90 FR 67 pgs. 15213-15218 - Air Plan Approval; Louisiana; Interstate Transport Requirements for the 2010 SO
2
NAAQS
Type: PRORULEVolume: 90Number: 67Pages: 15213 - 15218
Pages: 15213, 15214, 15215, 15216, 15217, 15218Docket number: [EPA-R06-OAR-2013-0465; FRL-12681-01-Region 6]
FR document: [FR Doc. 2025-05927 Filed 4-8-25; 8:45 am]
Agency: Environmental Protection Agency
Official PDF Version: PDF Version
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R06-OAR-2013-0465; FRL-12681-01-Region 6]
Air Plan Approval; Louisiana; Interstate Transport Requirements for the 2010 SO 2 NAAQS
AGENCY:
Environmental Protection Agency (EPA).
ACTION:
Proposed rule.
SUMMARY:
Pursuant to the Federal Clean Air Act (CAA or the Act), the Environmental Protection Agency (EPA) is proposing to approve the portion of the State Implementation Plan (SIP) submittal from the State of Louisiana demonstrating that the State satisfies the interstate transport requirements of section 110(a)(2)(D)(i)(I), also known as the "good neighbor" provision of the CAA, for the 2010 1-hour sulfur dioxide (SO 2 ) primary National Ambient Air Quality Standard (NAAQS). The good neighbor provision requires each State's implementation plan contain adequate provisions prohibiting the interstate transport of air pollution in amounts that will contribute significantly to nonattainment, or interfere with maintenance, of a NAAQS in any other State.
DATES:
Written comments must be received on or before May 9, 2025.
ADDRESSES:
Submit your comments, identified by Docket Number EPA-R06-OAR-2013-0465, at www.regulations.gov. Follow the online instructions for submitting comments. Once submitted, comments cannot be edited or removed from Regulations.gov. The 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. The 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, please contact Nevine Salem, (214) 665-7222, salem.nevine@epa.gov. For the full EPA public comment policy, information about CBI or multimedia submissions, and general guidance on making effective comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets.
Docket: The index to the docket for this action is available electronically at www.regulations.gov. While all documents in the docket are listed in the index, some information may not be publicly available due to docket file size restrictions or content ( e.g., CBI).
FOR FURTHER INFORMATION CONTACT:
Nevine Salem, (214) 665-7222, salem.nevine@epa.gov. We encourage the public to submit comments via https://www.regulations.gov. Please call or email the contact listed above if you need alternative access to material indexed but not provided in the docket.
SUPPLEMENTARY INFORMATION:
Throughout this document wherever "we," "us," or "our" is used, we mean the EPA.
I. Background
A. Infrastructure SIPs
On June 2, 2010, the EPA established a revised primary 1-hour SO 2 NAAQS with a level of 75 parts per billion (ppb), based on a 3-year average of the annual 99th percentile of daily maximum 1-hour average concentrations. 1 CAA section 110(a)(1) requires all States to submit, within three years after promulgation of a new or revised NAAQS, SIP submissions to provide for the implementation, maintenance, and enforcement of the NAAQS. 2 The EPA has historically referred to these SIPs as "infrastructure SIPs." Specifically, section 110(a)(1) provides the procedural and timing requirements for SIP submissions. Section 110(a)(2) lists specific elements that all States must meet related to a newly established or revised NAAQS, such as requirements for monitoring, basic program requirements, and legal authority that are designed to assure attainment and maintenance of the NAAQS.
Footnotes:
1 ? See 75 FR 35520 (June 22, 2010).
2 ?In 2012, the EPA retained the current secondary NAAQS for SO 2 . Thus, the CAA section 110(a)(1) requirement to submit an infrastructure SIP for this secondary standard was not triggered. The secondary SO 2 standard is 500 ppb averaged over three hours, not to be exceeded more than once per year. See 77 FR 20218 (April 3, 2012).
Section 110(a)(2)(D)(i)(I) of the CAA requires a State's SIP include provisions prohibiting any source or other type of emissions activity in the State from emitting any air pollutant in amounts that will contribute significantly to nonattainment, or interfere with maintenance, of the NAAQS in any other State. EPA has long interpreted this language to enact a "functional prohibition" on certain emissions from upwind States, necessitating the EPA's independent assessment whether those emissions will occur or have been adequately controlled in the State where they originate. 3 The EPA often refers to these requirements as Prong 1 (significant contribution to nonattainment of the NAAQS) and Prong 2 (interference with maintenance of the NAAQS). We are addressing Prongs 1 and 2 in this action. All other applicable infrastructure SIP requirements of the Louisiana SIP submission are addressed in separate rulemakings.
