90 FR 88 pgs. 19437-19447 - Air Plan Approval; Louisiana; Nonattainment Plan for the Evangeline Parish 2010 Sulfur Dioxide Primary National Ambient Air Quality Standard Nonattainment Area
Type: PRORULEVolume: 90Number: 88Pages: 19437 - 19447
Pages: 19437, 19438, 19439, 19440, 19441, 19442, 19443, 19444, 19445, 19446, 19447Docket number: [EPA-R06-OAR-2025-0173; FRL-12753-01-R6]
FR document: [FR Doc. 2025-08080 Filed 5-7-25; 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-2025-0173; FRL-12753-01-R6]
Air Plan Approval; Louisiana; Nonattainment Plan for the Evangeline Parish 2010 Sulfur Dioxide Primary National Ambient Air Quality Standard Nonattainment Area
AGENCY:
Environmental Protection Agency (EPA).
ACTION:
Proposed rule.
SUMMARY:
The Environmental Protection Agency (EPA) is proposing to approve Louisiana's State Implementation Plan (SIP) revision submitted to EPA on April 2, 2025, for the Evangeline Parish 2010 1-hour sulfur dioxide (SO 2 ) primary national ambient air quality standard (NAAQS) nonattainment area. EPA is proposing approval of the following Clean Air Act (CAA) SIP elements: The attainment demonstration for the SO 2 NAAQS, which includes an Agreed Order on Consent (AOC) for the Cabot Corporation's Ville Platte Plant (Cabot) facility; the reasonable further progress (RFP) plan; the reasonably available control measures (RACM) and reasonably available control technology (RACT) demonstration; the emission inventories; and the contingency measures. The State has demonstrated that its current Nonattainment New Source Review (NNSR) program covers this NAAQS; therefore, no revision to the SIP is required for the NNSR element.
DATES:
Comments must be received on or before June 9, 2025.
ADDRESSES:
Submit your comments, identified by Docket No. EPA-R06-OAR-2025-0173, 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 Andrew Lee, 214-665-6750, lee.andrew.c@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:
Andrew Lee, EPA Region 6 Office, Ozone and Infrastructure Section, 214-665-6750, lee.andrew.c@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 whenever "we," "us," or "our" is used, we mean EPA.
Table of Contents
I. Background
A. Evangeline Parish SO 2 Nonattainment Area
B. Requirements for SO 2 Nonattainment Area Plans
C. Attainment Demonstration Requirements for SO 2 Nonattainment Area Plans
II. Review of Modeled Attainment Plan
A. Model Selection and General Model Inputs
B. Meteorological Data
C. Emissions Data
D. Receptor Grid
E. Emission Limits
F. Background Concentrations
G. Summary of Results
III. Review of Other Plan Requirements
A. Emissions Inventory
B. RACM/RACT
[top] C. New Source Review (NSR)
D. Reasonable Further Progress (RFP)
E. Contingency Measures
F. Conformity
IV. Proposed Action
V. Incorporation by Reference
VI. Statutory and Executive Order Reviews
I. Background
A. Evangeline Parish SO 2 Nonattainment Area
On June 22, 2010, the EPA published a new 1-hour primary SO 2 NAAQS of 75 parts per billion (ppb), which is met at an ambient air quality monitoring site (or in the case of dispersion modeling, at an ambient air quality receptor location) when the 3-year average of the annual 99th percentile of 1-hour daily maximum concentrations does not exceed 75 ppb, as determined in accordance with appendix T of 40 CFR part 50. 1 On December 21, 2017, the EPA designated a portion of Evangeline Parish, Louisiana as nonattainment for the SO 2 NAAQS, effective April 9, 2018. 2 The EPA based the nonattainment designation on modeling for the 2013-2015 period submitted by the State, which demonstrated that the area violated the NAAQS with a modeled design value of 106 ppb. The primary source of SO 2 emissions in the area is the Cabot facility which manufactures various grades of carbon black for use in various industrial applications such as the production of rubber products.
Footnotes:
1 ? See 75 Federal Register (FR) 35520. See also 40 Code of Federal Regulations (CFR) 50.17(a) and (b).
2 ? See 83 FR 1098.
Section 191 of the CAA directs Louisiana to submit a SIP for the Evangeline Parish area within 18 months of the effective date of the designation, i.e., by no later than October 9, 2019. Under CAA section 192, Louisiana's SIP must demonstrate that Evangeline Parish will attain the NAAQS as expeditiously as practicable, but no later than 5 years from the effective date of designation, i.e., April 9, 2023. On November 3, 2020, the EPA issued a final action of Finding of Failure to Submit a SIP Required for Attainment of the 2010 1-Hour Primary SO 2 NAAQS for Evangeline Parish. 3 This finding triggers certain CAA deadlines for the EPA to impose mandatory emission offsets and highway funding sanctions, unless and until the State submits a SIP revision satisfying the CAA's completeness criteria. Additionally, this finding triggered the CAA section 110(c) requirement for EPA to promulgate a Federal implementation plan (FIP) within two years of the finding unless the State submits and obtains EPA approval of a SIP revision which corrects the deficiency before EPA promulgates a FIP.
Footnotes:
3 ? See 85 FR 69504, November 3, 2020.
On December 16, 2024, the EPA published the finding that the Evangeline Parish area failed to attain the 2010 SO 2 NAAQS by the April 9, 2023, CAA attainment date. 4 The determination was based upon evaluation of SO 2 emissions data and prior modeling for the area. EPA found that emissions increased when comparing the 2020-2022 period to the prior modeled emissions (2013-2015) underlying the EPA's nonattainment designation. Under section 179(d) of the CAA, following the finding of failure to attain by the attainment date, Louisiana shall submit a SIP revision by December 16, 2025, that provides for attainment of the NAAQS as expeditiously as practicable, but no later than December 16, 2029.
Footnotes:
4 ? See 89 FR 101475, April 9, 2023.
On April 2, 2025, Louisiana submitted the Evangeline Parish nonattainment SIP revision to the EPA. The SIP revision includes a newly established Administrative Order on Consent (AOC) containing the enforceable control strategy which is incorporated into the attainment demonstration (AD) for Evangeline Parish. This SIP revision contemplated in this proposed approval fulfills the SIP submittal requirement imposed by both CAA sections 191(a) and 179(d).
