2018-08067. Approval and Promulgation of Implementation Plans; Louisiana; Attainment Demonstration for the St. Bernard Parish 2010 SO2

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Proposed rule.

SUMMARY:

Pursuant to the Clean Air Act (the Act or CAA), the Environmental Protection Agency (EPA) is proposing to approve a State Implementation Plan (SIP) revision, as supplemented, for the St. Bernard Parish, Louisiana 2010 1-hour sulfur dioxide (SO₂) Primary National Air Quality Standard (NAAQS) nonattainment area. EPA is proposing approval of the following CAA SIP elements: The attainment demonstration for the SO₂ NAAQS, which includes an Agreed Order on Consent (AOC) for the Rain CII Carbon, LLC. (Rain) 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:

Written comments must be received on or before May 21, 2018.

ADDRESSES:

Submit your comments, identified by Docket No. EPA-R06-OAR-2017-0558, at http://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 Robert Imhoff, 214-665-7262, [e-mail]. For the full EPA public comment policy, information about CBI or multimedia submissions, and general guidance on making effective comments, please visit http://www2.epa.gov/​dockets/​commenting-epa-dockets.

Docket: The index to the docket for this action is available electronically at www.regulations.gov and in hard copy at the EPA Region 6, 1445 Ross Avenue, Suite 700, Dallas, Texas. While all documents in the docket are listed in the index, some information may be publicly available only at the hard copy location (e.g., copyrighted material), and some may not be publicly available at either location (e.g., CBI).

FOR FURTHER INFORMATION CONTACT:

Robert Imhoff, 214-665-7262, [e-mail]. To inspect the hard copy materials, please schedule an appointment with Robert Imhoff or Mr. Bill Deese at 214-665-7253.

SUPPLEMENTARY INFORMATION:

Throughout this document whenever “we,” “us,” or “our” is used, we mean the EPA.

Table of Contents

I. Why was Louisiana Required to Submit an SO₂ Plan for St. Bernard Parish?

II. Requirements for SO₂ Nonattainment Area Plans

III. Attainment Demonstration

IV. Review of Modeled Attainment Plan

A. Model Selection

B. Meteorological Data

C. Emissions Data

D. Receptor Grid

E. Emission Limits

F. Background Concentrations

G. Summary of Results

V. Review of Other Plan Requirements

A. Emissions Inventory

B. RACM/RACT

C. New Source Review (NSR)

D. Reasonable Further Progress (RFP)

E. Contingency Measures

VI. Conformity

VII. EPA's Proposed Action

VIII. Incorporation by Reference

XI. Statutory and Executive Order Reviews

I. Why was Louisiana required to submit an SO₂ plan for the St. Bernard Parish?

On June 22, 2010, the EPA promulgated a new 1-hour primary SO₂ NAAQS of 75 parts per billion (ppb), which is met at an ambient air quality monitoring site 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. See 75 FR 35520, codified at 40 CFR 50.17(a)-(b). On August 5, 2013, the EPA designated a first set of 29 areas of the country as nonattainment for the 2010 SO₂ NAAQS, including the St. Bernard Parish Nonattainment Area ^[1] within the State of Louisiana. See 78 FR 47191, codified at 40 CFR part 81, subpart C. These area designations were effective October 4, 2013. Section 191 of the CAA directs states to submit SIPs for areas designated as nonattainment for the SO₂ NAAQS to the EPA within 18 months of the effective date of the designation, i.e., by no later than April 4, 2015, in this case. Under CAA section 192, these SIPs are required to demonstrate that their respective areas will attain the NAAQS as expeditiously as practicable, but no later than 5 years from the effective date of designation, which is October 4, 2018.

For a number of areas, including the St. Bernard Parish, the EPA published a final “Findings of Failure to Submit State Implementation Plans Required for Attainment of the 2010 1-Hour Primary Sulfur Dioxide National Ambient Air Quality Standard (NAAQS)” Federal Register notice on March 18, 2016, that found that Louisiana and other pertinent states had failed to submit the required SO₂ nonattainment plan by the required CAA submittal deadline. See 81 FR 14736. This finding, effective on April 18, 2016, initiated 18-month and 24-month deadlines under CAA section 179(a) for the imposition of mandatory new source review and highway funding sanctions, respectively, unless by those deadlines the State had submitted a SIP revision deemed by the EPA to be complete. Additionally, under CAA section 110(c), the finding triggered a requirement that the EPA promulgate a federal implementation plan (FIP) within two years of the finding unless, by that time (a) the state has made the necessary complete submittal and (b) EPA has approved the submittal as meeting applicable requirements.

On November 9, 2017, LDEQ submitted a 2010 SO₂ Nonattainment Area SIP revision for St. Bernard Parish to EPA. The LDEQ determined that as a part of the attainment area demonstration, it should include permanent and enforceable restrictions for SO₂ emitted from the Rain CII Carbon, LLC. (Rain) facility. Such limits were originally memorialized into an Administrative Order on Consent (AOC) that was signed on November 9, 2017, and was included in the LDEQ's November 9, 2017, SIP submittal (also included in the docket to this action). In LDEQ's SIP submittal cover letter, dated November 9, 2017, LDEQ committed to “work toward a SIP revision submittal concerning the pyroscrubber (EQT 004) at the Rain facility no later than March 1, 2018.” In addition, in LDEQ's responses to comments, LDEQ committed to revise the Rain AOC to “incorporate limits, monitoring, and recordkeeping requirements that are reflective of the information used in the modeling demonstration in an updated submittal.” On February 8, 2018, LDEQ submitted a letter to the EPA, accompanied by a new AOC, dated February 2, 2018, executed between LDEQ and Rain, that includes new emissions limits for the Rain facility's cold stack and hot stack/pyroscrubber, as well as monitoring, testing and recordkeeping requirements. LDEQ submitted this as a source specific SIP revision and supplement to the SIP (included in the docket to this action). These emission limits include all operation regimes at the facility, with differing emission limits depending on the stage of operation of the Cold and Hot stacks during the Transitional regime.^[2] On February 26, 2018, EPA determined that the State's SO₂ Nonattainment Area SIP revision for St. Bernard Parish was complete under 40 CFR part 51, App. V.^[3] Consequently, the Act's section 179 sanctions that had or would have applied as a result of the State's previously not submitting a complete SIP no longer apply due to the determination of completeness. See the State's AOC and letter, included in the docket to this action, that serve as a supplement to the SIP, dated February 2, 2018 and February 8, 2018, respectively.^[4]

