Technical Support Document

for the

Texas Regional Haze State Implementation Plan

(TX TSD)

Prepared and Reviewed by:

Michael Feldman

Joe Kordzi

Erik Snyder

November 2014
ii

Table of Contents

I. Relationship of this TSD to our Proposal.................................................................................... 1

II. Background to Regional Haze .................................................................................................. 1

III. Evaluation of State Submittal .................................................................................................. 5

A. Identification of Areas: 40 CFR 51.308(d)........................................................................... 5

B. Reasonable Progress Goals Development............................................................................. 6

B.1. Establishment of Reasonable Progress Goals: 40 CFR 51.308(d)(1) ............................ 8

B.2. Reasonable Progress Goals Four Factor Analysis: 40 CFR 51.308(d)(1)(i)(A) .......... 10

B.3. Uniform Rate of Progress Determination: 40 CFR 51.308(d)(1)(i)(B) ....................... 25

B.4. Analysis of Reasonable Progress Goal: 40 CFR 51.308(d)(1)(ii)-(iii) ........................ 28

B.5. Reasonable Progress Goal To Be Considered by Administrator: 40 CFR 

51.308(d)(1)(v)...................................................................................................................... 31

B.6. Reasonable Progress State Consultation: 40 CFR 51.308(d)(1)(iv) ............................ 32

B.7. Reasonable Progress Goal Minimum: 40 CFR 51.308(d)(1)(vi)................................. 34

C. Baseline and Natural Visibility Conditions......................................................................... 35

C.1. Calculation of Baseline Conditions: 40 CFR 51.308(d)(2)(i)...................................... 35

C.2. Calculation of Natural Visibility Conditions: 40 CFR 51.308(d)(2)(iii) .................... 38

C.3. Natural Visibility Impairment: 40 CFR 51.308(d)(2)(iv)(A)....................................... 42

D. Long Term Strategy 40 CFR 51.308(d)(3). ........................................................................ 43

D.1. Long Term Strategy State Consultation: 40 CFR 51.308(d)(3)(i)............................... 44

D.2. Share of Reductions in Other States’ Progress Goals: 40 CFR 51.308(d)(3)(ii) ......... 49

D.3. Technical Basis for the Long Term Strategy: 40 CFR 51.308(d)(3)(iii) – (iv) ........... 50

D.4. Consideration of Long Term Strategy Factors: 40 CFR 51.308(d)(3)(v).................... 67

E. Monitoring Strategy/Other SIP Requirements 40 CFR 51.308(d)(4) ................................. 72

F. Best Available Retrofit Technology (BART) Requirements: 40 CFR 51.308(e) ............... 74

F.1. Identification and Analysis of BART: 40 CFR 51.308(e)(1) – (4)............................... 74

F.2 Alternate Emission Trading Program: 40 CFR 51.308(e)(2)-(3) ............................... 79

F.3. CAIR for BART: 40 CFR 51.308(e)(4)........................................................................ 79

F.4. Reasonable Progress and BART: 40 CFR 51.308(e)(5)............................................. 81

F.5 BART: 40 CFR 51.308(e)(6)...................................................................................... 81

G. 2018 Regional Haze SIP Revision: 40 CFR 51.308(f) ....................................................... 81

H. Five Year Progress Report: 40 CFR 51.308(g)................................................................... 82

I. Existing SIP Adequacy Determination: 40 CFR 51.308(h) ................................................. 83

J. Federal Land Manager Coordination: 40 CFR 51.308(i)..................................................... 84
iii

Tables

Table 1. Summary of Texas’ Visibility Impacts at Selected Class I Areas Outside of Texas....... 6

Table 2. Texas Reasonable Progress Goals for 20% Worst Days ................................................. 9

Table 3. Texas Reasonable Progress Goals for 20% Best Days.................................................... 9

Table 4. Percentage Source Category Contributions to SO4 and NO3 at the Five Class I Areas 

Texas Most Impacts...................................................................................................................... 11

Table 5. Annualized Cost of Controls for each Class I Area (controls at facilities within each 

Class I area’s AOI)........................................................................................................................ 13

Table 6. Total Estimated Cost of Texas Control Set ................................................................... 14

Table 7. TCEQ Projected Visibility Improvement to Selected Class I Areas from the Imposition 

of Potential Controls..................................................................................................................... 15

Table 8. Comparison of Texas 2002 Baseline SO2 emissions, 2015 CAIR EGUs Budget and 

2018 IPM Predicted SO2 Emissions ............................................................................................. 17

Table 9. 2018 Phase 1 EPA source apportionment modeling results, top ten facilities in Texas 

that impact visibility at Big Bend ................................................................................................. 20

Table 10. 2018 Phase 1 EPA source apportionment modeling results, top ten facilities in Texas 

that impact visibility at Guadalupe Mountains............................................................................. 21

Table 11. Summary of Uniform Rate of Progress ....................................................................... 26

Table 12. Summary of Uniform Rate of Progress based on EPA default Natural Conditions.... 26

Table 13. Estimated emission reductions and cost to meet the URP........................................... 27

Table 14. EPA correction to TCEQ’s estimated emission reductions and cost to meet the URP 28

Table 15. CENRAP’s PSAT Contribution to Visibility in the Texas Class I Areas on the Worst 

20% Days...................................................................................................................................... 29

Table 16. TCEQ Natural Visibility Calculations......................................................................... 40

Table 17: Visibility Metrics for the Class I Areas in Texas ........................................................ 43

Table 18. Texas’ 2002 Emissions Inventory (tons/year) ............................................................. 53

Table 19. Texas’ 2002 Biogenic Emissions Inventory (tons/year).............................................. 53

Table 20. Texas’ 2018 Emissions Inventory................................................................................ 54

Table 21. Projected light extinction for 20% worst days at Big Bend Wilderness Area in 2002 

(Mm-1)........................................................................................................................................... 57

Table 22. Projected light extinction for 20% worst days at Big Bend Wilderness Area in 2018 

(Mm-1)........................................................................................................................................... 57

Table 23. Projected light extinction for 20% worst days at Guadalupe Mountains in 2002 (Mm-1)

....................................................................................................................................................... 60

Table 24. Projected light extinction for 20% worst days at Upper Guadalupe Mountains in 2018 

(Mm-1)........................................................................................................................................... 60

Table 25. Contribution from Texas Emissions to Visibility Impairment (Mm-1) at Class I areas 

on 20% Worst Days in 2002 ......................................................................................................... 63

Table 26. Contribution from Texas Emissions (Mm-1) to Visibility Impairment at Class I areas 

on 20% Worst Days in 2018 ......................................................................................................... 64
iv

Figures

Figure 1. Map of Class I Areas...................................................................................................... 2

Figure 2. Location of the Class I Area in Texas and the Region .................................................. 3

Figure 3. Map of Regional Planning Organization Boundaries..................................................... 4

Figure 4. Natural Condition and URP estimates for Big Bend.................................................... 40

Figure 5. Natural Condition and URP estimates for the Guadalupe Mountains.......................... 41

Figure 6. 2018 projected percent contribution from all sources at Big Bend ............................... 58

Figure 7. 2018 projected percent contribution from point sources at Big Bend.......................... 59

Figure 8. 2018 projected percent contribution from all sources at Guadalupe Mountains.......... 61

Figure 9. 2018 projected percent contribution from point sources at Guadalupe Mountains...... 62

Figure 10. Projected 2018 total extinction and Texas contribution at Class I areas in Texas and 

other states .................................................................................................................................... 65
Texas Regional Haze SIP Evaluation Technical Support Document (TSD)

I. Relationship of this TSD to our Proposal

On March 31, 2009, the State submitted a Texas Regional Haze SIP revision to EPA for review 

and action. This TSD is our technical analysis of Texas’ SIP submittal under the federal Regional 

Haze rule requirements at 40 CFR 51.308. 

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(s) provides more detail than does this 

TSD. Also, this TSD treats the requirements of Section 51.308 in the order in which they appear 

in that regulation, whereas our Federal Register notice(s) groups the requirements into related 

areas so the concepts can be understood more easily. In this regard, the TSD can serve as a

checklist of whether the requirements have been addressed. Lastly, the TSD attempts to refer the 

reader to the specific portions of the Texas 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. Figure 2 shows the Class I areas within Texas—Big Bend National Park (Big Bend) 

and the Guadalupe Mountains National Park (Guadalupe Mountains)—and those in the 

surrounding region:
2

Figure 1. Map of Class I Areas
3

Figure 2. Location of the Class I Area in Texas and the Region

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 state implementation plans (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).
4

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.

