address others. Accordingly, EPA reviews each infrastructure SIP submission for compliance with the applicable statutory provisions of section 110(a)(2), as appropriate.

As an example, section 110(a)(2)(E)(ii) is a required element of section 110(a)(2) for infrastructure SIP submissions. Under this element, a state must meet the substantive requirements of section 128, which pertain to state boards that approve permits or enforcement orders and heads of executive agencies with similar powers. Thus, EPA reviews infrastructure SIP submissions to ensure that the state's implementation plan appropriately addresses the requirements of section 110(a)(2)(E)(ii) and section 128. The 2013 Guidance explains EPA's interpretation that there may be a variety of ways by which states can appropriately address these substantive statutory requirements, depending on the structure of an individual state's permitting or enforcement program (e.g., whether permits and enforcement orders are approved by a multi-member board or by a head of an executive agency). However they are addressed by the state, the substantive requirements of Section 128 are necessarily included in EPA's evaluation of infrastructure SIP submissions because section 110(a)(2)(E)(ii) explicitly requires that the state satisfy the provisions of section 128.

As another example, EPA's review of infrastructure SIP submissions with respect to the PSD program requirements in section 110(a)(2)(C), (D)(i)(II), and (J) focuses upon the structural PSD program requirements contained in part C and EPA's PSD regulations. Structural PSD program requirements include provisions necessary for the PSD program to address all regulated sources and new source review (NSR) pollutants, including Greenhouse Gases. By contrast, structural PSD program requirements do not include provisions that are not required under EPA's regulations at 40 CFR 51.166 but are merely available as an option for the state, such as the option to provide grandfathering of complete permit applications with respect to the fine particulate matter (PM_2.5) NAAQS. Accordingly, the latter optional provisions are types of provisions EPA considers irrelevant in the context of an infrastructure SIP action.

For other section 110(a)(2) elements, however, EPA's review of a state's infrastructure SIP submission focuses on assuring that the state's SIP meets basic structural requirements. For example, section 110(a)(2)(C) includes, inter alia, the requirement that states have a program to regulate minor new sources. Thus, EPA evaluates whether the state has an EPA-approved minor NSR program and whether the program addresses the pollutants relevant to that NAAQS. In the context of acting on an infrastructure SIP submission, however, EPA does not think it is necessary to conduct a review of each and every provision of a state's existing minor source program (i.e., already in the existing SIP) for compliance with the requirements of the CAA and EPA's regulations that pertain to such programs.

With respect to certain other issues, EPA does not believe that an action on a state's infrastructure SIP submission is necessarily the appropriate type of action in which to address possible deficiencies in a state's existing SIP. These issues include: (i) Existing provisions related to excess emissions from sources during periods of startup, shutdown, or malfunction (SSM) that may be contrary to the CAA and EPA's policies addressing such excess emissions; (ii) existing provisions related to “director's variance” or “director's discretion” that may be contrary to the CAA because they purport to allow revisions to SIP-approved emissions limits while limiting public process or not requiring further approval by EPA; and (iii) existing provisions for PSD programs that may be inconsistent with current requirements of EPA's “Final NSR Improvement Rule,” 67 FR 80186 (December 31, 2002), as amended by 72 FR 32526 (June 13, 2007) (NSR Reform). Thus, EPA believes that it may approve an infrastructure SIP submission without scrutinizing the totality of the existing SIP for such potentially deficient provisions and may approve the submission even if it is aware of such existing provisions. It is important to note that EPA's approval of a state's infrastructure SIP submission should not be construed as explicit or implicit re-approval of any existing potentially deficient provisions that relate to the three specific issues just described.

EPA's approach to review of infrastructure SIP submissions is to identify the CAA requirements that are logically applicable to that submission. EPA believes that this approach to the review of a particular infrastructure SIP submission is appropriate, because it would not be reasonable to read the general requirements of section 110(a)(1) and the list of elements in section 110(a)(2) as requiring review of each and every provision of a state's existing SIP against all requirements in the CAA and EPA regulations merely for purposes of assuring that the state in question has the basic structural elements for a functioning SIP for a new or revised NAAQS. Because SIPs have grown by accretion over the decades as statutory and regulatory requirements under the CAA have evolved, they may include some outmoded provisions and historical artifacts. These provisions, while not fully up to date, nevertheless may not pose a significant problem for the purposes of “implementation, maintenance, and enforcement” of a new or revised NAAQS when EPA evaluates adequacy of the infrastructure SIP submission. EPA believes that a better approach is for states and EPA to focus attention on those elements of section 110(a)(2) of the CAA most likely to warrant a specific SIP revision due to the promulgation of a new or revised NAAQS or other factors.

