90 FR 116 pgs. 25923-25929 - Air Plan Approval; Texas; Interstate Transport Requirements for the 2010 SO
2
NAAQS
Type: PRORULEVolume: 90Number: 116Pages: 25923 - 25929
Pages: 25923, 25924, 25925, 25926, 25927, 25928, 25929Docket number: [EPA-R06-OAR-2013-0388; FRL-12796-01-R6]
FR document: [FR Doc. 2025-11270 Filed 6-17-25; 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-2013-0388; FRL-12796-01-R6]
Air Plan Approval; Texas; 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 Texas demonstrating that the State satisfies the interstate transport requirements, also known as the "good neighbor" provision of the Clean Air Act, 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 to 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 July 18, 2025.
ADDRESSES:
Submit your comments, identified by Docket ID No. EPA-R06-OAR-2013-0388, at https://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 https://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, telephone number: (214) 665-7222, email address: 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. Copyrighted materials are available for review in person at EPA Region 6 office located at 1201 Elm Street, Suite 500, Dallas, Texas 75270.
SUPPLEMENTARY INFORMATION:
Throughout this document wherever "we," "us," or "our" is used, we mean the EPA.
I. Background
A. Infrastructure SIPs
[top] On June 2, 2010, the EPA established a revised primary 1-hour SO 2 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 to 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. The EPA has long interpreted this language to enact a "functional prohibition" on certain emissions from upwind states, necessitating the EPA's independent assessment of 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 Texas 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 SO2 NAAQS Designations Background
In this proposed action, the EPA has considered information from the 2010 1-hour SO 2 NAAQS designations process which is discussed in more detail in section III.C. of this document. 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, particularly for a more source-specific pollutant such as SO 2 , EPA notes that designations themselves are not dispositive of whether upwind emissions are impacting areas in downwind states. 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 (August 8, 2011); Final Response to Petition from New Jersey Regarding SO 2 Emissions From the Portland Generating Station, 76 FR 69052 (November 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).
After the promulgation of a new or revised NAAQS, the EPA is required to designate areas as "nonattainment," "attainment," or "unclassifiable" pursuant to section 107(d)(1)-(2) of the CAA. The process for designating areas following promulgation of a new or revised NAAQS is contained in section 107(d) of the CAA. The CAA requires the EPA to complete the initial designations process within two years of promulgating a new or revised standard. If the Administrator has insufficient information to make these designations by that deadline, the EPA has the authority to extend the deadline for completing designations by up to one year.
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 EPA Administrator signed Federal Register documents for Round 2 designations? 7 on June 30, 2016 (81 FR 45039 (July 12, 2016)) and on November 29, 2016 (81 FR 89870 (December 13, 2016)). Round 3 designations? 8 were signed on December 21, 2017 (83 FR 1098 (January 9, 2018)) and March 28, 2018 (83 FR 14597(April 5, 2018)). Round 4 designations? 9 were signed on December 21, 2020 (86 FR 16055 (March 26, 2021))? 10 and April 8, 2021 (86 FR 19576 (April 14, 2021)). 11
Footnotes:
5 ?The term "round" in this instance refers to which "round of designations."
6 ?The EPA and state documents and public comments related to the Round 1 final designations are in the docket at https://www.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 ?The EPA and state documents and public comments related to the Round 2 final designations are in the docket at https://www.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 ?The EPA and state documents and public comments related to Round 3 final designations are in the docket at https://www.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 ?The EPA and state documents and public comments related to Round 4 final designations are in the docket at https://www.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.
[top] For Texas, the EPA designated Atascosa, Fort Bend, Goliad, Lamb, Limestone, McLennan, and Robertson Counties as unclassifiable/attainment and Potter County as unclassifiable in Round 2. Designations for Freestone, Anderson, Milam, Rusk, Gregg, Panola, and Titus counties were delayed. Final designations for these counties were published on December 13, 2016 (81 FR 89870). Nonattainment designations were promulgated for three areas: (1) portions of Freestone and Anderson Counties; (2) portions of Rusk and Panola Counties;? 12 and (3) a portion of Titus County. An unclassifiable designation was promulgated for Milam County. After these designations were promulgated, the EPA underwent additional actions related to the area designations in TX. By the time Round
Footnotes:
12 ?We note that on March 25. 2025, the Fifth Circuit Court of Appeals issued a decision in Texas, et al. v. EPA (No. 17-60088) vacating the Rusk/Panola nonattainment area designation-mandate effective on July 8, 2025. See https://www.ca5.uscourts.gov/opinions/pub/23/23-60069-CV1.pdf.
In Round 4 the EPA designated the remaining counties-Bexar, Jefferson Robertson, and Titus as attainment/unclassifiable; Harrison and Orange as unclassifiable; and Howard, Hutchinson, and Navarro as nonattainment.