B. Requirements for SO 2 Nonattainment Area Plans
SO 2 Nonattainment area SIPs must meet the applicable requirements of CAA sections 110, 172, 191, and 192. The EPA's regulations governing nonattainment area SIPs are set forth at 40 CFR part 51, with specific procedural requirements and control strategy requirements found at subparts F and G, respectively. Soon after Congress enacted the 1990 Amendments to the CAA, the EPA issued comprehensive guidance on SIPs, in a document entitled the "General Preamble for the Implementation of Title I of the Clean Air Act amendments of 1990," published at 57 FR 13498 (April 16, 1992) (General Preamble). Among other things, the General Preamble addressed SO 2 SIPs and fundamental principles for SIP control strategies. Id., at 13545-49, 13567-68. On April 23, 2014, the EPA issued additional guidance for meeting the statutory requirements in SO 2 SIPs in a document titled, "Guidance for 1-Hour SO 2 Nonattainment Area SIP Submissions" (April 2014 SO 2 Guidance). 5 In this guidance, the EPA describes how a nonattainment area SIP can satisfy the following CAA requirements: an accurate emissions inventory of current emissions for all sources of SO 2 within the nonattainment area, an AD, RFP, RACM, (including RACT), NNSR program, enforceable emissions limitations and control measures, and adequate contingency measures for the affected area. 6
Footnotes:
5 ?"Guidance for 1-Hour SO 2 Nonattainment Area SIP Submissions" available at: https://www.epa.gov/sites/production/files/2016-06/documents/20140423guidance_nonattainment_sip.pdf.
6 ? See section V. of "Guidance for 1-Hour SO 2 Nonattainment Area SIP Submissions".
Under CAA sections 110(l) and 193, the EPA may not approve a SIP revision that would interfere with any applicable requirement concerning NAAQS attainment and RFP, or any other applicable requirement under the Act.
C. Attainment Demonstration Requirements for SO 2 Nonattainment Area Plans
CAA section 172(c)(1) requires a SIP to provide for attainment of the NAAQS. 40 CFR part 51, subpart G further delineates the control strategy requirements that SIPs must meet. Generally, SO 2 ADs consist of two components: (1) emission limits and other control measures that assure implementation of permanent, enforceable, and necessary emission controls and (2) a modeling analysis which demonstrates that the emission limits and control measures provide for attainment as expeditiously as practicable, but no later than the attainment date, and meet the requirements of 40 CFR part 51, appendix W ( Guideline on Air Quality Models ) and other EPA guidance.
[top] In all cases, the emission limits and control measures must be accompanied by appropriate methods and conditions to determine compliance. As discussed in the General Preamble, the emission limits and control measures should be quantifiable ( i.e., a specific amount of emission reduction can be ascribed to the measures), fully enforceable (specifying clear, unambiguous and measurable requirements for which compliance can be practicably determined), replicable (the procedures for determining compliance are sufficiently specific and non-subjective so that two independent entities applying the procedures would obtain the same result), and accountable (source specific limits must be permanent and must reflect the
Footnotes:
7 ? See published in the Federal Register at 57 FR 13498 (April 16,1992) at 13567-68.
40 CFR 51.112(a)(1) states that all applications of air quality modeling shall be based on the applicable models specified in the Guideline on Air Quality Models (Modeling Guideline). Appendix A to the Guideline on Air Quality Models delineates the EPA's preferred models and other recommended techniques, as well as guidance for their use in estimating ambient concentrations of air pollutants. 8?9? In 2005, based on extensive developmental and performance evaluation, the EPA promulgated AERMOD as the Agency's preferred near-field dispersion modeling for a wide range of regulatory applications addressing stationary sources ( e.g., for estimating SO 2 concentrations) in all types of terrain. 10
Footnotes:
8 ? See 80 FR 45340 (July 29, 2015).
9 ?The EPA published revisions to the Guideline on Air Quality Models on January 17, 2017, ( see 82 FR 5182) and on November 29, 2024 ( see 89 FR 95034).
10 ? See 70 FR 68218 (November 9, 2005).
The Modeling Guideline is periodically updated with the latest recommended techniques and guidance for usage, with the applicable requirements being those in effect at the time the modeling was completed. The version of the Modeling Guideline in effect at the time Louisiana developed its SIP was adopted in a Federal Register action on January 17, 2017, effective May 22, 2017. 11
Footnotes:
11 ? See 82 FR 5182 (January 17, 2017). The Modeling Guideline has since been revised effective March 21, 2025. See 89 FR 95034 (November 29, 2024). See also https://www.epa.gov/scram/2024-appendix-w-final-rule.
Based on and consistent with the Modeling Guideline's requirements, EPA has issued supplemental guidance on modeling for purposes of demonstrating attainment of the 2010 SO 2 NAAQS in its April 2014 SO 2 Guidance titled "Appendix A. Modeling Guidance for Nonattainment Areas" (April 2014 SO 2 Guidance Appendix A). The April 2014 SO 2 Guidance Appendix A provides specific SO 2 modeling guidance on the modeling domain, the source inputs, assorted types of meteorological data, and background concentrations.
As stated previously, ADs for the 2010 SO 2 NAAQS should demonstrate attainment of the NAAQS in the entire area designated as nonattainment ( i.e., not just at the violating monitor) by using air quality dispersion modeling to show that the mix of sources, control measures, and emission rates in an area will not lead to a violation of the SO 2 NAAQS. 12 For a short-term ( i.e., 1-hour) standard, the EPA has stated that dispersion modeling, using allowable emissions and addressing stationary sources in the area (and in some cases those sources located outside the nonattainment area which may affect attainment in the area) is technically appropriate, efficient, and effective in demonstrating attainment Dispersion modeling takes into consideration combinations of meteorological and emission source operating conditions that may contribute to peak ground-level concentrations of SO 2. Estimated concentrations should include ambient background concentrations, should follow the form of the standard, and should be calculated as described in section 2.6.1.2 of the August 23, 2010, clarification memo on "Applicability of Appendix W Modeling Guidance for the 1-hr SO 2 National Ambient Air Quality Standard."? 13
Footnotes:
12 ?April 2014 SO 2 Guidance pages 11-12.
13 ? See https://www3.epa.gov/ttn/naaqs/aqmguide/collection/cp2/20100823_page_1-hr_so2_naaqs_psd_program.pdf.
II. Review of Modeled Attainment Plan
This section discusses the EPA's review and analysis of the modeled attainment plan, including model selection and general model inputs, meteorological data, emissions data, receptor grid, emissions limits, and background concentrations. A complete, detailed discussion of the modeling requirements and our analysis is presented in the technical support document (TSD) contained in the public docket for this proposed action.
A. Model Selection and General Model Inputs
Louisiana's AD modeling conducted by Trinity Consultants, Inc. (TCI), on behalf of Cabot, used EPA's regulatory dispersion model, AERMOD, to determine the SO 2 emission reductions needed to bring the Evangeline Parish area into attainment. TCI relied upon AERMOD Version 23132 and the companion AERMOD User Guide (EPA, October 2023) documentation in developing this AD, as it was the most recent EPA approved version of AERMOD at the time the work was conducted. Regulatory default options were specified in developing the AD that are consistent with established practices for use of AERMOD in determining NAAQS compliance for SIP revisions. Included among those default options are stack tip downwash, buoyancy induced dispersion, default wind profile coefficients, default vertical potential temperature gradients, and final plume rise. EPA finds these selections appropriate.
