Technical Support Document

for the

Oklahoma Regional Haze State Implementation Plan and Federal 

Implementation Plan

(OK TSD)

Prepared and Reviewed by:

Michael Feldman

Joe Kordzi

November 2014
2

Table of Contents

I. Relationship of this TSD to our Proposal............................................................................... 4

A. Summary of Our Previous Action ......................................................................................... 4

B. Summary of our Proposal....................................................................................................... 4

II. Background to Regional Haze ............................................................................................... 5

III. Evaluation of State Submittal .............................................................................................. 8

A. Establishment of the Reasonable Progress Goals ................................................................ 8

A.2. Reasonable Progress Consultation ................................................................................... 11

A.3. Reasonable Progress “Four Factor” Analysis................................................................. 20

A.4. Uniform Rate of Progress Determination........................................................................ 27

A.5. Additional Analysis of Reasonable Progress Goal.......................................................... 29

A.6. Our Evaluation of Oklahoma’s Reasonable Progress Goals for the Wichita 

Mountains. ......................................................................................................................... 39

A.7. Reasonable Progress Goal To Be Considered by Administrator .................................. 42

A.8. Reasonable Progress Goal Minimum............................................................................... 42
3

Tables

Table 1. Comparison of Reasonable Progress Goals to Uniform Rate of Progress on 20% 

Worst Days for Oklahoma Class I area .......................................................................... 9

Table 2. Comparison of Reasonable Progress Goal to Baseline Conditions on Least 

Impaired Days for Oklahoma Class I area................................................................... 10

Table 3. Percent total contribution and point source contribution to total visibility 

impairment at Wichita Mountains for 2018................................................................. 17

Table 4. Sulfate controls identified for the Wichita Mountains in the Alpine 

Geophysics/CENRAP control sensitivity modeling analysis for Texas sources........ 19

Table 5 - Visibility at Wichita Mountains under CENRAP Control Sensitivity Scenario 

(Table IX-4 of the OK Regional Haze SIP) .................................................................. 22

Table 6 - Sources ODEQ Considered for Additional Controls Under Reasonable Progress

........................................................................................................................................... 22

Table 7 - Comparison of URP to the Reasonable Progress Goal on Most Impaired Days for 

the Wichita Mountains................................................................................................... 28

Table 8. 2002 Projected sources of light extinction at the Wichita Mountains (worst 

quintile days in) (from Table V-8 of the OK Regional Haze SIP).............................. 30

Table 9. 2018 Projected sources of light extinction at the Wichita Mountains (worst 

quintile days) (from Table VIII-10 of the OK Regional Haze SIP)............................ 31

Table 10. 2002 to 2018 Projected reduction in sources of light extinction at the Wichita 

Mountains (worst quintile days) (from Table VIII-10 of the OK Regional Haze SIP)

........................................................................................................................................... 32

Table 11. Projected light extinction for 20% worst days at the Wichita Mountains in 2002 

(Mm-1)............................................................................................................................... 33

Table 12. Projected light extinction for 20% worst days at the Wichita Mountains in 2018 

(Mm-1)............................................................................................................................... 33

Table 13. Projected sulfurous sources of light extinction at the Wichita Mountains (worst 

quintile days in 2002) (from Table V-1 of the OK Regional Haze SIP)..................... 34

Table 14. Projected sulfurous sources of light extinction at the Wichita Mountains (worst 

quintile days in 2018) (from Table VIII-3 of the OK Regional Haze SIP) ................ 35

Table 15. 2018 Phase 1 EPA Source Apportionment Modeling Results, Top Ten Modeled 

Facilities in Texas that Impact Visibility at Wichita Mountains................................ 42

Figures

Figure 1. Map of Class I Areas.................................................................................................... 5

Figure 2. Location of the Class I Area in Oklahoma ................................................................. 6

Figure 3. Map of Regional Planning Organization Boundaries............................................... 7

Figure 4. Glide Path and Reasonable Progress Goal at Wichita Mountains (20% Worst 

Days).............................................................................................................................. 9

Figure 5. Percent of total extinction in 2018 at Wichita Mountains (CENRAP PSAT 

modeling results, 2007) .............................................................................................. 16

Figure 6. Percent of total extinction in 2018 at Wichita Mountains due to point sources 

only (CENRAP PSAT modeling results, 2007)........................................................ 16
4

Oklahoma Regional Haze Technical Support Document (TSD)

I. Relationship of this TSD to our Proposal

A. Summary of Our Previous Action

In a previous rulemaking, we partially approved and partially disapproved portions of the 

Oklahoma regional haze State Implementation Plan (SIP).

1

 We approved certain core elements 

of the Oklahoma Regional Haze SIP, including Oklahoma’s: identification of sources that are 

BART eligible and subject to BART; its determination of baseline and natural visibility 

conditions; its coordination of regional haze and RAVI; monitoring strategy and other 

implementation requirements; its coordination with States and federal land managers; and a 

number of the State’s NOx, SO2, and PM BART determinations. We disapproved Oklahoma’s 

submitted SO2 BART determinations for Units 4 and 5 of the OG&E Muskogee plant; Units 1 

and 2 of the OG&E Sooner plant; and Units 3 and 4 of the AEP/PSO Northeastern plant. We 

also disapproved the long-term strategy in Oklahoma’s Regional Haze SIP because it failed to 

include appropriate controls for these six sources. To remedy these deficiencies in the Oklahoma 

Regional Haze SIP, we concurrently promulgated a Federal Implementation Plan (FIP) that 

established SO2 BART emission limits for these six sources in Oklahoma. We have 

subsequently replaced our FIP for two of the sources with approval of Oklahoma’s SIP revision 

BART determinations for those two sources.2 We did not take action on whether Oklahoma 

satisfied the reasonable progress requirements of Section 51.308(d)(1). In our proposed action, 

we stated that to properly assess whether Oklahoma had satisfied these requirements, we must 

first evaluate and act upon the Regional Haze SIP revision submitted by the State of Texas.3 Our 

proposed action here is limited to our review of Oklahoma’s submission under Section 

51.308(d)(1). 

B. Summary of our Proposal

Section 51.308(d)(1) requires that in establishing its Reasonable Progress Goal (RPG), a State 

must perform a number of tasks that are outlined in sections 51.308(d)(1)(i)(A)-(B), 

51.308(d)(1)(ii), and 51.308(d)(1)(iv)-(vi). These requirements are not severable from the 

approval of the state’s RPGs – they are all interdependent and must all be approvable in order 

that that state’s RPG can be approved. As we discuss above, we are proposing to disapprove all 

of these requirements except for section 51.308(d)(1)(vi). Therefore, we must propose to 

disapprove Oklahoma’s RPG under section 51.308(d)(1).

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 notice provides more detail than does this TSD. 

 

1

 Final action: 76 FR 81728 (December 28, 2011). Proposal: 76 FR 16188 (March 22, 2011).

2

 Approval of OK’s partial replacement for FIP: 79 FR 12944 (March 7, 2014). Partial FIP withdrawal: 79 FR 

12954 (March 7, 2014).

3

 76 FR 16177 (Mar. 22, 2011).
5

Also, this TSD attempts to refer the reader to the specific portions of the Oklahoma’s Regional 

Haze SIP that we relied upon for our analysis of particular portions of section 51.308.

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. Background to Regional Haze

In Section 169A of the 1977 Amendments to the Clean Air Act (CAA), Congress set forth a 

program for protecting visibility in Federal Class I areas which calls for the “prevention of any 

future, and the remedying of any existing, impairment of visibility in mandatory Federal Class I 

areas which impairment results from manmade air pollution.” Congress adopted the visibility 

provisions to protect visibility in 156 Federal Class I areas, which include certain national parks, 

memorial parks, and wilderness areas over a certain size, and all international parks. These areas 

are defined at 40 CFR 81.400, are listed by State at 40 CFR 81.401-81.437, and are depicted in 

Figure 1, with the Class I area within Oklahoma, the Wichita Mountains National Wildlife 

Refuge, depicted in Figure 2:

Figure 1. Map of Class I Areas
6

Figure 2. Location of the Class I Area in Oklahoma

On December 2, 1980, we promulgated regulations to address visibility impairment that is 

“reasonably attributable” to a single source or small group of sources. (45 FR 80084) These 

regulations represented the first phase in addressing visibility impairment and deferred action on 

regional haze that emanates from a variety of sources until monitoring, modeling and scientific 

knowledge about the relationships between pollutants and visibility impairment improved. 

In the 1990 Amendments to the CAA, Congress added Section 169B and called on us to issue 

Regional Haze Rules. The Regional Haze Rule that we promulgated on July 1, 1999 (64 FR 

35713) revised the existing visibility regulations to integrate provisions addressing regional haze 

visibility impairment and establish a comprehensive visibility protection program for Federal 

Class I areas. These regulations represented the second phase in addressing visibility 

impairment. States were required to submit SIPs to us that set out each state’s plan for 

complying with the Regional Haze Rule, including consultation and coordination with other 

states and with Federal Land Managers (FLMs). States were required to submit a Regional Haze 

SIP to us within three years after the date of designation of areas under the National Ambient Air 

Quality Standard (NAAQS) for fine particulate matter (PM2.5). We promulgated PM2.5 

designations on December 17, 2004, and thus, regional haze SIPs were to be submitted to us by 

December 17, 2007, which is also specified at 40 CFR 51.308(b).

The Regional Haze Rule addressed the combined visibility effects of various pollution sources 

over a wide geographic region. Consequently, all 50 states, including those without Class I 

areas, Washington, D.C., and the Virgin Islands, were required to submit Regional Haze SIPs (40 

CFR 51.300(b)(3)). We designated five Regional Planning Organizations (RPOs) to assist with 

the coordination and cooperation needed to address the visibility issue, as shown by Figure 3.
7

Figure 3. Map of Regional Planning Organization Boundaries

Oklahoma, through the ODEQ joined State clean air agencies from Arkansas, Iowa, Kansas, 

Louisiana, Minnesota, Missouri, Nebraska, and Texas in forming CENRAP, in 1999. CENRAP 

also includes federally recognized Indian tribes located within the geographic boundaries of its 

member states. The State of Oklahoma Department of Environmental Quality chose to 

participate in CENRAP to develop the technical analyses needed to fulfill the requirements of the 

Regional Haze Rule.
8

III. Evaluation of Oklahoma’s Submittal

In evaluating the Oklahoma Regional Haze SIP, we reviewed all the parts of the document, 

including the body of the SIP itself, and all appendices. In addition, we drew upon the following 

additional documents that may not have been specifically discussed in our TSD and/or the 

Federal Register publication(s) of our decision:

1. 40 CFR Part 51.

2. Appendix V to 40 CFR Part 51.

3. The “BART Guidelines” in Appendix Y to Part 51—Guidelines for BART 

Determinations Under the Regional Haze Rule, 70 FR 39104, July 6, 2005.

4. Guidance for Tracking Progress Under the Regional Haze Rule, EPA-454/B-03-004, 

September, 2003.

5. Guidance for Demonstrating Attainment of Air Quality Goals for PM2.5 and Regional 

Haze, January 2, 2001.

6. Guidance for Estimating Natural Visibility Conditions Under the Regional Haze Rule, 

EPA-454/B-03-005, September 2003.

7. The “Baseline Memo,” which is entitled, “2002 Base Year Emission Inventory SIP 

Planning: 8-Hour Ozone, PM2.5 and Regional Haze Programs, dated 11/18/2002, from 

Lydia Wegman to the Regional Air Directors.”

8. Guidance for Setting Reasonable Progress Goals Under the Regional Haze Program, 

dated June 1, 2007.

9. Visibility Monitoring Guidance, EPA-454/R-99-003, June 1999.

10. Emissions Inventory Guidance for Implementation of Ozone and Particulate Matter 

National Ambient Air Quality Standards (NAAQS) and Regional Haze Regulations, 

EPA-454/R-05-001, dated August, 2005.

11. Interim Air Quality Policy on Wildland and Prescribed Fires, April 23, 1998.

A. Establishment of the Reasonable Progress Goals 

For each mandatory Class I Federal area located within the State, Oklahoma must establish goals 

(expressed in deciviews) that provide for reasonable progress towards achieving natural visibility 

conditions. The reasonable progress goals must provide for an improvement in visibility for the 

most impaired days over the period of the SIP and ensure no degradation in visibility for the least 

impaired days over the same period. 

State Submittal: Pages 104-117

CENRAP modeling projected visibility conditions anticipated at the Wichita Mountains in 2018. 