II. Requirements for SO₂ Nonattainment Area Plans

Nonattainment area SIPs must meet the applicable requirements of the CAA, and specifically 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 residing 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 SO₂ SIPs and fundamental principles for SIP control strategies. Id., at 13545-49, 13567-68. On April 23, 2014, the EPA issued recommended guidance for meeting the statutory requirements in SO₂ SIPs, in a document entitled, “Guidance for 1-Hour SO₂ Nonattainment Area SIP Submissions.” ^[5] In this guidance, the EPA described the statutory requirements for a complete nonattainment area SIP, which includes: an accurate emissions inventory of current emissions for all sources of SO₂ within the nonattainment area, an attainment demonstration, demonstration of RFP, implementation of RACM (including RACT), an approvable NNSR program, enforceable emissions limitations, and adequate contingency measures for the affected area.

In order for the EPA to fully approve a SIP as meeting the requirements of CAA sections 110, 172 and 191-192 and EPA's regulations at 40 CFR part 51, the SIP for the affected area needs to demonstrate to EPA's satisfaction that each of the aforementioned requirements have been met. Under CAA sections 110(l) and 193, the EPA may not approve a SIP that would interfere with any applicable requirement concerning NAAQS attainment and RFP, or any other applicable requirement under the Act. Furthermore, no requirement in effect, or required to be adopted by an order, settlement, agreement, or plan in effect before November 15, 1990, in any area which is a nonattainment area for any air pollutant, may be modified in any manner unless it insures equivalent or greater emission reductions of such air pollutant.

III. Attainment Demonstration

The CAA section 172(c)(1) directs states with areas designated as nonattainment to demonstrate that the submitted plan provides for attainment of the NAAQS. 40 CFR part 51, subpart G further delineates the control strategy requirements that SIPs must meet, and the EPA has long required that all SIPs and control strategies reflect four fundamental principles of quantification, enforceability, replicability, and accountability. See General Preamble, at 13567-68. SO₂ attainment plans must 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 meets the requirements of 40 CFR part 51, Appendix W (Guideline on Air Quality Models; “the Guideline”), and demonstrates that these emission limits and control measures provide for timely attainment of the primary SO₂ NAAQS as expeditiously as practicable, but by no later than the attainment date for the affected area. In all cases, the emission limits and control measures must be accompanied by appropriate methods and conditions to determine compliance with the respective emission limits and control measures and must 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 assumptions used in the SIP demonstrations).

Preferred air quality models for use in regulatory applications are described in Appendix A of the EPA's Guideline on Air Quality Models (40 CFR part 51, Appendix W ).^[6] In 2005, the EPA promulgated AERMOD as the Agency's preferred near-field dispersion modeling for a wide range of regulatory applications addressing stationary sources (for example in estimating SO₂ concentrations) in all types of terrain based on extensive developmental and performance evaluation. On July 29, 2015, EPA proposed in the Federal Register “Revisions to the Guideline on Air Quality Models: Enhancements to the AERMOD Dispersion Modeling System and Incorporation of Approaches To Address Ozone and Fine Particulate Matter,” (the Guideline ), that provides for EPA's preferred models and other recommended techniques, as well as guidance for their use in estimating ambient concentrations of air pollutants.^[7] The Guideline provides additional regulatory options and updated methods or dispersion modeling with AERMOD; the final revisions to the Guideline were promulgated in a Federal Register action on January 17, 2017, and became effective on May 22, 2017.^[8] In addition to the Guideline, promulgated in 40 CFR part 51, Appendix W, EPA has issued supplemental guidance on modeling for purposes of demonstrating attainment of the 2010 SO₂ standard (see our April 23, 2014 SO₂ nonattainment area SIP guidance document referenced above). Appendix A of the 2014 guidance titled “Modeling Guidance for Nonattainment Areas,” is based on and is consistent with the Guideline. Appendix A of the SO₂ guidance memo follows and is consistent with the requirements in 40 CFR part 51 Appendix W. It also provides specific SO₂ modeling guidance on the modeling domain, the source inputs, assorted types of meteorological data, and background concentrations. Consistency with the recommendations in the SO₂ guidance is generally necessary for the attainment demonstration to offer adequately reliable assurance that the plan provides for attainment.

As stated previously, attainment demonstrations for the 2010 1-hour primary SO₂ NAAQS must demonstrate future attainment and maintenance of the NAAQS in the entire area designated as nonattainment (i.e., not just at the violating monitor) by using air quality dispersion modeling in accordance with the Guideline and SO₂ guidance to show that the mix of sources and enforceable control measures and emission rates in an identified area will not lead to a violation of the SO₂ NAAQS. 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 affected 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 in nonattainment areas because it takes into consideration combinations of meteorological and emission source operating conditions that may contribute to peak ground-level concentrations of SO₂.

The meteorological data used in the analysis should generally be processed with the most recent version of AERMOD. 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 SO₂ National Ambient Air Quality Standard.” ^[9]

IV. Review of Modeled Attainment Plan

The following discussion evaluates various features of the modeling that Louisiana used in the attainment demonstration, as well as a discussion of the EPA's additional modeling that was conducted as part of the review of the State's SIP. LDEQ submitted modeling at the time of the SIP submittal. However, the state's modeling did not include modeling for all operating scenarios at Rain. In addition, subsequent to the State's modeling, Rain provided updated estimates for stack parameters for the hot stack. LDEQ submitted additional modeling, as noted in the February 8, 2018 letter, that incorporated the updated stack parameters for the hot stack. The 1-hour SO₂ emission limits contained in the February 2, 2018 AOC were designed to ensure compliance with the SO₂ NAAQS. The EPA undertook an additional modeling analysis which also incorporated the amended stack parameters, and utilized more recent allowable emission rates from other contributing sources, an expanded receptor grid, and covered all operating scenarios. The EPA's additional modeling used a more recent version of AERMOD and utilized LDEQ's meteorology, modeling options, land use characterization, building downwash inputs, background concentrations, and source inventory. For the updated modeling, the EPA worked in collaboration with the LDEQ to identify updated emissions rates for the contributing sources based on current permitted limits. The State reviewed EPA's modeling files and agrees with its accuracy.^[10] Additional, more detailed discussion of the State's modeling and EPA's modeling is contained in the Technical Support Document (TSD) for this proposed action.