The most significant source, and only point source, addressed in the modeling for the area is Cabot. This facility is the principal cause of the modeled violations in the area. At the location of highest concentrations modeled in the area, the Cabot facility contributed more than 99% in total to the modeled violations. The modeling techniques used for this source are discussed later in this section.
The selection of terrain data corresponds to the geographic area represented by the Evangeline Parish nonattainment area, as well as the locations of buildings and structures nearby the source that influence concentrations in the area. TCI generated the necessary terrain inputs for AERMAP using U.S. Geological Survey (USGS) National Elevation Dataset (NED). Elevations from the NED data were determined for all sources and structures, and both elevations and representative hill heights were determined for receptors.
A detailed site characterization of the Cabot facility provided dimensional and locational data for structures and stacks necessary for addressing building-induced plume downwash. TCI used the EPA's Building Profile Input Program with PRIME algorithm (BPIPPRM, dated 04274) to generate direction-specific building parameters for modeling building wake effects through the assistance of TCI's BREEZE® software that fully incorporates the EPA sanctioned BPIPPRM. The location and height of each stack to be evaluated and those of nearby structures were processed in BPIPPRM to produce the building downwash parameters required by AERMOD.
The Cabot facility has four main production units, VP-1 through VP-4 (Units 1 through 4). During normal operations, all four units feed into the MAIN stack which will be installed with a wet gas scrubber pollution control device. When the MAIN stack and emission controls are undergoing scheduled maintenance, the Cabot facility will rely on its existing unit specific stacks that are monitored with the existing Predictive Emissions Monitoring System (PEMS). VP-3 (Unit 3) has its own flare stack (SFLR3) and dryer stack (SDRY3). VP-4 (Unit 4) has its own flare stack (SFLR4) whereas VP-1 and VP-2 uses a combined flare (SFLR12). VP-1, VP-2, and VP-4 use a combined dryer stack (SDRY124).
[top] TCI used site specific building and stack data to model all stacks in the Cabot facility at the lesser of actual stack height or Good Engineering Practice
B. Meteorological Data
In accordance with the Modeling Guideline and EPA's guidance cited previously, meteorological data must be selected from a nearby and representative source and adequately processed for use in AERMOD. The State's modeling relied on the most recent five years (2016-2021)? 14 of surface meteorological and coincident upper air data that was available at the time from the national weather service (NWS) Lake Charles Regional Airport meteorological station (WBAN No. 03937) (Lake Charles Station) to generate the necessary meteorological inputs for use in AERMOD. The Lake Charles station is the closest station to Cabot and was therefore selected as the most representative of meteorological conditions within the area of analysis due to proximity, similar terrain, and availability of recently collected data. TCI processed the surface and upper air data using the appropriate versions of AERMINUTE, AERSURFACE, and AERMET meteorological processing tools. AERMINUTE was used to process NOAA's 1-minute ASOS data, AERSURFACE was used to generate the surface characteristic values for the met station, and then AERMET used those files to generate meteorological data files for AERMOD.
Footnotes:
14 ?The 2020 meteorological data for Lake Charles Regional Airport do not meet U.S. EPA's data requirement for 90% completeness by quarter for wind direction, wind speed, and temperature. As such, 2020 was excluded from meteorological data calculations, leaving the five years of 2016-19 and 2021. See Table 2-2 of TCI's Modeling Report for a report of missing met data by year and quarter.
The Lake Charles station meets the EPA's criteria as being nearby and representative. The EPA also finds that TCI adequately processed the upper air and surface air data from the Lake Charles station in accordance with the Modeling Guideline and the EPA's AERMOD Implementation Guide? 15 to generate the necessary meteorological data to be used in the AERMOD model runs. Therefore, the EPA is proposing to find the selection and processing of these data acceptable.
Footnotes:
15 ? See November 2024 AERMOD implementation guide. This modeling project was completed prior to this version of the Guide, but the updates do not affect how AERMOD or its preprocessors function for this specific project. See https://gaftp.epa.gov/Air/aqmg/SCRAM/models/preferred/aermod/aermod_implementation_guide.pdf.
C. Emissions Data
The primary source contributing to modeled violations in the nonattainment area is the Cabot facility. This SIP revision includes an emission inventory for SO 2 sources that found that the Cabot facility is the only point source located within the Evangeline Parish nonattainment area and there are no major source SO 2 facilities within 50 miles of Cabot. Furthermore, there are no nearby sources outside the nonattainment area that could impact the concentration gradient created by the Cabot facility. The impacts of SO 2 emissions from non-point sources, for example mobile emissions, incineration, agricultural field burning, etc., were not explicitly modeled in AERMOD but instead represented via monitored background data.
The plant has four carbon black production units: VP-1 through VP-4. VP-3 has its own flare stack (SFLR3) and dryer stack (SDRY3). VP-4 has its own flare stack (SFLR4) whereas VP-1 and VP-2 have a combined flare stack (SFLR12). VP-1, VP-2, and VP-4 have a combined dryer stack (SDRY124). As discussed elsewhere, during normal operations, emissions from VP-1 through VP-4 will be routed through emission controls and the MAIN stack. Hence, there are six major emissions points of SO 2 at the Cabot facility: MAIN stack, SFLR3 flare stack, SDRY3 dryer stack, SFLR4 flare stack, SFLR12 flare stack, and SDRY124 dryer stack. Furthermore, there are several minor sources of SO 2 at the Cabot facility that were also accounted for in the State's modeling: sampling units (EQT 0041), plant-wide fugitive emissions (FUG 001), and unit process filters (EQT 0005, EQT 0007, EQT 0030, EQT 0032). LDEQ's previous modeling, submitted for EPA's designation of the area, showed that Cabot was the principal contributor to the highest modeled violations. 16
Footnotes:
16 ? See https://www.epa.gov/sites/default/files/2017-08/documents/16_la_so2_rd3-final.pdf.
The SIP's AD modeling covers operating scenarios with emissions through the wet gas scrubber (WGS) and MAIN stack as well as a number of operating scenarios for maintenance periods with emissions through the flare and dryer stacks. This approach enabled the determination of emission rates for each operating scenario that were shown through the modeling to be consistent with attainment of the NAAQS. EPA's review and analysis of the SIP revision's emissions limits and operating parameters for the facility can be found in section II, E. Emission Limits , of this document.
Additional details and evaluation of the emissions data utilized in the AD are provided in our accompanying TSD and TCI's Modeling Report.
