Approval and Promulgation of Implementation Plans; Louisiana; Attainment Demonstration for the St. Bernard Parish 2010 SO2, 17349-17358 [2018-08067]

Agencies

• ENVIRONMENTAL PROTECTION AGENCY

[Federal Register Volume 83, Number 76 (Thursday, April 19, 2018)]
[Proposed Rules]
[Pages 17349-17358]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-08067]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R06-OAR-2017-0558; FRL-9976-51--Region 6]


Approval and Promulgation of Implementation Plans; Louisiana; 
Attainment Demonstration for the St. Bernard Parish 2010 SO2 Primary 
National Ambient Air Quality Standard Nonattainment Area

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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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

[[Page 17350]]

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 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 
Robert Imhoff, 214-665-7262, [email protected]. For the full EPA 
public comment policy, information about CBI or multimedia submissions, 
and general guidance on making effective comments, please visit https://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, 
[email protected]. 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.
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    \1\ This designation was based on data from the Chalmette Vista 
monitoring site.
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    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

[[Page 17351]]

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\
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    \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.
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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.
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    \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.
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    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

[[Page 17352]]

reliable assurance that the plan provides for attainment.
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    \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).
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    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\
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    \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.
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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.
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    \10\ Email from [email protected] to [email protected] et 
al., February 21, 2018, 1:53 p.m., included in the docket to this 
action.
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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\
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    \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 https://www.epaarchive.cc/node/164075.html.
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    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

[[Page 17353]]

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.
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    \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
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    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.
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    \15\ Email from [email protected] to [email protected] et 
al., February 21 2018 1:53PM, included in the docket to this action.
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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.

[[Page 17354]]

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.
---------------------------------------------------------------------------

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

    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.
---------------------------------------------------------------------------

    \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

                        AOC Emission Limitations
------------------------------------------------------------------------
    Source ID      Source description      Sulfur dioxide (SO2) limit
------------------------------------------------------------------------
EQT 0003........  Waste Heat Boiler/   During normal, steady-state
                   Baghouse.            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[square]F. If
                                        stack flow rate >=70,000 SCFM
                                        and <110,000 SCFM and
                                        Temperature is >=220 [deg]F, SO2
                                        emissions shall be <=380 lb/hr.
EQT 0003........  Waste Heat Boiler/   Stage 1: when the flue gas flow
                   Baghouse.            rate <40,000 SCFM or Temperature
                                        <90 [deg]F as measured by the
                                        CEMS, SO2 emissions shall be
                                        <=10 lb/hr.
EQT 0003........  Waste Heat Boiler/   Stage 2: when the flue gas flow
                   Baghouse.            rate >=40,000 SCFM and <70,000
                                        SCFM:
                                        Temperature >=0 [deg]F
                                        and <110 [deg]F as measured by
                                        the CEMS, SO2 emissions shall be
                                        <=75 lb/hr.
                                        Temperature >=110 [deg]F
                                        and <150 [deg]F as measured by
                                        the CEMS, SO2 emissions shall be
                                        <=75 lb/hr.
                                        Temperature >=150 [deg]F
                                        and <220 [deg]F as measured by
                                        the CEMS, SO2 emissions shall be
                                        <=75 lb/hr.
EQT 0003........  Waste Heat Boiler/   Stage 3: when the flue gas flow
                   Baghouse.            rate >=70,000 SCFM and <110,000
                                        SCFM:
                                        Temperature >= 110
                                        [deg]F and <150 [deg]F as
                                        measured by the CEMS, SO2
                                        emissions shall be <=90 lb/hr.
                                        Temperature >=150 [deg]F
                                        and <=220 [deg]F as measured by
                                        the CEMS, SO2 emissions shall be
                                        <=90 lb/hr.
EQT 0003........  Waste Heat Boiler/   Stage 4: when the flue gas flow
                   Baghouse.            rate >=110,000 SCFM and
                                        Temperature >=220 [deg]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 [deg]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

[[Page 17355]]

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.
---------------------------------------------------------------------------

    \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.
---------------------------------------------------------------------------

    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\
---------------------------------------------------------------------------

    \19\ Email from [email protected] to [email protected] et 
al. March 27, 2018 1:28PM included in docket to this action.

Table 1--Summary of EPA Model Results With Number of Operating Scenarios
                      Modeled, if Greater Than One
------------------------------------------------------------------------
                                                           Design value
                   Operational status                        [mu]g/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\
---------------------------------------------------------------------------

    \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.

        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.

[[Page 17356]]

    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.
---------------------------------------------------------------------------

    \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.''
---------------------------------------------------------------------------

    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.
---------------------------------------------------------------------------

    \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
---------------------------------------------------------------------------

    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.
---------------------------------------------------------------------------

    \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.
---------------------------------------------------------------------------

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

[[Page 17357]]

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.
---------------------------------------------------------------------------

    \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[middot]008, 
February 1994. (See https://nepis.epa.gov/Exe/ZyPDF.cgi/2000H22J.PDF?Dockey=2000H22J.PDF).
---------------------------------------------------------------------------

    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 compre