For example, EPA's 2013 Guidance gives simpler recommendations with respect to carbon monoxide than other NAAQS pollutants to meet the visibility requirements of section 110(a)(2)(D)(i)(II), because carbon monoxide does not affect visibility. As a result, an infrastructure SIP submission for any future new or revised NAAQS for carbon monoxide need only state this fact in order to address the visibility prong of section 110(a)(2)(D)(i)(II).

Finally, EPA believes that its approach with respect to infrastructure SIP requirements is based on a reasonable reading of section 110(a)(1) and (2) because the CAA provides other avenues and mechanisms to address specific substantive deficiencies in existing SIPs. These other statutory tools allow EPA to take appropriately tailored action, depending upon the nature and severity of the alleged SIP deficiency. Section 110(k)(5) authorizes EPA to issue a “SIP call” whenever the Agency determines that a state's SIP is substantially inadequate to attain or maintain the NAAQS, to mitigate interstate transport, or to otherwise comply with the CAA. Section 110(k)(6) authorizes EPA to correct errors in past actions, such as past approvals of SIP submissions. Significantly, EPA's determination that an action on a state's infrastructure SIP submission is not the appropriate time and place to address all potential existing SIP deficiencies does not preclude EPA's subsequent reliance on provisions in section 110(a)(2) as part of the basis for action to correct those deficiencies at a later time. For example, although it may not be appropriate to require a state to eliminate all existing inappropriate director's discretion provisions in the course of acting on an infrastructure SIP submission, EPA believes that section 110(a)(2)(A) may be among the statutory bases that EPA relies upon in the course of addressing such deficiency in a subsequent action.

III. What are the Prong 1 and Prong 2 requirements?

For each new NAAQS, section 110(a)(2)(D)(i)(I) of the CAA requires each state to submit a SIP revision that contains adequate provisions prohibiting emissions activity in the state from contributing significantly to nonattainment, or interfering with maintenance, of the NAAQS in any downwind state. EPA sometimes refers to these requirements as prong 1 (significant contribution to nonattainment) and prong 2 (interference with maintenance), or conjointly as the “good neighbor” provision of the CAA.

IV. What is EPA's analysis of how South Carolina addressed Prongs 1 and 2?

In South Carolina's December 7, 2016, SIP revision, the State concluded that its SIP adequately addresses prongs 1 and 2 with respect to the 2010 1-hour NO₂ NAAQS. South Carolina provides the following reasons for its determination: (1) The SIP contains state regulations that directly or indirectly control NO_X emissions; (2) all areas in the United States are designated as unclassifiable/attainment for the 2010 1-hour NO₂ NAAQS; (3) monitored 1-hour NO₂ design values in South Carolina and surrounding states (Georgia, North Carolina, and Florida) are below the 2010 standard; and (4) point source emissions of NO_X in the State have trended downward. EPA preliminarily agrees with the State's conclusion based on the rationale discussed below.

First, South Carolina identifies SIP-approved portions of the following State rules that directly or indirectly control NO_X emissions: S.C. Regulation 61-62.5, Standard No. 5.2 (Control of Oxides of Nitrogen (NO _X )); Regulation 61-62.96 (Nitrogen Oxides (NO _X ) and Sulfur Dioxide (SO ₂ ) Budget Trading Program General Provisions); Regulation 61-62.5, Standard No. 7 (Prevention of Significant Deterioration); and Regulation 61-62.5, Standard No. 7.1 (Nonattainment New Source Review (NSR)). Regulation 61-62.5, Standard No. 5.2 requires NO_X controls on certain new stationary sources and requires certain existing sources that replace their burners to replace them with low NO_X burners or equivalent technology capable of achieving a 30 percent reduction from uncontrolled levels. Regulation 61-62.96 implemented the Clean Air Interstate Rule (CAIR) which created regional cap-and-trade programs to reduce SO₂ and NO_X emissions in 27 eastern states, including South Carolina, that contributed to downwind nonattainment and maintenance of the 1997 8-hour ozone NAAQS and the 1997 PM_2.5 NAAQS. Regulations 61-62.5, Standards No. 7 and 7.1 require any new major source or major modification to go through prevention of significant deterioration (PSD) or nonattainment new source review permitting, respectively.