This was based on the emissions reductions resulting from federal and State control programs 

that are either currently in effect or with mandated future-year emission reduction schedules that 

predate 2018. This included the Long-Term Strategies (LTSs) of Oklahoma, Texas, and other 

states, and presumptive emissions reductions expected to result from the submitted Oklahoma 

BART rule. CENRAP’s projections for 2018 for the 20% worst and best days for the Wichita 

Mountains, which the ODEQ used in developing its RPGs for the Wichita Mountains, are shown 
9

in Appendix D to the document titled “Technical Support Document for CENRAP Emissions 

and Air Quality Modeling to Support Regional Haze State Implementation Plans.”4

Based on the results of the reasonable progress four-factor analysis (described in the following 

section), the results of the CENRAP modeling, and additional information developed by 

CENRAP or obtained through direct consultations with States anticipated to impact visibility at 

Wichita Mountains, the ODEQ decided to adopt the CENRAP modeled 2018 visibility 

conditions as the RPGs for the Wichita Mountains Class I area. The ODEQ established a RPG

of 21.47 dv for the Wichita Mountains for 2018 for the 20% worst days. This represents a 2.3 dv 

improvement in visibility over a baseline of 23.81 dv. It calculated that under its RPGs, it would 

attain natural visibility conditions in 2102 at the Wichita Mountains. The ODEQ’s RPG for the 

20% worst days is shown on Table 1 below, which is adapted from Tables IX-3 and IX-4 of the 

Oklahoma Regional Haze SIP, and Figure 4, which is Figure IX-1 of the OK Regional Haze SIP.

Table 1. Comparison of Reasonable Progress Goals to Uniform Rate of Progress on 20% 

Worst Days for Oklahoma Class I area

Oklahoma 

Class I Area

Baseline 

Conditions

(dv)

Projected 

2018 

Visibility

(RPG)

(dv)

Improvement 

Projected by 

2018 using 

RPG

(dv)

Date

Natural

Visibility

Attained at

RPG Rate

2018 URP 

Goal (dv)

Improvement

by 2018

at URP

(dv)

Wichita 

Mountains 23.81 21.47 2.33 2102 20.01 3.80

Figure 4. Glide Path and Reasonable Progress Goal at Wichita Mountains (20% Worst 

Days)

 

4

 The TSD for CENRAP Emissions and Air Quality Modeling to Support Regional Haze State Implementation is 

found in Appendix 4-2 of the Oklahoma Regional Haze SIP. 
10

CENRAP’s projections for 2018 for the 20% best days for the Wichita Mountains, which 

represent ODEQ’s RPGs for the 20% best days, are shown in Table IX-2 of the Regional Haze 

SIP and in Appendix D to the TSD for CENRAP Emissions and Air Quality Modeling to

Support Regional Haze State Implementation.5 ODEQ’s RPGs for the 20% best days (CENRAP 

projection) are shown on Table 2 below, which is adapted from Table IX-2 of the Oklahoma 

Regional Haze SIP.

Table 2. Comparison of Reasonable Progress Goal to Baseline Conditions on Least 

Impaired Days for Oklahoma Class I area

Oklahoma Class I 

Area

Visibility Conditions on 20% Best Days (dv)

Achieved “No 

Degradation”

(Y/N)

Average for 20% Best 

Days (Baseline 2000-

2004)

RPG

(CENRAP Projection)

Wichita Mountains 9.78 9.23 Y

EPA Findings: 

 

5 The TSD for CENRAP Emissions and Air Quality Modeling to Support Regional Haze State Implementation is 

found in Appendix 4-2 of the Oklahoma Regional Haze SIP. 
11

The vehicle for ensuring continuing progress towards achieving the natural visibility goal is the 

submission of a series of Regional Haze SIPs from the states that establish two RPGs (i.e., two 

distinct goals, one for the “best” and one for the “worst” days) for every Class I area for each 

implementation period.6 See Appendix A of the TSD of our previous action on Oklahoma 

Regional Haze7for our review of the CENRAP emission inventory and modeling that was relied 

upon in establishing the RPG for Wichita Mountain.

Figure D-8b of Appendix D to the TSD for CENRAP Emissions and Air Quality Modeling to 

Support Regional Haze SIPs, and Table 2 above, demonstrate that the modeled RPG for the 20% 

best days shows an improvement in visibility of 0.54 dv at the Wichita Mountains in 2018. The 

ODEQ also submitted a RPG for the Wichita Mountains for the 20% worst days, as shown in 

Table 1 above. Table 1 demonstrates that the modeled RPG for the 20% worst days shows an 

improvement in visibility of 2.33 dv at the Wichita Mountains in 2018. ODEQ’s RPGs for the 

Wichita Mountains are consistent with the requirement that they provide for an improvement in 

visibility for the most impaired days over the period of the SIP and ensure no degradation in 

visibility for the least impaired days over the same period.

However, for the reasons discussed below, we are proposing to disapprove Oklahoma’s RPG for 

the Wichita Mountains. First, in our earlier action on the Oklahoma Regional Haze SIP, we 

disapproved the SO2 BART determinations for six EGUs at three power plants in Oklahoma and 

promulgated a FIP setting more stringent SO2 emission limits for these EGUs.8 Although we 

subsequently approved a SIP revision from Oklahoma addressing the BART requirements at one 

power plant,9and removed the FIP requirements for this facility,10 our FIP and the revised 

Oklahoma SIP require greater reductions overall in emissions of SO2 than was assumed in setting 

the RPGs for the Wichita Mountains. Second, we are proposing to disapprove Oklahoma’s 

RPGs for the Wichita Mountains because they were based on an incomplete consultation with 

Texas under 51.308(d) (1)(iv) that resulted in inadequate reasonable progress towards the 

national visibility goal. For these reasons, the RPGs for Wichita Mountains do not reflect the 

degree of visibility improvement anticipated from these measures. 

A.2. Reasonable Progress Consultation

In developing the RPGs for its Class I area, Oklahoma was required to consult with those States 

which may reasonably be anticipated to cause or contribute to visibility impairment at the 

Wichita Mountains.11 In any situation in which Oklahoma could not agree with another such 

State or group of States that a goal provides for reasonable progress, Oklahoma was required to

describe in its submittal the actions taken to resolve the disagreement. In reviewing Oklahoma’s 

SIP submittal, the Administrator takes this information into account in determining whether 

 

6

 See 70 FR 3915 and 64 FR 35714.

7

 Technical Support Document for the Oklahoma Regional Haze State Implementation Plan and Federal 

Implementation Plan, March 2011, Appendix A.

8

 76 FR 81728 (Dec. 28, 2011). 

9

 79 FR 12944 (March 7, 2014).

10

 79 FR 12954 (March 7, 2014).

11

 Section 51.308(d)(1)(iv). 
12

Oklahoma’s goal for visibility improvement provides for reasonable progress towards natural 

visibility conditions.

State Submittal: Pages 115-117, Appendix 10-1

The ODEQ identified several States that were projected through visibility modeling to contribute 

more than 1 Mm-1of light extinction at the Wichita Mountains in 2018 and invited these States 

to consult. It conducted four consultations.12 It directed its first consultation to the tribal leaders 

in Oklahoma and their environmental managers, on August 14, 2007. The ODEQ held the next 

three consultations as conference calls with representatives from CENRAP, EPA, the U.S. Fish 

and Wildlife Service, Arkansas, Iowa, Kansas, Louisiana, Minnesota, Missouri, Nebraska, and 

Texas.13 The ODEQ received written responses from the Arkansas Department of 

Environmental Quality, the TCEQ, and the Missouri Department of Natural Resources.14 The 

ODEQ sent a letter to the Iowa Department of Natural Resources as a follow up to the 

consultation calls for the Wichita Mountains. Below is a summary of Oklahoma’s consultations. 

For the first call with the States, held on August 16, 2007, the ODEQ discussed the current 

modeling results, comparing the projected visibility conditions in 2018 to the 2018 URP goal.15 

The ODEQ identified that the Wichita Mountains is projected in the 2108 CENRAP modeling to 

be 1.5 dv short of its 3.8 dv reduction needed to meet the URP. It also discussed the primary 

anticipated causes of regional haze for the Wichita Mountains in 2018, based on modeling and 

monitored data. According to the ODEQ, high SO2 concentrations at the Wichita Mountains 

reflect long range transport from Texas and the eastern two-thirds of United States. The ODEQ 

identified that point sources are the most significant contributors to haze at the Wichita 

Mountains based on the source apportionment results from the CENRAP modeling, with the 

largest contributing point sources being Texas EGUs. 

The ODEQ used the AOI data developed for the Alpine Geophysics report and considered the 

PSAT modeling results to identify areas, pollutants and source types that contribute to visibility 

impairment at the Wichita Mountains. The ODEQ identified that SO2 emissions that impact 

visibility conditions at the Wichita Mountains generally originate from the south and east. The 

ODEQ identified sources within the Area of Influence of the Wichita Mountains with a ratio of 

annual emissions of NOx or SO2 to distance (Q/D) greater than 5 based on 2018 projected 

emissions. The ODEQ then used the Alpine Geophysics report developed for CENRAP (as 

described in more detail in our TX TSD) to identify estimates of the costs of installing retrofit 

controls for these sources. The ODEQ applied a maximum cost threshold of $5,000/ton to the 

list of potential controls to eliminate controls that it considered too costly from additional 

analysis. The remaining sources were listed in the charts provided to the participants in the 

 

12

 Copies of agendas and presentation materials are available in the docket for this action and at 

http://www.deq.state.ok.us/AQDnew/rulesandplanning/Regional_Haze/SIP/Consultation/index.htm

13

 These calls were recorded, referenced in OK’s regional haze SIP, and placed on ODEQ’s website. 

14

 Copies of these letters can be found in Appendix 10-1 of the Oklahoma regional haze SIP.

15 A copy of the presentation containing the information discussed by ODEQ is available in the docket for this action 

and at: 

http://www.deq.state.ok.us/AQDnew/rulesandplanning/Regional_Haze/RegionalHazeStatesConsultation1_081607.p

pt
13

consultation process.16 For these sources, the ODEQ requested that the participating States 

provide any available information or comments relative to which listed sources are BART 

sources, planned expansions or installation of controls, feasibility of controls, cost of controls, 

and any modeling conducted that would indicate the sources’ levels of impact on the Wichita 

Mountains. It stated that it was not yet requesting reductions, but was merely soliciting 

additional information.

For the August 30, 2007 meeting, the ODEQ focused on the method used to calculate natural 

conditions at the Wichita Mountains. The ODEQ also reviewed and discussed information it had 

received following its request for information regarding the sources of interest that it had 

identified. ODEQ also noted that it had received information from Arkansas, Iowa, Kansas, 

Louisiana, and Nebraska after the first call but that it still needed information from Texas, 

Missouri, and Minnesota. Texas indicated that although it had contacted its EGUs, none had 

provided information as to how they intended to comply with CAIR. Texas stated that it had not 

received any enforceable commitments for controls from any of its EGUs. For other listed Texas 

sources, TCEQ said it was seeing significant decreases in emissions from controls or programs 

that were already in place. According to Texas, in general, growth assumptions for non-EGU 

Texas sources were wrong. Total emissions for Texas point sources, it claimed, were steadily 

declining in spite of great economic growth. Louisiana stated that one of it sources, Rhodia, was 

under a Consent Decree and reducing its emissions. Minnesota and Missouri also offered to 

provide some additional information to Oklahoma regarding their sources. 

For the third and final consultation meeting on September 25, 2007, the ODEQ again followed 

up on the information request regarding the sources of interest that it had identified. Texas stated 

that there were no changes to its EGUs projections since very few of its EGUs had committed to 

controls in order to meet CAIR. Texas again stated that Texas point source 2018 projections 

were unrealistic and that Texas point source emissions have historically been dropping even 

when the State has been growing substantially economically. The ODEQ stated that SO2 is 60% 

of the particulate issue with most of it coming from Texas, Louisiana, and other States all the 

way out to the east coast. The ODEQ finished the consultation call with a statement that it was 

considering the information provided from consultation and was using it in drafting its Regional 

Haze SIP. 

During the consultation process, Arkansas notified the ODEQ that it disagreed that its sources 

contribute significantly to visibility impairment at the Wichita Mountains. Missouri similarly 

informed the ODEQ that it considered current controls on Missouri sources to be sufficient. 

Later, the ODEQ also concluded based on modeled projections that Iowa would not contribute to 

visibility impairment at the Wichita Mountains in 2018 and informed Iowa that additional 

reductions were no longer requested.

During the consultation process, Oklahoma and Texas exchanged letters regarding the Wichita 

Mountains. On August 3, 2007, the ODEQ sent a letter to the TCEQ in which it noted that 

 

16 A spreadsheet with the list of potential controls shared with the States is available in the docket for this action and 

at: 

http://www.deq.state.ok.us/AQDnew/rulesandplanning/Regional_Haze/RegionalHazeStatesConsultation1_081607_

ControlAssumptions.xls
14

despite significant planned reductions in SO2 and NOx emissions from sources in Oklahoma and 

Texas, the Wichita Mountains was not projected to meet the URP. The ODEQ further noted that 

the analyses by CENRAP had made clear that the Wichita Mountains suffer from significant 

anthropogenic impacts from Texas. The ODEQ requested that the TCEQ require new and 

modified PSD sources to conduct analyses of their impacts on visibility at the Wichita Mountains 

and that the ODEQ be given an opportunity to review and comment on BACT determinations for 

proposed projects likely to have a certain impact on visibility at the Wichita Mountains. In 

addition, the ODEQ requested that the evaluations of visibility impacts be extended from within 

100 km of the Wichita Mountains to within 300 km of the Wichita Mountains in deference to 

FLM guidance. On October 15, 2007, the TCEQ sent a response to the ODEQ, agreeing that 

modeling showed emissions from Texas to be a significant source of visibility impairment at the 

Wichita Mountains. The TCEQ also noted, however, that significant reductions from Texas will 

be realized in the next several years. In response to the ODEQ’s specific request for the 

opportunity to comment on BACT for new and modified major sources, the TCEQ stated that it 

welcomed comment during the public review and comment period and would notify federal land 

managers and the ODEQ if modeling were to indicate that a proposed source might significantly 

impact the Wichita Mountains. In response to the ODEQ’s request that impact evaluations be 

extended to 300 km, the TCEQ stated that it was working with federal land managers on 

mutually acceptable criteria for determining when a proposed PSD source should conduct a 

Class I area review and would inform ODEQ on the outcome of these discussions. In addition, 

the TCEQ attached its draft RPG analysis for its two Class I areas, which included analyses the 

TCEQ used to determine that there are no reasonable costs of installing additional controls 

beyond CAIR to address Texas impacts at Big Bend National Park and the Guadalupe 

Mountains. 