D. Receptor Grid
Within AERMOD, air quality concentration results are calculated at discrete locations identified by the user; these locations are called receptors. TCI's modeling domain for this demonstration consisted of four nested receptor grids which increase in spacing as the receptors increase in distance from Cabot. The inner most grid consists of a circle approximately centered upon the location of Cabot's new MAIN stack, extending outward to one kilometer from the facility center filled with a gridded receptor array at 25-meter intervals. This 25-meter spaced grid also includes receptors on the property fence line, on the public road that bisects the plant, and the adjacent railway. The second grid consists of 100-meter spaced receptors filling the space between 1-kilometer and 2-kilometer circles. The third grid from the center extends from 2 to 5 km with receptors spaced 200 meters apart. The outermost rectangular grid (also trimmed to the shape of a circle) extends from 5 kilometers from the Cabot facility to 10 kilometers with receptors placed every 500 meters. Receptors were excluded within the boundary of the Cabot facility which is considered non-ambient air relative to its own emissions. The modeling domain and receptor network are sufficient to identify maximum impacts from the modeled sources, and detect significant concentration gradients, and are adequate for demonstrating attainment in the nonattainment area and the surrounding area.
E. Emission Limits
[top] An important aspect of a SIP is that the emission limits providing for attainment be quantifiable, fully enforceable, replicable, and accountable. See published in the Federal Register at 57 FR 13498 (April 16, 1992) at 13567-68. This SIP revision incorporates an Administrative Order on Consent (AOC) between LDEQ and Cabot. The AOC prescribes the emissions limits and operating parameters, among other requirements, for the emissions stacks and small sources associated with the four carbon black production units (VP-1 through VP-4) which are reflected in the modeling demonstration. Cabot's operations fall under two categories: Category 1-Series of operational scenarios for planned turnaround (every fifth year) and yearly planned outages of
In 2013, EPA and Louisiana entered into consent decrees with select carbon black facilities, including Cabot, in Louisiana for violations of the Prevention of Significant Deteriorations provision of the CAA. 17 As part of the EPA's Carbon Black Consent Decrees (CD), Cabot's Ville Platte plant in Evangeline Parish and others agreed (with Louisiana as an intervenor) to the installation of a wet gas scrubber pollution control system (WGS) that reduces SO 2 emission by at least 95 percent. Another requirement of the CD was to limit the use of flares at these facilities to periods when the control device is under maintenance, and to limit the hours of this planned maintenance. These CD requirements are reflected in the emission limits submitted in this SIP.
Footnotes:
17 ? See Appendix C: Cabot Corporation Consent Decree of LDEQ's SIP submittal.
Category 1: Planned turnaround (every fifth year) and yearly planned outages: Planned turnaround includes scheduled downtime for maintenance, repairs, and upgrades that can last up to 744 hours and occur every five (5) years). Yearly planned outages occur in years when turnarounds are not scheduled and can last up to 168 hours. During both periods, the WGS and MAIN stack (through which the WGS exhausts to atmosphere) are not operational. In lieu of being routed to the MAIN stack, emissions from the VP-1 and VP-2 are routed through SFLR12 flare and SDRY124 dryer stack, VP-3 emissions are routed through SFLR3 flare and SDRY3 dryer stack, and VP-4 emissions are routed through SFLR4 flare and SDRY124 dryer stack.
In situations where a flare becomes inoperable, the facility must cease feeding the carbon black feedstock to the associated carbon black production unit. Under category 1, there are five different operating scenarios allowed depending on the number of units operating, operating capacity and the feedstock selected. During Category 1 operations, when units VP-1 through VP-4 are transitioning from cold start to steady state operations, startup of the emission units shall be conducted in accordance with the sequence of operations in Table 1 of this document. No two units will simultaneously undergo startup. Table 2 provides the different operating scenarios that are allowed during Category 1 planned outage and turnaround periods along with the associated operating units and maximum sulfur feedstock allowed during each such scenario. Table 3 provides the maximum emission limit of each stack associated with each operating scenario in Category 1. Table 3 establishes emission rates for the next-to-last-step (worst case hours) and separate emission rates when all emission units are steady state. The next-to-last-step emission rates are higher due to the transitional state of the last unit in startup mode, where burners may be sputtering or not staying lit in transitional state but are firing consistently and uniformly in steady state.
Category 2: Normal Operations: Category 2 is defined as times when the WGS is fully operational with emissions routed through the WGS before being released to the atmosphere through the MAIN stack. During periods of normal operations, emissions from units VP-1 through VP-4 must be routed through the WGS and then out of the MAIN stack. Table 2 provides the maximum sulfur feedstock allowed during Category 2 normal operations, and Table 3 provides the allowable emission rate limits during Category 2 operations.
Operating Scenarios and Associated Emissions Limits: the operating parameters of the individual point sources of SO 2 for the crucial processes at the Cabot facility and the emission limitations are detailed in Tables 1 through 3 and described briefly here. During periods of planned outage/turnaround (in Category 1 operations) startup of emission units VP-1 through VP-4 shall be conducted in accordance with the sequence of operations in Table 1. Table 1 identifies the specific steps that are followed to bring the units up to production mode status. Each unit startup has two phases-transitional and steady-state. See the Category 1 description above for further explanation of transitional and steady state. Table 2 lists all allowable operating scenarios, including Category 2 operations, with the sulfur feedstock and capacity restrictions that the facility may operate under. The combination of Tables 1 and 2 are provided in TCI's Modeling Report (Tables 2-6 through 2-17) where each scenario with each step's emissions is identified. For example, under Table 2, Scenario 4, all dryers and flare stacks are emitting, but Scenario 1C of Table 2 has only one flare and one dryer stack operating, consistent with operating only VP-3. Table 3 was derived to identify the emission limits for each stack by which the facility must abide under each operating category and scenario. Continuing with our example, Table 3 lists the emission limits for each dryer and flare stack operating under Scenario 4 and Scenario 1C. For more details on these emissions allocations, see the Scenario Specific Emission Rates section of the TCI's Modeling Report, p2-11 through 2-20, especially Tables 2-6 through 2-17.
Footnotes:
18 ?Cabot will start the units in the following order only: VP-4 will always be started first, followed by VP-1 and/or VP-2. VP-3 will always be started last. For scenarios that have fewer units operational, the same order (after excluding non-operational units) will be maintained.
