TECHNICAL SUPPORT DOCUMENT

Louisiana Regional Haze State Implementation Plan

August 31, 201 6

S ubmitted August 11 , 2016

No material in this submittal package was designated as Confidential Business Information.

FOR FURTHER INFORMATION CONTACT:

Jennifer Huser

, United States Environmental Protection Agency Region 6, Air Planning Section (6MM

- AA ), 1445 Ross Avenue, Suite 1200, Dallas, Texas 75202

- 2733, (214) 665

- 7347I. Louisiana Regional Haze

A. Background on Regional Haze

Regional haze is visibility impairment that is produced by a multitude of sources and activities which are located across a broad geographic area and emit fine particulate matter ( PM 2.5 ) (e.g., sulfates, nitrates, organic carbon, elemental carbon, and soil dust), and their precursors (e.g., SO 2 , NO x , and in some cases, ammonia (NH 3 ) and volatile organic compounds (VOCs) ) . Fine particle precursors react in the atmosphere to form PM 2.5 that impairs visibility by

s cattering and absorbing light. Visibility impairment reduces th e clarity, color, and visi ble distance that one can see. PM 2.5 can also cause serious health effects and mortality in humans and contributes to environmental effects such as acid deposition and eutrophication.
Data from the existing visibility monitoring network, the “Interagency Monitoring of Protected Visual Environments” (IMPROVE) monitoring network, show that visibility impairment caused by air pollution occurs virtually all the time at most national parks (NPs) and wilderness areas (WAs). The average visual range 1 in many Class I areas ( i.e. , NPs and memorial parks, WAs, and international parks meeting certain size criteria) in the western United States is 100

- 150 kilometers, or about one

- half to two

- thirds of the visual range that would exist without anthropogenic air pollution. In most of t he eastern Class I areas of the United States, the average visual range is less than 30 kilometers, or about one

- fifth of the visual range that would exist under estimated natural conditions. 64 FR 35714, at 35715 (July 1, 1999).

B. Regional Haze Requirement s

The goal of the Regional Haze Rule (RHR) is to restore natural visibility conditions 2 by 2064 at the 156 Class I areas 3 identified in the 1977 Clean Air Act Amendments. The regional haze state implementation plans (SIPs) must contain measures that make “reasonable progress” toward this goal by reducing anthropogenic emissions that cause haze. The RHR sets out specific requirements for state’s initial regional haze SIPs. In particular, each plan must establish a long term strategy that ensures reasonable progress toward achieving natural visibility conditions in each Class I area affected by the emissions from sources within the state. In addition, for each Class I area within the state’s boundaries, the plan must establish a reasonable progress goal (RPG ) for the first planning period that ends on July 31, 2018. The long

- term strategy must include enforceable emission limits and other measures as necessary to achieve the RPG. Regional haze plans must also give specific attention to certain stationary sour ces that were in existence on August 7, 1977, but were not in operation before August 7, 1962. These sources, where appropriate, are required to install Best Available Retrofit Technology (BART) controls to

1 Visual range is the greatest distance, in kilometers or miles, at which a dark object can be viewed against the sky.

2 40 CFR 51.301(q) defines natural conditions: “Natural conditions include naturally occurring phenomena that reduce visibility as measured in terms of light extinction, visual range, contrast, or coloration.”

3 Louisiana has one Class I area within its bor ders, namely the Breton National Wilderness Area (Breton).eliminate or reduce visibility impairment. More d etails on regional plan requirements are

summarized in the Regional Haze Rule. 64 FR 35714

.