Several months after this initial exchange of letter, the two States again exchanged letters. On 

March 25, 2008, following comments made by us and the federal land managers on Texas’ draft 

Regional Haze SIP, the TCEQ sent a letter to the ODEQ regarding emissions that affect the 

Wichita Mountains. The TCEQ provided a copy of the PSAT modeling results developed by 

CENRAP indicating the contribution for each source area to visibility impairment at the Wichita 

Mountains. The TCEQ stated in the letter that PSAT modeling indicated that the probable 

impacts of Texas sources at the Wichita Mountains will be reduced by 2018 due to expected 

emission reductions from current and planned controls. A list of sources that are within the area 

of interest and have an emissions over distance ratio equal to or greater than five (Q/D >5) was 

included with the letter, along with information on projected emissions and distance to Wichita 

Mountains for those sources. The TCEQ then requested concurrence from Oklahoma on this 

assessment and a verification that Oklahoma was not depending on any additional reductions 

from Texas sources in order to meet RPG for the Wichita Mountains. On May 12, 2008, the 

ODEQ sent a response to the TCEQ in which it noted that it concurred with the information the 

TCEQ had provided. The ODEQ stated that it had developed its RPG for the worst 20% days for 

the Wichita Mountains through the CENRAP deliberations and that its RPG did not anticipate 

emission reductions beyond those that Texas already planned to implement and upon which 

CENRAP modeling studies have relied. The letter also states that reaching the Wichita 

Mountains’ RPG requires constraints on emissions from new, modified, and existing sources. 

The letter then recaps the ODEQ’s initial request made in its August 3, 2007 consultation letter 

that all sources within 300 km conduct an analyses of the impacts to the Wichita Mountains and 
15

that it be given the opportunity to comment on BACT for proposed sources projected to 

significantly contribute to visibility impairment at the Wichita Mountains. 

EPA Findings: 

We reviewed the information developed by the ODEQ and the participating States during the 

consultation process, as well as the CENRAP source apportionment modeling results and 

additional data developed by CENRAP and Alpine Geophysics. We propose to agree with the 

following conclusions made by the ODEQ in its consultations: 

With all the reductions anticipated to occur in the contributing States, the CENRAP modeling 

projects that the Wichita Mountains will fall short of meeting the URP goal for this planning 

period.

In consultation, ODEQ did not ask for additional controls for NOx sources. We agree with 

ODEQ’s treatment of NOx sources for this planning period since NOx is not the predominant 

cause at the Wichita Mountains in 2002 or 2018. ODEQ presented information about source 

apportionment modeling results indicating the impact of a state’s emissions and add-on SO2

controls for sources in Arkansas, Iowa, Louisiana, Missouri, Oklahoma and Texas as estimated 

for the Alpine Geophysics report. These sources lie within the AOI of Wichita Mountains, have 

a Q/D greater than 5 and have controls estimated to be less than $5000/ton. This data17 served as 

a starting point for discussions of potential reductions, visibility impacts, and the potential for 

visibility improvements from controls.

Texas is a significant contributor to the visibility impairment at the Wichita Mountains. Point 

sources are the most significant contributors to haze at the Wichita Mountains, and the largest 

contributing point sources are Texas EGUs. Figure 5 below shows the CENRAP source 

apportionment modeling results18 in terms of the percent of the total visibility impairment 

projected for 2018 at the Wichita Mountains. Figure 6 shows the percent of the total visibility 

impairment from point sources alone.19 Table 3 summarizes the percent of visibility impairment 

at the Wichita Mountains from Oklahoma and nearby states. Texas (all sources and pollutants) is 

projected to contribute 27.5% of the visibility impairment at the Wichita Mountains, compared to 

16.3% for Oklahoma sources, 4.8% from Louisiana sources and 4.2% from sources in the 

Eastern U.S. Point sources in Texas are projected to account for 14% of all visibility impairment 

projected in 2018 at Wichita Mountains, compared to 3.9% from Oklahoma point sources, 3.4% 

from Louisiana point sources and 3.2% from point sources in the Eastern U.S. As discussed 

above, these model results include estimated reductions due to the implementation of CAIR, 

other on-the-book federal and State rules, and some assumptions for BART reductions in 

Oklahoma and other states. Extinction due to point source SO2 emissions in Texas (7.83 Mm-1) 

is almost 3.5 times larger than the next largest contribution from point source SO2 emissions 

(2.27 Mm-1 from point sources in the Eastern U.S.). Extinction due to point source SO2

 

17 Ref the ODEQ consultation spreadsheet.

18 CENRAP model results are from the CENRAP PSAT tool developed by ENVIRON for CENRAP available as 

CENRAP_PSAT_Tool_ENVIRON_AUG27_2007.mdb 

19

 We note that this calculation does not include Rayleigh scattering. 
16

emissions in Louisiana (2.16 Mm-1), Oklahoma (1.23 Mm-1) and Missouri (1 Mm-1) are smaller 

still.

Figure 5. Percent of total extinction in 2018 at Wichita Mountains (CENRAP PSAT 

modeling results, 2007)

Figure 6. Percent of total extinction in 2018 at Wichita Mountains due to point sources 

only (CENRAP PSAT modeling results, 2007)
17

Table 3. Percent total contribution and point source contribution to total visibility 

impairment at Wichita Mountains for 2018

TX OK LA KS AR MO

Eastern 

U. S.

Total Impairment, All Source 

Categories, All Pollutants 27.5% 16.3% 4.8% 3.8% 2.3% 2.8% 4.2%

Total Impairment, Point 

Sources Only, All Pollutants 14.0% 3.9% 3.4% 1.4% 1.3% 1.7% 3.2%

In response to the information and analysis provided by ODEQ and ODEQ’s request for 

comment on the information provided, Arkansas sent a response letter disagreeing with ODEQ’s 

analysis that Arkansas’ sources contribute significantly to Oklahoma’s ability to achieve 

reasonable progress for WM. Arkansas also provided additional information indicating that 

additional reductions were anticipated at large point sources in the State due to implementation 

of BART. ODEQ did not ask for additional SO2 controls from Arkansas sources. Given the 

relatively small projected contribution from all Arkansas sources and point source SO2 emissions 

when compared to other contributing regions, we believe this to be reasonable for this planning 

period. 
18

ODEQ initially invited Iowa to consult and shared information on potential add-on controls 

within the AOI of Wichita Mountains with costs estimated in the Alpine Geophysics repot. After 

further consideration of the source apportionment results, ODEQ sent Iowa a letter after the 

consultation calls stating that they did not require additional controls from Iowa. We find that 

ODEQ not requiring additional controls for Iowa sources to be reasonable because Iowa sources 

as a whole contribute less than 1% to the total visibility impairment at Wichita Mountains and 

point source SO2 emissions contribute only 0.48 Mm-1to the total extinction. These 

contributions are small when compared to other contributing regions and the anticipated benefit 

from controlling any specific source would represent only a fraction of this contribution. 

During the consultation call, Louisiana provided additional information on those sources with 

cost-effective add-on controls as identified by ODEQ from data in the Alpine Geophysics report. 

Louisiana identified that Rhodia is under a federal consent decree. ODEQ did not ask Louisiana 

for additional controls to address visibility impairment at Wichita Mountains. As discussed 

below and in the FIP TSD, our additional analysis confirms that impacts from sources in Texas 

are much larger than anticipated impacts from individual sources in Louisiana. Combined 

impacts from four units at two EGU facilities in Texas (Monticello and Big Brown) are 

estimated to be larger than impacts from all Louisiana point sources combined. 

During the consultation calls, Missouri stated that the cost numbers were not accurate for the 

Missouri sources identified by ODEQ and sent in amended cost numbers. In addition, Missouri 

sent a letter stating that for Missouri sources, current controls are sufficient to achieve targets in 

Missouri and Arkansas class I areas. Therefore, Missouri stated that it is intuitive that additional 

controls are also sufficient for Wichita Mountains which is further away (200-250 miles from 

Missouri). In addition, under RACT, it plans to install controls for large SO2 sources. In 

addition, Missouri stated that its impacts on haze for Wichita Mountains are not of similar level 

to east Texas as shown by the CENRAP source apportionment results. ODEQ reviewed 

Missouri’s information provided and did not ask Missouri to install additional control in the first 

planning period to address visibility impairment at Wichita Mountains. We find this to be 

reasonable. Given the relatively small contribution to extinction from all point source emissions 

of SO2 (1 Mm-1), additional anticipated reductions under RACT, and that impacts from these 

sources are addressed when evaluating the impacts to other Class I areas closer to these sources, 

we find it reasonable for ODEQ to not ask for additional controls at this time. 

During the consultations, Oklahoma identified Texas sources that had large emissions located 

near the Wichita Mountains. Both the ODEQ and the TCEQ shared lists of specific facilities that 

were identified to be of interest with respect to visibility at Wichita Mountains due to their size 

and location. Oklahoma used the Alpine Geophysics study estimates of the cost-effectiveness of 

add-on controls at some of these facilities (shown in table 4 below) and the ODEQ specifically 

requested additional information on feasibility and cost of controls for those facilities with 

estimated controls less than $5,000/ton. The cost effectiveness for all of the point sources 

identified by Oklahoma except one was below $3,000/ton. The cost effectiveness values of less 

than $3,000/ton for 8 of the 9 Texas sources identified by Oklahoma are within the range of cost 

effectiveness values that Oklahoma, other states, and we have considered reasonable for 

installing controls in the BART and RPG evaluations. In addition, the cost effectiveness values 
19

for all but two of the Texas sources identified by Oklahoma are below $2700/ton threshold Texas 

used in the development of its reasonable progress and LTS. 

Table 4. Sulfate controls identified for the Wichita Mountains in the Alpine 

Geophysics/CENRAP control sensitivity modeling analysis for Texas sources

Plant Name and Unit

Source Type for 

Control

Control 

Measure

Tons 

Reduced

CE 

(%)

Annualized 

Cost 

($2005)

$/Ton 

Reduced

SOMMERS DEELY 

SPRUCE PWR 1

Utility Boilers -

Medium Sulfur 

Content

FGD Wet 

Scrubber 9,752.2 90 25,000,104 2,564

SOMMERS DEELY 

SPRUCE PWR 2

Utility Boilers -

Medium Sulfur 

Content

FGD Wet 

Scrubber 9,592.6 90 25,000,104 2,606

BIG BROWN 1 Utility Boilers -

Medium Sulfur 

Content

FGD Wet 

Scrubber 20,827.7 90 32,766,310 1,573

BIG BROWN 2 Utility Boilers -

Medium Sulfur 

Content

FGD Wet 

Scrubber 21,276.5 90 32,766,310 1,540

COLETO CREEK 

PLANT 1

Utility Boilers -

Medium Sulfur 

Content

FGD Wet 

Scrubber 14,486.3 90 36,014,449 2,486

HOUSTON PLANT Sulfuric Acid Plants 

- Contact Absorber 

(98% Conversion)

Increase % 

Conversion to 

Meet NSPS 

(99.7)

3,486.3 85 670,008 192

HOUSTON PLANT Sulfuric Acid Plants 

- Contact Absorber 

(98% Conversion)

Increase % 

Conversion to 

Meet NSPS 

(99.7)

5,954.0 85 2,510,927 422

DEER PARK PLANT Petroleum Industry FGD 4,941.7 90 8,474,217 1,715

COMO PLT 

(Shut Down)

Petroleum Industry FGD 3,231.4 90 6,865,014 2,124

STREETMAN 

PLANT

Mineral Products 

Industry

FGD 2,443.2 50 9,903,980 4,054

MONTICELLO STM 

ELE STN 1

Utility Boilers -

Medium Sulfur 

Content

FGD Wet 

Scrubber 17,230.0 90 32,196,462 1,869

MONTICELLO STM 

ELE STN 2

Utility Boilers -

Medium Sulfur 

Content

FGD Wet 

Scrubber 17,725.5 90 32,196,462 1,816

WELSH POWER 

PLANT 1

Utility Boilers -

Medium Sulfur 

Content

FGD Wet 

Scrubber 10,548.9 90 30,088,020 2,852

During the consultation calls for the Wichita Mountains, Texas stated that the Texas EGUs cost 

numbers for the six EGUs included in the above table are accurate and that most of the facilities 

under CAIR were not going to install additional cost controls. 
20

For this planning period, we propose to find that Oklahoma reasonably determined that 

additional SO2 reductions from Arkansas, Louisiana, Missouri, and Iowa were not necessary for 

reasonable progress. This proposed determination is based, in part, on our review of the 

CENRAP modelling showing the projected impact from sources in these States and the relative 

contributions from SO2 point sources in these States. 