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| Step | Action | |||
| 1 | Check emergency systems. All four process units (VP-1 through VP-4) are off. | |||
| 2 | All units warm up. | |||
| 3 | Purge gas header system. | |||
| 4 | Light dryers, purge filters. | |||
| 5 | First Unit transitional i.e., any one of VP-1 through VP-4, depending on scenario? 18 | Second Unit is off | Third Unit is off | Fourth Unit is off. |
| 6 | First Unit Steady State | Second Unit is off | Third Unit is off | Fourth Unit is off. |
| 7 | First Unit Steady State | Second Unit Transitional | Third Unit is off | Fourth Unit is off. |
| 8 | First Unit Steady State | Second Unit Steady State | Third Unit is off | Fourth Unit is off. |
| 9 | First Unit Steady State | Second Unit Steady State | Third Unit Transitional | Fourth Unit is off. |
| 10 | First Unit Steady State | Second Unit Steady State | Third Unit Steady State | Fourth Unit is off. |
| 11 | First Unit Steady State | Second Unit Steady State | Third Unit Steady State | Fourth Unit Transitional. |
| 12 | First Unit Steady State | Second Unit Steady State | Third Unit Steady State | Fourth Unit Steady State. |
| Scenario | Description | Maximum sulfur feedstock (%) | |||
| Category 1 | 1A | 4.0% Sulfur Feedstock with VP-1 (SFLR12 and SDRY124) Operational at Normal Capacity | 4.00 | ||
| Category 1 | 1B | 4.0% Sulfur Feedstock with VP-2 (SFLR12 and SDRY124) Operational at Normal Capacity | 4.00 | ||
| Category 1 | 1C | 3.5% Sulfur Feedstock with VP-3 (SFLR3 and SDRY3) Operational at Normal Capacity | 3.50 | ||
| Category 1 | 1D | 4.0% Sulfur Feedstock with VP-4 (SFLR4 and SDRY124) Operational at Normal Capacity | 4.00 | ||
| Category 1 | 2 | 3.5% Sulfur Feedstock with all Flares and Dryers Operational at Normal Capacity except for VP-3 | 3.50 | ||
| Category 1 | 3A | 2.5% Sulfur Feedstock with VP-3 and VP-1 Operational at Normal Capacity | 2.50 | ||
| Category1 | 3B | 2.5% Sulfur Feedstock with VP-3 and VP-2 Operational at Normal Capacity | 2.50 | ||
| Category 1 | 3C | 2.5% Sulfur Feedstock with VP-3 and VP-4 Operational at Normal Capacity | 2.50 | ||
| Category 1 | 44 | 2.3% Sulfur Feedstock with all Units Operational at Reduced Capacity | 2.30 | ||
| Category 1 | 55 | 2.00% Sulfur Feedstock with all Units Operational at Normal Capacity | 2.00 | ||
| Category 2 | 66 | MAIN (WGS Operational for all hours) | 4.00 | ||
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| Category | Source stack | Scenario | Maximum % sulfur | Capacity | Emission rates for the next-to-last-step (worst case hour-transition) | lb/hr | Emission rates for the last step (all units in steady state) | lb/hr |
|---|---|---|---|---|---|---|---|---|
| 1 | SDRY3 | 1C | 3.5 | Normal | 409 | 192.2 | ||
| 3A | 2.5 | Normal | 275 | 129.2 | ||||
| 3B | 2.5 | Normal | 275 | 129.2 | ||||
| 3C | 2.5 | Normal | 275 | 129.2 | ||||
| 4 | 2.3 | Reduced | 168.9 | 79.3 | ||||
| 5 | 2.0 | Normal | 210.4 | 98.8 | ||||
| SDRY124 | 1A | 4.0 | Normal | 501.3 | 387.1 | |||
| 1B | 4.0 | Normal | 674.7 | 528.8 | ||||
| 1D | 4.0 | Normal | 500.3 | 316.2 | ||||
| 2 | 3.5 | Normal | 1,058.5 | 910.3 | ||||
| 3A | 2.5 | Normal | 219.7 | 219.7 | ||||
| 3B | 2.5 | Normal | 301.8 | 301.8 | ||||
| 3C | 2.5 | Normal | 186.1 | 186.1 | ||||
| 4 | 2.3 | Reduced | 413 | 413 | ||||
| 5 | 2.0 | Normal | 467.8 | 467.8 | ||||
| SFLR12 | 1A | 4.0 | Normal | 767.6 | 380.4 | |||
| 1B | 4.0 | Normal | 1,015 | 486.3 | ||||
| 2 | 3.5 | Normal | 1,215.3 | 883.5 | ||||
| 3A | 2.5 | Normal | 215.8 | 215.8 | ||||
| 3B | 2.5 | Normal | 277.5 | 277.5 | ||||
| 4 | 2.3 | Reduced | 382.2 | 382.2 | ||||
| 5 | 2.0 | Normal | 448.1 | 382.2 | ||||
| SFLR3 | 1C | 3.5 | Normal | 884.6 | 722.9 | |||
| 3A | 2.5 | Normal | 615.2 | 486 | ||||
| 3B | 2.5 | Normal | 615.2 | 486 | ||||
| 3C | 2.5 | Normal | 615.2 | 486 | ||||
| 4 | 2.3 | Reduced | 377.8 | 298.5 | ||||
| 5 | 2.0 | Normal | 470.7 | 371.8 | ||||
| SFLR4 | 1D | 4.0 | Normal | 929.8 | 613.8 | |||
| 2 | 3.5 | Normal | 528.4 | 528.4 | ||||
| 3C | 2.5 | Normal | 361.4 | 361.2 | ||||
| 4 | 2.3 | Reduced | 199.3 | 199.3 | ||||
| 5 | 2.0 | Normal | 280 | 280 | ||||
| 2 | MAIN (WGS) | 6 | 4.0 | Normal | 151.1 | 151.1 |
Cabot may operate under any of these scenarios during any time of the year with the restriction that Cabot is only allowed to operate the flares and dryer stacks under Category 1 for up to 168 hours for yearly planned outages and up to 744 hours during every fifth year for planned turnaround. Cabot shall utilize the WGS and MAIN stack for all other hours.
Small Sources at Cabot: In addition to the major sources of emissions at the Cabot facility, there are several permitted small sources of SO 2 emissions at the facility that must operate under the emission limits in Table 4 and Table 5. Furthermore, Small Source Category 1 Sources in Table 4 shall not operate simultaneously with VP-1 through VP-4 after step 4 of Table 1. Since these are only used as vents during warm up (those first 4 steps) and fired with natural gas only, when MAIN is not up to temperature yet, and those first steps are not part of the worst-case transition scenarios, these were not modeled in any scenario. Small Source Category 2 Sources in Table 4 may be operated for readiness testing only (approximately 20 minutes each) under non-emergency conditions after step 4 of Table 1. These five small sources were modeled at all times when MAIN was emitting (when WGS was operational), but not during outage/turnaround times when the units are transitioning. Small Source Category 3 Sources of Table 5 will operate at reduced emission rates compared to current permitted values after the installation of the WGS. The purge gas filters will be heated with electric heaters instead of dryer gases, so no emissions were modeled for these sources.