C. Relationship of this TSD and Our Proposed Approval of the SIP Action Submitted by LDEQ on August 26, 2016 to Our July 3, 2012 Final Partial Approval and Partial Limited Disapproval of the Louisiana Regional Haze SIP

The Act requires each state to develop plans to meet various air quality requirements, including protection of visibility. (CAA sections 110(a), 169A, and 169B). The plans developed by a state are referred to as State Implementation Plans or SIPs. A state must submit its SIPs and SIP revisions to EPA for approval. Once approved, a SIP is federally enforceable, that is enforceable by EPA and citizens under the Act. If a state fails to make a required SIP submittal or if we find that a state’s required submittal is incomplete or unapprovable in whole or in part, then we must promulgate a Federal Implementation Plan (FIP) to fill this regulatory ga p within 2 years unle ss we approve a SIP revision correcting the deficiencies before promulgating a FIP. (CAA section 110(c)(1)).
To address the first implementation period, the State of Louisiana submitted a RH SIP on June 13, 2008. EPA acted on that submittal in two separate actions: a limited disapproval (77 FR 3364 1 ; June 7, 2012 ) because the SIP relied on the Clean Air Interstate Rule (CAIR) to address the impact of emissions from the State’s electric generating units (EGUs); and a partial limited approval/partial disappro val (77 FR 39425 ; July 3, 2012 ) noting deficiencies in the SIP revision that did not meet the applicable requirements of the CAA and EPA’s regulations as set forth in sections 169A and 169B of the CAA and in 40 CFR 51.300

- 308. On August 11 , 2016 , Louisian a submitted a SIP revision intended to cure the deficiencies noted in our partial limited approval/partial disapproval concerning BART for four non

- EGU sources. This TSD and our proposed approval provide our analysis of that submittal. However, the defic iencies stemming from Louisiana’s reliance on CAIR for EGU BART are not addressed by this submittal or our proposed action. We will address EGU BART for Louisiana in a future rulemaking.

D. Portions of the Louisiana Regional Haze SIP Addressed by EPA and Remaining Items Addressed by This Action

In our July 3, 2012 final partial limited approval and partial disapproval of the June 13, 2008 Louisiana RH SIP, we found that the following elements satisfied the federal requirements insofar as they do not rely on the sulfur dioxide (SO2) and nitrogen oxides (NO X ) reductions from the Clean Air Interstate Rule (CAIR):

 I dentification of affected Class I areas;

 E stablishment of baseline, natural and current visibility conditions, including the Uniform Rate of Progress (URP);

 C oordination of reasonably attributable visibility impairment (RAVI) and RH requirements; RH monitoring strategy and other SIP requirements under Title 40 of the Code of Federal Regulations (denoted as 40 CFR), Part 51.308(d)(4);

 Louisi ana’s commitment to submit periodic RH SIP revisions and periodic progress reports describing progress towards the state’s Reasonable Progress Goals (RPGs);

 Louisiana’s commitment to make a determination of the adequacy of the existing SIP at the time a p rogress report is submitted and;

 Louisiana’s coordination with the Federal Land Managers ( FLMs )

.

We also found that certain elements of the Best Available Retrofit Technology (BART) evaluations and determinations were not fully adequate to meet the federa l regulations. For the BART Sources, the following deficiencies were noted in the BART analyses:

 SO 2 , NO X , and PM BART for Mosaic ;

 SO 2 , NO X , and PM BART for certain BART

- Subject Units at the Phillips 66 Company Alliance Refinery (formerly ConocoPhillips) ;

 SO 2 BART for EcoServices Units 1 and 2; and

 SO 2 and NO X BART for Sid Richardson
In addition to finding the listed BART analyses deficient, we also found that the submittal did not include enforceable emissions limitations or compliance schedules within the SIP for those sources subject to BART.
The purpose of this TSD and the proposed Federal Register notice associated with this TSD is to supersede the portions of the previous actions addressing non

- EGU BART that were found deficient in the partial li mited approval and partial disapproval action ( 77 FR 39425 )

. This TSD contains our evaluation of the revised Louisiana RH SIP submittal provided by LDEQ on August 11 , 2016

. This TSD is not meant to be a complete rationale for our decision. It merely provides additional information for some of the technical aspects of the basis for this action when needed. In some of the non

- technical areas, our Federal Register (FR) notice provides more detail than does the TSD. The TSD also refer s the reader to the specific p ortions of the Louisiana RH SIP submittal that we relied upon for our analysis of particular portions of 40 CFR 51. 3 08.
Throughout this document, we often use language such as, “we find” or other similar phrases that on the surface would suggest a final determination has been made. However, all aspects of our TSD should be considered to be part of our proposal and are subject to change based on comments and other information we may receive during our public comment period.