A. Model Selection

Louisiana's attainment demonstration modeling used the Guideline preferred model, AERMOD (version 15181 of AERMOD) with default options (e.g., without use of the ADJ_U* option) and rural dispersion coefficients for this application. We note that since LDEQ originally started their modeling, the AERMOD system has been updated to version 16216r, which is the current preferred version of AERMOD. Based on the parameters and options chosen by LDEQ, and considering the information in the the Model Change Bulletin,^[11] we do not expect significant changes to modeled concentration values due to the difference in AERMOD versions. We did not rerun the AERMET meteorological processor data even though the version also changed from 14134 to 16216. The EPA made changes to AERMET in the updated version (16216) to add an additional option (ADJ_U*) to be used in certain situations but that option is not required and was not used by LDEQ.^[12] The other changes between AERMET version 14134 and 16216 are minimal and would not result in discernable changes to LDEQ's SIP modeled concentrations.^[13]

LDEQ used building information (height, width, and length) to analyze potential building downwash in their modeling, and also chose to use rural characterization instead of urban characterization for vertical mixing and boundary layer calculations. The EPA reviewed the building downwash analysis and concurs with the choice of rural setting for the dispersion. Our review indicates that the modeling options and settings are acceptable and appropriate in the modeling submitted and EPA's modeling (see the TSD for more detail).

B. Meteorological Data

The modeling utilized surface meteorological data obtained from the New Orleans International Airport and upper air data from the Slidell National Weather Station from 2011-2015. The New Orleans International Airport is the closest National Weather Service site, 27 km distant from the Vista monitor, and is representative of the meteorology in the St. Bernard Parish due to the proximity and the similarity of the terrain. The data was processed using the meteorological processing tools, AERMINUTE (14347) and AERMET (14134). Newer versions of the processing programs are available, but based on the changes that the EPA made in AERMINUTE and AERMET (discussed above) we would not expect to see any significant changes even if the data was processed with the latest version of AERMINUTE (v15272) and AERMET (v16216). Therefore, the EPA finds the selection and processing of this data to be acceptable.

C. Emissions Data

There are three major sources of SO₂ emissions located in relative close proximity to the Chalmette-Vista monitor, which is the monitor that recorded SO₂ NAAQS violations on which the 2013 nonattainment designation of the area was based. These sources are located in St. Bernard Parish: Valero Refining, Chalmette Refining, and Rain. Through analysis of air permit data for facilities within 20 kilometers (km) of the violating monitor, LDEQ determined that these three major sources in the area were the main sources of concern accounting for over 99% of the point source allowable SO₂ emissions in the parish. This is confirmed by review of all SO₂ sources in St. Bernard Parish provided by LDEQ in their emission inventory analysis part of their submittal. LDEQ also evaluated major sources (greater than 100 tpy of SO₂) in the 20-50 km area surrounding the violating monitor and determined that most are located to the north in St. Charles Parish and to the west in Jefferson Parish and not in the predominant wind direction that generates exceedances at the monitor nor at the preliminary modeling maximum area to the west of Rain. LDEQ determined that there are no other major sources within 20 km of the monitor based on the 2014 NEI inventory of actual emissions (See TSD for additional information). Two additional facilities, ConocoPhillips and New Orleans Sewer Treatment, were determined to have possible impacts somewhere in St. Bernard Parish and may not have been fully represented by the background monitoring values, so they were modeled explicitly. Maximum allowable emissions and federally enforceable permit limits were used for all modeled sources within St. Bernard Parish. LDEQ included many small sources of SO₂ in the modeling, 12 sources were included with allowable emission rates of less than 1 tpy with the smallest being 0.005 tpy. Emergency equipment and other very small sources were omitted. Intermittent engines were modeled with annualized emissions based on the ratio of the operating hours to 8760 hours. The remainder of the sources are captured by the background concentrations. The inclusion of these sources assures that Louisiana incorporated all sources in the modeling that are considered to possibly create concentrations and/or concentration gradients in St. Bernard Parish that are not represented by the background monitoring data.

LDEQ used site specific building and stack data and modeled all stacks at the lesser of their actual stack height, or Good Engineering Practice (GEP) stack height as determined by the BPIP PRIME preprocessor. Building downwash influences obtained from the BPIP PRIME output were included in the modeling. For a more detailed analysis and conclusions on what sources were included in the modeling, and how they were modeled see the TSD.

As discussed in the TSD, Rain was identified as the primary contributor to exceedances at the Vista monitor. Louisiana and EPA modeling support the establishment of additional emission limits for Rain. Rain is a coke calcining operation that includes a waste heat recovery boiler. During normal operations, the exhaust from the calining operation is routed through the recovery boiler and then through a scrubber and finally to the atmosphere through what is termed the “cold stack.” During start up and times when the recovery boiler is down, emissions are routed to the atmosphere through what is known as the “hot stack.” The modeling covers three operation scenarios: Cold stack operation, hot stack operation, and a transitional period with emissions through both stacks. This third operation scenario was further divided into four stages based on flow and temperatures through the cold stack. Because of the wide range of emission rates and plume buoyancy during the startup this approach enabled the determination of emission rates for each stage that were shown through the modeling to be consistent with attainment of the NAAQS. The modeling includes current conditions reflecting the operation of the scrubber and the new cold stack for estimating the impacts of emissions through the cold stack. The 1-hour SO₂ emission limits contained in the February 2, 2018 AOC were designed to ensure compliance with the SO₂ NAAQS. This AOC also incorporated updated information from Rain concerning the hot stack flow rates and temperatures that required additional modeling and refinement of the AOC SO₂ emission limits for the transitional modeling. The modeling also included the two other major sources in St. Bernard Parish (Chalmette Refinery and Valero Refinery) modeled at their short-term SO₂ emission allowables in their existing permits.^[14] See below for further details on the emission rates in the State's and EPA's attainment modeling.