Figure 3. Map of Regional Planning Organization Boundaries

Texas, through the Texas Commission on Environmental Quality (TCEQ) joined state air

agencies from Arkansas, Iowa, Kansas, Louisiana, Minnesota, Missouri, Nebraska, and 

Oklahoma in forming CENRAP, an RPO, in 1999. CENRAP also includes federally recognized

Indian tribes located within the geographic boundaries of its member states. Texas chose to 

participate in CENRAP to jointly develop the technical analyses needed to address the 

requirements of the regional haze Rule.
5

III. Evaluation of State Submittal

In evaluating the Texas 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, EPA454/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. Identification of Areas: 40 CFR 51.308(d)

Texas must address regional haze in each mandatory Class I Federal area located within it and in 

each mandatory Class I Federal area located outside it which may be affected by emissions from 

within it.

State Submittal

Chapter 1, Chapter 11

The TCEQ identified two Class I areas within Texas: Big Bend National Park, in Brewster 

County, which borders the Rio Grande and Mexico, and the Guadalupe Mountains National Park 

in Culberson County, which borders New Mexico. The TCEQ is responsible for developing 

Reasonable Progress Goals (RPGs) for these two Class I areas. The TCEQ also determined that 

emissions from sources in Texas impact visibility at a number of Class I areas outside of Texas. 

Table 1 summarizes CENRAP source apportionment modeling results the TCEQ presents as 

Texas’s share of visibility impairment at selected nearby Class I areas, based on the 20% worst 

days for 2002 and 2018. These CENRAP source apportionment modeling results indicate that 
6

Texas emissions impact the visibility at a number of Class I areas in other states, including the 

Breton Wilderness Area in Louisiana, the Great Sand Dunes in Colorado, Caney Creek and the 

Upper Buffalo in Arkansas, the Wichita Mountains in Oklahoma, and several Class I areas in 

New Mexico. 

 

Table 1. Summary of Texas’ Visibility Impacts at Selected Class I Areas Outside of Texas

Class I area State 2002 Impacts (Mm-1

) 2018 Impacts (Mm-1)

Texas total Total, All sources Texas total Total, All sources

Carlsbad Caverns New Mexico 16.62 47.80 15.39 44.43

Salt Creek New Mexico 13.41 52.50 10.24 46.67

White Mountain New Mexico 7.40 32.91 6.22 29.80

Wheeler Peak New Mexico 1.85 21.96 1.59 20.80

Wichita Mountains Oklahoma 28.15 100.03 20.79 75.56

Great Sand Dunes Colorado 1.25 27.88 1.11 26.77

Rocky Mountains Colorado 0.58 32.13 0.51 29.41

Caney Creek Arkansas 14.89 133.93 9.74 85.84

Upper Buffalo Arkansas 5.19 131.79 3.38 86.16

Hercules-Glades Missouri 6.59 140.05 4.45 92.49

Mingo Missouri 2.01 159.83 1.28 99.24

Breton Louisiana 4.20 123.99 3.23 94.06

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

Implementation (TSD for CENRAP modeling) 1provides additional source apportionment model 

results for the 20 percent best and 20 percent worst days for 2002 and 2018. 

EPA Findings: The submittal supports a finding that Texas has properly identified its own Class I 

areas and the Class I areas affected by Texas emissions.

B. Reasonable Progress Goals Development

This section focuses on how Texas established their RPGs for the two Class I areas, Big Bend 

and Guadalupe Mountains. We go through each of the RPG requirements of Section

51.308(d)(1) in the order in which they appear in that regulation, explain the methodology the 

state used in establishing its goals, and then provide our analysis of how the state analyzed those 

elements. 

Background to Establishing Reasonable Progress Goals:

51.308(d)(1) of the regional haze rule requires that states establish “reasonable progress goals”

for each Class I area. Reasonable progress goals are defined as “interim goals that represent 

incremental visibility improvement over time toward the goal of natural background conditions 

and are developed in consultation with other affected States and Federal Land Managers.”2 These 

 

1 See Appendix E of the TSD for CENRAP Emissions and Air Quality Modeling to Support Regional Haze 

State Implementation, found in Appendix 8.1 of the Texas Regional Haze SIP. 

2 Office of Air Quality Planning & Standards, U.S. Environmental. Protection Agency, Guidance for Setting 

Reasonable Progress Goals Under the Regional Haze Program (June 1, 2007).
7

goals are to be expressed in deciviews and provide for improvement on the 20-percent haziest 

days, and provide for no degradation on the 20-percent clearest days. The guidance on 

reasonable progress provides an overview of the process for developing RPGs, potential methods 

for identifying which source categories should be evaluated for controls, and suggestions for 

evaluating the four statutory factors with respect to potentially affected stationary sources.3

The Regional Haze Rule requires that for each Class I area, states (1) determine the amount of 

progress needed to reach natural background conditions in 60 years; (2) identify the “uniform 

rate of progress” or “glidepath” over that 60-year period; (3) identify the amount of progress that 

would result if the uniform rate of progress were achieved during the planning period; and (4) 

identify the emissions measures that would be needed to achieve that amount of progress and 

analyze whether the measures were reasonable based on four statutory factors listed in the CAA.

If a state found that the amount of progress necessary to achieve the uniform rate of progress (or 

some greater amount) was reasonable, then Regional Haze Rule requires the state to adopt that 

amount of progress as its RPG.4If a state found that the amount of progress necessary to achieve 

the uniform rate of progress was unreasonable, however, then the state could set a different RPG, 

but only after providing an analysis and rationale supporting its determination based on the four 

statutory factors.5 The four statutory factors that a state must consider to establish its goals under 

CAA 169(g) are: the cost of compliance; the time necessary for compliance; the energy and nonair quality environmental impacts of compliance; and the remaining useful life of existing 

sources that contribute to visibility impairment. A state must demonstrate how these factors are 

taken into consideration in selection of the RPG for each Class I areas in the state. In establishing 

an RPG, the state must consult with other states with emissions sources that may be reasonably 

be anticipated to cause or contribute to visibility impairment at Class I areas in that state. 

(51.308(d)(1)(iv). 

Overall, the improvement in visibility resulting from implementation of the measures found to be 

reasonable, considering the uniform rate of progress, is the amount of progress that represents a 

state’s progress goal. The state should identify key pollutants and source categories for the first 

planning period that contribute to visibility impairment at the Class I area. Next, identify source 

categories responsible for emitting the identified pollutants. Next, identify control measures for 

contributing source categories that have the greatest impact of visibility at Class I areas, 

considering cost and the other factors. (Reasonable Progress Guidance 4-1). States should factor 

in emissions reductions from state, local and federal controls. After reviewing reductions of 

visibility impairing pollutant from other state, local or federal control measures, the state then 

will identify any additional measures that are reasonable, after considering the four statutory 

factors.6 Based on contribution from certain source categories and the magnitude of emissions, a 

 

3 The final also requires that States, in establishing their RPGs, consult with other States that were anticipated to 

contribute to visibility impairment in the Class I area under consideration. The rule requires States to describe in 

their SIPs any actions taken to resolve disagreements over the apportionment of emission measures necessary to 

achieve the RPGs. 64 Fed. Reg. at 35,732; 40 C.F.R. § 51.308(d)(1)(iv). This requirement will be discussed in 

Section B.6.of this TSD and in the OK TSD. 

4 64 Fed. Reg. at 35,732.

540 C.F.R. § 51.308(d)(1)(ii).

6 While visibility is not an explicitly listed factor to consider when determining whether additional controls are 

reasonable, the purpose of the four-factor analysis is to determine what degree of progress toward natural visibility 
8

state has flexibility to decide whether further controls are warranted. (Reasonable Progress

Guidance 4-2).