We agree with the ODEQ’s approach for identifying those States with sources that may impact 

visibility at the Wichita Mountains and its decision to invite those States to consult. Through the 

consultation process, the ODEQ was able to gain additional information regarding the potential 

impacts from nearby States. We do not agree, however, with the ODEQ’s approach to 

consultation to address impacts from emissions from Texas. At the time that Oklahoma was 

developing its SIP, it had (1) abundant information showing the impact of Texas sources on 

visibility at the Wichita Mountains, particularly from EGU sources in northeast Texas, and (2) 

evidence that cost-effective controls on these sources were likely available. Despite this 

information, the ODEQ neither requested that the TCEQ further investigate controls at these 

sources nor did it request additional reductions from Texas sources to address the impacts of 

emissions from these sources at the Wichita Mountains. The Regional Haze Rule requires States 

to use the consultation process under Sections 51.308(d)(1)(iv) in the development of RPGs to 

ensure that all States, including downwind States, take a hard look at what measures are 

necessary for ensuring reasonable progress towards improving and maintaining visibility at Class 

I areas. Lacking development of critical information during its consultations with Texas, we 

believe that Oklahoma did not have adequate information to reasonably establish its RPG for the 

Wichita Mountains, and, as explained below, should have requested that the TCEQ further 

investigate these sources or requested additional reductions from Texas sources to ensure that all 

reasonable measures to improve visibility were included in Texas’ LTS and incorporated into 

Oklahoma’s RPG for the Wichita Mountains.

A.3. Reasonable Progress “Four Factor” Analysis 

In establishing RPGs for a Class I area, Oklahoma is required by CAA §169A(g)(1) and Section

51.308(d)(1)(i)(A) to “[c]onsider the costs of compliance, the time necessary for compliance, the 

energy and non-air quality environmental impacts of compliance, and the remaining useful life of 

any potentially affected sources, and include a demonstration showing how these factors were 

taken into consideration in selecting the goal.” 

State Submittal: Pages 107-114, Appendix 4-2

The ODEQ analyzed the largest sources of visibility impairing pollutants within Oklahoma, 

including sources of sulfur, nitrates, ammonia, VOCs, and directly emitted coarse and fine 

particles. The ODEQ calculated that sulfurous pollutants contribute approximately 44% and 

nitrate bearing pollutants contribute approximately 21% of the total light extinction (or visibility 

impairment) to the Wichita Mountains. The ODEQ also calculated that sources from all source 

categories combined within Oklahoma contribute only approximately 13% of the total pollutants 

that contribute to light extinction at the Wichita Mountains in the 2002 modeled base year.
21

To evaluate any additional control measures necessary to demonstrate reasonable progress, the 

ODEQ initially relied on a study commissioned by CENRAP. CENRAP contracted with Alpine 

Geophysics to conduct an evaluation of possible additional point-source controls for CENRAP 

states for 201820. CENRAP did not consider additional controls outside the borders of its 

member states in the Alpine Geophysics evaluation. The evaluation relied on AirControlNet,21 a

database tool released by us in 2006 to enable cost-benefit analyses of potential add-on emissions 

control measures and strategies. Alpine Geophysics prepared cost estimates for NOx and SO2

reductions in 2005 dollars for point sources in CENRAP states. Alpine Geophysics and the 

CENRAP analysis included the following:

 The remaining useful life of a source affects the annualized costs of retrofit controls and 

was included in the methods used for calculating annualized costs in the control cost 

equations modified from EPA’s AirControlNet. Average retirement rates were applied to 

control technologies within the control analysis equations and source-specific retirement 

information (if available) was included in the CENRAP emission projections. Since 

AirControlNET’s control cost equations take into consideration the useful remaining life 

of installed equipment and estimate the costs of compliance with these measures, two of 

the four reasonable progress goal considerations for these sources are addressed.

 The Iowa Department of Natural Resources and Kansas Department of Health and 

Environment staff added area-of-influence (AOI) data and distance calculations to each 

Class I area in every CENRAP member state.

 The Alpine Geophysics report also relies on a suite of early photochemical modeling 

sensitivity runs to estimate a sensitivity factor for each Class I area’s area of influence in 

the form of pollutant concentration reduced per ton per day precursor emissions reduced.

CENRAP then developed a modeling scenario to estimate the effectiveness of a specific suite of 

controls on facilities in the CENRAP states based on the identified potential add-on controls and 

cost information developed by Alpine Geophysics. CENRAP decided to base its control 

sensitivity analysis on a maximum estimated cost of $5,000 per ton of emissions of NOx or SO2. 

It also evaluated only those point sources predicted to emit 100 tons or more of SO2 or NOx in 

the year 2018. CENRAP further refined the sources for analysis, considering controls only for 

those sources with emissions of NOx or SO2 greater than or equal to five tons per year per 

kilometer of distance (Q/D greater than 5) to the Wichita Mountains or the nearest other Class I 

area. This distance-weighing criterion limited the sensitivity evaluation to sources with the 

greatest likely influence on visibility. For EGU sources meeting the Q/D and cost-effectiveness 

criteria for SO2 controls (scrubbers), a control efficiency of 90% was applied. NOx control 

efficiencies applied varied from 35% to 95% depending on the control technology or 

combination of control technologies (SCR, SNCR, LNB, flue gas-recirculation) that were 

determined to be less than $5000/ton. (See Tables 6.6 and 6.7 of the Alpine Geophysics report). 

The CENRAP control sensitivity modeling run included emission reductions in the CENRAP 

 

20 Appendix 4-2 of the Oklahoma Regional Haze SIP, available in our docket.

21 Additional information and a copy of the AirControl NET software can be found at: 

http://www.epa.gov/ttn/ecas/AirControlNET.htm
22

states at those point sources where the cost-effectiveness and Q/D criteria discussed above were 

met. This modeling was developed as a starting point for discussion and development of refined 

analyses as needed.22

As depicted in Table 5, the CENRAP control case sensitivity evaluation projected that visibility 

at the Wichita Mountains would be improved by an additional 0.75 dv on the worst 20% days 

over what the ODEQ projects as its RPG of 21.47 dv for 2018, if controls were implemented at 

the sources that met this combination of baseline emissions, potential for cost-effective add-on 

controls, and location (21.47-20.72 = 0.75). 

Table 5 - Visibility at Wichita Mountains under CENRAP Control Sensitivity Scenario 

(Table IX-4 of the OK Regional Haze SIP)

Observed Visibility in 2002-2004 108.15 Mm-123.81 dv

Visibility projected by 2018 using RPG 85.63 Mm-121.47 dv

Visibility by 2018 at uniform rate of progress 73.97 Mm-120.01 deciviews

Visibility projected by 2018 under control scenario 81.40 Mm-1 20.97 (20.72)23 dv

ODEQ pointed out that even if all CENRAP member states compelled sources to install and 

operate controls as effectively as the Alpine Geophysics evaluation envisions, the Wichita 

Mountains would still fall significantly short of meeting the URP glide path for the 20% worst 

days in 2018. Furthermore, ODEQ pointed out that most of the sources under consideration for 

control in the Alpine Geophysics evaluation are located in Texas or other states outside of 

ODEQ’s territorial jurisdiction. ODEQ also stated that the control scenario presented in the 

Alpine Geophysics evaluation includes some already implemented, prohibitively costly, 

technically infeasible, or otherwise unreasonable controls.

Following this analysis, ODEQ examined additional controls for sources within Oklahoma. The 

list of sources considered for additional controls under RP is shown in Table IX-5 of the 

Oklahoma Regional Haze SIP, and is reproduced in Table 6 below:

Table 6 - Sources ODEQ Considered for Additional Controls Under Reasonable Progress

Company County

Industrial 

classification

Possible 

Control 

Equipment

ODEQ 

Determination

Public Service 

Company of 

Oklahoma

Caddo Electric services 

utility

Selective 

catalytic 

reduction

Subject to 

BART; controls 

 

22 “The results of the modeling were not intended to be prescriptive; instead, they were intended to be a starting 

point for control discussions that would require much greater refinement.” CENRAP TSD, page 2-37.

23

 ODEQ mistakenly referred to an estimated visibility of 20.97 dv for the control scenario instead of the correct 

value of 20.72 dv. See correspondence from ODEQ (Lee Warden) to EPA (Michael Feldman) on 7/14/2014.
23

(2 oil or gas-fired 

boilers)

required under 

BART

Western Farmers 

Electric Cooperative Choctaw

Electric services 

utility

(1 coal-fired 

boiler)

Selective 

catalytic 

reduction and 

flue gas 

desulfurization 

wet scrubber

Not Subject to 

BART; no 

additional 

emission 

reductions 

planned

Public Service 

Company of 

Oklahoma

Comanche

Electric services 

utility

(2 natural gas 

fired combustion 

turbines)

Selective 

catalytic 

reduction plus 

water injection

Subject to 

BART; controls 

required under 

BART

Great Lakes Carbon 

Corporation Garfield

Products of 

petroleum and 

coal

(2 process units)

Flue gas 

desulfurization

Not Subject to 

BART; no

additional 

emissions 

reductions 

planned

International Paper 

(formerly 

Weyeregional 

hazeaeuser) Valliant 

Paper Mill

McCurtain

Paperboard Mill

(wood bark, 

residual oil, and 

natural gas fired 

boilers)

Selective noncatalytic 

reduction (urea 

based), 

selective 

catalytic 

reduction, low 

NOx burners, 

and wet flue 

gas 

desulfurization

Source agreed to 

reduce emissions 

and was granted 

a BART waiver

Grand River Dam 

Authority Mayes

Electric services 

utility

(coal fired 

boilers)

Selective 

catalytic 

reduction, low 

NOx burner 

with over-fire 

air, and flue 

gas 

desulfurization 

wet scrubber

Not Subject to 

BART; no 

emissions 

reductions 

planned

Associated Electric 

Cooperative 

Incorporated

Mayes

Electric services 

utility

(natural gas-fired 

combustion 

turbines)

Selective 

catalytic 

reduction plus 

water injection

Not subject to 

BART; no 

emissions 

reductions 

planned
24

Oklahoma Gas & 

Electric Muskogee

Electric services 

utility

(3 coal-fired 

boilers)

Low NOx 

coal-and-air 

nozzles with 

close-coupled 

and separated 

over-fire air 

and flue gas 

desulfurization 

wet scrubber

Subject to 

BART; controls 

required under 

BART

Oklahoma Gas & 

Electric Noble

Electric services 

utility

(2 coal-fired 

boilers)

Low NOx 

coal-and-air 

nozzles with 

close-coupled 

and separated 

over-fire air

Subject to 

BART; controls 

required under 

BART

Holcim United 

States Incorporated Pontotoc

Cement 

manufacturing

(coal-fired kilns)

Selective 

catalytic 

reduction and 

flue gas 

desulfurization

Not Subject to 

BART; no 

emissions 

reductions 

planned

LaFarge Building 

Materials Rogers

Cement 

manufacturing

(coal-fired kilns)

Selective noncatalytic 

reduction (urea 

based) and 

selective 

catalytic 

reduction

Portland cement 

plant at this 

location granted 

BART waiver

Public Service 

Company of 

Oklahoma

Rogers

Electric services 

utility (2 coalfired boilers)

Selective 

Catalytic 

Reduction

Subject to 

BART; controls 

required under 

BART

Sinclair Oil 

Corporation Tulsa Petroleum Refining Industry

Flue gas 

desulfurization

Source was 

granted a BART 

waiver, but 

emissions 

reductions 

planned under 

refinery consent 

decrees

In its analysis, the ODEQ considered the four statutory factors under Section 51.308(d)(1)(i)(A) 

in its evaluation of the potential for additional controls. In summary, the ODEQ analyzed the 

cost of compliance by reviewing the cost information previously developed by CENRAP and 

made changes to the cost information based on its knowledge of the particular facilities and 

experience with implementing ozone reduction strategies. The ODEQ’s analysis focused on 

moderate cost controls for sources likely to contribute to visibility impairment at the Wichita 
25

Mountains. In considering the time necessary for compliance, the ODEQ determined that any 

such controls would have to be installed and in operation by 2018. It did not identify any 

detrimental non-air quality environmental impacts associated with any controls considered, and 

any energy impacts were factored into the cost of controls. In considering the remaining useful 

life of any potentially affected sources, the ODEQ stated that none of the sources considered for 

additional emission reductions had indicated plans to shut down. 

The ODEQ also evaluated the major sources of each visibility impairing pollutant within the 

State. In its analyses of additional SO2 control, it noted that the three largest sources of sulfur 

emissions in the State, OG&E Muskogee, OG&E Sooner, and AEP/PSO Northeastern, were 

subject to BART.24 The ODEQ also stated that sulfur controls at the Grand River Dam 

Authority (GRDA) would be costly and result in little visibility benefit given the location of the 

facility. Furthermore, the GRDA already utilized flue gas desulfurization. It noted that 

additional sulfur emission reductions were already required due to consent decrees on refineries. 