Footnotes:
3 ? See Genon Rema LLC v. EPA, 722 F.3d 513, 520-24 (3d Cir. 2013); Appalachian Power Co. v. EPA, 249 F.2d 1032, 1045-47 (D.C. Cir. 2001); see also 71 FR 25328, 25335 (April 28, 2006) (explaining that the SIP/FIP process under section 110 and the petitioning process for direct federal regulation under section 126 provide independent means of effectuating the same "functional prohibition" found in CAA section 110(a)(2)(D)(i)(I)).
B. 2010 1-Hour SO 2 NAAQS Designations Background
In this proposed action, the EPA has considered information from the 2010 1-hour SO 2 NAAQS designations process, as discussed in more detail in section III.C of this notice. For this reason, a brief summary of the EPA's designations process for the 2010 1-hour SO 2 NAAQS is included here. 4
Footnotes:
4 ?While designations may provide useful information for purposes of analyzing transport, the EPA notes that designations themselves are not dispositive of whether or not upwind emissions are impacting areas in downwind states. The EPA has consistently taken the position that CAA section 110(a)(2)(D)(i)(I) requires elimination of significant contribution and interference with maintenance in other states, and this analysis is not limited to designated nonattainment areas. Nor must designations for nonattainment areas have first occurred before states or the EPA can act under section 110(a)(2)(D)(i)(I). See, e.g., Clean Air Interstate Rule, 70 FR 25162, 25265 (May 12, 2005); Cross State Air Pollution Rule, 76 FR 48208, 48211 (Aug. 8, 2011); Final Response to Petition from New Jersey Regarding SO 2 Emissions From the Portland Generating Station, 76 FR 69052 (Nov. 7, 2011) (finding facility in violation of the prohibitions of CAA section 110(a)(2)(D)(i)(I) with respect to the 2010 1-hour SO 2 NAAQS prior to issuance of designations for that standard).
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After the promulgation of a new or revised NAAQS, the EPA is required to designate areas as "nonattainment," "attainment," or "unclassifiable" pursuant to CAA section 107(d)(1)-(2). The process for designating areas following promulgation of a new or revised NAAQS is contained in CAA section 107(d). The EPA promulgated the 2010 1-hour SO 2 NAAQS on June 2, 2010. See 75 FR 35520 (June 22, 2010). The EPA Administrator signed the first round? 5 of designations; Round 1? 6 for the 2010 1-hour SO 2 NAAQS on July 25, 2013, designating 29 areas in 16 States as nonattainment for the 2010 1-hour SO 2 NAAQS. See 78 FR 47191 (August 5, 2013). The Federal Register notices for Round 2 designations? 7 published on July 12, 2016 (81 FR 45039) and on December 13, 2016 (81 FR 89870). Round 3 designations? 8 were published on January 9, 2018 (83 FR 1098) and April 5, 2018 (83 FR 14597). Round 4 designations? 9 were published on March 26, 2021 (86 FR 16055)? 10 and April 14, 2021 (86 FR 19576). 11
Footnotes:
5 ?The term "round" in this instance refers to which "round of designations."
6 ?EPA and state documents and public comments related to the Round 1 final designations are in the docket at regulations.gov with Docket ID No. EPA-HQ-OAR-2012-0233 and at EPA's website for SO 2 designations at https://www.epa.gov/sulfur-dioxide-designations.
7 ?EPA and state documents and public comments related to the Round 2 final designations are in the docket at regulations.gov with Docket ID No. EPA-HQ-OAR-2014-0464 and at EPA's website for SO 2 designations at https://www.epa.gov/sulfur-dioxide-designations.
8 ?EPA and state documents and public comments related to Round 3 final designations are in the docket at regulations.gov with Docket ID No. EPA-HQ-OAR-2017-0003 and at EPA's website for SO 2 designations at https://www.epa.gov/sulfur-dioxide-designations.
9 ?EPA and state documents and public comments related to Round 4 final designations are in the docket at regulations.gov with Docket ID No. EPA-HQ-OAR-2020-0037 and at EPA's website for SO 2 designations at https://www.epa.gov/sulfur-dioxide-designations.
10 ?The Round 4 2010 1-hour SO 2 NAAQS designations action was signed by former EPA Administrator Andrew Wheeler on December 21, 2020, pursuant to a court-ordered deadline of December 31, 2020. For administrative purposes only, and in compliance with requirements of the Office of the Federal Register, former Acting Administrator Jane Nishida re-signed the same action on March 10, 2021, for publication in the Federal Register .