B.1. Establishment of Reasonable Progress Goals: 40 CFR 51.308(d)(1)

For each mandatory Class I Federal area located within the state, it 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

Chapter 10

The TCEQ states that its RPGs are derived from the CENRAP modeling and reflect emissions 

reductions programs already in place, including CAIR and additional refinery SO2 reductions as 

a result of our refinery consent decrees. The TCEQ states that these RPGs assume that either 

CAIR will remain in place or will be replaced by a comparable program to reduce visibility 

impairing pollution from Electric Generating Units (EGUs) in Texas and in the eastern United 

States. The CENRAP’s projections for 2018 for the 20% worst and best days for the Big Bend 

and Guadalupe Mountains, are also shown in Appendix D to the document titled “Technical 

Support Document for CENRAP Emissions and Air Quality Modeling to Support Regional Haze 

State Implementation Plans.”7

Based on the results of Texas’ required reasonable progress four-factor analysis (described in the 

following section) and the results of the CENRAP modeling, the TCEQ adopted the CENRAP 

modeled 2018 visibility conditions as the RPGs for the Big Bend and Guadalupe Mountains

Class I areas. TCEQ established a RPG of 16.6 dv for Big Bend and 16.3 dv for Guadalupe 

Mountains for the 20% worst days for 2018. 

Texas established the following Reasonable Progress Goals (RPGs), as summarized in Tables 2 

and 38:

 

conditions is reasonable. Therefore, we believe it is appropriate to consider the projected visibility benefit of the 

controls when determining if cost-effective controls are warranted to make reasonable progress.

7 See Appendix D of the TSD for CENRAP Emissions and Air Quality Modeling to Support Regional Haze State 

Implementation, found in Appendix 8.1 of the Texas Regional Haze SIP. 

8 Reproduced from Tables 10-2 and 10-3 of the Texas regional haze SIP.
9

Table 2. Texas Reasonable Progress Goals for 20% Worst Days

Class I Area

Baseline 

Conditions

(dv)

Projected 

2018 

Visibility

(RPG) (dv)

Improvement

Projected by

2018 using

RPG

(dv)

Improvement

by 2018

at URP

(dv)

Date

Natural

Visibility

Attained at

RPG Rate

Big Bend 17.30 16.6 0.7 1.7 2155

Guadalupe Mountains 17.19 16.3 0.9 1.2 2081

Table 3. Texas Reasonable Progress Goals for 20% Best Days

Class I Area

Baseline 

Conditions

(dv)

Projected 2018

Visibility (RPG)

(dv)

Improvement

by 2018

(dv)

Big Bend 5.8 5.6 0.2

Guadalupe Mountains 5.9 5.7 0.2

EPA Findings

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. See 70 FR 3915; see also 64 FR 35714. See the CENRAP Modeling 

TSD for our review of the CENRAP emission inventory and modeling that was relied upon in 

establishing the RPGs for Big Bend and Guadalupe Mountains.

Table 3 above demonstrates that the modeled RPGs for the 20% best days show an improvement 

in visibility of 0.2 dv at both Texas Class I areas in 2018. TCEQ also submitted RPGs for the 

two Texas Class I areas for the 20% worst days, as shown in Table 2 above. Table 2

demonstrates that the modeled RPGs for the 20% worst days show an improvement in visibility 

of 0.7 dv and 0.9 dv at Big Bend and Guadalupe Mountains, respectively. Texas projects that it 

will not meet the national goal of restoring natural visibility conditions by 2064 for either of its 

two Class I areas. TCEQ calculated that under its RPGs, it would attain natural visibility 

conditions in 2155 at Big Bend and 2081 at Guadalupe Mountains. 9 

Although Texas’ RPGs do provide for some 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, we believe the overall RPG goals that Texas established for its own Class I 

 

9

 As we note elsewhere, this assumes Texas’ calculation for the natural visibility conditions at Big Bend and the 

Guadalupe Mountains.
10

areas of Big Bend and Guadalupe Mountains do not provide for reasonable progress based on the 

four reasonable progress factors that a state is required to consider in selecting a RPG under 

(d)(1)(i)(A). For the reasons discussed below, we believe the record supports a finding that the 

RPGs identified for the Texas Class I areas are not reasonable. We address our finding regarding 

whether the Texas regional haze SIP satisfies the requirements under Section 51.308(d)(1) to set

RPGs below.

B.2. Reasonable Progress Goals Four Factor Analysis: 40 CFR 51.308(d)(1)(i)(A)

In establishing a RPG for any mandatory Class I Federal area within Texas, Texas is required by 

CAA §169A(g)(1) and 40 CFR 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.” 

This requirement is often referred to as the reasonable progress “four factor analysis.” 

State Submittal

Chapter 10

Chapter 10 of Texas’ submittal describes how the TCEQ evaluated the reasonable progress four 

factors in analyzing additional controls and establishing the RPGs. Texas assessed the costs of 

potential controls and reductions for Texas point sources at ten Class I areas, including the two 

Texas Class I areas and those in nearby states. Appendix 10-1 of the Texas Regional Haze SIP,

Analysis of Control Strategies and Determination of Reasonable Progress Goals, provides 

Texas’ analysis of how it established these goals. The analysis contained in Appendix 10.1 is 

used by Texas in both establishing its RPG, and as discussed later, in the development of its 

Long-Term Strategy (LTS) for Class I areas outside of Texas. See also Chapter 10, Appendices 

10-2 and 10-4.

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

in visibility that are anticipated to result from federal, state, and local control programs. Based 

on the emissions reductions from these measures, CENRAP modeled the projected visibility 

conditions anticipated at each Class I area in 2018 and the TCEQ used these results to establish 

its RPGs. The TCEQ states it developed its RPGs after considering the regulatory factors 

required under Section 51.308(d)(1)(i)(A), discussed above. The TCEQ focused its control 

strategy analysis on point source emissions of SO2 and NOX, as the sources of these pollutants 

are the main anthropogenic pollutants that affect visibility at Class I areas in Texas. It examined 

visibility impairment at the Texas Class I areas and Class I areas in nearby states. The TCEQ 

stated that source apportionment modeling results, summarized in Chapter 11 of the Texas 

regional haze SIP, demonstrate that NOx and SO2 are the main anthropogenic pollutants that

affect visibility at the Class I areas in Texas and Class I areas in surrounding states. Source 

apportionment modeling also indicated that sulfur emissions that impact visibility are dominated 

by point sources, while impacts from NOx emissions are more evenly distributed between area, 

mobile and point sources. The following table10 summarizes the source category contributions 

 

10

 Reproduced from Table 3 in Appendix 10-1 of the Texas regional haze SIP.
11

from the 2002 base case CENRAP source apportionment modeling for the five Class I areas 

whose visibility is most impacted by Texas emissions. In evaluating the emission inventory 

projections, Texas concluded that for SO2, point sources are responsible for over 90% of the 

projected 2018 statewide emissions, and for NOx, point sources comprise over 45 % of the 

projected statewide emissions. The TCEQ noted that NOx emissions are more evenly distributed 

among point, mobile, and area sources, and that states have very limited authority to reduce 

mobile source emissions and are already addressing road and non-road mobile emissions. The 

TCEQ noted the largest category of area source NOx is upstream oil and gas production, and it is 

taking all steps it has determined are reasonable at this time to control these sources as part of the 

Dallas-Fort Worth ozone SIP and is investing $4,000,000 in a grant program to assist with the 

retrofitting of gas-fired, rich burn compressor engines. TCEQ also noted uncertainty in upstream 

oil and gas emission estimates. Thus, the TCEQ reasoned that since point sources are the single 

largest pollution category for SO2 and NOx, it should concentrate its RPG strategy on analyzing 

controls for point sources.