II. Best Available Retrofit Technolo gy (BART)

A. Identification of BART Eligible Sources and Subject to BART S ources

States are required to identify all the BART

- eligible sources within their boundaries by utilizing the three eligibility criteria in the BART Guidelines (70 FR 39104, at 3915 7

- 5 8) and the Regional Haze regulations (40 CFR 51.301): (1) One or more emission units at the facility fitwithin one of the 26 categories listed in the BART Guidelines; (2) the emission unit(s) began

operation on or after August 6

, 1962, and the unit wa s in existence on August 6, 1977; and (3) the potential emissions of any visibility

- impairing pollutant from subject units are 250 tons or more per year. Sources that meet these three criteria are considered BART

- eligible. Once a list of the BART

- eligible sources within a state has been compiled, states must determine whether to make BART determinations for all of them or to consider exempting some of them from BART because they may not reasonably be anticipated to cause or contribute to any visibility impa irment in a Class I area. The BART Guidelines present several options that rely on modeling analyses and/or emissions analysis approaches to determine if a source may reasonably be anticipated to cause or contribute to visibility impairment in a Class I ar ea. A source that may not be reasonably anticipated to cause or contribute to any visibility impairment in a Class I area is not “subject to BART,” and for such sources, a state need not apply the five statutory factors to make a BART determination.

In det ermining BART for sources that are subject to BART , the state must consider the five statutory factors in section 169A of the CAA: (1) the costs of compliance; (2) the energy and

non

- air quality environmental impacts of compliance; (3) any existing polluti on control technology in use at the source; (4) the remaining useful life of the source; and (5) the degree of improvement in visibility which may reasonably be anticipated to result from the use of such technology. See also 40 CFR 51.308(e)(1)(ii)(A).

Th e BART Guidelines (70 FR 39164, July 6, 2005) describe the BART analysis as consisting of the following five steps:

 Step 1: Identify All Available Retrofit Control Technologies;

 Step 2: Eliminate Technically Infeasible Options;

 Step 3: Evaluate Control Ef fectiveness of Remaining Control Technologies;

 Step 4: Evaluate Impacts and Document the Results; and

 Step 5: Evaluate Visibility Impacts.
As mentioned previously, Louisiana submitted the 2008 RH SIP to address the first regional haze implementation period on June 13, 2008. On July 3, 2012, the EPA finalized a partial limited approval and partial disapproval of the Louisiana RH SIP (77 FR at 39425). This included a disapproval of portions of the BART determinations made by Louisiana. Following EPA’s partial limited approval and partial disapproval action, the Louisiana Department of Environmental Quality (LDEQ) worked closely with the BART facilities and with EPA Region 6
to revise the Regional Haze SIP. LDEQ submitted a revised Louisiana RH SIP on August 11

, 2016.

1. Mosaic Fertilizer Uncle Sam Plant

Mosaic Fertilizer, LLC owns and operates the Uncle Sam Plant in St. James Parish, Louisiana and produces phosphoric acid and sulfuric acid. In the original LA RH submittal, Louisiana determined that Mosaic was not subject to BART based on modeling future controls that were to be installed on the A Train Sulfuric Acid Stack.In our July 3, 2012 final action, we approved Louisiana’s identification of BART

- eligible

so urces and determination of sources subject to BART, with the exception of the State’s determination that the Mosaic Fertilizer Uncle Sam Plant was exempted from BART. Our basis and analyses for our disapproval of Louisiana’s determination that Mosaic was e xempted from BART is found in our February 28, 2012 proposed rulemaking, July 3, 2012 final rulemaking, and the associated TSDs. 4 LDEQ agreed that Mosaic should have been identified as subject to BART, and therefore required to conduct a five factor BART a nalysis.