11 ?On August 21, 2015 (80 FR 51052), EPA separately promulgated air quality characterization requirements for the 2010 1-hour SO 2 NAAQS in the Data Requirements Rule (DRR). The DRR requires state air agencies to characterize air quality, through air dispersion modeling or monitoring, in areas associated with sources that emitted in 2014 2,000 tons per year (tpy) or more of SO 2 , or that have otherwise been listed under the DRR by EPA or state air agencies. In lieu of modeling or monitoring, state air agencies, by specified dates, could elect to impose federally enforceable emissions limitations on those sources restricting their annual SO 2 emissions to less than 2,000 tpy, or provide documentation that the sources have been shut down. EPA used the information generated by implementation of the DRR to help inform Round 4 designations for the 2010 1-hour SO 2 NAAQS.
For Louisiana, the EPA designated St. Bernard Parish area as nonattainment during the initial round of SO 2 designations? 12 effective October 4, 2013 based on available monitoring data. The agency published the Data Requirements Rule (DRR) on August 21, 2015 (80 FR 51052) to provide expectations for collection of data, either monitoring or modeling, for the remaining designations. In the DRR, the EPA identified 16 sources in Louisiana which the State was required to characterize air quality through modeling or monitoring or impose federally enforceable controls. In Round 2 designations, EPA designated De Soto Parish as attainment/unclassifiable and Calcasieu Parish as unclassifiable effective August 12, 2016. 13 In Round 3 designations, the EPA designated Pointe Coupee Parish, and Rapides Parish as attainment/unclassifiable; St. Mary Parish as unclassifiable; and Evangeline Parish as nonattainment effective April 9, 2018. 14 Also, during Round 3, the EPA designated the remaining areas without DRR sources as attainment/unclassifiable effective April 9, 2018. In Round 4, the EPA designated the remaining Parishes-East Baton Rouge, St. Charles, St. James, and West Baton Rouge-as attainment/unclassifiable, completing the area designations for the 2010 1-hour SO 2 NAAQS in Louisiana effective April 30, 2021.
Footnotes:
12 ? See 78 FR 47191 (August 5, 2013).
13 ? See 81 FR 45039 (July 12, 2016).
14 ? See 83 FR 1089 (January 9, 2018).
II. Relevant Factors Used To Evaluate 2010 1-Hour SO 2 Interstate Transport SIPs
Although SO 2 is emitted from a similar universe of point and nonpoint sources as is directly emitted fine particulate matter (PM 2.5 ) and the precursors to ozone and PM 2.5 , interstate transport of SO 2 is unlike the transport of PM 2.5 or ozone, which disperse over a wide area and can contribute to nonattainment or maintenance issues hundreds of miles from precursor-emitting sources or activities. SO 2 emissions usually do not undergo long-range transport in the atmosphere. The transport of SO 2 relative to the 2010 1-hour SO 2 NAAQS is more analogous to the transport of lead (Pb) relative to the Pb NAAQS in that emissions of SO 2 typically result in 1-hour pollutant impacts of greatest concern near the emissions source. However, ambient 1-hour concentrations of SO 2 do not decrease as quickly with distance from the source as do 3-month average concentrations of Pb, because SO 2 gas is not removed by deposition as rapidly as are Pb particles. Emitted SO 2 has wider-ranging impacts than emitted Pb, but it does not have such wide-ranging (far downwind) impacts that treatment in a manner similar to ozone or PM 2.5 would be appropriate. Accordingly, the approaches that the EPA has adopted for ozone or PM 2.5 transport are too regionally focused, and the approach for Pb transport is too tightly circumscribed to the source, to be appropriate for assessing SO 2 transport. SO 2 transport is therefore a unique case and necessitates an approach that lies between these other approaches to assessing pollutant transport.
In this proposed rulemaking, and consistent with prior SO 2 transport analyses, the EPA focused on a 50 kilometer (km)-wide zone around sources of interest because the physical properties of SO 2 result in relatively localized pollutant impacts near an emission source that drop off with distance. Given the properties of SO 2 , the EPA believes that significant impacts in a downwind State are unlikely at distances greater than 50 km from a source and thus, we are focusing our review on areas within 50 km of the State lines. This scale of analysis is consistent with the "urban scale" which is the largest appropriate spatial scale for SO 2 monitors and is useful for assessing SO 2 transport and trends in area-wide air quality. 15
Footnotes:
15 ?For the definition of spatial scales for SO 2 , see 40 CFR part 58, appendix D, section 4.4 ("Sulfur Dioxide (SO 2 ) Design Criteria"). For further discussion on how the EPA applies these definitions with respect to interstate transport of SO 2 , see the EPA's proposed rulemaking on Connecticut's SO 2 transport SIP. See 82 FR 21351, 21352, 21354 (May 8, 2017).