Table 4. Percentage Source Category Contributions to SO4 and NO3 at the Five Class I Areas 

Texas Most Impacts

Big Bend Guadalupe Mountains

Point Mobile Area Point Mobile Area

SO4 67.1 2.8 6.9 75.6 3.5 8.5

NO3 26.6 28.6 14.3 29.2 36.5 13.9

Wichita Mountains Salt Creek White Mountain 

Point Mobile Area Point Mobile Area Point Mobile Area 

SO4 78.2 3.7 9.2 73.8 3.9 8.1 75.2 4.1 8.1

NO3 28.1 44.7 13.4 35.8 29.9 17.1 27.9 40.3 12.0 

Having narrowed the scope of the control analysis to point sources of NOx and SO2, the TCEQ 

developed a list of potential controls and costs associated with those controls to inform their four 

factor analysis. It used the control strategy analysis developed by CENRAP as the starting point 

for its analysis. CENRAP contracted with Alpine Geophysics to conduct an evaluation of 

possible additional point-source add-on controls for sources in CENRAP states. The Alpine 

Geophysics evaluation relied on AirControlNET,11 a database tool we released in 2006 to enable 

cost-benefit analyses of potential emissions control measures and strategies. Alpine Geophysics 

prepared cost estimates for potential add-on controls for NOx and SO2 reductions in 2005 dollars 

for point sources in CENRAP states. The Iowa Department of Natural Resources and Kansas 

Department of Health and Environment staff developed Area-of- Influence (AOI) data for each 

Class I area in every CENRAP member state, as well as distance calculations for each source to 

each Class I area for inclusion in the Alpine Geophysics analysis. Available SO2 and NOx 

control strategies in the AirControlNET dataset were applied to EGU and non-EGU sources to 

 

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

http://www.epa.gov/ttn/ecas/AirControlNET.htm
12

develop a master list of available incremental control strategies for the CENRAP states. 12 The 

TCEQ reviewed this information for Texas sources and made changes based on additional 

information and past experience. The TCEQ also added some additional sources from sourcetypes not included in the CENRAP AirControlNET dataset. This work resulted in a list of 

potential add-on controls for reducing SO2 and NOx at Texas point sources, an estimate of the 

costs associated with each control, and identification of the AOIs for each Class I area. 

The TCEQ states its analysis focused on moderate cost controls for sources it believed were 

likely to contribute to visibility impairment at Class I areas. In an effort to further narrow the list 

of potential controls, the TCEQ followed the screening process summarized below and as 

detailed in Section 10-1.3 of Appendix 10-1 of the Texas regional haze SIP:

 Identified controls at sources with potential control strategy costs greater than $2,700 

per ton SO2 or NOx were initially screened out. 

 Remaining sources were reduced by eliminating those the TCEQ believed were so 

distant from any of the ten Class I areas that any reduction in emissions would likely 

not have a perceptible impact on visibility. 

 Remaining sources were further reduced by eliminating those that did not possess a 

ratio of the estimated projected 2018 base annual emissions (tons) of SO2 or NOx to 

distance (kilometers) of greater than five, to any Class I area. 

 Any source with predicted 2018 emissions less than 100 tons per year was excluded. 

Separate from the above described screening process, the TCEQ also excluded additional NOx 

controls on cement kilns from consideration, as it concluded it had already required all the 

measures it had determined are reasonable to control NOx emissions from these sources in the 

latest Dallas-Fort Worth ozone SIP revision. The TCEQ reasoned, based on a study performed 

for the Dallas-Fort Worth ozone SIP revision,13 that a 35 to 50% NOx control range was the most 

appropriate control level to address ozone formation. The TCEQ developed a source cap that

required a reduction of approximately 9.69 tons per day (tpd) of NOx emissions from the cement 

kilns in Ellis County starting March 2009. The types of controls considered by the CENRAP 

study, based on industrial categories, are listed below:

SO2 control at 24 facilities from 15 sites 

 Natural Gas Transmission - Flue Gas Desulfurization (FGD) 

 Crude Petroleum - Sulfur recovery and/or tail gas treatment 

 Inorganic chemical plants - coal washing and Spray Dryer Absorber (SDA) on 

boilers, increase efficiency of sulfuric acid plants 

 Electric Generating Units (EGU) - coal washing and FGD wet scrubbing 

 

12 Lists of NOx and SO2 controls meeting cost thresholds ranging from $1,500/ton to $10,000/ton developed by 

Alpine Geophysics are available in the docket to this action (See spreadsheets titled “nox_cost_ton__2_” and 

“so2_cost_ton”)

13

 Assessment of NOx Emissions Reduction Strategies for Cement Kilns - Ellis County Final Report, TCEQ 

Contract No. 582-04-65589, Work Order No.05-06, Prepared by: ERG, Inc., 10200 Alliance Road, Suite 190, 

Cincinnati, Ohio 45242-4716. Available at: 

http://www.tceq.state.tx.us/assets/public/implementation/air/sip/agreements/BSA/CEMENT_FINAL_REPORT_705

14_final.pdf
13

 Carbon black – FGD 

NOx control for 24 facilities at 15 sites 

 Natural Gas Transmission- Low NOx Burners (LNB), Selective Catalytic Reduction 

(SCR) + LNB 

 EGU - LNB with Close Coupled Over-Fired Air (LNC1), and with both LNC1 and 

Separated Over-Fired Air (LNC3) 

 Flat Glass - LNB, SCR 

 Paper Mills SNCR and Oxygen Trim (OT) with water injection 

 Chemical Plant Boiler - SCR 

The total cost of controls and the resulting emission reductions were calculated by summing up 

the individual costs of those identified controls located within the AOI of Big Bend or the 

Guadalupe Mountains. The TCEQ also performed this calculation for eight additional Class I 

areas in other states impacted by Texas’ emissions: Breton Island, Caney Creek, Carlsbad 

Caverns, Salt Creek, Upper Buffalo, Wheeler Peak, White Mountain, and the Wichita 

Mountains. The annualized costs14 that would result from the imposition of the above controls 

within each Class I area’s AOI are shown below.

Table 5. Annualized Cost of Controls for each Class I Area (controls at facilities within each 

Class I area’s AOI)

Class I Area NOx SO2

Big Bend $24,100,000 $215,900,000

Breton Island $27,000,000 $231,000,000

Caney Creek $28,600,000 $245,900,000

Carlsbad Caverns $24,100,000 $255,500,000

Guadalupe Mountains $33,800,000 $254,900,000

Salt Creek $27,000,000 $251,900,000

Upper Buffalo $24,100,000 $233,800,000

Wheeler Peak $22,700,000 $229,500,000

White Mountains $23,000,000 $244,500,000

Wichita Mountains $28,100,000 $269,500,000

Many of these controls are in more than one AOI. The TCEQ reviewed the total cost of all statewide point source controls identified by TCEQ following the process described above as 

summarized below (13 facilities with SO2 controls and 15 facilities with NOx controls). 

 

14

 Annualized costs are the total yearly costs, typically the sum of the yearly capital cost (amortized over the life of 

the control) and the yearly operational cost. In this instance, the TCEQ relied upon our AirControlNET model 

which for these types of controls typically assumed a 30 year control life.
14

Table 6. Total Estimated Cost of Texas Control Set15

Pollutant Reduction (tpy) Estimated Cost

Sulfur Dioxide (SO2) 155,873 $270,800,000

Nitrogen Oxides (NOx) 27,132 $53,500,000

Total Costs $324,300,000

The TCEQ used the results of the 2018 CENRAP state-wide photochemical grid modeling 

analyses (that includes the 2018 modeling and a CENRAP control case modeling scenario) to 

estimate the visibility benefit that would result in 2018 from controlling those sources in Texas 

identified by it following the process described above. CENRAP developed a modeling scenario 

to estimate the effectiveness of a specific suite of controls on facilities in the CENRAP states. 

CENRAP decided to base its control sensitivity analysis on a maximum estimated cost of $5,000 

per ton of emissions of NOx or SO2 reduced estimated in the Alpine Geophysics report and 

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

2018.16 Similar to the Texas analysis, 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 to the nearest Class I area. This distance-weighing 

criterion limited the sensitivity evaluation to sources with the greatest likely influence on 

visibility. The CENRAP control sensitivity modeling run included emission reductions beyond 

CAIR and BART in the CENRAP states at all point sources where the cost-effectiveness and 

Q/d17 criteria discussed above were met, and projected the resulting visibility conditions in 2018 

at the CENRAP Class I areas. This modeling was developed as a starting point for discussion 

and development of refined analyses as needed. 18

The TCEQ used the CENRAP control sensitivity analysis and the CENRAP 2018 visibility 

projection modeling as the starting point for estimating the visibility benefit of implementing 

only the controls identified by it above for Texas point sources. The TCEQ used the results of 

this modeling analysis and the source apportionment modeling results to determine an 

“effectiveness ratio” for NOx and SO2 reductions, which it states provides an estimate of 

improvement in visibility for every ton of NOx and SO2 reduced in order to produce “an order of 

magnitude estimate of the likely visibility improvements resulting from the point source.” See 

Appendix 10-2 and 10-4 of the Texas regional haze SIP for additional information on the 

methodology Texas used to develop this estimate.