Except for the emission points addressed in the February 2, 2018 AOC, the emission limits for the other relevant sources inside St. Bernard Parish, as outlined in Louisiana's attainment demonstration and supplement to the SIP, correspond to the sulfur limitations on a 1-hour basis found in their permits. The emission limits for Rain are all on a 1-hour average basis; and equal the modeled emissions rates. The EPA finds Louisiana's choice of included sources to be appropriate. However, EPA found that the modeled emission rates utilized by LDEQ in their modeling for several sources reflected permit limits that have been modified. For EPA's modeling, we used the updated emission rates. The State reviewed the emission ^[15] rates used by EPA and determined that they were either accurate or slightly conservative.

D. Receptor Grid

Within AERMOD, air quality concentration results are calculated at discrete locations identified by the user; these locations are called receptors. LDEQ placed receptors within St. Bernard Parish with 100 meter (m) spacing extending 2 km from the fence line of the three major facilities in St. Bernard Parish; spacing is 250 m from 2-7 km; 500 m interval from 7-11 km; and 1,000 m interval from 11-50 km and beyond. In addition, receptors were placed along facility fence lines for the three major facilities, which define the ambient air boundary for a particular source. A receptor grid extends approximately 50 km to the east of the Valero refinery (easternmost large source of SO₂ in St Bernard Parish), but does not go all the way to the eastern edge of the Parish as there are no point sources of SO₂ in that area and the modeled design value isopleths were declining and had declined to less than half the level of the NAAQS. EPA conducted modeling with an expanded receptor grid to ensure that the receptor grid is large enough to capture all areas of concern that may be near the 1-hour SO₂ NAAQS in and near St. Bernard Parish. The EPA modeling analysis also included some receptors to the south of Rain and the Chalmette refinery area in Orleans Parish and Plaquemines Parish. EPA also placed receptors to confirm that no violations would occur on the properties of the three major source facilities if all emissions were modeled except for emissions from that facility (e.g. for the Chalmette Refinery property with all emissions except those from the Chalmette Refinery sources). See the TSD for additional information. The expanded 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

An important prerequisite for approval of an attainment plan is that the emission limits that provide for attainment be quantifiable, fully enforceable, replicable, and accountable. See General Preamble at 13567-68.

Louisiana entered an AOC with Rain on November 9, 2017, and a new AOC on February 2, 2018, pursuant to the Louisiana Environmental Quality Act (La. R.S. 30:2001, et seq.). Both AOCs were submitted to EPA as part of the State's SIP revision submittal as a source-specific SIP revision. Louisiana issued a permit to Rain on October 27, 2017 (Permit No. 2500-00006-V3) ^[16] that included the previous November 9, 2017, AOC limits, but has not yet issued a revised permit to include the new AOC limits that are now included in the February 2, 2018, AOC. In its February 2, 2018 AOC, LDEQ has committed to modify the permit to include all federally enforceable applicable limits listed in the AOC. Louisiana issued the new AOC (February 2, 2018) to incorporate emission limits, monitoring, and recordkeeping requirements that are reflective of the information used in the modeling demonstration. The new AOC also incorporated updated information from Rain concerning the hot stack flow rates and temperatures that required additional modeling and refinement of the AOC SO₂ emission limits for the transitional modeling. We are proposing to approve the February 2, 2018, Rain AOC as a source-specific SIP revision to make it permanent and federally enforceable. The limits in the table below are hourly limits and compliance with the limits is determined using 1-hour average data.

The emissions limits relied upon in the modeling for the other two major sources within the area that could contribute to nonattainment in the area already are federally enforceable because they are reside in NSR SIP permits Valero No. 1500-00001-V16 and Chalmette has 11 permits.^[17] The February 2, 2018 AOC for Rain will become federally enforceable as a source-specific revision to the Louisiana SIP if EPA finalizes this proposed approval. The AOC has a compliance date of May 3, 2018.

AOC Emission Limitations

Source ID	Source description	Sulfur dioxide (SO2) limit
EQT 0003	Waste Heat Boiler/Baghouse	During normal, steady-state operations, with no emissions through the Pyroscrubber Stack (EQT 0004), SO2 emissions shall be ≤510 lb/hr when stack flow rate ≥110,000 SCFM and stack temperature ≥220□F. If stack flow rate ≥70,000 SCFM and <110,000 SCFM and Temperature is ≥220 °F, SO2 emissions shall be ≤380 lb/hr.
EQT 0003	Waste Heat Boiler/Baghouse	Stage 1: when the flue gas flow rate <40,000 SCFM or Temperature <90 °F as measured by the CEMS, SO2 emissions shall be ≤10 lb/hr.
EQT 0003	Waste Heat Boiler/Baghouse	Stage 2: when the flue gas flow rate ≥40,000 SCFM and <70,000 SCFM: • Temperature ≥0 °F and <110 °F as measured by the CEMS, SO2 emissions shall be ≤75 lb/hr. • Temperature ≥110 °F and <150 °F as measured by the CEMS, SO2 emissions shall be ≤75 lb/hr. • Temperature ≥150 °F and <220 °F as measured by the CEMS, SO2 emissions shall be ≤75 lb/hr.
EQT 0003	Waste Heat Boiler/Baghouse	Stage 3: when the flue gas flow rate ≥70,000 SCFM and <110,000 SCFM: • Temperature ≥ 110 °F and <150 °F as measured by the CEMS, SO2 emissions shall be ≤90 lb/hr. • Temperature ≥150 °F and ≤220 °F as measured by the CEMS, SO2 emissions shall be ≤90 lb/hr.
EQT 0003	Waste Heat Boiler/Baghouse	Stage 4: when the flue gas flow rate ≥110,000 SCFM and Temperature ≥220 °F as measured by the CEMS, SO2 emissions shall be ≤50 lb/hr.
EQT 0004	Pyroscrubber Stack	Non-transition operations: No flow through EQT 0003, SO2 emissions shall be ≤2020 lb/hr.
EQT 0004	Pyroscrubber Stack	Transition Stage 1: EQT 0003 flow rate <40,000 SCFM, SO2 emissions shall be ≤1,000 lb/hr.
EQT 0004	Pyroscrubber Stack	Transition Stage 2: 40,000 SCFM ≤EQT 0003 flow rate <70,000 SCFM, SO2 emissions shall be ≤650 lb/hr.
EQT 0004	Pyroscrubber Stack	Transition Stage 3: 70,000 SCFM ≤EQT 0003 flow rate 110,000 SCFM, SO2 emissions shall be ≤650 lb/hr.
EQT 0004	Pyroscrubber Stack	Transition Stage 4: EQT 0003 flow rate ≥110,000 SCFM, SO2 emissions shall be ≤400 lb/hr and temperature ≥1,000 °F.
SCFM in Table is wet flow at standard conditions of 20C and standard atmospheric pressure (1,013.25 millibars).