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 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 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 analytical approach that examines potential impacts that are further from the source than would be examined for Pb transport but less regional in scope than ozone or PM 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 emissions 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. 13
Footnotes:
13 ?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).
As discussed in section III, and in further detail in the Technical Support Document (TSD) for this action, the EPA reviewed Texas' SO 2 SIP submittal, and the particular HYSPLIT back trajectories Texas relied upon in its SIP. The State's submission did not have sufficient information to fully assess whether Texas was meeting its CAA good neighbor requirements for the 2010 SO 2 NAAQS. Therefore, we elected to review and assess other available information regarding SO 2 emissions and air quality in Texas to assist in our own evaluation. We independently analyzed such information to determine whether Texas meets the interstate transport requirements described in the CAA. 14
Footnotes:
14 ?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 Texas and downwind states. Any such future action, such as area designations under any NAAQS, will be based on their own administrative records and the EPA's analyses of information that becomes 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 Texas and in neighboring states within 50 km of the Texas border. A WOE approach can be appropriate in instances, such as this case, to determine whether SO 2 emissions from Texas contribute to nonattainment or maintenance issues in adjoining states. A WOE analysis that is based solely 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 requirement is met.
In other SO 2 transport actions, the EPA has typically been able to use a WOE analysis 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 support the EPA's proposed determination that, under baseline conditions and likely future emissions scenarios, no Texas sources are contributing or will contribute to any out-of-state SO 2 nonattainment or maintenance concerns, and therefore it is not necessary for the 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. 15
Footnotes:
15 ? 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. Texas' SIP Submission and EPA's Analysis
A. State Submission
On April 23, 2013, the Texas Commission on Environmental Quality (TCEQ) 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), that addresses 2010 SO 2 interstate transport requirements Prongs 1 and 2.
[top] On January 11, 2016 (81 FR 1127), the EPA approved most elements of the Texas infrastructure SIP submittal, but we took no action on the interstate transport provisions of section 110(a)(2)(D)(i)(I) pertaining to Texas' significant contribution to nonattainment (Prong 1) and interference with maintenance (Prong 2) of the NAAQS in other states or the
In the portions of Texas' 2013 submittal addressing interstate transport (for section 110(a)(2)(D)(i)(I)), the State relied on the back trajectory analysis? 16 to assess the impacts of SO 2 emissions emitted in Texas and transported to neighboring states. Texas used the HYSPLIT? 17 model version 4 (2012) developed by the National Oceanic and Atmospheric Administration (NOAA) to construct back trajectories, where ambient air network monitors with the highest observed SO 2 values were chosen as receptor sites for the back trajectory analysis. The receptor sites that Texas chose for this analysis were a single monitor in each of the surrounding states, sites which were not necessarily sited to characterize high or maximum SO 2 concentrations (especially from large emitting SO 2 sources) reaching into other states to determine whether Texas meets the interstate transport requirement described in the CAA. Texas chose receptor locations for the HYSPLIT modeling that were very distant from Texas and the SO 2 sources within Texas.
Footnotes:
16 ?Back trajectory analysis involves tracing the path of an air parcel backward in time to understand its origin and how it has traveled. Back trajectory analysis uses meteorological data to simulate the path of an air parcel (a small volume of air) moving backward from a specific location and time to its origin.
17 ?HYSPLIT-Hybrid Single Particle Lagrangian Integrated Trajectory Model.
In the submittal, Texas acknowledged that the back trajectory analysis does not (and cannot) assume a link between a mean-trajectory path and an SO 2 concentration. A mean-trajectory-path provides only an indication/prediction of the direction (and locations over which) a parcel of air might have traveled and that more analysis would be needed to determine the sources and levels of contribution of air pollutants to a particular location. Texas also stated that the back trajectory HYSPLIT method quantifies the directions and frequency of air traveling to the monitor but cannot identify the precise routes of pollutant particle travel or its concentrations in the air parcels. 18
Footnotes:
18 ?See Chapter 2 of the State's submission in the docket for this rule making.
While HYSPLIT can be informative for evaluating air quality issues, the utility and accuracy of back trajectory analysis depends on the quality and resolution of the meteorological data used and should be coupled with other information on emissions data sources and ambient pollution levels near borders or across borders. Texas' submission neither evaluated SO 2 emissions levels or likely levels of contribution from Texas sources to the receptor locations it used for its HYSPLIT analysis, nor established that those receptor locations were adequate to ensure SO 2 nonattainment and maintenance issues in other states were properly identified. Therefore, the EPA elected to review and assess other available information, as described below and in more detail in the TSD for this action, regarding SO 2 emissions and air quality for sources in Texas to assist in our evaluation and to fully assess whether Texas was meeting its CAA good neighbor obligations for the 2010 SO 2 NAAQS.