| Small source categories 1 and 2 | Category | Source ID | Modeling scenario | Operating hours | lb/hr | Source description |
|---|---|---|---|---|---|---|
| 1 | EQT 0008 | 627 | 0.02 | VP-2 Main Filter. | ||
| EQT 0026 | 200 | 0.03 | VP-1 Reactor Warm-up Vent. | |||
| EQT 0027 | 200 | 0.03 | VP-2 Reactor Warm-up Vent. | |||
| EQT 0028 | 200 | 0.03 | VP-3 Reactor Warm-up Vent. | |||
| EQT 0029 | 200 | 0.03 | VP-4 Reactor Warm-up Vent. | |||
| EQT 0048 | 477 | 0.04 | VP-1 Main Filter. | |||
| 2 | EQT 0011 | 6 | 100 | 0.36 | Emergency and Test Only (ULSD)-Standby Air Blower Diesel Engine. | |
| EQT 0022 | 6 | 100 | 0.51 | Emergency and Test Only (ULSD)-Standby Fire Pump Diesel Engine. | ||
| EQT 0051 | 6 | 100 | 0.02 | Emergency and Test Only (NG)-Dryer Drive Generator. | ||
| EQT 0052 | 6 | 100 | 0.01 | Emergency and Test Only (NG)-Feedstock Area Generator. | ||
| EQT 0053 | 6 | 100 | 0.01 | Emergency and Test Only (NG)-Lab Area Generator. |
[top]
| Small Source Category 3 | Source ID | Operating hours | Currently permitted max SO 2 emission rate (lb/hr) | Permitted max SO 2 emission rate for dryer purge gas filters (lb/hr)? 19 | Post-WGS max SO 2 emission rate for dryer purge gas filters (lb/hr) | Source description |
|---|---|---|---|---|---|---|
| EQT 0014 | 8,760 | 1,335.85 | 51.23 (VP-1) 55.50 (VP-2) | 0 (VP-1) 0 (VP-2) | Units 1, 2, 4 Pellet Dryer and Oil Heaters (combined stack)-includes VP1 And VP2 Purge Gas Filter emissions. | |
| EQT 0034 | 8,760 | 51.23 | 51.23 (VP-4) | 0 (VP-4) | Unit 4 Pellet Dryer Purge Gas Filter. | |
| EQT 0038 | 8,760 | 412.37 | 46.96 (VP-3) | 0 (VP-3) | Unit 3 Pellet Dryers (Combined Stack)-includes VP3 Purge Gas Filter emissions. | |
| EQT 0050 | 8,760 | 0.01 | VP4 Supplemental Feedstock Heater. |
Monitoring and Recordkeeping: Under this Louisiana attainment SIP, during Category 2 operations, the Cabot facility is required to monitor its release of SO 2 via continuous emissions monitoring system (CEMS) at the MAIN stack to measure compliance at the source and ensure that the facility does not exceed its SIP limits. The CEMS will continuously monitor the SO 2 emissions in accordance with the requirements in 40 CFR 60.13, appendix B, Performance Specification 2 and 6, for SO 2, and appendix F, quality assurance procedures. To demonstrate compliance, emissions data will be collected at least four times per hour and then those four data points will be averaged to produce that hour's measured concentration.
Footnotes:
19 ?These sources are already included in the Modeled Max Emission Rate.
For Category 1 operations, emissions from the dryer stacks and flares will be calculated via a Predictive Emission Monitoring System (PEMS). To make the calculations, the system shall record: the weight percent of sulfur in feedstock oil to all reactors, the total pounds of feedstock oil processed in the reactors, the total pounds of sulfur entering all reactors (feedstock oil sulfur content times amount processed), and the amount of SO 2 emitted from the process (80 percent of the sulfur feed times 2). During startup and transition periods, records must be kept of scenario and time information for each step, identifying the corresponding step in Table 1, the operating scenario in Table 2, and applicable emission limits in Table 3 until steady state for all operating units is attained.
The owner or operator of the facility must maintain records for a minimum of five years and must demonstrate compliance with all applicable recordkeeping requirements. The owner or operator must maintain records of the CEMS data for the exhaust gas sulfur content, temperature, and velocity from the scrubber stack. The owner or operator must maintain records of the PEMS data for the feed rate monitoring and the sulfur content of the carbon black oil feed blend. Additionally, records documenting any hourly period that exceeds the emission limits or standards mandated by the Administrative Order on Consent must be maintained. Finally, copies of each performance test and relative accuracy audit and all associated records must be maintained.
As required in LDEQ's SIP submittal, all exceedances of the applicable emission limits or failure to meet other requirements must be reported to LDEQ no later than April 30 of the subsequent year after violation. The report must include an explanation of the exceedance or failure; if the violation was due to a startup, shutdown, or malfunction (SSM) event; and a description of any action taken to rectify the issue.
The SIP revision requires the Cabot facility to complete construction and commissioning of the WGS and CEMS on the MAIN stack and comply with all requirements of the AOC by July 30, 2026.
If the EPA finalizes this proposed action, the emission limits and source configuration requirements, as well as the monitoring, recordkeeping and reporting requirements of the Administrative Order on Consent will become federally enforceable as a source-specific revision to the Louisiana SIP.
F. Background Concentrations
To satisfy the EPA modeling requirements, the SIP's AD must also incorporate background concentrations into its modeling. The AD estimates the combined impacts of facility-specific emission rates and monitored background concentrations. Regional sources not explicitly modeled in AERMOD, but that contribute to ambient SO 2 concentrations within the nonattainment area, are represented via background monitoring data. Louisiana identified three monitors that were approximately equidistant from the Cabot facility, including: the Lake Charles monitor (AQS ID: 22-019-0008), Port Allen monitor (AQS ID: 22-121-0001), and Baton Rouge monitor (AQS ID: 22-033-0009). Louisiana stated that the Lake Charles monitor and the Port Allen monitor would provide an unrepresentative and overly conservative background concentration measurement for the Evangeline Parish area due to the influence of industrial site emissions near those monitors. Louisiana identified the Baton Rouge monitor as representative of background concentrations due to its similar local emissions characteristics and the stability of SO 2 concentrations measured at this monitor. The EPA has determined that Louisiana's selection of the Baton Rouge monitor is appropriate.
Once a suitable monitor is selected, Appendix W prescribes tiered approaches for incorporating that data as background concentration. LDEQ selected the "Tier 2" approach recommended by the August 23, 2010, clarification memo on "Applicability of Appendix W Modeling Guidance for the 1-hour SO 2 National Ambient Air Quality Standard" based on monitored design values. In accordance with EPA's guidance on background concentrations, LDEQ's "Tier 2" approach identified separate background values for each hour of the day for each of the four seasons, totaling 96 background values. Each of these values represents a three-year average (2020-2022) of the second highest hourly concentration for the applicable hour of the day for the applicable season. The seasonal, hourly-averaged 2020-2022 SO 2 background values for the AD were developed from data collected at the Baton Rouge monitor. The background values ranged from 0.300 ppb to 8.167 ppb. EPA concludes that the methodology used by LDEQ to model background values is appropriate. This is also discussed in TCI's Modeling Report and our TSD.