The two other facilities that are located outside of St. Bernard Parish that were included in the modeling are not located in a direction such that they can contribute to the maximum concentrations in St. Bernard Parish (not upwind) so would have a negligable impact on maximum modeled concentrations within St. Bernard Parish. Therefore, LDEQ did not require new SO₂ emission limits on these facilities (ConocoPhillips, and New Orleans Sewer Treatment). EPA has reviewed the facilities' data and notes that the ConocoPhillips facility is 27 km away from the Vista monitor and neither ConocoPhillips nor the New Orleans facility (less than 3 tons per year emissions) are upwind of the maximum modeled concentrations and thus are not critical to demonstrating attainment in the area. EPA agrees with LDEQ's decision not to establish emission limits for these facilities in this SIP.

F. Background Concentrations

To develop background concentrations for the nonattainment area, Louisiana relied on 2012-2014 SO₂ data from the Meraux monitor and meteorological data from the Vista monitor (no meteorological data are collected at Meraux). The Meraux and Chalmette Vista (Vista) sites are located only 5 km apart and in similar topography; therefore, meteorological conditions at the Vista monitor are representative of those at Meraux.^[18] In determining the monitored background concentration, LDEQ excluded monitored data when the major sources (Rain, Chalmette Refinery and Valero Refinery) were impacting the monitor. A 68-degree sector containing all three sources was identified and hourly SO₂ values corresponding to hours when the wind direction was from within that 68-degree arc and wind speeds were greater than 2 miles per hour were excluded. The 2nd highest value for each season and hour of day was determined for each of the three years 2012-2014. These values were averaged and the resulting set of values were utilized as background. LDEQ also examined more recent monitoring data and determined that subsequent years had lower design values.

These background values are representative of the contribution due to other sources within the St. Bernard Parish and surrounding areas that were not explicitly modeled. See the TSD for additional information. Using this approach, the EPA finds the State's treatment of SO₂ background levels to be suitable for the modeled attainment demonstration.

G. Summary of Results

The modeling analysis including the February 2, 2018 AOC emission limits for the Rain facility resulted in concentrations below the level of the 1-hour primary SO₂ NAAQS. The EPA has reviewed Louisiana's attainment demonstration, conducted additional modeling runs and agrees that Louisiana's submittal and supplemental materials, along with the new AOC limits (February 2, 2018), result in demonstrating attainment of the 1-hour SO₂ NAAQS before the attainment deadline of October 4, 2018. LDEQ reviewed EPA's modeling files and has affirmed that they are accurate and representative.^[19]

Table 1—Summary of EPA Model Results With Number of Operating Scenarios Modeled, if Greater Than One

Operational status	Design value μg/m3
Cold Stack Normal Operations (Two Scenarios)	192.4
Hot Stack Normal Operations	171.3
Transition (Seven Scenarios)	190.0
Rain Property	146.4
Valero Property	125.5
Chalmette Refinery Property	148.3

We therefore propose to determine that Louisiana's plan provides for attainment of the 2010 primary SO₂ NAAQS in the St. Bernard Parish nonattainment area prior to October 4, 2018.

V. 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. As noted above, the state must develop and submit to the EPA a comprehensive, accurate and current inventory of actual emissions from all sources of SO₂ emissions in each nonattainment area, as well as any sources located outside the nonattainment area which may affect attainment in the area. See CAA section 172(c)(3).

In its submittal, Louisiana included a current emissions inventory for the St. Bernard Parish nonattainment area based on the 2011-2015 period. Two other sources outside St. Bernard Parish were also included in the modeling, but were not critical to the modeling and thus further emission reductions (or including existing limits in this SIP) were not necessary for these two sources (ConocoPhillips and New Orleans Sewer Treatment).

The State principally relied on 2011 as the most complete and representative record of annual SO₂ emissions because it coincided with the EPA's National Emissions Inventory (NEI), which includes a comprehensive inventory of all source types (point, nonpoint and onroad and off-road mobile sources). Changes to the methodology for the NEI for off-road sources made the 2014 NEI values incomparable to the previous years, but additional emissions information was provided to supplement the 2011 NEI data.

The state of Louisiana compiles a statewide EI in accordance with the CAA Amendments of 1990, LAC 33:III.918 and 919 (Recordkeeping and Annual Reporting and Emissions Inventory). Louisiana supplemented the 2011 NEI data with their 2013 point source EI in the SIP submittal as shown in the following table: ^[20]

2013 St. Bernard Parish Point Source Emissions Inventory

	Tons per year
Rain Chalmette Coke Plant	3061.88
Chalmette Refinery	255.46
Valero Refinery	200.74
TOCA Gas Processing Plant	3.27
Chalmette Cane Sugar Refinery	0.76
ELOI Bay Platform No. 1	0.41
Southern Natural Gas Co.—Toca Compressor Station	0.17
2013 Point Source Totals	3522.69

In addition, the State further supplemented the emissions inventory information and SIP submittal with newer, more specific emissions information for Rain in the February 2, 2018 AOC, which included revised emission limits and operating parameters utilized in the attainment demonstration modeling.