[top] As discussed in section III, and in further detail in the Technical Support Document (TSD) for this action, the EPA reviewed Louisiana's SO 2 SIP submittal. The State's submission did not have sufficient information to fully assess whether Louisiana was meeting its CAA good neighbor requirements for the 2010 SO 2 NAAQS. Therefore, we elected to
Footnotes:
16 ?This proposed action is based on the information contained in the administrative record for this action and does not prejudge any future EPA action that may make other determinations regarding the air quality status in Louisiana and downwind states. Any such future action, such as area designations under any NAAQS, would be based on separate administrative records and the EPA's analyses of information that become available at that time. Future available information may include, monitoring data and modeling analyses conducted by states, air agencies, and third-party stakeholders.
Consistent with our prior evaluations of other States' SO 2 transport obligations, we conducted a weight of evidence (WOE) analysis evaluating several sources of information, including current air quality data from monitors as well as available emissions and/or source modeling for sources in Louisiana and in neighboring States within 50 km of the Louisiana border. A WOE approach can be appropriate in instances, such as in this case, to determine whether or not SO 2 emissions from Louisiana contribute to nonattainment or maintenance issues in adjoining States. A WOE analysis that is based strictly on available data may not be sufficient in all instances for evaluating interstate SO 2 transport, and additional analysis may be necessary. Further, the term "WOE" does not establish the legal or technical meaning for what constitutes significant contribution to nonattainment or interference with maintenance for the 2010 SO 2 NAAQS. Rather, the term refers to the gathering and consideration of a wide range of information, on a case-by-case basis, to make a determination regarding whether a statutory or regulatory standard is met.
In other SO 2 transport SIP actions, the EPA has generally been able to use a WOE analysis of available information to reach a conclusion that there are no SO 2 nonattainment or maintenance issues in the relevant areas of other States, or that no sources in the upwind State are contributing to those issues. If the available evidence indicated, however, that an upwind source, sources, or emissions activities were contributing to an out-of-state SO 2 nonattainment or maintenance problem, then further analysis and a regulatory determination would be necessary concerning what amount of those emissions, if any, constituted "significant contribution" under Prong 1 or Prong 2 of the good neighbor provision.
We find that there is sufficient information to allow the EPA to make a determination that under baseline conditions and likely future emissions scenarios no Louisiana sources are contributing or will contribute to any out-of-state SO 2 nonattainment or maintenance concerns, therefore it is not necessary for purposes of this action to render a determination concerning what amount of emissions would be "significant" and therefore subject to prohibition under the good neighbor provision. 17
Footnotes:
17 ? Cf. Genon Rema v. EPA, 722 F.3d 513 (3d Cir. 2013) (upholding EPA grant of CAA section 126(b) petition and establishment of direct federal emissions control requirements on SO 2 source in Pennsylvania found to be significantly contributing to nonattainment and interfering with maintenance of the 2010 SO 2 NAAQS in New Jersey).
III. Louisiana's SIP Submission and EPA's Analysis
A. State Submission
On June 4, 2013, Louisiana submitted to the EPA a SIP revision to address the requirements of CAA section 110(a)(1) and (2), including section 110(a)(2)(D)(i)(I) for the 2010 SO 2 NAAQS. The submittal cited Louisiana's approved Clean Air Interstate Rule SIP revision as verification that the State met and would continue to meet the requirements of 110(a)(2)(D)(i)(I) for the 2010 SO 2 NAAQS. A copy of the submittal is in the docket for this action. Other portions of this SIP revision were addressed in 81 FR 68322 (October 4, 2016).
The 2005 Clean Air Interstate Rule? 18 (CAIR) covered 28 eastern States (including Louisiana) and the District of Columbia. CAIR was designed to address interstate transport of ozone and fine particulate matter (PM 2.5 ) pollution. CAIR required the covered eastern States to make reductions in SO 2 and nitrogen oxides (NO X ) emissions that significantly contribute to the nonattainment or interference with the maintenance of the 1997 PM 2.5 and 1997 ozone NAAQS in any downwind State (70 FR 25161, May 12, 2005). CAIR addressed interstate transport for the 1997 PM 2.5 and 1997 ozone NAAQS but did not address interstate transport for the 2010 SO 2 NAAQS. Subsequently, the D.C. Circuit invalidated CAIR and required that the rule be revised. 19 The court, however, left CAIR in place in order to "temporarily preserve the environmental values covered by CAIR" until the EPA could, by rulemaking, replace CAIR consistent with the court's opinion. 20 In 2011, the EPA promulgated the Cross-State Air Pollution Rule (CSAPR) to replace CAIR. 21 CSAPR addresses interstate transport for the 1997 PM 2.5 , 1997 ozone and 2006 PM 2.5 NAAQS. CSAPR replaced CAIR beginning on January 1, 2015. 22 Neither CAIR nor CSAPR directly addresses interstate transport for the 2010 SO 2 NAAQS. Because CAIR is no longer in place (and was only allowed to remain temporarily in place pending its replacement at the time of Louisiana's submission, see 76 FR 48208, 48223-24 (Aug. 8, 2011)) and because it did not address the 2010 SO 2 NAAQS, Louisiana's sole reliance on CAIR is not adequate on its own to demonstrate the State meets the requirements of CAA section 110(a)(2)(D)(i)(I).