G. Summary of Results
[top] The attainment plan establishes new emissions limits for the Cabot facility needed to attain the 1-hour SO 2 NAAQS. LDEQ determined that the impact of these reduced maximum allowable emissions limits and installation of a new scrubber stack at the facility yielded a 5-year modeled
Footnotes:
20 ?Table 2-20 of TCI's Modeling Report was not updated for the Category 2 final modeling results; yet TCI's Figures D-41 and D-42 do represent the final modeling for Category 2 with a max DV of "5.28E+01" (52.8 µg/m3). EPA performed confirmatory modeling using TCI's modeling files to confirm TCI's final modeling representations for Category 2.
The EPA concludes that LDEQ's modeling is a suitable demonstration. Based on our review of the SIP, EPA has determined that the SIP submission satisfies the applicable CAA requirements and, if approved, would provide for attainment of the SO 2 NAAQS.
III. Review of Other Plan Requirements
A. Emissions Inventory
The emissions inventory and source emission rate data for an area serve as the foundation for air quality modeling and other analyses that enable states to: (1) estimate the degree to which different sources within a nonattainment area contribute to violations within the affected area; and (2) assess the expected improvement in air quality within the nonattainment area due to the adoption and implementation of control measures. A nonattainment SIP must include a comprehensive, accurate, and current inventory of actual emissions from all sources of SO 2 in the nonattainment area as well as any sources located outside the nonattainment area that may affect attainment in the area. See CAA section 172(c)(3). In its submittal, LDEQ included a current emissions inventory for the Evangeline Parish area covering the 2018-2023 period. LDEQ did not specifically provide projected emissions for the 2029 attainment year; however, the EPA has determined the projected emissions based on the proposed SIP limits for the facility, the only major source within the nonattainment area. The EPA identified three possible projected 2029 attainment year scenarios to estimate projected emissions: Cabot undergoes no period of turnaround during the year, Cabot undergoes a planned outage not to exceed 168 hours during the year, and Cabot undergoes a period of turnaround not to exceed 744 hours as allowed every fifth year. This information is provided in Table 6. 21
Footnotes:
21 ?Presented in Table 6 is an estimation of the attainment year projected worst-case emissions that can occur during operating Scenario 2: 3.5% Sulfur Feedstock with all Flares and Dryers Operational at Normal Capacity except for VP-3. During this period each unit will be in steady state except for VP-3 which can be in transitional state for up to three hours. During annual periods of turnaround with less than 168 hours of outage, worst case scenarios we assumed up to 5 separate periods of turnaround. For turnaround periods occuring every fifth year, totaling less than 744 hours of outage, worse case scenarios we assumed up to 10 separate periods of turnaround.
The State of Louisiana compiled a statewide EI in accordance with the CAA Amendments of 1990, LAC 33:III.918 and 919 (Recordkeeping and Annual Reporting and Emissions Inventory). LDEQ chose the year 2018 as the base year for its analyses as the most complete and representative record of annual SO 2 emissions because: (1) it was the most recent periodic inventory year available; and (2) it was also the year that the EPA designated the Evangeline Parish area as nonattainment for the 2010 SO 2 NAAQS. The 2018 baseline area source emissions inventories were developed in accordance with the requirements of the Air Emissions Reporting Requirements (AERR) rule.
A summary of the State's submitted emissions inventory is provided in the following table:
| Category | 2018 Actual emissions (tons/year) | 2029 Projected emissions (tons/year) |
|---|---|---|
| Point-Cabot (no turnaround) | 11,069.91 | 662 |
| Point-Cabot (annual <168 hours outage period) | 11,069.91 | 848 |
| Point-Cabot (every fifth year <744 hours turnaround period) | 11,069.91 | 1,477 |
The EPA agrees that the State's emissions inventories for point, nonpoint, and mobile sources are appropriate because they have been accumulated and reported in accordance with established methods and criteria. The EPA proposes that the emissions inventory is representative and satisfies the EI requirement.
B. RACM/RACT
CAA section 172(c)(1) requires states to adopt and submit all RACM, including RACT, as needed to attain the standards as expeditiously as practicable. Section 172(c)(6) requires the SIP to contain enforceable emission limits and control measures necessary to provide for timely attainment of the standard. The plan relies on ambient SO 2 concentration reductions achieved by implementation of the limits established in the AOC with the Cabot facility. The Cabot facility plans to install post combustion controls to reduce SO 2 emissions (lb/hr) from the facility as well as mandate explicit operating parameters in order to ensure attainment in the area.
The control strategy at the Cabot facility incorporates post-combustion flue gas desulfurization via controls for the MAIN stack by requiring the installation of a wet gas scrubber (WGS). Furthermore, the flares and dryer stacks (SDRY3, SDRY124, SFLR12, SFLR 3, and SFLR4) shall only be operated in periods of planned outage of the WGS or periods of turnaround while maintenance is being undertaken on the WGS (MAIN stack), while maintaining compliance with specific parameters set forth in the SIP.
[top] The final emission limitations as included in the Administrative Order on Consent are provided earlier in this document in section II.E., Emission Limitations of this document. The Cabot facility is required to complete construction and commissioning of the WGS and comply with all requirements of the AOC by July 30, 2026. Furthermore, the requirement to construct and operate a WGS is consistent with requirements set forth in the 2013 carbon black consent decree entered with Cabot. Louisiana provides in the SIP a discussion of the current status of implementation and anticipated construction schedule to
C. New Source Review (NSR)
The EPA has approved both Louisiana's NNSR and Emission Reduction Credits (ERC) banking programs. (LAC 33:111.504 was approved on September 30, 2002;? 22 LAC 33:III.Chapter 6 was approved on September 27, 2002 (67 FR 60877)). Note that per a rule revision promulgated November 20, 2012 (AQ 327), (See App. D to SIP), revisions to LDEQ's ERC banking program (LAC 33:III.Chapter 6) were made such that creditable SO 2 reductions could be banked and traded as ERC. No further revisions to LAC 33:III.504 or Chapter 6 are required to implement the NNSR program in Evangeline Parish. These approved rules provide for appropriate new source review for SO 2 major sources undergoing construction or major modification in Evangeline Parish without need for modification of the approved rules. Therefore, the EPA concludes that the SIP satisfies this CAA requirement.
Footnotes:
22 ? See 67 FR 61270.