Louisiana also developed SO₂ emissions projections for the 2018 attainment year. Nonpoint and mobile emissions data was taken from the NEI database. Emissions projections for nonpoint and mobile sources are based on the reductions established in 2005, 2008, and 2011. The emissions estimate for 2018 point sources is based on FY 2013 emissions.

Because St. Bernard Parish is currently an SO₂ nonattainment area, nonattainment new source review (NNSR) requires SO₂ increases from new major sources and major modifications to be offset at > 1 to 1, therefore, the emissions estimate for 2018 point sources is based on FY 2013 emissions at 3,523 tons per year (tpy). Nonpoint and mobile emissions data was taken from the NEI database. The combined emissions estimate for 2018 nonpoint and mobile sources is approximately 625 tpy, approximately the same as current emissions, almost all of which are from nonpoint sources.

The EPA agrees that the State's emissions inventories for point, nonpoint and mobile sources are appropriate because they rely on well-established and vetted estimates of emissions for the current period and attainment year, respectively.

B. RACM/RACT

To be approved by the EPA, the SIP must provide for attainment of the standard based on SO₂ emission reductions from control measures that are permanent and enforceable. At a minimum, states must consider all RACM and RACT measures that can be implemented in light of the attainment needs for the affected area, and include all necessary measures in order to attain the NAAQS. The definition for RACT is that control technology which is necessary to achieve the NAAQS (see 40 CFR 51. 100(o)). Since SO₂ RACT is already defined as the technology necessary to achieve NAAQS, control technology which failed to achieve the SO₂ NAAQS would, by definition, fail to be SO₂ RACT. See General Preamble at 57 FR 13498, 13547.^[21] Louisiana's submittal and supplement meets this requirement for the 1-hour SO₂ NAAQS in the St. Bernard Parish nonattainment area as the control measures implemented in the plan have been shown to achieve attainment.

The plan relies on ambient SO₂ concentration reductions achieved by implementation of an AOCand permitted limits at Rain and permitted limits at Valero and Chalmette Refining. Rain achieved reductions by replacing the existing stack for the Waste Heat Boiler/Baghouse (EQT003) with a new stack with a height of approximately 199 feet; ^[22] and replacing the lime injection system with an SO₂ scrubber and baghouse.^[23] The Waste Heat Boiler/Baghouse began venting through the new stack on October 10, 2013. The SO₂ scrubbing system was operational before February 29, 2016. The impact of these measures had an apparent positive impact on the measured SO₂ concentrations at the relevant (Chalmette Vista) SO₂ monitor based on the recent reduction in observed concentrations.

Further improvements will be achieved through the implementation of the February 2, 2018 AOC that sets operating parameters and emission limits for all three operating states: 1) Emit through Hot Stack; 2) Emit through Cold Stack; and 3) Transition between the two states during which emissions are through both stacks. It also further reduced the emission limits for the cold stack providing for an additional 57-78% reduction in cold stack emissions.

The final emission limitations as included in the February 2, 2018 AOC are provided in Section IV.E. Emission Limitations above.

Valero Refining completed SO₂ reductions and revised their permit to incorporate the lowering of flare emissions due to the installation of a flare gas recovery system in Permit No. 2500-00001-V12 issued March 9, 2016. The Chalmette Refinery made all the consent decree SO₂ reductions with the last requirements met by December 31, 2016, with a flare management plan (Permit No. 3016-V4). Rain has installed controls to help reduce its impacts, e.g., the installation and venting through a taller stack by October 10, 2013, and the installation and operation of a SO₂ scrubber by February 29, 2016.

Motor Vehicles in the general area have reduced SO₂ emissions through the implementation of federal programs, such as Tier 3 vehicle emission and fuel standards that have begun in 2017. Tier 3 sets new vehicle emissions standards and lowers the sulfur content of gasoline, considering the vehicle and its fuel as an integrated system. Specifically, Federal gasoline will not contain more than 10 parts per million (ppm) of sulfur on an annual average basis by January 1, 2017.

Louisiana has determined that these measures for Rain in addition to the permitted limits at Valero Refining, and Chalmette Refining, provide for timely attainment and meet the RACT requirements.^[24] The EPA concurs and proposes to conclude that the state has satisfied the requirement in section 172(c)(1) to adopt and submit all RACM, including RACT, as needed to attain the standards as expeditiously as practicable.

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 (67 FR 61270); 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 SO₂ 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 St. Bernard Parish. These rules provide for appropriate new source review for SO₂ major sources undergoing construction or major modification in St. Bernard Parish without need for modification of the approved rules. Therefore, the EPA concludes that this requirement has already been met for this area.

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 EPA for the purpose of ensuring attainment of the applicable NAAQS by the applicable attainment date.” This definition is most appropriate for pollutants that are emitted by numerous and diverse sources, where the relationship between any individual source and the overall air quality is not explicitly quantified, and where the emission reductions necessary to attain the NAAQS are inventory-wide. See April 2014 SO₂ Guidance memo, page 40.^[25] EPA has also previously explained that the definition is generally less pertinent to pollutants like SO₂ that usually have a limited number of sources affecting areas of air quality that are relatively well defined, and emissions control measures for such sources result in swift and dramatic improvement in air quality.^[26] For SO₂, there is usually a single “step” between pre-control nonattainment and post-control attainment. Therefore, for SO₂, with its discernible relationship between emissions and air quality, and significant and immediate air quality improvements, RFP is best construed as “adherence to an ambitious compliance schedule.” See General Preamble at 74 FR 13547 (April l6, 1992). This means that the State must ensure that affected sources implement appropriate control measures as expeditiously as practicable in order to ensure attainment of the standard by the applicable attainment date.