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, 19 evaluating available information such as air quality, emission sources, modeling, and emission trends in Texas and the states that border Texas. To identify which sources and emissions activities in Texas 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)? 20 and Emissions Inventory System (EIS). 21 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:
19 ?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.
20 ?EPA's NEI is available at https://www.epa.gov/air-emissions-inventories/national-emissions-inventory.
21 ?The EIS Gateway was 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 Texas originate from point sources. In 2020, total SO 2 emissions from point sources in Texas comprised approximately 77 percent of the total SO 2 emissions in the State. Non-point sources, on road, and non-road emissions sources contribute to a much smaller portion of total SO 2 emissions; these emissions are also more dispersed throughout the State and are therefore unlikely to contribute to high ambient concentrations of SO 2 when compared to point source contributions. Further analysis? 22 shows that facilities with reported emissions greater than 100 tons per year (tpy) represent approximately 4 percent of the total number of Texas SO 2 point sources but are responsible for 184,480 tons of SO 2 or 96 percent of the total 2020 SO 2 emissions.23 Based on this analysis, the EPA focused our WOE analysis on SO 2 emissions from Texas' 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:
22 ? See EPA's TSD for a more detailed discussion.
| Category | 2020 Emissions (tpy) | Percent of total SO 2 emissions |
|---|---|---|
| Point | 192,372 | 77% |
| Nonpoint | 55,135 | 22 |
| On road | 865 | <1 |
| Nonroad | 66 | <1 |
| SO 2 Emissions Total | 248,438 | 100 |
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As described in this section, the EPA proposes that an assessment of Texas' 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 Texas' SO 2 point source emissions of more than 100 tpy of SO 2 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 Texas, and assessment of federal regulations and SIP-approved regulations affecting Texas' SO 2 sources. The EPA's evaluation is informed by all available data at the time of this rulemaking. 24
Footnotes:
24 ?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.
1. EPA's Prong 1 Evaluation-Contribute Significantly to Nonattainment
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? 25 of whether Texas has met its Prong 1 transport obligations was accomplished by considering all available information, including the following: SO 2 ambient air quality in Texas and neighboring states; SO 2 emissions trends for Texas and neighboring states; potential ambient impacts of SO 2 emissions from certain facilities? 26 in Texas on neighboring states; Texas' SIP-approved regulations specific to SO 2 emissions and permit requirements; and other SIP-approved or federally enforceable regulations which may reduce SO 2 emissions either directly or indirectly.
Footnotes:
25 ?A detailed review of the 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.
26 ?The physical properties of SO 2 result in relatively localized pollutant impacts very 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 concerns in the relevant areas in other states bordering Texas, and as such the EPA proposes to determine that Texas' 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 within 50 km of the Texas border recording violations of the 2010 SO 2 NAAQS, all these monitors have design values (DV)? 27 that are below the 75 ppb standard. Current DVs for Texas's AQS SO 2 monitors within 50 km of another State's border remained below the 2010 1-hour SO 2 NAAQS from 2019-2022, similarly, SO 2 monitors in neighboring states (Arkansas, Louisiana, New Mexico, and Oklahoma) within 50 km of Texas have 2023 DVs (2021-2023) below the 2010 1-hour SO 2 NAAQS;
Footnotes:
27 ?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 Texas and surrounding States (Arkansas, Louisiana, and Oklahoma), when considered with other factors discussed as part of EPA's WOE analysis, further support that Texas' sources will not significantly contribute to any State's nonattainment of the 2010 1-hour SO 2 NAAQS.
• Source-specific analyses of every Texas source emitting 100 tpy or more and located within 50 km of the state border indicate that the sources do not contribute to nonattainment in other states. These analyses draw upon available emissions data, monitoring data, air quality modeling, control requirements, unit retirement, 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 provides overall support for the EPA's proposed conclusion that SO 2 emissions from the following Texas areas are not likely to pose a transport concern.
Texas Northeast Region Sources
Evaluation of wind rose and monitoring data shows while monitors are located in the predominant wind direction from the largest sources in the area and in close proximity to these sources, these monitors are not measuring violations. In addition, wind roses indicate winds in the area infrequently blow towards LA. The presence of monitors near to the source in the direction of the predominant winds that are not measuring violations indicates that these sources will not cause a violation further away, across state lines. Finally, there are no large sources in the neighboring states near the state lines in which emissions could interact in such a way that Texas sources would be contributing to a violation.