D. Reasonable Further Progress (RFP)
Section 171(1) of the CAA defines RFP as "such annual incremental reductions in emissions of the relevant air pollutant as are required by [part D] or may reasonably be required by the [EPA] for the purpose of ensuring attainment of the applicable [NAAQS] by the applicable attainment date." For purposes of SO 2 , the EPA issued guidance prescribing how states could satisfy this requirement when developing their nonattainment SIPs. 23 Since pollutants like SO 2 usually have a limited number of sources affecting areas of air quality that are relatively well defined, and emissions control measures for such sources generally provide significant and immediate improvements in air quality, there is usually a single "step" between pre-control nonattainment and post-control attainment. Therefore, due to the discernible relationship between emissions and air quality, EPA interprets RFP in the SO 2 context as "adherence to an ambitious compliance schedule" which "ensures that affected sources implement appropriate control measures as expeditiously as practicable" to ensure attainment by the applicable attainment date. 24
Footnotes:
23 ? See "Guidance for 1-Hour SO 2 Nonattainment Area SIP Submissions", U.S. Environmental Protection Agency, Office of Air Quality Planning and Standards, April 23, 2014, which can be accessed at: https://www.epa.gov/sites/production/files/2016-06/documents/20140423guidance_nonattainment_sip.pdf.
24 ? See General Preamble, 57 FR 13498, 13547 (April 16, 1992).
Section 172(c)(2) of the CAA requires the Evangeline Parish Attainment Plan SIP provide for reasonable further progress towards attainment. EPA has determined that once control requirements and emissions limits have been implemented, these measures will provide for attainment in the area. Cabot entered into an AOC that requires compliance by July 30, 2026, and if finalized as a SIP revision, will become federally enforceable. Louisiana provides in the SIP a discussion of the current status of implementation and anticipated construction schedule to support the compliance date. Therefore, Louisiana concluded that its SIP submittal provides for RFP in accordance with EPA's SO 2 guidance and the Preamble. The EPA finds that the SIP submittal satisfies the CAA requirements for RFP.
E. Contingency Measures
As discussed in our 2014 SO 2 guidance, section 172(c)(9) of the CAA defines contingency measures as specific measures to be undertaken if the area fails to make RFP or fails to attain the NAAQS by the applicable attainment date. Contingency measures are to become effective without further action by the State or the EPA. These contingency measures consist of other available control measures that are not included in the control strategy for the nonattainment area SIP. EPA guidance describes special features of SO 2 planning that influence the suitability of alternative means of addressing the requirement in section 172(c)(9) for SO 2 contingency measures. Because SO 2 control plans are based on what is directly and quantifiably necessary emissions controls, any violations of the NAAQS are likely related to source violations of a source's permit or agreed order terms. Therefore, an appropriate means of satisfying this requirement for SO 2 is for the State to have a comprehensive enforcement program that identifies sources of violations of the SO 2 NAAQS and undertakes an aggressive follow-up for compliance and enforcement.
Louisiana's plan satisfies the contingency measure requirement with this kind of comprehensive enforcement program and follow-up for compliance. The EPA proposes to approve Louisiana's plan for meeting the contingency measure requirement in this manner.
F. Conformity
Generally, as set forth in section 176(c) of the CAA, conformity requires that actions by Federal agencies do not cause new air quality violations, worsen existing violations, or delay timely attainment of the relevant NAAQS. General conformity applies to Federal actions, other than certain highway and transportation projects, if the action takes place in a nonattainment area or maintenance area ( i.e., an area which submitted a maintenance plan that meets the requirements of section 175A of the CAA and has been redesignated to attainment) for ozone, particulate matter, nitrogen dioxide, carbon monoxide, lead, or SO 2 . EPA's General Conformity Rule (40 CFR 93.150 to 93.165) establishes the criteria and procedures for determining if a Federal action conforms to the SIP. With respect to the 2010 SO 2 NAAQS, Federal agencies are expected to continue to estimate emissions for conformity analyses in the same manner as they estimated emissions for conformity analyses under the previous NAAQS for SO 2 . EPA's General Conformity Rule includes the basic requirement that a Federal agency's general conformity analysis be based on the latest and most accurate emission estimation techniques available (40 CFR 93.159(b)). When updated and improved emissions estimation techniques become available, EPA expects the Federal agency to use these techniques. EPA finds that the Evangeline Parish SO 2 Attainment Plan SIP Revision submission would not interfere with attainment of the NAAQS or worsen existing violations and therefore meets these conformity requirements.
[top] Transportation conformity determinations are not required in SO 2 nonattainment and maintenance areas. EPA concluded in its 1993 transportation conformity rule that highway and transit vehicles are not significant sources of SO 2 . Therefore, transportation plans, transportation improvement programs and projects are presumed to conform to applicable
IV. Proposed Action
EPA is proposing to approve Louisiana's April 2, 2025, submission as a SIP revision for attaining the 2010 1-hour SO 2 NAAQS for the Evangeline Parish nonattainment area. As part of this action, EPA is also proposing to approve as a source-specific revision to the SIP and incorporate by reference into the State's SIP, the Administrative Order on Consent between LDEQ and Cabot, which provides the enforceable control strategy for the Evangeline Parish area.
The SO 2 nonattainment plan includes Louisiana's AD for the Evangeline Parish SO 2 nonattainment area. LDEQ explicitly modeled air quality based on the Cabot facility's updated emission limits; through that modeling, LDEQ provided sufficient information that the revised limits at the Cabot facility would allow the area to meet the standard. Therefore, EPA concludes that the modeling in LDEQ' plan adequately demonstrates that the control requirements that apply to relevant sources in the area, including the one-hour SO 2 emission limits for the Cabot facility, provide for attainment in the area. This nonattainment plan also addresses requirements for emission inventories, RACT/RACM, RFP, and contingency measures. Louisiana has previously addressed requirements regarding nonattainment area NSR. EPA has determined that Louisiana's SO 2 nonattainment plan meets the applicable requirements of CAA sections 172, 179(d), 191, and 192. EPA is taking public comments for thirty days following the publication of this proposed action in the Federal Register . EPA will take these comments into consideration in our final action.
V. Incorporation by Reference
In this action, we are proposing to include in a final rule regulatory text that includes incorporation by reference. In accordance with the requirements of 1 CFR 51.5, we are we are proposing to incorporate by reference revisions to the Louisiana source-specific requirements as described in section IV. of this document, Proposed Action. We have made, and will continue to make, these documents generally available electronically through www.regulations.gov (please contact the person identified in the FOR FURTHER INFORMATION CONTACT section of this preamble for more information).
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. 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 Order 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 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 oxides.
Authority:
42 U.S.C. 7401 et seq.
Dated: April 30, 2025.
Walter Mason,
Regional Administrator, Region 6.
[FR Doc. 2025-08080 Filed 5-7-25; 8:45 am]
BILLING CODE 6560-50-P