Footnotes:
18 ?May 12, 2005 (70 FR 25162).
19 ? North Carolina v. EPA, 531 F. 3d 896, 901 (D.C. Cir. 2008), modified, 550 F. 3d 1176 (D.C. Cir. 2008).
20 ?550 F. 3d at 1178.
21 ?76 FR 48207 (August 8, 2011).
22 ?CSAPR has been subject to extensive litigation, and on July 28, 2015, the D.C. Circuit issued a decision generally upholding CSAPR but remanding without vacating the CSAPR emissions budgets for a number of states.?Louisiana's ozone season NO X budgets were not included in the remand. EME Homer City Generation v. EPA, 795 F.3d 118, 138 (D.C. Cir. 2015). On October 26, 2016, we finalized an update to CSAPR that addresses the 1997 ozone NAAQS portion of the remand as well as the CAA requirements addressing interstate transport for the 2008 ozone NAAQS. 81 FR 74504 (October 26, 2016).
[top] Both CAIR and CSAPR focused on achieving widespread reductions in PM 2.5 precursor pollutants, which include SO 2 . While the programs reduced SO 2 emissions from power plants, they did so with the goal of reducing PM 2.5 levels, not with the goal of preventing contribution to nonattainment or interference with maintenance of the SO 2 standard. Louisiana did not provide an analysis to show how the reductions from these programs would sufficiently address SO 2 to prevent prohibited impacts. Moreover, these rules required emissions reductions through emissions trading programs for power plants. As such, they were not designed to ensure a particular level of emissions reduction at a particular power plant, and did not address SO 2 emissions at all from non-power plant sources or emissions activities. Thus, despite these programs, individual power plant and non-power plant sources that are near State borders may be able to continue to emit at uncontrolled levels, potentially contributing to SO 2 nonattainment or maintenance issues in other States. As such, these programs alone cannot be relied upon to demonstrate prohibited
While the rationale provided by Louisiana is not an adequate basis on its own by which the EPA can determine the approvability of the State's submission, the EPA may elect to consider additional information to assist in reaching a conclusion as to whether the submission may be approved, in whole or in part, as satisfying the Act's requirements, or does not meet the Act's requirements. Here, the EPA may consider all relevant information, or generate new data and analysis, to make an independent judgment in evaluating States' compliance with the good neighbor provision, which concerns the effects of States' emissions in other States. Therefore, the EPA considered additional available information as described below and in more detail in the TSD for this action, to determine if Louisiana's SIP complies with 110(a)(2)(D)(i)(I) requirements.
B. EPA's Evaluation Methodology
For this CAA section 110(a)(2)(D)(i)(I) evaluation of the 2010 SO 2 NAAQS, the EPA conducted a WOE analysis for Prong 1 and Prong 2 separately, 23 evaluating available information such as air quality, emission sources, modeling and emission trends in Louisiana, and the States that border Louisiana. To identify which sources and emissions activities in Louisiana could potentially impact downwind air quality in other States with respect to the 2010 1-hour SO 2 NAAQS, the EPA used information in the EPA's National Emissions Inventory (NEI)? 24 and Emissions Inventory System (EIS). 25 The NEI is a comprehensive and detailed estimate of air emissions for criteria pollutants, criteria pollutant precursors, and hazardous air pollutants from air emissions sources, updated every three years using information provided by the States and other information available to the EPA. For analyses, we largely relied on data from the 2020 NEI, because it is the most recently available, complete, and quality assured dataset. However, in evaluating emissions trends, both State-wide and at the facility level, the EPA also considered data from prior NEI reports and EIS queries, as part of the overall WOE analysis.
Footnotes:
23 ?In North Carolina v. EPA, 531 F.3d at 910-911 (D.C. Cir. 2008), the D.C. Circuit explained that the regulating authority must give Prong 2 "independent significance" from Prong 1 by evaluating the impact of upwind state emissions on downwind areas that, while currently in attainment, are at risk of future nonattainment.
24 ?EPA's NEI is available and accessible to the public at https://www.epa.gov/air-emissions-inventories/national-emissions-inventory.
25 ?The EIS is EPA's database used to receive and store emissions data and generate emissions inventories. The EIS Gateway is a web-based tool developed to provide only registered EPA, State, local and Tribal users with access to emission inventory data for sources in their jurisdiction.