Mosaic conducted and submitted a n initial BART analysis to LDEQ on July 17, 2015. During our review of the initial BART analysis, several items were noted as failing to follow the BART Guidelines. In response to an EPA issued CAA Section 114 In formation Request 5

, Mosaic corrected the deficiencies and submitted to EPA and LDEQ a revised BART analysis. 6

Mosaic used the three step process in the Regional Haze Rule to determine if the units are BART

- eligible. A stationary source is evaluated to de termine whether it contains any emissions units in one or more of the 26 relevant source categories. If the stationary source includes an emissions unit in one or more of these source categories, then the next step requires the source to determine whether each of these emissions units began operation after August 7, 1962 and was in existence on August 7, 1977. The last step is to evaluate the current potential to emit emission rate of each visibility

- impairing pollutant (NOx, PM, and SO2) separately to det ermine whether the total potential to emit emission rate from these emissions units equals 250 tpy or more for any visibility

- impairing pollutant. Using this process, Mosaic identified the following units as subject to BART:

 A Train Single Absorption H2SO 4 Plant

 A Train Startup Burner

 A Train Fugitive Emissions

 D Train Double Absorption H2SO4 Plant

 D Train Startup Burner

 D Train Fugitive Emissions

 Phosphate Rock Transfer, Storage, and Handling Operations

 Sulfur Unloading Pit

 Sulfur Storage Tank A

 Sulfur Storage Tank B

 Dock Fugitive Emissions

 No. 1 Packaged Steam Boiler

 No. 2 Packaged Steam Boiler
Mosaic also concluded that the emissions units comprising the plant’s E Train are not BART

eligible because they were not “in existence” on August 7, 1977. Cons truction of the E Train began in 1991, as indicated by the January 14, 1991 preconstruction air permit application

4 77 FR 11839 and 77 FR 39425.

5 CAA Section 114 Letter from Ms. Wren Stenger to Mr. David Oubre dated September 1, 2015. A copy of this letter and its attachments can be found in the docket for this proposed rulemaking.

6 CAA Section 114 Response letter from Mr. David Oubre to Ms. Wren Stenger dated September 30, 2015. A copy of this letter and its attachments can be found in the docket for this proposed rulemaking.submitted to LDEQ, along with the August 16, 1991 air permit (Permit No. 2091) issued by

LDEQ authorizing its construction. 7

On October 5, 20 09, Mosaic entered into a Consent Decree with the United States and Louisiana Department of Environmental Quality to address alleged violations of the Clean Air Act. 8 Requirements of the settlement included the installation of controls at the Uncle Sam plant. Those controls included:

 A scrubber system installed on the A Train in February 2011 reducing SO 2 emissions by 9,460 tons per year; and

 Improving the dual absorp tion system on the D Train in July

- September 2001 resulting in 576 tons per year reduction of SO 2 emissions

. In conducting the five factor BART analysis, Mosaic concluded and LDEQ agreed that the existing operations and emissions control technologies are consistent with the future case modeled in the BART analysis

. LDEQ further concluded that additional emission controls would not be cost effective and would not provide sufficient visibility benefits to be warranted

. Based on the se conclusions, LDEQ conclu ded that the current controls, operating conditions, and emissions limits satisfy BART

. LDEQ ’ s review is in Section II of the SIP submittal . EPA has reviewed and agrees with LDEQ’s conclusion that the current controls and emissions limits represent BART for S O 2 , NOx, and PM

. Section 51.308( e ) requires that Louisiana ’s Regional Haze SIP include emissions limitations representing BART. Louisiana incorporated the emission limits that constitute BART for SO 2 , NOx, and PM in an Administrative Order on Consent (AOC) No. AE

- AOC

- 14

- 00274A

. The revised determination and AOC establish enforceable and permanent emission limits and operating conditions.

2. Phillips 66 Alliance Refinery (formerly ConocoPhillips Co.)

The Phillips 66 Company (Phillips 66) operates a refinery near Belle Chasse, Louisiana and is a subject to BART source. Phillips 66 entered into a Consent Decree (CD) with the United States of America and the State of Louisiana on December 5, 2005, as part of the National Refinery Initiative. 9 As a part of the settlement, Phillips 66 installed controls on the fluidized catalytic cracker, the process refinery flares, and the crude unit heater.