The ODEQ identified that three of the four largest NOx point sources and a number of smaller 

sources close to Wichita Mountains would be controlled under BART. Similar to its analysis for 

SO2, the ODEQ also stated that NOx controls at the GRDA would be costly and result in little 

visibility benefit given the location of the facility. The ODEQ determined that controls for other 

point and area sources, especially those associated with oil and gas activities, would be 

expensive and that violations would entail large costs to detect and enforce. The ODEQ stated 

that improved emission inventories in the future could help in developing State rules for area 

sources. In addition, the ODEQ stated that new oil and gas sources are covered by new source 

performance standards. 

Based on the above analysis of the four factors, the ODEQ concluded that retrofitting these 

identified point sources of NOx and SO2 would impose unreasonable costs for negligible 

visibility improvement. The ODEQ reasoned that most of the largest sources of SO2 and NOx 

were already being controlled through BART, consent decrees or other regulatory mechanisms; 

already had adequate controls in place; or are located too far from the Wichita Mountains, and 

therefore have too little visibility impact to justify the cost of additional controls. The ODEQ 

concluded that further emission reductions from such sources were unreasonable. It also stated 

that it would be unreasonable to require severe or over-control of Oklahoma sources to 

compensate for the contribution from Texas, other States, and foreign countries, especially 

considering that the vast majority of the visibility impairment at the Wichita Mountains 

originates from sources beyond the borders of Oklahoma.

The ODEQ determined that the majority of VOC emissions are from biogenic sources. 

Anthropogenic sources of VOC are largely covered under federal mandates and have a small 

contribution to visibility impairment. Fine and coarse particulate emissions are also primarily 

due to natural sources such as dust storms and fires. The ODEQ noted that despite the 

prominence of agricultural burning and wildfires in the Oklahoma emissions inventory, it does 

not believe that these sources contribute significantly to regional haze at the Wichita Mountains 

or at any other Class I area. It pointed out that there are State regulations already in place (see 

 

24 In our FIP (76 FR 81728), we disagreed with the ODEQ’s BART determinations for these three facilities (two 

units at each facility) and required a more stringent level of control. 
26

the Oklahoma Administrative Code 252:100-13-7(4)) to address the burning of forestland, 

cropland, and rangeland. In addition, pursuant to the regional haze requirements at Section 

51.308(d)(3)(v)(E), the ODEQ considered smoke management techniques for purposes of 

agricultural and forestry management. The ODEQ stated that it believes that most emissions of 

fine and coarse PM originate from natural sources, and that even those originating in Oklahoma 

are beyond the regulatory purview of ODEQ. 

EPA Findings:

In establishing its RPGs for 2018 for the 20% worst days, the ODEQ relied on the improvements 

in visibility that were anticipated to result from federal and State control programs that were 

either currently in effect or with mandated future-year emission reduction schedules that predate 

2018, including the long-term strategies of Oklahoma, Texas, and other States, and presumptive 

emission reductions expected to result from the submitted Oklahoma BART rule. Based on the 

emission reductions from these measures, CENRAP modeled the projected visibility conditions 

anticipated at each Class I area in the region in 2018, and the ODEQ used these results to 

establish its RPGs.

We agree with the ODEQ’s decision to focus the analysis of the four statutory factors on point 

sources, as the CENRAP modeling results and ODEQ’s analysis in Section V.F of the Oklahoma 

Regional Haze SIP indicate that sulfate is the predominant pollutant that affects the State’s 

ability to meet the URP goals in 2002 on the worst 20% days at the Wichita Mountains, and 

comes primarily from point sources. CENRAP modeling results also indicate that Oklahoma 

point sources contribute only 3.25 Mm1of the total 111.03 Mm-1visibility extinction at the 

Wichita Mountains in 2002 and only 2.95 Mm1of the total 86.56 Mm1 projected for 2018. This 

modeling projection does not include the level of controls required under BART by the FIP and 

the revised SIP for the three largest sources of SO2 in the State. The ODEQ also considered 

sources of VOC emissions, coarse and fine PM emissions, mobile source emissions and area 

source emissions in its discussion and analysis of the four factors.

There are large EGU sources of SO2 for which the ODEQ did not propose control, including the 

GRDA Units 1 and 225, Muskogee Unit 6, and Hugo Unit 1. Oklahoma considered these sources 

for additional control under reasonable progress but ultimately for the reasons described above, 

declined to further control them. However, the total contribution from those sources not 

identified for control is only a fraction of the 1.23 Mm-1projected from all SO2 point sources, 

and none of the those sources are located such that we would anticipate significant visibility 

benefits at the Wichita Mountains on the 20% worst days should they be controlled. The 20% 

worst days at the Wichita Mountains are dominated by days impacted by emissions from sources 

in Texas. The largest impacts from sources in Oklahoma rarely occur on the 20% worst days as 

identified by the IMPROVE monitor data during the baseline period. For these reasons and 

others that we more fully explore herein, we believe that Oklahoma has adequately controlled its 

own sources for reasonable progress to the extent necessary for this planning period.

 

25

 Both GRDA Units 1 and 2 plan to install low NOx burners and overfire air in order to reduce NOx by 

construction permit No. 2009-179-C (M-2)(PSD). Unit 2 of the GRDA is fitted with a dry scrubber. We have 

recently became aware that Unit 1 (which is not scrubbed) is scheduled to be retired or converted to natural gas and 

a third natural gas powered unit may be added under a draft permit evaluation.
27

As the ODEQ notes in several places in its SIP, point sources in Texas account for a much 

greater portion of the visibility impact at the Wichita Mountains than Oklahoma point sources. 

Compared to the 1.23 Mm-1 due to point source emissions of SO2 in Oklahoma discussed above, 

Texas point source emissions of SO2 are projected to contribute 7.83 Mm-1 to the total extinction 

in 2018. We agree with the ODEQ’s statement regarding this situation: “The vast majority of 

visibility impairment at the Wichita Mountains comes from sources beyond the borders of the 

State of Oklahoma. The federal Regional Haze Rule in 40 C.F.R. Section 51.308(d)(3)(ii) does 

not require DEQ to compensate for the lack of control of emissions in Texas, other States, and 

foreign countries.” The Regional Haze Rule does not require a State to over control its own 

sources in order to compensate for under controlled sources from another State. However, the 

Regional Haze Rule does require, under Section 51.308(d)(1)(iv), that in developing its RPGs, 

Oklahoma consult with those States which may reasonably be anticipated to cause or contribute 

to visibility impairment at the Wichita Mountains to identify reasonable measures for improving 

visibility at its Class I area. 

A.4. Uniform Rate of Progress Determination 

Section 51.308(d)(1)(i)(B) requires Oklahoma to analyze and determine the URP needed to 

attain natural visibility conditions by 2064. To calculate the URP, Oklahoma must compare 

baseline visibility conditions to natural visibility conditions at the Wichita Mountains and 

determine the uniform rate of visibility improvement (measured in deciviews) that would need to 

be maintained during each implementation period in order to attain natural visibility conditions 

by 2064. In establishing the RPG, Oklahoma must consider the URP and the emission reduction 

measures needed to achieve it for the period covered by the implementation plan. In a previous 

final rulemaking,26 we found that ODEQ appropriately calculated the URP for the Wichita 

Mountains. Therefore, the only portion of 40 CFR 51.308(d)(1)(i)(B) that we address is 

Oklahoma’s requirement to consider the emission reduction measures needed to achieve the URP 

when establishing the RPG for the Wichita Mountains.

State Submittal: Pages 36 and 107-114

In establishing the RPGs for the Wichita Mountains, the ODEQ compared the baseline visibility 

conditions to the natural visibility conditions and determined the URP needed in order to attain 

natural visibility conditions by 2064. It calculated that the URP results as a visibility 

improvement of 3.80 dv for the period covered by this SIP revision submittal (up to and 

including 2018). The ODEQ noted that the CENRAP modeling results indicated that complete 

elimination of all anthropogenic emissions in Oklahoma are likely to be insufficient to meet the 

URP at the Wichita Mountains and that a majority of the visibility impairment at the Wichita 

Mountains comes from sources beyond Oklahoma’s borders. 

After considering the URP, the results of the CENRAP modeling and the four reasonable 

progress factors, the ODEQ determined that meeting the URP goal for 2018 was not reasonable. 

It then adopted the 2018 projected visibility conditions from the CENRAP photochemical 

modeling as the RPGs for the 20% best days and 20% worst days for the Wichita Mountains.

 

26

 76 FR 81728 (Dec. 28, 2011). 
28

Table 7 - Comparison of URP to the Reasonable Progress Goal on Most Impaired Days for 

the Wichita Mountains

Extinction Deciview

Natural Visibility Conditions 21.23 Mm-17.53 dv

Baseline Visibility Conditions (2002-2004) 108.15 Mm-123.81 dv

Improvement Needed to Reach Natural Conditions 86.91 Mm-116.28 dv

Improvement by 2018 at Uniform Rate of Progress 34.18 Mm-13.80 dv

Improvement by 2018 under Oklahoma’s RPG 22.52 Mm-12.33 dv

Rate of Improvement from 2004-2018 under 

Oklahoma’s RPG (dv/year) - 0.166 dv/year

Shortfall between Oklahoma’s RPG and the URP (for 

this implementation period) - -1.47 dv

Improvement by 2064 Extrapolated from Oklahoma’s 

RPG 68.38 Mm-1

10.01 dv

Visibility in 2064 from Oklahoma’s RPG (extrapolated) 39.76 Mm-113.80 dv

Visibility in 2102 Extrapolated from Oklahoma’s RPG 

(natural visibility conditions achieved) 21.23 Mm-1

7.53 dv

EPA Findings: 

The ODEQ believes the RPGs it established for the Wichita Mountains are reasonable, and that it 

is not reasonable to achieve the URP in 2018. In support of this conclusion it included a 

discussion of the pollutant contributions and the sources of visibility impairment at the Wichita 

Mountains (see Sections IX.D and E of the Oklahoma Regional Haze SIP). The ODEQ also took 

several other factors into consideration in determining that it was not reasonable to achieve the 

glide path in 2018 and that the RPG adopted by it is reasonable. 

We evaluated the analysis provided by the ODEQ along with the CENRAP modeling results, 

CENRAP emission inventories and other information in examining the RPGs established by 

ODEQ. Our review of the CENRAP emission inventory, modeling protocol and model results 

can be found in our CENRAP Modeling TSD. Below we present a summary of that evaluation:

 The ODEQ demonstrated through the CENRAP control sensitivity modeling, that 

application of a wide suite of controls across CENRAP States determined to meet a 

cost-effective threshold of $5,000/ton and emissions in relation to location criteria, 

would also not be sufficient to meet the URP goal, falling approximately 0.71 dv 

deciview short of the goal. However, we note that this control sensitivity modeling 

also demonstrated that an additional improvement of 0.75 dv was achievable through 

implementation of the identified controls. Based on source apportionment data, a 
29

large portion of that improvement would likely result from implementation of 

identified controls in Texas. A 0.75 dv improvement represents nearly 33% 

additional improvement over the 2.3 dv improvement projected to occur between the 

baseline period and 2018 due to all of the reductions included in the model from on 

the book controls, implementation of CAIR and assumptions of reductions due to 

BART.

 Evidence in the record demonstrated that additional reductions at sources in Texas 

were likely feasible, result in visibility improvement, and be cost-effective, but the 

ODEQ did not pursue this with Texas. Consequently, we believe the ODEQ did not 

have sufficient information to adequately consider emission reductions for sources in 

Texas in establishing its RPGs and demonstrating that it is reasonable. 

 We believe the current approach to estimate natural conditions used by ODEQ 

follows our default methods and is acceptable to establish the 2064 goal, calculate the 

URP, and evaluate the RPGs established by Oklahoma. 

 We note the more recent IMPROVE monitored data at the Wichita Mountains 

indicates that more progress than anticipated by the CENRAP modeling has 

occurred.27 The most recent five-year (2009-2013) average conditions for the 20% 

worst days is 21.2 dv. This is below the level anticipated in the CENRAP projection 

for 2018 of 21.5 dv. We believe that this observed improvement is the result of 

meteorological conditions, reduction in the impact from fires, and reduction in the 

impacts from SO2 emissions. More recent emission inventory data shows reductions 

in emissions in most States beyond what was projected in the 2018 modeling, 

including large reductions in emissions from the Eastern United States. Emissions 

from non-EGU Texas point sources are lower than have been projected in the 

modeling. We note that additional reductions are still needed to meet or exceed the 

URP goal for 2018 of 20.01 dv. As discussed above, emissions at some of the 

sources that impact visibility the most are still above the emission levels projected in 

the model and cost-effective controls are likely available at these sources. Based on 

information provided by the TCEQ, we do not expect large additional emission 

reductions of SO2 in Texas between 2013 and 2018 under federal programs and the 

SIP as submitted.28

Based on the above considerations, we propose to agree with the ODEQ’s demonstration that it 

is not reasonable to meet the URP for the Wichita Mountains for this planning period. We also 

agree with the ODEQ that emissions and transport from outside of Oklahoma will severely limit 

the rate of progress achievable at the Wichita Mountains on the 20% worst days. As the ODEQ 

itself (and we through our analysis detailed in the FIP TSD) have demonstrated, there are large 

visibility impacts at the Wichita Mountains from outside Oklahoma, the largest percentage 

coming from point sources in Texas. In addition, we believe the ODEQ has also demonstrated 

there is the likelihood of a sizeable visibility improvement from controlling a subset of these 

sources, with likely cost-effective controls.