The TCEQ summarizes the estimated visibility improvement that would result in 2018 from the 

 

15

 Reproduced from Table 4 in Appendix 10-1 of the Texas regional haze SIP.

16 See Section 2.14 of the Technical Support Document for CENRAP Emissions and Air Quality Modeling to 

Support Regional Haze State Implementation Plans, September 12, 2007.

17 Q/D is the ratio of annual emissions over distance to a Class I area.

18 “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.
15

imposition of all the above controls as follows19:

Table 7. TCEQ Projected Visibility Improvement to Selected Class I Areas from the Imposition 

of Potential Controls

Class I Area

Visibility

Improvement

(dv)

Big Bend 0.16

Breton Island 0.05

Caney Creek 0.33

Carlsbad Caverns 0.22

Guadalupe Mountains 0.22

Salt Creek 0.18

Upper Buffalo 0.16

Wheeler Peak 0.04

White Mountains 0.24

Wichita Mountains 0.36

After identification of potential controls for multiple sources, estimation of aggregate costs 

associated with those controls and estimation of the overall visibility improvement anticipated 

from implementation of those controls as described above, the TCEQ then weighed the four 

statutory factors in determining the reasonableness of additional controls and selecting the RPGs 

for Big Bend and Guadalupe Mountains. In general, the cost of compliance was the key factor 

considered by the TCEQ. It determined that the time necessary for compliance was not a critical 

factor for the determination of applicable additional controls for Texas sources. It stated that to 

the extent energy impacts are quantifiable for a particular control, they were included in its cost 

estimates. However, it stated that “including [energy and non-air quality environmental] impacts 

on a source-by-source basis would have added further weight against finding that the potential 

additional controls were reasonable to apply.”20 The TCEQ also stated that for the purposes of 

initial analysis, no limited remaining useful life was assumed. The TCEQ describes the cost of 

compliance as a factor used to determine whether compliance costs for sources are reasonable 

compared to the emission reductions and visibility improvement they will achieve. The TCEQ 

weighed the four reasonable progress factors as follows:

B.2.a. Cost of Compliance

The TCEQ concluded that at a total estimated cost of over $300 million and (in its view) no 

perceptible visibility benefit, it was not reasonable to implement additional controls. All units in 

Texas that met the emissions over distance threshold were assessed. The TCEQ states it adopted 

its $2,700 cost threshold to limit the proposed controls group to cost-effective measures. 

Annualized cost values, and emissions reductions based on proposed efficiencies listed in 

AirControlNET, were used. Modifications for Texas included the consideration of flue gas 

 

19 Table 5 in Appendix 10-1 of the Texas Regional Haze SIP.

20

 Page 10-8 of the Texas Regional Haze SIP.
16

desulfurization for carbon black units.

B.2.b. Time Necessary for Compliance

The TCEQ determined that the time necessary for compliance was not a critical factor for the 

determination of applicable additional controls for its sources. It noted that in our CAIR 

regulatory impact statement, we estimated that approximately 30 months is required to design, 

build, and install SO2 scrubbing technology for a single EGU boiler. The TCEQ stated that the 

total time for a single facility to comply with one of the NOx caps would be about five years. It 

estimated that completion by 2018 would still be anticipated. For mobile sources, MOBILE and 

NONROAD model runs were completed for the 2018 emissions inventory. These model runs 

incorporated the degree of fleet and expected engine replacement prior to 2018. The completion 

of other proposed controls were anticipated by 2018.

B.2.c. Energy and Non-Air Quality Environmental Impacts of Compliance

The TCEQ stated that to the extent energy impacts are quantifiable for a particular control, they 

were included in its cost estimates. However, it stated that “including [energy and non-air 

quality environmental] impacts on a source-by-source basis would have added further weight 

against finding that the potential additional controls were reasonable to apply. Source-by-source 

review of the non-air quality impacts of the potential controls would possibly have led to a 

different determination about the unreasonableness of the set of potential additional controls.”21 

The TCEQ noted that scrubbers, SCR systems, and Selective Non-Catalytic Reduction (SNCR) 

systems installed under the EGU control strategies would require electricity to operate fans and 

other ancillary equipment. However, it noted that estimates were given that the electricity and 

steam required by controls installed to meet SO2 and NOX emission caps would be less than 

1%of the total electricity and steam production of EGUs. The TCEQ noted that scrubbers, coal 

washing, and spray dryers would require additional safeguards for fuel handling and waste 

handling systems to avoid additional non-air environmental impacts such as increased effluents 

in waste water discharges and storm water runoff. The TCEQ expected that solid waste disposal 

and wastewater treatment costs would be less than five percent of the total operating costs of 

pollution control equipment. It noted that these factors would have to be considered specific to 

individual sources. 

B.2.d. Remaining Useful life

The TCEQ noted that CENRAP considered the remaining useful life in modeling for mobile 

sources that assumes reduced emissions per vehicle mile traveled due to the turnover of the onroad mobile source fleet. It noted that for sources with a relatively short remaining useful life, 

this consideration would have weighed more heavily against a determination that controlling 

those sources would have been reasonable. The TCEQ believed that this factor was not critical 

for its sector analyses for the 2018 timeline and did not assume any limited useful equipment 

life. Only units that were scheduled for shutdown under enforceable decrees were eliminated 

from the 2018 inventory and further analysis.

 

21

 Texas Regional Haze SIP, page 10-8.
17

B.2.e. TCEQ Noted Uncertainty in Visibility Projections Due to CAIR 

The TCEQ noted that the majority of the emissions reductions underlying the predicted visibility 

improvements in 2018 resulting from controls already in effect or scheduled to become effective 

will result from the CAIR program in particular. The CAIR program allows interstate trading of 

allowances, and does not put specific emission limits on specific sources. Further, it notes that 

because emission allowances can be purchased by EGUs, visibility improvement may be less or 

more that that predicted by the CENRAP’s modeling. CENRAP used our Integrated Planning 

Model (IPM) to predict the emissions reductions expected from CAIR in 2018. The TCEQ 

assumed that any replacement for CAIR will include interstate trading of emissions allowances. 

The TCEQ presents a comparison22 of its baseline 2002 SO2 emissions, the CAIR budget for 

EGUs in 2015 and the IPM predicted SO2 emissions for the 2018 planning year:

Table 8. Comparison of Texas 2002 Baseline SO2 emissions, 2015 CAIR EGUs Budget and 

2018 IPM Predicted SO2 Emissions

SO2 Emissions

Texas SO2

Emissions

(tpy)

Current (2002 base case) 550,000

EPA’s CAIR budget for Texas EGUs for 2015 225,000

IPM projection CENRAP modeled for 2018 350,000

The TCEQ notes that the IPM model analysis used by CENRAP predicts that by 2018 EGUs in 

Texas will purchase approximately 125,000 tpy of emissions allowances from out of state. This 

represents more than 50% of Texas’ total CAIR SO2 budget. The TCEQ states that it requested 

that key EGUs in Texas review and comment on the predictions of the IPM model. However, no 

EGU made an enforceable commitment to any particular pollution control strategy and preferred 

to retain the flexibility offered by the CAIR program.

B.2.f. The TCEQ Reasonable Progress Conclusion

The TCEQ’s assessment of reasonable progress rested primarily on its calculation of the total 

cost of the controls it analyzed versus the visibility benefits at the ten Class I areas it analyzed. It 

concluded, “At a total estimated cost exceeding $300 million and no perceptible visibility 

benefit, Texas has determined that it is not reasonable to implement additional controls at this 

time.”23 

 

22

 Reproduced from Table 10-7 in the Texas Regional Haze SIP. 

23

 Texas Regional Haze SIP, page 10-7.
18

EPA Finding

Section 51.308(d)(1)(iii) requires that in determining whether the state’s goal for visibility 

improvement provides for reasonable progress towards natural visibility conditions, the 

Administrator will evaluate the demonstrations developed by the state pursuant to Sections 

51.308(d)(1)(i) and (d)(1)(ii). We perform that evaluation beginning in this section.