In our July 3, 2012 final action, we determined that LDEQ did no t provide a complete BART evaluation for the units covered by the CD. LDEQ did not analyze the controls using the five step process required by 40 CFR 51.308(e). Also, no emission limits for BART for these units were included in the LA RH SIP. Several othe r units were determined to be subject to BART at the Phillips 66 Alliance Refinery. For the cooling water tower and gas

- fired heaters,

7 Permit Application submitted by Agrico to LDEQ on January 14, 1991, and Permit No. 2091 issued to Agrico on August 16, 1991. Agrico was the predecessor in ownership to Mosaic Fertilizer, LLC of the Uncle Sam Plant

. A copy of these documents is provided in the LDEQ SIP submittal, Exhibit 1 of Attachment 1 (BART Analysis)

8 Civil Action No. 09

- 6662. A copy of this CD is available in the docket for this proposed rulemaking.

9 Civil Action No. H

- 05

- 0285. A copy of this CD is available in the docket for this rulemaking.we approved the BART analysis provided for PM (cooling water tower) , and NO X (gas

- fired

heaters) and agreed that no additional controls were necessary. We also approved the BART analysis and conclusions for emissions of PM, SO 2 , and NO X for the Product Dock No. 1 MVR Loading, the Product Dock No. 2 MVR Loading, and Coke Transfer a nd Storage.

On January 27 , 2014 , Phillips 66 provided a revised BART analysis to LDEQ to include the five step analysis of for the fluidized catalytic cracker (FCCU) , the process refinery flares, and the crude unit heater. In this BART analysis, Phillips 66 provided information including emission reductions resulting from the installation of controls mandated in the Consent Decree. Controls installed include:

 A wet gas scrubber (WGS) installed on the FCCU in 2009 that reduced SO 2 emissions by 2500 tpy and PM emissions by 220 tpy. Selective Catalytic Reduction (SCR) installed in February 2015 that reduce d NOx emissions by 760 tpy.

 SCR was installed on the crude unit heater in 2009 that reduced NOx emissions by 700 tpy; NOx Continuous Emissions Monitoring wa s also installed on this unit;

 Flare gas recovery was installed for the process refinery flares in 2011 that reduced NOx emissions by 16 tpy and SO 2 emissions by 330 tpy;

 The low pressure and high pressure flares meet New Source Performance Standards (NSPS ) Subpart J requirements (EQT 308F

- D

- 1 and 309

- D

- 2);

 The CO Boilers meet NSPS J requirements (EQT 301

- B

- 2A and 301

- B

- 2B);

 Crude Charge Heater meets NSPS Subpa rt J requirements (EQT 191

- H

- 1).

In addition to controls required by the CD, the Crude Charge Heater is controlled by SCR and am ine scrubbing for NOx and SO 2

. In a review of controls found at refineries around the United States, Phillips 66 concluded that t here are no appropriate add

- on c ontrols to reduce PM emissions, and therefore good combustion techniques employed by Phillips 66 constitute BART. With respect to SO 2 , the refinery is required by CD to comply with fuel gas H 2 S limits mandated by NSPS Subpart J for Petroleum Refineries through the use of a fuel gas amine scrubbing system that applie s to all heaters in the refinery, and represents the most stringent available SO 2 control system. Therefore, for SO 2 and PM, the controls implemented as required by the CD, represent the top level of control and therefore a detailed BART analysis was not n ecessary. The Crude Charge Heater pollutants are controlled to the following levels:

 SO2: <=0.1 grains H2S/dscf (or 162 ppmvd H2S) in refinery fuel on a 3

- hr rolling average basis. This control level is achieved by amine scrubbing of the Phillips 66 refi nery fuel gas on a facility

- wide basis for all process heaters ;

 PM: 0.00745 lb PM/MMBtu of refinery fuel gas fired on an annual average basis using good combustion techniques based on AP

- 42 Table 1.4.2 (1998). Consistent with all other refinery fuel gas he aters operated in the U.S., there are no a dd

- on controls for PM emissions; and

 NOx: 0.0185 lb NOx/MMBtu of refinery fuel gas fired on a 365 day rolling average basis, controlled using a SCR control system.