In its submittal and supplement, the LDEQ provided its rationale for concluding that the plan met the requirement for RFP in accordance with EPA guidance. Specifically, LDEQ's rationale is based on the General Preamble and EPA 2014 SO₂ guidance interpreting the RFP requirement being satisfied for SO₂ if the plan requires “adherence to an ambitious compliance schedule” that “implement[s] appropriate control measures as expeditiously as practicable.” The submittal and supplement provide for attainment as expeditiously as practicable, i.e., by the attainment date of October 4, 2018, and thereby satisfy the requirement for RFP. As noted previously, there are three major sources in the area that are the main sources of concern: Valero Refining, Chalmette Refining, and Rain. The two point sources (Valero and Chalmette) are subject to emissions reductions from consent decrees that have been included in NSR SIP permits. Valero Refining completed all the consent decree's SO₂ reductions and revised their permit to incorporate the lowering of flare emissions due to the flare gas recovery system in Permit No. 2500-00001-V12 issued March 9, 2016. The Chalmette Refinery made all the consent decree's SO₂ reductions with the last requirements met by December 31, 2016, with a flare management plan (Permit No. 3016-V4). Rain entered into a February 2. 2018, AOC that requires compliance by May 3, 2018, and if finalized as a SIP revision, will become federally enforceable. Therefore, Louisiana concluded that its SIP submittal and supplement provide for RFP in accordance with the approach to RFP described in the EPA's SO₂ guidance and the Preamble. The EPA concurs and proposes to conclude that the SIP submittal and supplement provides for RFP.

E. Contingency Measures

As discussed in our 2014 SO₂ guidance, Section 172(c)(9) of the CAA defines contingency measures as such measures in a SIP that are to be implemented in the event that an 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, where the area has failed to (1) achieve RFP or (2) attain the NAAQS by the statutory attainment date for the affected area. These control measures are to 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 SO₂ planning that influence the suitability of alternative means of addressing the requirement in section 172(c)(9) for contingency measures for SO₂. Because SO₂ control measures are by definition 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 SO₂ is for the state to have a comprehensive enforcement program that identifies sources of violations of the SO₂ NAAQS and to undertake an aggressive follow-up for compliance and enforcement.

For its contingency program, Louisiana proposed to operate a comprehensive program to identify sources of violations of the SO₂ NAAQS and undertake aggressive compliance and enforcement actions. Louisiana has regulatory authority to implement emergency rules for cause which may include violations of the NAAQS. More specifically, Louisiana proposed an analysis to determine the cause of any violation of the SO₂ NAAQS, followed by identification and implementation of appropriate control measures at major SO₂ sources through the use of emergency rules and/or administrative orders. Because the LDEQ has the ability to issue administrative orders and/or emergency rules that do not require public notice or comment and would use that process, as needed, to quickly implement measures to protect public health, the EPA believes that this approach continues to be a valid approach for the implementation of contingency measures to address the 2010 SO₂ NAAQS.

As noted above, EPA guidance describes special features of SO₂ planning that influence the suitability of alternative means of addressing the requirement in section 172(c)(9) for contingency measures for SO₂, such that in particular an appropriate means of satisfying this requirement is for the state to have a comprehensive enforcement program that identifies sources of violations of the SO₂ NAAQS and to undertake an aggressive follow-up for compliance and enforcement. Louisiana's plan provides for satisfying the contingency measure requirement in this manner. The EPA concurs and proposes to approve Louisiana's plan for meeting the contingency measure requirement in this manner.

VI. 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 SO₂ 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 SO₂. 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.

Transportation conformity determinations are not required in SO₂ nonattainment and maintenance areas. EPA concluded in its 1993 transportation conformity rule that highway and transit vehicles are not significant sources of SO₂. Therefore, transportation plans, transportation improvement programs and projects are presumed to conform to applicable implementation plans for SO₂. (See 58 FR 3776, January 11, 1993.)

VII. EPA's Proposed Action

The EPA is proposing to approve Louisiana's SIP submission, which the State submitted to EPA on November 9, 2017, and supplemented on February 8, 2018, as meeting the requirements for attainment as expeditiously as practicable but no later than October 4, 2018, and other nonattainment area planning requirements for the St. Bernard Parish Nonattainment Area. This 2010 1-hour SO₂ SIP submittal includes Louisiana's attainment demonstration for the St. Bernard Parish Nonattainment Area, including a new February 2, 2018 AOC for Rain that serves as a source-specific SIP revision, and the other CAA required elements including RFP, a RACT/RACM demonstration, base-year and projection-year emission inventories, and contingency measures. We are proposing to approve the February 2, 2018, Rain AOC as a source-specific revision to the SIP. Louisiana also demonstrated it met the requirements regarding NNSR for SO₂ and the EPA approved this program.

The EPA has determined that Louisiana's SO₂ attainment plan meets applicable requirements of the sections 110, 172, 173, 191, and 192 of the CAA. EPA's analysis is discussed in this proposed rulemaking and in our TSD that is available on-line at www.regulations.gov,, Docket No. EPA-R06-OAR-2017-0558. The TSD provides additional explanation of the EPA's analysis supporting this proposal.

VIII. 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 proposing to incorporate by reference revisions to the Louisiana source-specific requirements as described in the Proposed Action section above. We have made, and will continue to make, these documents generally available electronically through www.regulations.gov and in hard copy at the EPA Region 6 office (please contact Robert Imhoff, 214-665-7262, [e-mail] for more information).

IX. 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, 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 proposed 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) and 13563 (76 FR 3821, January 21, 2011);
• Is not an Executive Order 13771 (82 FR 9339, February 2, 2017) regulatory action because SIP approvals are exempted 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 (Public Law 104-4);
• Does not have Federalism implications as specified in Executive Order 13132 (64 FR 43255, August 10, 1999);
• Is not an economically significant regulatory action based on health or safety risks subject to Executive Order 13045 (62 FR 19885, April 23, 1997);
• Is not a significant regulatory action subject to Executive Order 13211 (66 FR 28355, May 22, 2001);
• Is not subject to requirements of Section 12(d) of the National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 note) because application of those requirements would be inconsistent with the CAA; and
• Does not provide EPA with the discretionary authority to address, as appropriate, disproportionate human health or environmental effects, using practicable and legally permissible methods, under Executive Order 12898 (59 FR 7629, February 16, 1994).

In addition, the SIP is not approved to apply on any Indian reservation land or in any other area where EPA or an Indian tribe has demonstrated that a tribe has jurisdiction. In those areas of Indian country, the 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
• Reporting and recordkeeping requirements
• Sulfur oxides

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

Dated: April 12, 2018.