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

sources, as the CENRAP modeling results and the TCEQ’s analysis in Chapter 11 and appendix 

10-1 of the Texas regional haze SIP indicate that the predominant anthropogenic pollutants that 

affects Texas’ ability to meet the URP goals in 2018 on the worst 20% days at the Texas Class I 

areas are largely due to sulfate and nitrate, primarily from point sources. We agree with the 

TCEQ’s assessment that the cost of compliance is the dominant factor, and its incorporation of 

the other factors into the cost, where applicable. We note, however, that because the TCEQ did 

not evaluate controls on a source-by-source basis, source–specific factors related to the 

evaluation of the reasonable progress four factor analysis could not be considered. We also 

agree with the TCEQ’s decision to consider visibility benefits in weighing the factors and to 

assist in its consideration of the cost of compliance. While visibility is not an explicitly listed 

factor to consider when determining whether additional controls are reasonable, the purpose of 

the four-factor analysis is to determine what degree of progress toward natural visibility 

conditions is reasonable. Therefore, we believe it is appropriate to consider the projected 

visibility benefit of the controls when determining if cost-effective controls are warranted to 

make reasonable progress. However, the TCEQ did not discriminate between and analyze 

controls on those source(s) with the highest potential visibility benefit at each Class I area. We 

disagree with the set of potential controls identified by the TCEQ and how it analyzed and 

weighed the four reasonable progress factors in a number of key areas, as described below. 

The TCEQ’s Cost-Effectiveness Threshold Approach 

The TCEQ eliminated controls with an estimated cost-efficiency greater than $2,700/ton from 

any further analysis, regardless of their potential visibility benefits. Given the large number of 

sources and their large geographic distribution, some consideration of location and emissions 

data is needed before controls should have been eliminated from further analysis. Texas 

supports its selection of this value with reference to “EPA estimated cost of implementing CAIR 

was up to $2700/ton.” However, although we demonstrated that CAIR was acceptable in lieu of 

BART, CAIR was not designed as a reasonable progress strategy. A state should look beyond 

BART for additional reductions when developing its long-term strategy to achieve reasonable 

progress at its Class I areas.24 As a result of the application of this $2700/ton threshold, 

potentially cost-effective controls were not evaluated at sources that may result in meaningful 

visibility benefits at Guadalupe Mountains or Big Bend. For example, potential SO2 controls for 

the Tolk Station were estimated in the Alpine Geophysics analysis to cost an average of 

 

24

 Per Section 51.308(e)(5), “After a State has met the requirements for BART or implemented emissions trading 

program or other alternative measure that achieves more reasonable progress than the installation and operation of 

BART, BART-eligible sources will be subject to the requirements of paragraph (d) of this section in the same 

manner as other sources.” 
19

approximately $3,100/ton and result in nearly 20,000 tpy reduced across the two units. Applying 

the $2,700/ton threshold, the TCEQ did not consider potential controls on any EGUs in West 

Texas to improve visibility at the two Class I areas located in West Texas despite the potential 

visibility benefits from controlling these large point sources. Sensitivity analysis work 

performed by CENRAP suggests to us that a threshold in the range of $4,000/ton to $5,000/ton 

would be reasonable for purposes of identifying potential cost-effective controls for further 

analysis.25

The TCEQ’s Weighing of the Four Factors for Individual Sources.

The TCEQ constructed a large potential control set consisting of a mix of large and small 

sources, located at various distances from Class I areas, with a large geographical distribution. 

Because of the variation in size, type, and location of these sources, the potential to impact 

visibility and potential benefit from controls at a given Class I area can vary greatly between the 

identified sources. This potential control set identified by the TCEQ included controls on some 

sources that would likely result in significant visibility benefits, but also included controls on 

many sources with much less anticipated visibility benefits. Because it only estimated the

visibility benefit of all the controls together, the TCEQ was not able to assess the potential 

benefit of controlling individual sources with significant, and potentially cost-effective, visibility 

benefits. Also, we believe that individual benefits were masked by the inclusion of those 

controls with little visibility benefit that only served to increase the total cost figures. For 

example, the TCEQ identified SO2 controls at Big Brown to be approximately $1,500/ton, 

significantly less than its $2,700/ton threshold. These controls were estimated to achieve greater 

than 40,000 tpy SO2 emission reductions. Despite this evidence in the record of an identified 

cost-effective control that results in large emission reductions, and source apportionment 

modeling identifying large impacts from EGU sources in northeast Texas, the TCEQ did not 

separately evaluate the visibility benefit from the implementation of this control, or appropriately 

weigh the four reasonable progress factors in determining the reasonableness of this individual 

control. 

Because individual sources were not considered by the TCEQ, we found it is necessary to 

conduct an additional analysis to determine whether this approach materially affected the 

outcome of the TCEQ analysis. As we demonstrate in detail in our FIP TSD, by analyzing 

sources individually, we believe we have identified a small number of sources that are 

responsible for much of Texas’ collective visibility impact on the Texas’s Class I areas, which if 

controlled, would provide for visibility benefit at Texas’ Class I areas. That modeling is 

summarized below.

Our preliminary modeling study identified those facilities with the largest impacts on the Texas 

Class I areas on the 20% worst days in 2018.26 This modeling includes the same projections the 

 

25 See “Sensitivity Run Specifications for CENRAP Consultation,” available in the docket for this action 

26 As discussed later in this TSD, this study also looked at impacts from Texas sources on Class I areas in other 

States. 
20

TCEQ used to account for predicted reductions due to CAIR. The projected impacts27 in 2018 

from the top ten facilities in Texas that impact visibility at Big Bend and the Guadalupe 

Mountains are summarized in Tables 9 and 10 below (see our FIP TSD for more details). Texas 

point sources combined are projected in 2018 to contribute approximately 8% (3.56 Mm-1) to the 

total visibility impairment at Big Bend, and 9% (3.84 Mm-1) to the total visibility impairment at 

Guadalupe Mountains. These results below show that some facilities can have large impacts on 

certain days and significant impacts on the 20% worst days, even including facilities like Big 

Brown which is more than 700 km from Big Bend and more than 800 km from the Guadalupe 

Mountains. We note that Texas decided to invite states to consult using the CENRAP Particulate 

Matter Source Apportionment Technology (PSAT) results and included states with greater than

0.5 inverse megameter impact (from all sources in the state) on one of Texas’ Class I areas.28 

These results also suggest that controlling a small number of sources will result in visibility 

benefits at both Class I areas, and that rather than evaluating controls at all facilities identified by 

Texas combined, a subset of those facilities (and some additional facilities not identified) may be 

reasonable. See the FIP TSD for our evaluation of costs and potential visibility benefits of 

controls at selected Texas point sources. 

Table 9. 2018 Phase 1 EPA source apportionment modeling results, top ten facilities in Texas 

that impact visibility at Big Bend

Rank Facility Name

Extinction 

(Mm-1) 20% 

worst days

% Contribution 

to Total Visibility 

Impairment 20% 

worst days

Max 

extinction 

during 20% 

worst days

1 SOMMERS DEELY S 0.276 0.57% 1.193

2 COLETO CREEK PL 0.216 0.44% 0.937

3 BIG BROWN 0.212 0.44% 0.923

4 RELIANT ENERGY10.103 0.21% 0.441

5 LIGNITE-FIRED P20.101 0.21% 0.428

6 MONTICELLO STM 0.096 0.20% 0.413

7 W A PARISH STAT 0.090 0.18% 0.385

8 BIG SPRING CARB 0.084 0.17% 0.356

9 SANDOW STEAM EL 0.080 0.16% 0.342

10 MARTIN LAKE ELE 0.080 0.16% 0.342

1 Limestone 

2 San Miguel

 

27 We occasionally present visibility in extinction, rather than deciviews (dv). Light extinction, in units of inverse 

megameters (Mm-1), is the amount of light lost as it travels over one million meters. The haze index, in units of 

deciviews (dv), is calculated directly from the total light extinction, bext, as follows: HI = 10 ln(bext /10). 

Extinction is an appropriate measure for the visibility impairment contribution from individual sources because it 

avoids the sensitivity of the logarithmic transformation for calculating deciviews to the overall level of visibility 

impairment including the impacts of other sources.