In evaluating BART at the FCCU Regenerator Vent, Phillips 66 determined that SO 2 was the major contributor to visibility impairment. In 2003, SO 2 emissions from the FCCU Regenerator Vent were 2,678.6 tpy. In 20 1 1, SO 2 emissions from FCCU Regenerator Vent were103 tpy. This represents an actual pre

- BART

- to

- post

- BART SO 2 annual emission reduction of

2,575.6 tpy. It also reflects a greater than 96% reduction in SO 2 emissions, based on an analysis of two years of data. Upon review of the RACT/BACT/LAER Clearinghouse for controls available on an FCCU, Phillip s 66 determined, and LDEQ agreed, that the SCR and WGS controls for NOx, SO 2, and PM are among the most stringent controls available for the FCCU Regeneration Vent Controls implemented as requirements of the CD represent BART and will control emissions of the BART pollutants to the following levels:

 SO 2 : <=25 ppmvd SO 2 on a 365

- day rolling average basis @ 0% O 2 ; also, <= 50 ppmvd SO 2 on a 7 day rolling average basis @ 0% O 2 ;

 PM: <=0.5 lb PM/1000 lb of coke burn on a 3

- hr average basis; and

 NOx: <=20 ppmvd NOx on a 365

- day rolling average basis @ 0% O 2 ; also, <=40 ppmvd NOx on a 7

- day rolling average basis @ 0% O 2

. In evaluating BART for the Low Pressure and High Pressure Flares, Phillips 66 determined that there are currently no technically feasible add

- on air emission controls systems for elevated candle

- type flares. Current control technology incorporates the following work practices to reduce flare emissions and represents BART:

 Flare Gas Recovery System used to reduce the amount of flare gas combusted in the flare ; and

 Amine scrubbing of the recovered flare gas to reduce the concentration of H 2 S prior to the gas stream being routed to the refinery fuel gas system

.

LDEQ ’ s review is in Section II of the SIP. EPA has reviewed and agrees with L DEQ’s conclusion that the se controls represent BART for SO 2 , NOx and PM . Further

, EPA agrees that with the control strateg ies selected, the subject

- to

- BART units at Phillips 66 represent among the most stringent or “top level” controls available and meet the BART requirements at 40 CFR 51 Appendix Y.OV.D.1.9

.

Section 51.308( e ) requires that Louisiana ’s Regional Haze SIP include emissions limitations representing BART. Louisiana included the revised BART determination and an Administrative Order on C onsent (AOC) No. AE

- AOC

- 14

- 00211A. The revised determination and AOC establish enforceable and permanent emission l imits and operating conditions.

3. Eco

- Services Operations, LLC

The Eco

- Services Operations, LLC facility is a sulfuric acid plant located in Baton Rouge, Louisiana. Eco

- Services was previously known as Rhodia and Solvay. The plant produces sulfuric acid by using two sulfuric acid production trains, Unit 1 and Unit 2. On April 27, 2007, Eco

- Services entered into a Consent Decree with the United States of America and the State of Louisiana to resolve alleged violations of the Clean Air Act, including New Source Review, Prevention of Significant Deterioration, and the New Source Performance Standard for Sulfuric Acid Plants

. 10

10 Civil Action No. 2:07CV134WL. A copy of this CD is available in the docket for this proposed rulemaking.In our July 3, 2013 final action, we approved Louisiana’s BART evaluation. Our basis

and analyses for our approval of Louisiana’s BART determination for E co

- S ervices is found in our February 28, 2012 proposed rulemaking, July 3, 2012 final rulemaking, and the associated TSDs. 11 However, we determined that the SIP failed to include the SO 2 emission limits for the subject

- to

- BART unit into the SIP. Section 51.308( e ) requires that Louisiana ’s Regional Haze SIP include emissions limitations representing BART. Louisiana included an Administrative Order on Consent (AOC) No. AE

- AOC

- 14

- 00957 , which contained the applicable emissions limitations for BART . The revised determination and AOC establish enforceable and permanent emission limits and operating conditions.