A.5. Additional Analysis of Reasonable Progress Goal 

 

27

 Available at: http://vista.cira.colostate.edu/tss/

28 TCEQ comment letter to EPA on draft modeling platform dated June 24, 2014. ‘2018 EMP signed.pdf’
30

Section 51.308(d)(1)(ii) provides that for the period of the SIP, if Oklahoma establishes a RPG

that provides for a slower rate of improvement in visibility than the rate that would be needed to 

attain natural conditions by 2064, it must demonstrate based on the factors in section

51.308(d)(1)(i)(A) that the rate of progress for the SIP to attain natural conditions by 2064 is not 

reasonable; and that the progress goal it adopted is reasonable. As part of its SIP assessment, 

Oklahoma must provide to the public for review the number of years it would take to attain 

natural conditions if visibility improvement continues at the rate of progress it selected as 

reasonable.

Section 51.308(d)(1)(iii) provides that in determining whether Oklahoma’s goal for visibility 

improvement provides for reasonable progress towards natural visibility conditions, the 

Administrator will evaluate the demonstrations developed by Oklahoma pursuant to sections

51.308(d)(1)(i) and (d)(1)(ii). Because this language relates to our review of Regional Haze SIPs

and does not require a response from the state, it is not separately evaluated here.

State Submittal: Pages 104-114

The ODEQ’s RPG for the 20% worst days establishes a slower rate of progress than the URP for 

the Wichita Mountains. As shown in Table IX-1 of the Oklahoma Regional Haze SIP, under the 

RPG adopted by ODEQ, it projected that natural visibility conditions will not be attained at the 

Wichita Mountains by 2064. ODEQ calculated that under the rate of progress selected by it as 

reasonable, it would attain natural visibility conditions at the Wichita Mountains in 2102. 

In the Oklahoma Regional Haze SIP, the ODEQ states that the RPGs it established for the 

Wichita Mountains are reasonable and that it is not reasonable to achieve the URP in 2018. In 

support of this conclusion, it included a discussion of the pollutant contributions and the sources 

of visibility impairment at the Wichita Mountains (see Sections IX.D and E of the Oklahoma 

Regional Haze SIP). The ODEQ also took several other factors into consideration in 

determining that it was not reasonable to achieve the glide path in 2018 and that the RPG 

adopted by it is reasonable. Tables 8, 9, and 10 below summarize the visibility modeling source 

apportionment results by pollutant and source region for the 2002 base year and the 2018 

projection modeling performed by CENRAP.

Table 8. 2002 Projected sources of light extinction at the Wichita Mountains (worst 

quintile days in) (from Table V-8 of the OK Regional Haze SIP)

(All values in 

Mm1) Sum Sulfurous Nitrate

Organic 

carbonaceous

Elemental 

carbonaceous Soils Coarse

Texas 28.15 13.98 7.89 3.05 1.42 0.29 1.51

Oklahoma 14.72 1.77 6.43 2.26 1.08 0.26 2.91

Rayleigh 

scattering 11.00

boundary 

conditions 9.17 3.93 .87 3.61 0.69 0.02 0.05

East 8.12 7.49 0.15 0.34 0.13 0.01 0.00

Kansas 3.82 0.92 1.94 0.57 0.30 0.05 0.05

Louisiana 3.47 2.60 0.30 0.42 0.14 0.01 0.00
31

secondary 

biogenic 2.91 2.91

secondary 

anthropogenic 2.57 2.57

Indiana 2.53 2.41 0.07 0.02 0.02 0.00 0.00

Missouri 2.47 1.13 1.06 0.19 0.07 0.02 0.01

Canada 2.35 1.62 0.58 0.09 0.05 0.01 0.00

Mexico 2.25 1.79 0.37 0.04 0.02 0.01 0.02

Illinois 2.05 1.55 0.42 0.04 0.03 0.00 0.00

Arkansas 1.97 1.03 0.49 0.31 0.13 0.01 0.01

Ohio 1.68 1.61 0.02 0.02 0.02 0.00 0.00

Tennessee 1.51 1.29 0.11 0.07 0.03 0.00 0.00

Kentucky 1.47 1.35 0.05 0.04 0.02 0.00 0.00

Alabama 1.41 1.30 0.03 0.06 0.02 0.00 0.00

Iowa 1.16 0.46 0.57 0.06 0.03 0.03 0.01

Nebraska 1.11 0.32 0.63 0.08 0.04 0.02 0.02

West 0.93 0.37 0.29 0.20 0.07 0.01 0.01

Minnesota 0.78 0.30 0.31 0.11 0.04 0.01 0.00

Mississippi 0.52 0.32 0.06 0.10 0.03 0.00 0.00

Michigan 0.47 0.42 0.02 0.01 0.01 0.00 0.00

New Mexico 0.46 0.14 0.28 0.02 0.01 0.00 0.01

Colorado 0.45 0.16 0.25 0.02 0.01 0.00 0.00

North Dakota 0.41 0.23 0.14 0.02 0.01 0.00 0.00

Wyoming 0.36 0.18 0.16 0.01 0.00 0.00 0.00

Wisconsin 0.33 0.25 0.05 0.02 0.01 0.00 0.00

South Dakota 0.23 0.05 0.12 0.02 0.02 0.01 0.01

Gulf of Mexico 0.22 0.15 0.06 0.01 0.00 0.00 0.00

initial conditions 0.00 0.00 0.00 0.00 0.00 0.00 0.00

total 111.03 49.12 23.72 17.28 4.47 0.79 4.64

Table 9. 2018 Projected sources of light extinction at the Wichita Mountains (worst 

quintile days) (from Table VIII-10 of the OK Regional Haze SIP)

2018 Model projection 

(All values in 

Mm-1) Sum Sulfurous Nitrate

Organic 

carbonaceous

Elemental 

carbonaceous Soils Coarse

Texas 20.79 9.68 6.08 2.57 0.68 0.30 1.49

Oklahoma 12.28 1.58 4.99 2.10 0.72 0.24 2.65

Rayleigh 

scattering 11.00

boundary 

conditions 9.11 3.77 1.03 3.55 0.69 0.02 0.05

East 3.15 2.67 0.07 0.31 0.08 0.01 0.00

Kansas 2.90 0.63 1.36 0.56 0.26 0.05 0.05

Louisiana 3.65 2.77 .30 0.45 0.12 0.01 0.00

secondary 

biogenic 2.84 2.84
32

secondary 

anthropogenic 2.22 2.22

Indiana 0.92 0.86 0.02 0.02 0.01 0.00 0.00

Missouri 2.10 1.15 0.71 0.17 0.04 0.02 0.01

Canada 2.00 1.39 0.46 0.09 0.05 0.01 0.00

Mexico 2.10 1.72 0.30 0.04 0.02 0.01 0.02

Illinois 1.06 0.78 0.22 0.04 0.02 0.00 0.00

Arkansas 1.71 1.04 0.30 0.27 0.08 0.01 0.01

Ohio 0.49 0.45 0.01 0.02 0.01 0.00 0.00

Tennessee 0.79 0.65 0.05 0.07 0.02 0.00 0.00

Kentucky 0.70 0.63 0.03 0.03 0.01 0.00 0.00

Alabama 0.55 0.47 0.01 0.05 0.01 0.00 0.00

Iowa 0.99 0.49 0.39 0.05 0.02 0.03 0.01

Nebraska 0.81 0.25 0.42 0.07 0.02 0.02 0.02

West 0.80 0.33 0.22 0.18 0.05 0.01 0.01

Minnesota 0.64 0.31 0.22 0.07 0.02 0.01 0.00

Mississippi 0.36 0.19 0.04 0.10 0.02 0.00 0.00

Michigan 0.40 0.38 0.01 0.01 0.00 0.00 0.00

New Mexico 0.39 0.13 0.23 0.01 0.00 0.00 0.01

Colorado 0.31 0.11 0.16 0.02 0.01 0.00 0.00

North Dakota 0.38 0.23 0.12 0.01 0.01 0.00 0.00

Wyoming 0.80 0.33 0.22 0.18 0.05 0.01 0.01

Wisconsin 0.80 0.33 0.22 0.18 0.05 0.01 0.01

South Dakota 0.16 0.04 0.08 0.02 0.01 0.01 0.01

Gulf of Mexico 0.33 0.22 0.10 0.00 0.00 0.00 0.00

initial conditions 0.00 0.00 0.00 0.00 0.00 0.00 0.00

total 87.54 33.58 18.38 16.33 3.09 .80 4.36

Table 10. 2002 to 2018 Projected reduction in sources of light extinction at the Wichita 

Mountains (worst quintile days) (from Table VIII-10 of the OK Regional Haze SIP)

2002 to 2018 Projected reduction 

(All values in 

Mm-1) Sum Sulfurous Nitrate

Organic 

carbonaceous

Elemental 

carbonaceous Soils Coarse

Texas 7.36 4.30 1.81 0.48 0.74 0.00 0.02

Oklahoma 2.43 0.19 1.44 0.17 0.36 0.01 0.27

Rayleigh 

scattering 0.00

boundary 

conditions 0.06 0.16 -0.16 0.06 0.00 0.00 0.00

East 4.97 4.82 0.08 0.03 0.05 0.00 0.00

Kansas 0.92 0.29 0.58 0.01 0.04 0.00 0.00

Louisiana -0.18 -0.17 0.00 -0.03 0.02 0.00 0.00

secondary 

biogenic 0.06 0.06

secondary 

anthropogenic 0.35 0.35

Indiana 1.61 1.55 0.05 0.00 0.01 0.00 0.00
33

Missouri 0.37 -0.02 0.35 0.02 0.02 0.00 0.00

Canada 0.36 0.23 0.12 0.00 0.00 0.00 0.00

Mexico 0.15 0.07 0.07 0.00 0.00 0.00 0.00

Illinois 0.99 0.77 0.20 0.00 0.02 0.00 0.00

Arkansas 0.26 -0.01 0.19 0.04 0.04 0.00 0.00

Ohio 1.19 1.17 0.01 0.00 0.01 0.00 0.00

Tennessee 0.72 0.64 0.07 0.00 0.01 0.00 0.00

Kentucky 0.76 0.73 0.03 0.00 0.01 0.00 0.00

Alabama 0.86 0.83 0.01 0.01 0.01 0.00 0.00

Iowa 0.17 -0.03 0.18 0.01 0.01 0.00 0.00

Nebraska 0.30 0.06 0.21 0.01 0.02 0.00 0.00

West 0.13 0.04 0.07 0.01 0.02 0.00 0.00

Minnesota 0.14 -0.01 0.09 0.04 0.02 0.00 0.00

Mississippi 0.16 0.13 0.02 0.00 0.01 0.00 0.00

Michigan 0.06 0.05 0.01 0.00 0.00 0.00 0.00

New Mexico 0.07 0.00 0.06 0.01 0.00 0.00 0.00

Colorado 0.14 0.05 0.09 0.00 0.01 0.00 0.00

North Dakota 0.03 0.00 0.02 0.00 0.01 0.00 0.00

Wyoming -0.44 -0.15 -0.06 -0.18 -0.04 -0.01 0.00

Wisconsin -0.47 -0.08 -0.17 -0.16 -0.04 -0.01 -0.01

South Dakota 0.06 0.01 0.04 0.00 0.01 0.00 0.00

Gulf of Mexico -0.11 -0.07 -0.04 0.00 0.00 0.00 0.00

initial conditions 0.00 0.00 0.00 0.00 0.00 0.00 0.00

total 23.49 15.54 5.34 .96 1.38 -0.01 0.28

Tables 11 and 12 (compiled from data in Section V.E. and VIII.E of the OK Regional Haze SIP) 

show the contributions to total extinction for each source category and species for 2002 and 

2018, respectively. Tables 13, and 14 show the modeled source category source apportionment 

results for each region for sulfurous sources of light extinction for 2002 and 2018. 