Second, there are no designated nonattainment areas for the 2010 1-hour NO₂ NAAQS. On February 17, 2012 (77 FR 9532), EPA designated the entire country as “unclassifiable/attainment” for the 2010 1-hour NO₂ NAAQS, stating that “available information does not indicate that the air quality in these areas exceeds the 2010 1-hour NO₂ NAAQS.”

Third, the 2013-2015 NO₂ design values in South Carolina and surrounding states are well below the 100 ppb standard. The highest monitored design values during this time period are 56 to 65 percent below the NAAQS with Georgia and Florida recording the highest design values (48 and 44 ppb, respectively).

Fourth, NO_X point source emissions data provided in the SIP submittal show that NO_X emissions decreased from 72,885 tons in 2008 to 41,070 tons in 2014, a reduction of approximately 44 percent.

For all the reasons discussed above, EPA has preliminarily determined that South Carolina does not contribute significantly to nonattainment or interfere with maintenance of the 2010 1-hour NO₂ NAAQS in any other state and that South Carolina's SIP includes adequate provisions to prevent emissions sources within the State from significantly contributing to nonattainment or interfering with maintenance of this standard in any other state.

V. Proposed Action

As described above, EPA is proposing to approve South Carolina's December 7, 2016, SIP revision addressing prongs 1 and 2 of CAA section 110(a)(2)(D)(i) for the 2010 1-hour NO₂ NAAQS.

VI. Statutory and Executive Order Reviews

Under the CAA, the Administrator is required to approve a SIP submission that complies with the provisions of the Act and applicable federal regulations. See 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in reviewing SIP submissions, EPA's role is to approve state choices, provided that they meet the criteria of the CAA. Accordingly, this proposed action merely proposes to approve state law as meeting federal requirements and does not impose additional requirements beyond those imposed by state law. For that reason, this proposed action:

• Is not a “significant regulatory actions” subject to review by the Office of Management and Budget under Executive Orders 12866 (58 FR 51735, October 4, 1993) and 13563 (76 FR 3821, January 21, 2011);
• Does not impose an information collection burden under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
• Is certified as not having a significant economic impact on a substantial number of small entities under the Regulatory Flexibility Act (5 U.S.C. 601 et seq.);
• 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);
• Does not have Federalism implications as specified in Executive Order 13132 (64 FR 43255, August 10, 1999);
• Is not an economically significant regulatory actions based on health or safety risks subject to Executive Order 13045 (62 FR 19885, April 23, 1997);
• Is not a significant regulatory actions subject to Executive Order 13211 (66 FR 28355, May 22, 2001);
• Is not subject to requirements of section 12(d) of the National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 note) because application of those requirements would be inconsistent with the CAA; and
• Does not provide EPA with the discretionary authority to address, as appropriate, disproportionate human health or environmental effects, using practicable and legally permissible methods, under Executive Order 12898 (59 FR 7629, February 16, 1994).

In addition, this proposed rule for the state of South Carolina does not have Tribal implications as specified by Executive Order 13175 (65 FR 67249, November 9, 2000), because it does not have substantial direct effects on an Indian Tribe. The Catawba Indian Nation Reservation is located within the State of South Carolina. Pursuant to the Catawba Indian Claims Settlement Act, S.C. Code Ann. 27-16-120, “all state and local environmental laws and regulations apply to the [Catawba Indian Nation] and Reservation and are fully enforceable by all relevant state and local agencies and authorities.” EPA notes this action will not impose substantial direct costs on Tribal governments or preempt Tribal law.

List of Subjects in 40 CFR Part 52

• Environmental protection
• Air pollution control
• Incorporation by reference
• Intergovernmental relations
• Nitrogen dioxide
• Ozone
• Reporting and recordkeeping requirements

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