4. Sid Richardson Carbon Company

The Sid Richardson Carbon Company Addis Plant was determined to be a subject to BART source in Louisiana’s original Regional Haze SIP revision. 12 It is located in West Baton Rouge Parish, Louisiana. In our July 3, 2013 final action, we appr oved Louisiana’s determination that the high efficiency fabric filters already in use at the facility are BART for PM . However, we determined that there was not sufficient information in the record to support the BART analysis conclusions for NO x and SO 2

. In response to our action, Sid Richardson conducted updated modeling using the same emission parameters and approved updated EPA modeling guidance. The revised protocol was submitted via email to EPA in July 2013, and was approved by EPA on October 17, 2013

. 13 The modeling conducted in 2013 in response to our action used the methods and guidance of FLAG 2010 and the 8/31/2009 Memorandum “Clarification on EPA

- FLM Recommended Settings for CALMET”, along with the most recent versions of the CALPUFF system of programs. The 2007 analysis modeling used methods and guidance from FLAG 2000, along with older versions of the CALPUFF system of programs that were current in 2007. The FLAG 2010 guidance document includes new IMPROVE equations to calculate visibility i mpacts. The FLAG 2010/IMPROVE equations include new higher background concentrations and relative humidity adjustment factors for the hygroscopic effects for each of the major species that account for most of the visibility effects. Higher natural backgro und concentrations and higher relative humidity adjustment factors for the 2013 analysis resulted in higher background visibility than the data and methods used in the 2007 analysis. The visibility impacts from the Addis P lant, when included with the updat ed natural background visibility, results in a lower delta

- deciview impact because of the higher natural background visibility.

There were also significant changes in the CALMET parameters that impacted the modeling results. While the 2007 analysis relie d on values determined by the modeler and approved in the protocol, the 2013 analysis followed the 8/31/2009 Memorandum for CALMET

11 77 FR 11839 and 77 FR 39425.

12 The State’s revised SIP submittal indicates that Sid Richardson’s Addis Plant is a subject

- to

- BART source, but this is an error. T

his section of the SIP submittal also refers to Louisiana’s BART threshold as 0.05dv, but this is a typo. Louisiana’s SIP approved BART threshold is 0.5dv. Both of these errors are harmless because, as explained, Louisiana’s SIP revision adequately demon strates that the Addis Plant is not subject to BART based on updated modeling information.

13 Emails to and from Ellen Belk and Sid Richardson re modeling protocolsettings. For example, the value RMAX1, which sets the distance that surface observations

modify the Step 1 Wind Fields to de velop the Step 2 Wind Fields, for 2007 was set at 30 km while the 2013 protocol set the RMAX1 at 100 km. The smaller value used in the 2007 analysis means that the surface observations did not influence the wind fields beyond 30 km, whereas the 2013 analy sis influenced the wind fields out to a much greater distance. The change in the CALMET three

- dimensional Meteorological Grid changed the overall visibility impact results

. The emission rates used in the 2007 modeling analysis were based on the highest a nnual emission rates from the period of 2001

- 2003, which occurred in 2002. The daily emission rates were back

- calculated from these annual emission rates. These daily rates did not necessarily represent the worst

- case scenario emission rates because they w ere based on annual averages. The emission rates used in the 2013 modeling analysis represented the worst

- case scenario emission rates because they were derived from the permitted lbs/hr limits. The emission rates used in the 2013 modeling analysis were gr eater than those used in the 2007 modeling analysis.

EPA reviewed and approved the revised modeling protocol and results. The highest 98 th percentile for the 2001

- 2003 period was 0.344 delta

- deciviews and the highest 98 th percentile for the highest year was 0.397 delta

- deciviews for the year 2002. These modeling results demonstrate that the Sid Richardson Carbon Company Addis Plant ha s less than a 0 .5 deciview impact on Breton island and therefore EPA agrees with LDEQ’s co nclusion that this source is not subject to BART.