Texas Southeast Region Sources
Orange area: There is currently one operating source in this area, the Orion Orange Carbon Black Plant. The Orange monitor was located to characterize the emissions from this source and has consistently been in attainment with low DVs. In addition, wind-patterns are predominantly from the south, not toward the Louisiana state line. The low concentrations at the monitor and the predominant wind direction indicate that this source will not cause a violation in Louisiana. In addition, the nearest large sources in Louisiana are 34 km to the east, making it unlikely that this source would contribute to nonattainment in Louisiana. There is another source that was evaluated, the International Paper Orange Mill, which shut down in 2023. This source has fewer emissions than the Orion facility and is slightly further from the state line indicating that were it operating it would be less likely to cause or contribute to nonattainment.
Beaumont area: There are two sources in this area, the ExxonMobil refinery and the Arkema Beaumont Plant. The Beaumont monitor is positioned to the south of these facilities and has consistently been in attainment, with DVs well below the NAAQS. Wind patterns suggest emissions are likely to remain localized, and the distance of these sources from the border indicate these sources do not pose a transport concern.
[top] Port Arthur area: We evaluated four sources in this far southeastern portion of the state for impacts in Louisiana: Total refinery, Motiva refinery, Valero Refinery and Oxbow Calcining. The monitors in the vicinity of these sources all have DVs below the NAAQS. The Port Arthur, West 7th monitor, in particular, is a DRR monitor which was located to characterize impacts from Oxbow. The lack of measured violations in the vicinity of the facilities and the predominant wind patterns (not frequently blowing toward Louisiana) indicate that these sources are not causing violations in Louisiana. In addition, the nearest large sources in Louisiana are 59 km away in the Lake Charles area. Because of this long distance, Texas sources would not be expected to contribute to nonattainment
Wichita County Sources
There are two sources in the area of Wichita Falls: Works 4 Glass Plant and Shepherd Air Force Base. Based on the topography, the relatively low emissions of the two sources, and distance to the state line, the EPA proposes to find these sources do not cause nonattainment in Oklahoma. In addition, there are no nearby emission sources in Oklahoma that emissions from Texas could potentially interact with to contribute to nonattainment in Oklahoma.
Northwest Region Sources
We evaluated seven (7) sources in this portion of Texas bordering southeastern New Mexico. For the three largest sources, modeling was available either under the DRR or through permitting actions which indicated impacts in New Mexico would not contribute to nonattainment. For the remaining sources, the lower reported emissions, distance from New Mexico, absence of SO 2 sources greater than 100 tpy in the immediate area of the Texas-New Mexico border, coupled with topographical and wind features of the area indicate these sources do not pose a transport concern.
Based on this evaluation, as more thoroughly discussed in our TSD for this action, EPA proposes to find that sources within Texas 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
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 Texas 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 Texas 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 conducted for significant contribution to nonattainment (Prong 1), which evaluated SO 2 ambient air quality in Texas and neighboring states and potential ambient impacts of SO 2 emissions from certain facilities in Texas on neighboring states.
Based on the EPA's analysis, we propose to find that SO 2 levels near the Texas border in neighboring states do not indicate an inability to maintain the 2010 SO 2 NAAQS that could be attributed in part to sources in Texas, and as such, the EPA proposes to determine that Texas' SIP submittal 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 monitors in Texas within 50 km of another state's border and in neighboring states (Arkansas, Louisiana, New Mexico, and Oklahoma) within 50 km of Texas' border are below the standard, indicating that these areas are currently in attainment of the 2010 1-hour SO 2 NAAQS;
• State-wide emissions trends in Texas indicate generally declining SO 2 emissions and consequently declining impacts to 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 Texas statutes, SIP-approved measures, and federal emissions control programs control SO 2 emissions from certain sources with Texas; and
• Texas' SIP-approved PSD, major New Source Review (NSR) regulations and minor source NSR permit programs address future and new 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 surrounding states.
Based on the evaluation outlined in our TSD for this action, the EPA proposes to find that SO 2 emissions from Texas 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 remaining portions of Texas' April 23, 2013, SIP submittal addressing interstate transport for the 2010 1-hour SO 2 NAAQS. Based on the EPA's WOE analysis, more thoroughly discussed in the TSD, the EPA proposes to determine that emissions from Texas will not contribute significantly to nonattainment in, or interfere with maintenance of, any other state with respect to the 2010 1-hr SO 2 NAAQS. We therefore propose to find that Texas' 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);
• Is not subject to Executive Order 14192 (90 FR 9065, February 6, 2025) because SIP actions are exempt from review under Executive Order 12866;
• 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 CAA.
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).
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List of Subjects in 40 CFR Part 52
Environmental protection, Air pollution control, Incorporation by reference, Reporting and recordkeeping requirements, Sulfur dioxide.
Authority:
42 U.S.C. 7401 et seq.
Dated: June 5, 2025.
Walter Mason,
Regional Administrator, Region 6.
[FR Doc. 2025-11270 Filed 6-17-25; 8:45 am]
BILLING CODE 6560-50-P