28 See Appendix 4-1: Summary of Consultation Calls.
21

Table 10. 2018 Phase 1 EPA source apportionment modeling results, top ten facilities in Texas 

that impact visibility at Guadalupe Mountains

Rank Facility Name

Extinction 

(Mm-1) 

20% worst 

days

% Contribution 

to Total Visibility 

Impairment 20% 

worst days

Max 

extinction 

during 20% 

worst days

1 TOLK STATION 0.302 0.65% 1.004

2 BIG BROWN 0.235 0.50% 0.809

3 BIG SPRING CARB 0.226 0.48% 0.775

4 SOMMERS DEELY S 0.208 0.44% 0.688

5 HARRINGTON STAT 0.184 0.39% 0.606

6 MONTICELLO STM 0.114 0.24% 0.391

7 WAHA PLANT 0.113 0.24% 0.387

8 RELIANT ENERGY10.111 0.24% 0.372

9 MARTIN LAKE ELE 0.104 0.22% 0.351

10 COLETO CREEK PL 0.066 0.14% 0.227

1 Limestone 

The TCEQ’s Cost of Compliance Analysis Assumed Future CAIR Reductions as a Baseline

We based our determination that CAIR was better than BART in part on a finding that CAIR 

resulted in an overall improvement in visibility determined by comparing the average differences 

over all affected Class I areas. We noted at the time that BART is one component of a long-term 

strategy to make reasonable progress, but it is not the only component. 29 Thus, when assessing 

reasonable progress, a state should look beyond BART for additional reductions when 

determining what long-term strategy will achieve reasonable progress at its Class I areas. A 

critical decision point in performing cost analysis for potential controls is the determination of an 

emission baseline. As we state above, the TCEQ projected that Texas EGUs would purchase 

approximately 125,000 tpy of emissions allowances from out of state. The TCEQ relied on the 

IPM predictions as discussed above to estimate 2018 emission levels for EGUs. The TCEQ also 

notes that there is uncertainty in the size and distribution in emissions in the future projections. 

Nevertheless, the TCEQ utilized this future projection of 2018 emissions as the starting point for 

its estimation of emission reductions and the associated costs of additional controls. 

For example, Big Brown Unit 1’s SO2 emissions in 2002 were 34,448 tpy. The IPM predictions 

that were incorporated into the 2018 emission level assume that a roughly 1/3 reduction in these 

emissions will occur in response to CAIR by switching to a coal with a lower sulfur content, 

resulting in a 2018 SO2 emission level of 23,142 tpy. The TCEQ’s cost-effectiveness calculation 

for post-combustion controls on Big Brown Unit 1 was based on reducing that projected 2018 

SO2 emission level of 23,142 tpy by 90%, resulting in a reduction of 20,828 tpy. This results in 

a cost of $32,766,310/yr, or a cost-effectiveness calculation of $1,573/ton. However, the 

 

29

 70 FR 39137 (July 6, 2005).
22

installation of a scrubber would allow Big Brown flexibility in fuel choice thus allowing the unit 

to continue to burn the higher average sulfur fuel it currently burns, instead of moving to the low 

sulfur coal predicted by IPM. 

Big Brown Unit 1’s SO2 emissions in 2012 were 32,100 tons. The issue of scrubber efficiency 

aside, a reduction of 90% from these actual emission levels would result in an SO2 reduction in 

the range of 29,000 to 31,000 tpy. While the numerator ($) in the cost-effectiveness metric of 

$/ton will increase slightly beyond what was estimated by Alpine Geophysics due to an increased 

sulfur loading to the scrubber, the denominator (tons) would increase by roughly 50%, thus 

improving (lowering) the overall cost-effectiveness of controlling Big Brown Unit 1 

significantly.30 Estimates for scrubbers at units at Monticello are similarly impacted by the costmethodology used by Texas in estimating cost-effectiveness on a cost-per-ton basis. 

We believe that in performing its control analysis, the TCEQ should have given greater 

consideration to the flexibility in the CAIR trading program and the resulting uncertainty in the 

projected emissions. In other words, the TCEQ could have recognized that implementation of 

reasonable controls under the Regional Haze Rule would likely not be in addition to anticipated 

reductions due to CAIR predicted by IPM, but would replace or complement any controls 

predicted by IPM.

The TCEQ’s Assumptions of SO2 Control Efficiency of Scrubbers 

We note that the control efficiency of scrubbers evaluated by CENRAP and Texas, based on the 

data from AirControlNET, was assumed to be 90%. As we discuss in detail in our FIP TSD, we 

establish that SO2 scrubbers are capable of achieving emission reductions of at least 95% for dry 

scrubbers and 98% for wet scrubbers. These additional reductions would further reduce the price 

on a $/ton basis and increase the visibility benefit anticipated due to controls.

The TCEQ’s Evaluation of Potential Visibility Improvements 

In considering the cost of compliance to determine whether compliance costs for sources were 

reasonable, the TCEQ compared those costs to the emissions reduction and visibility 

improvement those sources would achieve. While visibility is not an explicitly listed factor to 

consider when determining whether additional controls are reasonable, the purpose of the fourfactor analysis is to determine what degree of progress toward natural visibility conditions is 

reasonable. Therefore, we consider it appropriate to consider the projected visibility benefit of 

the controls when determining if the controls are needed to make reasonable progress. We 

discuss this in more detail in our FIP TSD.

In evaluating and dismissing the estimated visibility benefit from the control set identified by the 

TCEQ, the TCEQ states that the estimated benefit is not perceptible (less than 1 dv) and that it is 

less than 0.5 dv, the threshold used under BART requirements used to determine if a facility 

contributes to visibility impairment. The 0.5 dv BART threshold referred to applies to the 

maximum anticipated visibility impact on a single day due to the short-term maximum actual 

 

30

 See our cost-effectiveness calculations for retrofitting Big Brown and other Texas EGU with scrubbers in the FIP 

TSD.
23

baseline emissions from a single facility, compared to clean background conditions. The 

reasonable progress analysis presented by the TCEQ contemplates the visibility benefit 

anticipated for an average tpy emission reduction (as opposed to the impact from the total shortterm maximum emissions from the sources) averaged across the 20% worst days, which would 

be anticipated to be significantly lower. See our FIP TSD for a detailed discussion of the 

different metrics and modeling typically used for BART and reasonable progress analyses. 

Furthermore, in a situation where the installation of BART may not result in a perceptible 

improvement in visibility, the visibility benefit may still be significant, as explained by the 

Regional Haze Rule:31

Even though the visibility improvement from an individual source may not be 

perceptible, it should still be considered in setting BART because the contribution to haze 

may be significant relative to other source contributions in the Class I area. Thus, we 

disagree that the degree of improvement should be contingent upon perceptibility.

As we stated in our Oklahoma final decision32:

Given that sources are subject to BART based on a contribution threshold of no greater 

than 0.5 deciviews, it would be inconsistent to automatically rule out additional controls 

where the improvement in visibility may be less than 1.0 deciview or even 0.5 deciviews. 

A perceptible visibility improvement is not a requirement of the BART determination 

because visibility improvements that are not perceptible may still be determined to be 

significant.

The TCEQ’s “Order of Magnitude Estimate” for Visibility Improvement 

The TCEQ produced an “order of- magnitude estimate” of the visibility improvements resulting 

from the level of aggregate emission reductions that would result from its point source control 

strategy using PSAT results and effectiveness ratios. This methodology assumes that all 

emission reductions within a PSAT region have the same effectiveness in reducing visibility 

impairment. The estimated effectiveness factor applied equally to all emission reductions 

located in the East Texas source region, including Sommers Deely Spruce (440 km from Big 

Bend and 680 km from Guadalupe Mountains) and Monticello (850 km from Big Bend and 920 

km from Guadalupe Mountains). Given the large difference in distances between these two 

facilities and the Class I areas, it is reasonable to expect that the effectiveness of emission 

reductions could vary greatly between the two. We find that the TCEQ’s analysis is insufficient 

to determine the visibility benefit of controlling the source or subset of sources with the most 

effective controls for improving visibility conditions at a Class I area or a number of Class I 

areas and that the potential visibility benefits from controlling these sources may be significant. 