Anne Idsal,

Regional Administrator, Region 6.

Footnotes

1.  This designation was based on data from the Chalmette Vista monitoring site.

2.  Operations at Rain can be divided into three scenarios: Cold stack operation, hot stack operation, and a transitional period with emissions through both stacks.

3.  February 26, 2018 Completeness Determination Letter from Wren Stinger, EPA Region 6 to Chuck Carr Brown, LDEQ.

4.  As noted above, in the “Findings of Failure to Submit State Implementation Plans Required for Attainment of the 2010 1-Hour Primary Sulfur Dioxide National Ambient Air Quality Standard (NAAQS),” the finding also triggered a requirement that the EPA promulgate FIP within two years of the finding unless, by that time (a) the state has made the necessary complete submittal and (b) EPA has approved the submittal as meeting applicable requirements.

5.  “Guidance for 1-Hour SO₂ Nonattainment Area SIP Submissions” available at https://www.epa.gov/​sites/​production/​files/​2016-06/​documents/​20140423guidance_​nonattainment_​sip.pdf.

6.  The EPA published revisions to the Guideline on Air Quality Models on January 17, 2017. See 82 FR 5182 (January 17, 2017).

7.  80 FR 45340 (July 29, 2015).

8.  82 FR 5182 (January 17, 2017) and 82 FR 14324 (March 20, 2017).

9.  Memorandum from Tyler Fox (EPA OAQPS) “Applicability of Appendix W Modeling Guidance for the 1-hr SO₂ National Ambient Air Quality Standard.” August 23, 2010.

10.  Email from [e-mail] to [e-mail] et al., February 21, 2018, 1:53 p.m., included in the docket to this action.

11.  https://www3.epa.gov/​ttn/​scram/​models/​aermod/​aermod_​mcb12_​v16216.pdf.

12.  ADJ_U* is an option to adjust friction velocity during light winds in the nighttime and was not an issue in this modeling that needed to be utilized as maximum concentrations were during other time of day and meteorological conditions.

13.  When the EPA updated AERMET there were model change bulletins and other information that describe the exact changes. See https://www.epa.gov/​scram/​meteorological-processors-and-accessory-programs#aermet. The EPA provided sensitivity runs to identify results from the differences in files under the Test Cases section at http://www.epaarchive.cc/​node/​164075.html.

14.  Permit No 2500-00001-V16 for Chalmette Refining in the docket as 8-10-17 Valero-Meraux Refinery-permit 2500-0001-V16.pdf (Note the Permit No 2500-0001-V9 included reductions in SO₂ from a Consent Decree); Chalmette Refining Permits (No. 2500-0005-V5, 2933-V6, 2822-V2, 3004-V7, 3011-V3, 3015-V3, 3016-V3, 3017-V5, 3018-V5 30222-V7, 3023-V7) in the docket as Chalmette Refining-Final Permits.pdf

15.  Email from [e-mail] to [e-mail] et al., February 21 2018 1:53PM, included in the docket to this action.

16.  See docket to this action at 10-27-17 NSR-Title V Rain v3 Final.pdf.

17.  Permit No 2500-00001-V16 for Chalmette Refining in the docket as 8-10-17 Valero-MerauxRefinery-permit 2500-0001-V16.pdf (Note the Permit No 2500-0001-V9 included reductions in SO₂ from a Consent Decree); Chalmette Refining Permits (No. 2500-0005-V5, 2933-V6, 2822-V2, 3004-V7, 3011- V3, 3015-V3, 3016-V3, 3017-V5, 3018-V5 30222-V7, 3023-V7) in the docket as ChalmetteRefining-Final Permits.pdf

18.  We note that the meteorological data collected at the Vista monitor do not meet all the requirements for use as input for air quality modeling. See Section IV. B. for a discussion of the meteorological data used for modeling.

19.  Email from [e-mail] to [e-mail] et al. March 27, 2018 1:28PM included in docket to this action.

20.  The EPA reviewed more recent inventories (2014-2016) and confirmed that emissions were similar with Rain emissions being slightly higher on average and the two refineries (Valero and Chalmette) were lower in more recent years. See St. Bernard EI 2014-2016.xlsx in the docket.

21.  See CAA section 110(a)(2)(A) and CAA 172(c)(1) that provides that “[s]uch plan shall provide for the implementation of all reasonably available control measures as expeditiously as practicable (including such reductions in emissions from existing sources in the area as may be obtained through the adoption, at a minimum, of reasonably available control technology) and shall provide for attainment of the national primary ambient air quality standards.”

22.  Pursuant to an AOC, entered into by LDEQ and Rain, Rain was to replace the stack with a new stack of approximately 199 feet. The new stack was in operation prior to December 31, 2013. Enforcement Tracking No. AE-AOA-13-00490, effective June 20, 2013.

23.  Rain CII Chalmette NSR Title V Permit October 27 2017, in docket as 10-27-17 NSR-Title V Rain v3 Final.pdf

24.  Permit No 2500-00001-V16 for Chalmette Refining in the docket as 8-10-17 Valero-MerauxRefinery-permit 2500-0001-V16.pdf (Note the Permit No 2500-0001-V9 included reductions in SO₂ from a Consent Decree); Chalmette Refining Permits (No. 2500-0005-V5, 2933-V6, 2822-V2, 3004-V7, 3011- V3, 3015-V3, 3016-V3, 3017-V5, 3018-V5 30222-V7, 3023-V7) in the docket as ChalmetteRefining-Final Permits.pdf.

25.  April 23, 2014 Guidance for 1-Hour SO₂ Nonattinment Area SIP Submissions which can be found at: https://www.epa.gov/​sites/​production/​files/​2016-06/​documents/​20140423guidance_​nonattainment_​sip.pdf.

26.  See SO₂ Guideline Document, U.S. Environmental Protection Agency, Office of Air Quality Planning and Standards, Research Triangle Park, N.C. 27711, EPA-452/R-94·008, February 1994. (See https://nepis.epa.gov/​Exe/​ZyPDF.cgi/​2000H22J.PDF?​Dockey=​2000H22J.PDF).