As shown in Table 1, the majority of SO 2 emissions in Louisiana originate from point sources. In 2020, total SO 2 emissions from point sources in Louisiana comprised approximately 87 percent of the total SO 2 emissions in the State. Non-point sources, on road and non-road emissions sources are individually much smaller also more dispersed throughout the State and are therefore unlikely to contribute to high ambient concentrations when compared to point source contributions. Further analysis? 26 shows that facilities with reported emissions greater than 100 tons per year (tpy) represent approximately 6 percent of the total number of Louisiana SO 2 point sources but are responsible for 82,980 tons of SO 2 or 97 percent of the total 2020 SO 2 emissions. 27 Based on this analysis, the EPA focused our WOE analysis on SO 2 emissions from Louisiana's larger point sources ( i.e., point sources emitting over 100 tpy of SO 2 ) that are located within 50 km of one or more State borders.
Footnotes:
26 ? See EPA's TSD for a more detailed discussion.
27 ? See Table 9 in the EPA's TSD.
| Category | 2020 emissions (tpy) | Percent of total SO 2 emissions |
|---|---|---|
| Point | 85,239 | 87 |
| Nonpoint | 12,537 | 13 |
| On road | 158 | <1 |
| Nonroad | 10 | <1 |
| SO 2 Emissions Total | 97,999 | 100 |
As described in this section, the EPA proposes that an assessment of Louisiana's satisfaction of the Prong 1 and 2 requirements under CAA section 110(a)(2)(D)(i)(I) for the 2010 1-hour SO 2 NAAQS may be reasonably based upon several factors. These factors include evaluation of the predicted downwind impacts projected in previous relevant modeling studies for the source and nearby areas, assessment of Louisiana's SO 2 point source emissions of more than 100 tpy of SO 2 per facility that are located within approximately 50 km of another State, assessment of other States' point sources emitting more than 100 tpy of SO 2 located within approximately 50 km of Louisiana, and assessment of federal regulations and SIP-approved regulations affecting Louisiana's SO 2 sources. The EPA's evaluation is informed by all available data at the time of this rulemaking. 28
Footnotes:
28 ?EPA notes that the evaluation of other states' satisfaction of section 110(a)(2)(D)(i)(I) for the 2010 1-hour SO 2 NAAQS can be informed by similar factors found in this proposed rulemaking but may not be identical to the approach taken in this or any future rulemaking for Louisiana, depending on available information and state-specific circumstances.
The EPA notes that if this information were insufficient to draw a reasonable conclusion concerning whether Louisiana is "significantly contributing" or not, then it would not be possible to propose approval based only on this information. In other words, in general, the absence of information concerning whether interstate transport is occurring is not in itself sufficient justification for approving a good neighbor SIP submission. For example, if there were inadequate monitoring or modeling information to characterize the effects of a large, near-border source of SO 2 emissions, it may be appropriate to conduct, or ask the State to conduct, further analysis to better characterize that source and its effects, in order to reach a determination concerning whether the good neighbor provision is being met. See, e.g., 88 FR 41344 (June 26, 2023) (proposing approval of Tennessee SO 2 transport SIP submission based on updated modeling conducted to better characterize emissions from the Eastman Chemical facility). In this case, the information available to the EPA, as analyzed in the accompanying TSD and summarized below, is fully sufficient to conclude that Louisiana is not and will not emit SO 2 pollution in violation of the good neighbor provision for the 2010 SO 2 NAAQS.
1. EPA's Prong 1 Evaluation-Contribute Significantly to Nonattainment
[top] Prong 1 of the "good neighbor" provision requires States' plans to prohibit emissions that will contribute significantly to nonattainment of the NAAQS in another State. The EPA's evaluation? 29 of whether Louisiana has met its Prong 1 transport obligations was accomplished by considering all available information, including the following: SO 2 ambient air quality in Louisiana and neighboring States; SO 2 emissions trends for Louisiana and neighboring States; potential ambient impacts of SO 2 emissions from certain
Footnotes:
29 ?A detailed review of EPA's evaluation of emissions, air monitoring data, other technical information, and rationale for proposed approval of this SIP revision as meeting CAA section 110(a)(2)(D)(i)(I) for the 2010 1-hour SO 2 NAAQS may be found in the TSD.
30 ?The physical properties of SO 2 result in relatively localized pollutant impacts near the emissions source. Therefore, the EPA selected a spatial scale with dimensions up to 50 km from point sources.