Table 11. Projected light extinction for 20% worst days at the Wichita Mountains in 2002 

(Mm-1)

Total1 Point Area Non-road On-road Biogenic

SO4 49.12 38.76 4.59 1.0 0.79 0.05

NO3 23.72 6.8 3.41 3.16 6.87 2.61

POA 17.28 0.86 5.79 0.66 0.3 0.6

EC 4.47 0.1 1.89 1.14 0.51 0.14

Soil 0.79 0.05 0.65 0.0 0.0 0.07

CM 4.60 0.04 4.01 0.0 0.01 0.53

Rayleigh 

scattering 11

Sum 111.03 46.61 20.34 5.96 8.48 4.0

1Totals include contributions from boundary conditions and secondary organic matter

Table 12. Projected light extinction for 20% worst days at the Wichita Mountains in 2018 

(Mm-1)
34

Total1 Point Area Non-road On-road Biogenic

SO4 33.33 24.64 4.51 0.28 0.1 0.04

NO3 18.10 6.25 3.96 2.18 1.92 2.76

POA 15.98 1.19 4.99 0.61 0.11 0.47

EC 3.00 0.09 1.45 0.55 0.11 0.11

Soil 0.79 0.08 0.62 0.0 0.0 0.07

CM 4.30 0.05 3.70 0.0 0.01 0.53

Rayleigh 

scattering 11

Sum 87.54 32.3 19.23 3.62 2.25 3.98

1Totals include contributions from boundary conditions and secondary organic matter

Table 13. Projected sulfurous sources of light extinction at the Wichita Mountains (worst 

quintile days in 2002) (from Table V-1 of the OK Regional Haze SIP)

(All values 

in Mm-1) Total Point Area

Non-road 

Mobile

On-road 

Mobile Biogenic

Texas 13.98 11.56 1.85 0.28 0.29 0.00

East 7.49 6.90 0.40 0.09 0.10 0.00

boundary 

conditions 3.93

Louisiana 2.60 1.93 0.56 0.08 0.03 0.00

Indiana 2.41 2.29 0.09 0.02 0.02 0.00

Mexico 1.79 1.67 0.09 0.01 0.01 0.00

Oklahoma 1.77 1.28 0.33 0.06 0.09 0.01

Canada 1.62 1.50 0.08 0.02 0.01 0.00

Ohio 1.61 1.54 0.02 0.02 0.02 0.00

Illinois 1.55 1.47 0.03 0.03 0.02 0.00

Kentucky 1.35 1.23 0.08 0.02 0.01 0.00

Alabama 1.30 1.16 0.11 0.02 0.02 0.00

Tennessee 1.29 1.15 0.08 0.03 0.02 0.00

Missouri 1.13 0.95 0.14 0.03 0.02 0.00

Arkansas 1.03 0.73 0.21 0.04 0.03 0.01

Kansas 0.92 0.71 0.16 0.04 0.02 0.00

Iowa 0.46 0.42 0.01 0.02 0.01 0.00

Michigan 0.42 0.37 0.02 0.02 0.01 0.00

West 0.37 0.28 0.03 0.03 0.01 0.02

Mississippi 0.32 0.25 0.01 0.04 0.01 0.00

Nebraska 0.32 0.25 0.03 0.03 0.01 0.00

Minnesota 0.30 0.24 0.03 0.02 0.01 0.01

Wisconsin 0.25 0.23 0.01 0.01 0.01 0.00

North 

Dakota 0.23 0.21 0.01 0.01 0.00 0.00

Wyoming 0.18 0.15 0.02 0.01 0.00 0.00
35

all other 0.49 0.28 0.17 0.03 0.01 0.00

total 49.12 38.76 4.59 1.00 0.79 0.05

Table 14. Projected sulfurous sources of light extinction at the Wichita Mountains (worst 

quintile days in 2018) (from Table VIII-3 of the OK Regional Haze SIP)

(All values 

in Mm-1)

Total Point Area Non-road 

Mobile 

On-road 

Mobile 

Biogenic 

Texas 9.68 7.83 1.73 0.08 0.04 0.00 

East 2.67 2.27 0.37 0.01 0.01 0.00 

boundary 

conditions 3.77

Louisiana 2.77 2.16 0.56 0.05 0.00 0.00 

Indiana 0.86 0.78 0.07 0.00 0.00 0.00 

Mexico 1.72 1.61 0.09 0.01 0.00 0.00 

Oklahoma 1.58 1.23 0.33 0.01 0.01 0.00 

Canada 1.39 1.28 0.08 0.02 0.00 0.00 

Ohio 0.45 0.41 0.03 0.01 0.00 0.00 

Illinois 0.78 0.74 0.03 0.00 0.00 0.00 

Kentucky 0.63 0.54 0.07 0.01 0.00 0.00 

Alabama 0.47 0.37 0.09 0.01 0.00 0.00 

Tennessee 0.65 0.56 0.07 0.01 0.00 0.00 

Missouri 1.15 1.00 0.14 0.00 0.00 0.00 

Arkansas 1.04 0.82 0.21 0.01 0.00 0.01 

Kansas 0.63 0.46 0.17 0.00 0.00 0.00 

Iowa 0.49 0.48 0.01 0.00 0.00 0.00 

Michigan 0.38 0.35 0.02 0.01 0.00 0.00 

West 0.33 0.28 0.03 0.00 0.00 0.02 

Mississippi 0.19 0.16 0.01 0.02 0.00 0.00 

Nebraska 0.25 0.21 0.04 0.00 0.00 0.00 

Minnesota 0.31 0.27 0.04 0.00 0.00 0.00 

Wisconsin 0.21 0.20 0.01 0.00 0.00 0.00 

North 

Dakota 0.23 0.22 0.01 0.00 0.00 0.00 

Wyoming 0.21 0.18 0.02 0.00 0.00 0.00 

all other 0.50 0.23 0.27 0.00 0.00 0.00 

total 33.33 24.64 4.51 0.28 0.10 0.04 

The ODEQ indicated that Oklahoma’s ability to meet the URP is impeded primarily by the 

following: the significant contribution of emissions from Texas and other areas outside the 

ODEQ’s jurisdiction; the uncertainty in the effect of CAIR; the economic and energy cost of 

additional controls on Oklahoma point sources; the lack of a quality-assured enhanced Oklahoma 

emissions inventory and ODEQ’s reluctance to target area sources for emissions controls until 

such an emissions inventory is developed; the ODEQ’s lack of jurisdiction over non-road and 

on-road mobile sources; and, the limitations involved with utilizing the default EPA method to 
36

determine natural visibility conditions. The ODEQ’s discussion of these factors in the Oklahoma 

Regional Haze SIP is summarized below:

 As discussed in the previous section, in considering the URP, the ODEQ determined that 

the CENRAP modeling results indicate that complete elimination of all anthropogenic 

emissions in Oklahoma is likely to be insufficient to meet the URP at the Wichita 

Mountains.

 The CENRAP control sensitivity modeling scenario demonstrated that if all CENRAP 

member states compelled sources to install and operate add-on controls as identified in 

the Alpine Geophysics evaluation at facilities meeting the CENRAP selected criteria for 

cost-effectiveness of $5,000/ton and Q/D greater than 5, the Wichita Mountains would 

still fall short of meeting the URP glide path for the 20% worst days in 2018.

 ODEQ stated that as the data in Tables 8 through 14 demonstrate, most of the visibility 

impairment at the Wichita Mountains comes from sources beyond the borders of the State 

of Oklahoma, including Texas, eastern states, international sources, and other areas 

outside the ODEQ’s jurisdiction. For instance, based on the CENRAP’s modeling, Texas 

contributes 28.15 Mm-1(13.94 Mm-1 from point sources), Eastern states 8.12 Mm-1(7 

Mm-1 from point sources), areas outside the modeling domain 9.17 Mm-1, and Oklahoma 

14.72 Mm-1 (3.25 Mm-1 from point sources) of the total 111.03 Mm-1 light extinction at 

the Wichita Mountains on the 20% worst days in 2002 (see Section V.F. of the Oklahoma 

Regional Haze SIP and Table 8 above). The modeling domain includes the continental 

U.S., Northern Mexico, and Southern Canada and contributions from all other sources 

outside of the modeling domain are captured by the “boundary conditions.” We note that 

the total extinction of 111.03 Mm-1includes 11 Mm-1due to Rayleigh scattering, or light 

extinction due to scattering of light by atmospheric gases. 

 Based on the CENRAP’s 2018 projection modeling, Texas contributes 20.79 Mm-1

(10.58 Mm-1 from point sources), Eastern states contribute 3.15 Mm-1, areas outside the 

modeling domain contribute 9.11 Mm-1, and Oklahoma contributes 12.28 Mm-1 (2.97 

Mm-1 from point sources) of the total 87.54 Mm-1 light extinction at the Wichita 

Mountains on the 20% worst days in 2018 (see Section VIII. of the Oklahoma Regional 

Haze SIP and Table 9 above). We note that the total extinction of 87.54 Mm-1includes 

11 Mm-1due to Rayleigh scattering, or light extinction due to scattering of light by 

atmospheric gases. 

 The ODEQ stated that it is unreasonable to require severe control of Oklahoma sources to 

compensate for the contribution (and lack of additional controls) from Texas, other states, 

and foreign countries, especially considering that the vast majority of the visibility 

impairment at the Wichita Mountains originates from sources beyond the borders of 

Oklahoma. It also noted that additional emissions reductions from sources outside 

Oklahoma would be necessary to achieve progress in visibility improvement at the 

Wichita Mountains. 
37

 Since the Clean Air Interstate Rule (CAIR)/Cross State Air Pollution Rule (CSAPR) is a 

cap and trade program that allows trading SO2 and NOx emissions allowances among 

EGUs, there is uncertainty in the eventual geographic location of emissions reductions 

within the states covered by CSAPR. The ODEQ argued that this uncertainty cascades to

uncertainty in predicting the visibility improvement at the Wichita Mountains, especially 

since CAIR/CSAPR is predicted to provide the majority of the emissions reductions in 

underlying the 2018 visibility projections. 

 In determining whether it is reasonable to require Oklahoma point sources to install 

controls under reasonable progress, the ODEQ noted that it had already considered 

controls for the majority of the point sources in Oklahoma that are likely to contribute to 

visibility impairment at the Wichita Mountains under the BART review process, refinery 

consent decrees, or other controls already included in the reasonable progress goal (see 

table 6). In its analysis of the four reasonable progress factors under 40 CFR 

51.308(d)(1)(i)(A), the ODEQ eliminated exorbitantly costly controls and sources already 

subject to reasonable controls from consideration, which left very few existing sources in 

Oklahoma left for consideration. The ODEQ also evaluated the major sources of each 

visibility impairing pollutant within the state. After considering the four reasonable 

progress factors, the ODEQ concluded that because of the considerable distance between 

the set of point sources under consideration and the Wichita Mountains and the sources’ 

likely minimal visibility impact, requiring controls under reasonable progress for 

Oklahoma point sources would result in high economic and energy costs and was 

therefore not reasonable. It also considered sources of VOC emissions, course and fine 

PM emissions and area source emissions in their discussion and analysis of the four 

factors. 

 The ODEQ stated that it lacks confidence in the estimated considerable contribution of 

area sources, especially oil and gas industrial processes, to the Oklahoma NOx emissions 

inventory presented in the SIP. It noted that it would like to develop a quality-assured 

enhanced emissions inventory before considering emissions controls on area sources. In 

particular, it stated it would like to further refine an oil and gas emissions inventory it 

developed in 2008, so that its future control assessments can build on that information. 

 The ODEQ noted that it lacks jurisdiction over non-road and on-road mobile sources, 

which contribute to the Oklahoma NOx emissions inventory presented in the SIP. Since 

many non-road and on-road mobile sources move to and from other states, the ODEQ 

stated it relies on the federal motor vehicle emissions control programs and other EPA 

regulations to limit emissions from this sector.

 Only a small portion of VOC emissions in Oklahoma originate from area, industrial, 

point, and mobile sources (see section IV of the Oklahoma Regional Haze SIP). Taking 

into consideration the small and uncertain contribution of anthropogenic sources of VOC 

to visibility impairment at the Wichita Mountains, the ODEQ did not find further controls 

on sources of VOC emission reasonable. 
38

 The ODEQ stated it believes that most coarse and fine PM emissions from Oklahoma 

originate from natural sources. It stated it lacks confidence in the Oklahoma emissions 

inventory presented in this SIP, which assigns most coarse PM emission to road dust. It

noted that unpaved roads typically lack the traffic necessary to justify the expense of 

pavement. The ODEQ also stated that it believes that dust storms, which occur naturally 

in dry environments, are a significant source of coarse PM emissions affecting visibility 

at the Wichita Mountains. It noted that despite the prominence of agricultural burning 

and wildfires in the Oklahoma emissions inventory, it does not believe that these sources 

contribute significantly to regional haze at the Wichita Mountains nor at any other Class I 

area. It pointed out that there are State regulations already in place (see the Oklahoma 

Administrative Code 252:100-13-7(4)) to address the burning of forestland, cropland, and 

rangeland. In addition, pursuant to the regional haze requirements at 40 CFR 

51.308(d)(3)(v)(E), ODEQ considered smoke management techniques for purposes of 

agricultural and forestry management. The ODEQ stated that it believes that most 

emissions of fine and coarse PM originate from natural sources, and that even those 

originating in Oklahoma are beyond its regulatory purview. 