Based on the EPA's analysis, we propose to determine that there are no SO 2 nonattainment issues in the relevant areas in other States bordering Louisiana, and as such the EPA proposes to determine that Louisiana's SIP satisfies the requirements of Prong 1 of CAA section 110(a)(2)(D)(i)(I). This proposed determination is based on the following considerations:
• There are no monitors recording violations of the 2010 1-hour SO 2 NAAQS located in Louisiana including within 50 km of its border. Additionally, all monitors within 50 km of the Louisiana border have design values (DV)? 31 that are below the 75 ppb SO 2 NAAQS. Current DVs for Louisiana's AQS SO 2 monitors within 50 km of another State's border have remained below the 2010 1-hour SO 2 NAAQS from 2019-2023; similarly, SO 2 monitors in neighboring States (Texas, Arkansas, and Mississippi) within 50 km of Louisiana have 2023 DVs (2021-2023) below the 2010 1-hour SO 2 NAAQS;
Footnotes:
31 ?The design value is the 3-year average of the 99th percentile 1-hour daily maximums at a monitor. A control strategy should be designed to bring the value to attainment of the standard.
• Downward SO 2 emissions trends in Louisiana and its surrounding States (Texas, Arkansas, and Mississippi), when considered together with the other factors discussed as part of EPA's WOE analysis, further support that Louisiana's sources will not significantly contribute to any other States' nonattainment of the 2010 1-hour SO 2 NAAQS;
• A source-specific analyses of every Louisiana 100 tpy source located within 50 km of the State border indicates that the sources do not contribute to nonattainment in other States. These analyses draw upon available emissions data, monitoring data, air quality modeling, control retirements, wind rose data, and other relevant information to assess the likelihood of air quality impacts from these sources to areas in surrounding States. A detailed discussion of each source-specific analysis is contained in section IV.B.1 of the TSD accompanying this action. Below we cover some of the principal evidence that confirms that emissions from Louisiana do not contribute to nonattainment in other States.
? The closest monitor to the Nelson facilities has consistently recorded DVs well below the standard for years 2012-2023, indicating that these facilities are not causing exceedances in Louisiana and would not cause exceedances in Texas.
? Now retired, the monitor in the vicinity of the Reynolds facility in Calcasieu Parish recorded DVs well below the standard from 2017-2020. Considering this historic air quality data with emissions trends in Calcasieu Parish (largely unchanged since 2017) support a determination that these sources are not likely to contribute to nonattainment in Texas.
? Finally, the Orange monitor, located 2 km from the border of Louisiana in Texas, has also recorded DVs below the standard from 2019-2023, further supporting a determination that emissions from Calcasieu Parish sources are not contributing to nonattainment across the border with Texas.
? For the St. Bernard Parish sources, nearby monitors (Chalmette Vista and Meraux) have consistently recorded DVs below the NAAQS. Coupling this monitored air quality information with the fact that these sources are 49 km from the State line supports a determination that emissions from these sources are not contributing to nonattainment across the border into Mississippi.
? For the sources in northwestern Louisiana, low DVs at the Shreveport monitor, coupled with predominant wind patterns that are more likely to transport emissions from these facilities to this monitor than to Texas, support that the northwestern Louisiana sources of emissions are unlikely contributing to nonattainment in Texas. Additionally, DRR modeling results for Dolet Hills Power Station and International Paper's Mansfield Mill indicate no SO 2 air quality violations in DeSoto Parish. When considered with the facts that Dolet Hills has since shutdown and emissions from Mansfield Mill have since decreased, the modeling results are an overestimation of current conditions, further supporting a determination that emissions from Mansfield Mill will not contribute to nonattainment in Texas. For the remainder of the northwestern Louisiana sources, wind rose data and the size and distance (18 km to 48 km) between the sources and the nearest border support a determination that these sources will not contribute to nonattainment of the NAAQS in Texas.
? For the Baton Rouge area sources, the EPA considered DRR modeling from Big Cajun II that predicted maximum concentrations below the standard within Pointe Coupee Parish. Coupling these results in combination with the fact that emissions from the sources included in the modeling have dropped 85% since the modeling was conducted supports a determination that Big Cajun II will not contribute to nonattainment of the NAAQS in Mississippi. Additionally, two active monitors (Capitol and Port Allen) downwind of Oxbow have consistently low DVs, and given Oxbow's 46 km distance from the border, this evidence further indicates that these Baton Rouge area sources will not contribute to nonattainment of the standard in Texas.
? For the DeRidder Paper Mill, the small magnitude of the source's SO 2 emissions, the lack of other nearby sources, and wind rose data showing the lack of winds from the east, indicate that this source is not contributing to nonattainment of the NAAQS in Texas.
? For the Bogalusa Mill, extrapolation of PSD modeling predicts maximum impacts from the facility well below the standard, the small magnitude of the source's SO 2 emissions, lack of any other nearby sources, and wind rose data showing the lack of winds from the west, support the EPA's determination that this source is not contributing to nonattainment of the standard in Mississippi.