 The ODEQ also discussed the uncertainty in its estimate of natural visibility conditions at 

the Wichita Mountains, and how that may impact the evaluation of the established RPG

and the need for additional controls. Our Western default natural visibility conditions for 

the Wichita Mountains is based on an algorithm for estimating natural conditions, and is 

consistent with EPA’s designation of 98°W longitude as the division between East and 

West. However, the ODEQ noted that because Oklahoma lies near the boundary between 

East and West, it does not strictly belong to either region. It noted that there is a lack of 

data from the south central U.S. to formulate natural visibility estimates for this region, 

and that it believes that the default western target does not represent the actual conditions 

at the Wichita Mountains. In addition, the ODEQ stated that Oklahoma’s designation as 

a “Western” State for purposes of estimating natural visibility conditions at the Wichita 

Mountains is inconsistent with airflow patterns, which suggest that a considerable portion 

of the emissions contributing to visibility impairment at the Wichita Mountains originate 

from Eastern states. It stated that because of the extremely general character of these 

estimates and their inherent assumptions, they should be considered as broad regional 

averages that do not necessarily apply to specific points, and that include a large margin 

of error. The ODEQ indicated that in the future it may update the estimates of natural 

particulate mass concentrations for each component based on recent peer-reviewed 

literature rather than using the default values or that it may refine the current default 

approach. Given that the actual natural visibility conditions at the Wichita Mountains 

may differ markedly from the estimated natural visibility conditions, the ODEQ does not 

find that it is reasonable to require additional controls for Oklahoma sources. 

Furthermore, the ODEQ suggested that if natural conditions account for a greater 

proportion of the presently observed visibility impairment than what is reflected by our 

Western default estimate, natural visibility conditions may be achievable around 2064 

with the reasonable progress goal selected by ODEQ. 
39

A.6. Our Evaluation of Oklahoma’s Reasonable Progress Goals for the Wichita 

Mountains.

In the sections above, we discuss how Oklahoma constructed its RPGs for the Wichita 

Mountains, how in doing so it consulted with Texas and other States, applied the four reasonable 

progress factors in evaluating sources within Oklahoma for additional controls in the 

development of that RPG, and calculated the URP for the Wichita Mountains. In this section we 

consider those efforts and present our evaluation of Oklahoma’s RPGs for the Wichita 

Mountains.

We believe that with the exception of certain BART sources, Oklahoma appropriately concluded 

that no additional reasonable progress measures for Oklahoma sources were necessary during 

this first planning period. However, BART is a component of reasonable progress, and the RPGs 

selected by the ODEQ for the Wichita Mountains do not include the level of reductions 

necessary to meet the requirements under Section 51.308(e) for BART. In our December 28, 

2011 rulemaking, we disapproved the SO2 BART determinations for certain units and 

promulgated a BART FIP to impose controls for these units.29 Therefore, implementation of our 

SO2 BART FIP and the revised BART SIP for the AEP units is expected to result in greater 

reasonable progress than is anticipated in Oklahoma’s February 19, 2010, Regional Haze SIP

submittal.30.

In addition, as required by Section 51.308(d)(1)(iv), Oklahoma’s development of its RPGs must 

be informed by its consultations with other States. Oklahoma demonstrated that the unrealistic 

scenario of eliminating all Oklahoma sources would not be sufficient to meet the URP for 2018. 

It realized that efforts to meet the goal of natural visibility by 2064 would require further 

emission reductions from other States in the region. The CENRAP modeling, monitoring data 

and other technical analyses that informed consultations demonstrated that NOx and SO2 are the 

primary causes of haze at the Wichita Mountains with SO2 from point sources being the 

predominant driver. It also showed that SO2 point sources in Texas were a significant 

contributor to the haze at the Wichita Mountains. Furthermore, the control and cost information 

developed by CENRAP and Alpine Geophysics showed that cost-effective controls on Texas 

sources were likely available, some with a cost-effectiveness on a $/ton basis within TCEQ’s 

own benchmark. The Regional Haze Rule envisioned that a State would use the consultation 

processes under Sections 51.308(d)(1)(iv) in the development of its RPGs, and 51.308(d)(3)(i) 

regarding the development of its long-term strategy, in identifying visibility impairing emissions 

that cross State boundaries, and in the coordination of strategies to reduce those emissions. 

However, despite this information in the record about the impact of Texas sources on the Wichita 

Mountains, the ODEQ did not request that the TCEQ further investigate these sources, nor did it 

request additional reductions from Texas sources to address this impact. As we discuss in 

Section V.E, we believe that the technical analysis developed by Texas did not provide the 

information necessary to identify reasonable reductions from its sources, and inform 

 

29

 76 FR 81728 (Dec. 28, 2011).

30

 In our August 21, 2013, proposed approval of Oklahoma’s June 20, 2013, regional haze SIP revision we proposed 

to find that the SO2 emission reductions associated with Oklahoma’s revised BART determination for Northeastern 

Units 3 and 4, when combined with enforceable commitments from ODEQ, will be consistent with the levels of 

control assumed in the CENRAP modeling and relied on by other States as part of their reasonable progress 

demonstrations (78 FR 51586).
40

consultations in order to develop coordinated management strategies with Oklahoma. Therefore, 

due to this absence of the development of this critical information during consultations, we 

believe that Oklahoma did not have adequate information to establish its RPG for the Wichita 

Mountains, and should have requested that the TCEQ further investigate these sources or 

requested additional reductions from Texas sources to ensure that all reasonable measures to 

improve visibility were included in Texas’ LTS and incorporated into Oklahoma’s RPG for the 

Wichita Mountains. Thus, the basic intent of our consultation requirements was not realized. 

In addition to the explicit statutory requirement under Section 51.308(d)(1)(ii) to consider the 

four reasonable progress factors, the Regional Haze Rule also establishes an analytical 

requirement to ensure that each State considers the emission reduction measures necessary to 

attain the URP. The Regional Haze Rule provides that we will evaluate Oklahoma’s 

consideration of the four factors in Section 51.308(d)(1)(i)(A), its analysis of the URP required 

under Section 51.308(d)(1)(i)(B) and the demonstration developed pursuant to Section 

51.308(d)(1)(ii), “[i]n determining whether the State’s goal for visibility improvement provides 

for reasonable progress.” As explained in the preamble to the Regional Haze Rule, the URP 

analysis was adopted to ensure that States use a common analytical framework and to ensure an 

informed, equitable, and transparent decision making process that would, among other things, 

ensure that the public would be provided with the information necessary to understand the 

emission reductions needed, the costs of such measures, and other factors associated with 

improvements in visibility. We note that this analytical requirement is met only through 

consultation and is not restricted to the consideration of only those sources within the State with 

the impacted Class I area. As we stated in the Regional Haze Rule regarding this requirement31: 

In doing this analysis, the State must consult with other States which are 

anticipated to contribute to visibility impairment in the Class I area under 

consideration. Because haze is a regional problem, States are encouraged to work 

together to develop acceptable approaches for addressing visibility problems to 

which they jointly contribute. If a contributing State cannot agree with the State 

establishing the reasonable progress goal, the State setting the goal must describe 

the actions taken to resolve the disagreement.

However, Oklahoma’s consultation was incomplete. While the analyses developed by CENRAP 

provide a great deal of information on contributions to visibility impairment and a set of 

potential available add-on controls and cost associated with those controls, the data was 

insufficient to fully assess the impacts and available emission reduction measures for Texas 

sources. Given the large contributions from sources in Texas and EGU point sources in 

particular, Oklahoma could not reasonably consider all the emission reductions needed to meet 

or approach the URP without considering emission reduction measures available for those 

sources in Texas that contribute the most to visibility impairment at Wichita Mountains. In 

summary, we propose to find the following:

 Oklahoma has demonstrated that it is not reasonable to require additional emission 

reductions for its sources for this planning period.

 

31

 64 FR 35732 (July 1, 1999).
41

 BART is a component of developing the RPGs, and the RPGs are inadequate because 

BART controls were not adequately considered. We note this deficiency is 

addressed by our BART FIP and the revised Oklahoma SIP.

 Oklahoma’s consultations with Texas were flawed, which prevented it from 

adequately developing its RPGs for the Wichita Mountains.

 Also because Oklahoma’s consultations with Texas were flawed, Oklahoma did not 

consider the emission reduction measures necessary to achieve the URP for the 

Wichita Mountains and did not adequately demonstrate that the RPGs it established 

were reasonable based on the four statutory factors under 51.308(d)(1)(ii). 

In consideration of these flaws, we propose to disapprove Oklahoma’s submission under Section 

51.308(d)(1), except for those portions addressing Section 51.308(d)(1)(vi), which we propose to 

approve.

Our Additional Analysis of Impacts from Texas Sources

As the ODEQ itself (and we through our analysis detailed in the FIP TSD and described briefly 

below) have demonstrated, there are large visibility impacts at the Wichita Mountains from 

outside Oklahoma, the largest percentage coming from point sources in Texas. In addition, we 

believe the ODEQ has also demonstrated there is the likelihood of a sizeable visibility 

improvement from controlling a subset of these sources, with likely cost-effective controls.

As discussed in detail in the FIP TSD, in evaluating the Texas and OK Regional Haze SIPs, we 

determined that additional technical analyses concerning Texas’ visibility impacts on Class I 

areas was necessary. Our modeling study provides information on projected 2018 visibility 

impacts of individual selected sources that we determined have the greatest potential to impact 

visibility at surrounding Class I areas. We performed a modeling analysis using CAMx based on 

the 2018 CENRAP emission inventory and utilized source apportionment for a small subset of 

sources in Texas, which we selected using a Q/D analysis. In conducting this analysis, we 

focused on the percent contribution of these Texas sources compared to other sources of 

visibility impairment. Our study confirms that a small number of Texas sources are responsible 

for the majority of the impact from Texas point sources at the Wichita Mountains. For example, 

the three Texas facilities with the largest predicted impact in 2018, are modeled to contribute a 

combined 4.25% to the total visibility impairment at Wichita Mountains. These three facilities 

alone have a larger impact than all the point source emissions in any single nearby state, 

including Oklahoma. The top impacting facility alone has a projected contribution of 1.73% of 

the total visibility impairment at Wichita Mountains. 

We note that in its consultation process ODEQ used a contribution threshold of greater than one 

inverse megameter (Mm-1) of light extinction, when determining if emissions from a state were 

significant and consultation with that state was required. Without regard to the suitability of this 

as a threshold, our modeling study projects that impacts from some individual facilities in Texas 

in 2018, even after accounting for predicted reductions due to CAIR included in the 2018 

CENRAP emission inventory, exceed the 1 Mm-1threshold for the 20% worst days ODEQ 

selected to apply to an entire state’s impact. For example, our projected impacts in 2018 from 

the top ten facilities in Texas that impact visibility at Wichita Mountains are summarized in 
42

Table 15 below. We note that, although the modeled impacts from Martin Lake are less than 

Monticello and Big Brown, we estimate that the predicted emission impacts from this facility 

would be larger than 1 Mm-1if it were modeled at its recent average annual emission level (see 

the FIP TSD for more details).

Table 15. 2018 Phase 1 EPA Source Apportionment Modeling Results, Top Ten Modeled 

Facilities in Texas that Impact Visibility at Wichita Mountains

Rank Facility Name Extinction 

(Mm-1)

% Contribution to 

Total Visibility 

Impairment

1 Monticello 1.275 1.73%

2 Big Brown 1.169 1.59%

3 Martin Lake 0.686 0.93%

4 Works No 4 0.635 0.86%

5 Reliant Energy (Limestone) 0.478 0.65%

6 Oklaunion Power 0.417 0.57%

7 Sommers Deely Spruce 0.410 0.56%

8 HW Pirkey Power 0.368 0.50%

9 Coleto Creek 0.354 0.48%

10 Welsh Power 0.349 0.47%

A.7. Reasonable Progress Goal To Be Considered by Administrator

The language under Section 51.308(d)(1)(v), “The reasonable progress goals established by the 

State are not directly enforceable but will be considered by the Administrator in evaluating the 

adequacy of the measures in the SIP to achieve the progress goal adopted by the State,” is a 

statement relating to our review of Regional Haze SIPs. Since it does not require a response 

from the state, it is not separately evaluated here.

A.8. Reasonable Progress Goal Minimum 

Oklahoma may not adopt a reasonable progress goal that represents less visibility improvement 

than is expected to result from implementation of other requirements of the CAA during the 

applicable planning period. 

State Submittal: Pages 104-114, Appendix 4-2

The RPGs established by Oklahoma are based on CENRAP 2018 modeling projections. The 

modeling projections conducted by CENRAP contain projections of the visibility conditions that 

are anticipated to be realized at each Class I area between the 2002 base year and the 2018 future 

year. These projections are based on the emissions reductions resulting from federal and State 

control programs that are either currently in effect or with mandated future-year emission 

reduction schedules that predate 2018, including the LTSs of Oklahoma, Texas, and other states, 
43

and presumptive emissions reductions expected to result from the submitted Oklahoma BART 

rule.

EPA Findings: 

ODEQ’s RPGs are based on the visibility improvement predicted by CENRAP’s modeling 

projections between the baseline year and 2018. Since CENRAP’s 2018 modeling projections 

are based on local, State, and federal control programs that are either currently in effect or with 

mandated future-year emission reduction schedules, the ODEQ’s RPGs represent at least as 

much visibility improvement as is expected to result from implementation of other requirements 

of the CAA (i.e., requirements other than regional haze) during the applicable planning period. 

We therefore propose to approve Oklahoma’s submission under section 51.308(d)(1)(vi) that its 

RPG for the Wichita Mountains does not represent less visibility improvement than is expected 

to result from the implementation of other requirements of the CAA during this planning period.