? Further there are SIP-approved and federal emissions control regulations within Louisiana that will continue to ensure that SO 2 emissions will be effectively controlled for existing and new sources or modifications.
Based on this evaluation, as more thoroughly discussed in our TSD for this action, the EPA proposes to find that sources within Louisiana will not significantly contribute to nonattainment of the 2010 1-hour SO 2 NAAQS in any other State.
2. EPA's Prong 2 Evaluation-Interference With Maintenance
[top] Prong 2 of the "good neighbor" provision requires State plans to prohibit emissions that will interfere with maintenance of a NAAQS in another State. The EPA's evaluation of whether Louisiana has met its Prong 2 transport obligations was accomplished by considering all available information, with a focus on current air quality data, SO 2 emissions trends for Louisiana and neighboring States, and how existing and future sources of SO 2 are addressed through existing SIP-approved and federally enforceable regulations. This evaluation builds upon the analysis
Based on the EPA's analysis, we propose to find that SO 2 levels in neighboring States near the Louisiana border do not indicate an inability to maintain the SO 2 NAAQS that could be attributed in part to sources in Louisiana, and as such the EPA proposes to determine that Louisiana's SIP satisfies the requirements of Prong 2 of CAA section 110(a)(2)(D)(i)(I). This determination is based on the following considerations:
• Current 2021-2023 DVs for SO 2 monitors in Louisiana within 50 km of another State's border and in neighboring States (Texas, Arkansas, and Mississippi) within 50 km of Louisiana's border are below the standard, indicating that these areas are all currently in attainment of the 2010 1-hour SO 2 NAAQS;
• State-wide emissions trends in Louisiana and surrounding States indicate generally declining SO 2 emissions and consequently ambient air concentrations in the relevant areas;
• Source-specific analyses show that facility-level emissions are decreasing as a result of emissions unit shutdowns and control technology installation, indicating that emissions are not anticipated to increase relative to baseline emissions;
• Current Louisiana statutes, SIP-approved measures, and federal emissions control programs control SO 2 emissions from certain sources within Louisiana; and
• Louisiana's SIP-approved PSD, major New Source Review (NSR) regulations and minor source NSR permit programs address future new and modified SO 2 sources above major and minor permitting thresholds with the intent of ensuring that the SO 2 NAAQS will not be exceeded as a result of new facility construction or existing facility modification within the State or in surrounding States.
Based on this evaluation, as more thoroughly discussed in our TSD for this action, the EPA proposes to find that sources within Louisiana will not interfere with maintenance of the 2010 1-hour SO 2 NAAQS in any other State.
IV. Proposed Action
The EPA is proposing to approve the Prong 1 and Prong 2 portions of the infrastructure SIP submission submitted by the State of Louisiana on June 4, 2013, addressing interstate transport for the 2010 1-hour SO 2 NAAQS. Based on the EPA's WOE analysis and as more thoroughly discussed in the TSD, the EPA proposes to determine that emissions from Louisiana will not contribute significantly to nonattainment in, or interfere with maintenance of, any other State with respect to the 2010 SO 2 NAAQS. We therefore propose to find that Louisiana's SIP contains adequate provisions consistent with CAA section 110(a)(2)(D)(i)(I).
V. 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. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in reviewing SIP submissions, the EPA's role is to approve State choices, provided that they meet the criteria of the CAA. Accordingly, this 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 action:
• Is not a significant regulatory action subject to review by the Office of Management and Budget under Executive Orders 12866 (58 FR 51735, October 4, 1993);
• 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 subject to Executive Order 13045 (62 FR 19885, April 23, 1997) because it approves a State program;
• Is not a significant regulatory action subject to Executive Order 13211 (66 FR 28355, May 22, 2001); and
• 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 Clean Air Act.
In addition, the SIP is not approved to apply on any Indian reservation land or in any other area where the EPA or an Indian Tribe has demonstrated that a Tribe has jurisdiction. In those areas of Indian country, the proposed rule does not have Tribal implications and will not impose substantial direct costs on Tribal governments or preempt Tribal law as specified by Executive Order 13175 (65 FR 67249, November 9, 2000).
List of Subjects in 40 CFR Part 52
Environmental protection, Air pollution control, Incorporation by reference, Intergovernmental relations, Sulfur dioxide, Reporting and recordkeeping requirements.
Authority:
42 U.S.C. 7401 et seq.
Dated: March 21, 2025.
Walter Mason,
Regional Administrator, Region 6.
[FR Doc. 2025-05927 Filed 4-8-25; 8:45 am]
BILLING CODE 6560-50-P