Our own source apportionment modeling has confirmed that individual sources within the 

CENRAP modeling PSAT regions had significantly different impacts, leading us to believe that 

TCEQ’s reliance on an aggregate analysis materially affected its conclusion that existing and 

scheduled controls would achieve reasonable progress.33 

 

31

 70 FR 39130 (July 6, 2005)

32

 76 FR 81739 (Dec. 28, 2011).

33

 See the FIP TSD.
24

Upgrades to Existing Controls 

The CENRAP analysis and the additional analysis performed by the TCEQ did not consider the 

reasonableness of control upgrades or increased utilization of existing controls. We note that the 

AirControlNET database does not include general information for the cost and effectiveness of 

scrubber upgrades as the cost and reductions from these potential upgrades are typically very 

specific to the existing equipment and site-specific conditions. Many Texas EGU’s are equipped 

with older vintage scrubbers and/or have scrubber bypasses that divert a portion of the exhaust 

gas around the control equipment. In some cases, excess scrubbing capacity is simply not being 

utilized. Texas includes many of these sources with controls in the maps showing area of 

influence and “high priority” sources for other state’s Class I areas, as well as in the table of 

sources within the Class I areas AOI, in their correspondence with other states (see Appendix 4.3 

of the Texas regional haze SIP). However, Texas did not provide any analysis of the four-factors 

on these partially controlled sources or include these sources in a Q/D analysis to identify those 

sources with the largest potential to impact visibility due to emissions and distance. There are a 

number of EGUs with existing controls with 2018 projected emissions large enough to have a 

Q/D many times greater than threshold (Q/D > 5) used by Texas. Furthermore, even with these 

existing controls, some of these EGUs are among the largest SO2 sources in the state. For 

example, the Martin Lake facility has a Q/D for Guadalupe Mountains (958 km away) greater 

than 37 using the projected 2018 SO2 emissions.34 The 2018 projected emissions includes 

predicted emission reductions due to CAIR at many of these controlled facilities, suggesting 

some increase in control efficiency and/or burning fuels with a lower average sulfur content is 

already included in the 2018 projections. Absent any additional analysis, however, it is not 

possible to determine whether additional reductions beyond those included in the 2018 emission 

inventory for these facilities are cost-effective, result in visibility benefits at the Class I areas and 

are reasonable. For example, emissions at Martin Lake unit 1 in the CENRAP emission 

inventory are projected to decrease from 24,832 tpy in 2002 to 11,351 tpy in 2018. As we 

discuss in our FIP TSD, based on coal data submitted to the U. S. Energy Information 

Administration, upgrading the existing scrubber to 95% control efficiency would result in an 

approximate emission reduction of an additional 7,000 tpy beyond those reductions projected to 

occur due to CAIR. Scrubber upgrades across all three Martin Lake units could result in 

emission reductions of approximately 21,000 tpy beyond the level of control assumed in the 

2018 projections. Given the size of these sources, the size of the impact from Texas emissions, 

and the source apportionment data indicating the large impact from SO2 emissions from EGUs, 

we believe it was unreasonable for Texas to not perform any analysis on these sources or request 

additional information from the facilities concerning potential upgrades. As documented in our 

FIP TSD, scrubber upgrades are often very cost-effective on a cost per ton basis. Our analysis in 

the FIP TSD demonstrates that many of these older SO2 scrubbers can be cost-effectively 

upgraded. The importance of this omission becomes clear from our analysis that shows that for a 

cost-effectiveness of approximately $600/ton or less, over 100,000 tpy of SO2 emission 

reductions can be achieved from a small number of scrubber upgrades, resulting in cost-effective 

visibility benefits at Texas Class I areas and Class I areas in other states. Thus, we find that this 

omission by TCEQ materially affected the outcome of its four-factor analysis. See our FIP TSD 

 

34 We note that recent actual emissions at the facility are roughly twice as large as the 2018 projected value. Based 

on 2002 emissions, the Q/D for Guadalupe Mountains for SO2 emissions is approximately 69. 
25

for a detailed discussion of the visibility benefits anticipated from scrubber upgrades. 

Our Conclusion Regarding the TCEQ’s Analysis of the Four Reasonable Progress Factors:

For the reasons described above, we believe the record supports a finding that Texas’ analysis of 

the reasonable progress factors does not meet the requirements of Section 51.308(d)(1)(i)(A). 

B.3. Uniform Rate of Progress Determination: 40 CFR 51.308(d)(1)(i)(B)

Section 51.308(d)(1)(i)(B) requires states to analyze and determine the uniform rate of visibility 

improvement (measured in dv) that would need to be maintained during each implementation 

period in order to attain natural visibility conditions by 2064. Also, in establishing its RPGs, 

Texas must consider the uniform rate of improvement in visibility and the emission reduction 

measures needed to achieve it for the period covered by the SIP.

State Submittal

Chapter 5, Chapter 10, Appendix 10-3

Under Section 51.308(d)(1)(i)(B), as part of its RPGs determination, the TCEQ analyzed and 

determined the URP needed to reach natural visibility conditions by the year 2064. Also in 

establishing its RPGs, the TCEQ considered the uniform rate of improvement in visibility and 

the emission reduction measures needed to achieve this rate for the period covered by the SIP. In 

so doing, the TCEQ compared the baseline visibility conditions to the natural visibility 

conditions for Big Bend and the Guadalupe Mountains, and determined the URP needed to attain 

natural visibility conditions by 2064. The TCEQ constructed the URP by plotting a straight 

graphical line from the baseline level of visibility impairment to the level of visibility conditions 

representing no anthropogenic impairment in 2064 for both Big Bend and the Guadalupe 

Mountains. See Sections III.C.1 and C.2 of this TSD for a discussion on TCEQ’s calculations of 

baseline and natural visibility conditions 

The first benchmark year is 2018 and the calculated improvement required to attain the desired 

rate of progress is 1.7 deciviews for Big Bend and 1.2 dv for Guadalupe Mountains. Using the 

baseline visibility values and natural visibility values discussed above, the TCEQ calculated the 

URP for Big Bend to be 0.12 dv/year, and that for the Guadalupe Mountains to be 0.08 dv/yr. 

Table 11 summarizes the calculations performed by TCEQ. This is demonstrated graphically in 

Figures 10-1 and 10-2 of the Texas Regional Haze SIP. As discussed in Section C.2. below, the 

TCEQ used a “refined” methodology to estimate natural visibility conditions rather than the our 

default natural visibility conditions. As a reference, we have included alternate calculations 

using the EPA default values in the table 12 below. Appendix 10-3 of the Texas Regional Haze 

SIP presents a comparison of the calculated URP using both the Texas derived natural conditions 

and the EPA default natural conditions. This information is summarized below:
26

Table 11. Summary of Uniform Rate of Progress

Visibility Metric Big Bend Guadalupe Mts.

Baseline Conditions 17.30 dv 17.19 dv

Natural Visibility 10.09 dv 12.26 dv

Total Improvement by 2064 7.21 dv 4.93 dv

Uniform Rate of Progress 0.12 dv/year 0.08 dv/year

Improvement needed by 2018 1.7 dv 1.2 dv

Table 12. Summary of Uniform Rate of Progress based on EPA default Natural Conditions

Visibility Metric Big Bend Guadalupe Mts.

Baseline Conditions 17.30 dv 17.19 dv

Natural Visibility 7.2 6.8

Total Improvement by 2064 10.1 10.39

Uniform Rate of Progress 0.17 dv/year 0.17 dv/year

Improvement needed by 2018 2.36 2.42

The TCEQ notes that the URP calculations above have some degree of uncertainty due to its 

assumptions in calculating the natural visibility. It notes that because of this, and due to a 

request from some Federal Land Managers to illustrate how sensitive this natural visibility 

estimate is to the assumption of the amount of natural fine soil and coarse mass, it has also 

generated URPs that assume 80% fine soil and coarse mass is natural. The TCEQ presents the 

80% and 100% URP cases as Figures 5-2 and 5-3 of its Regional Haze SIP. These figures 

indicate that assuming 80% of the fine soil and coarse mass is natural would lower the natural 

visibility calculation from 10.09 to 9.2 dv for Big Bend, and from 12.26 to 11.0 dv for the 

Guadalupe Mountains. The TCEQ notes this calculation is displayed for informational purposes 

only has no other significance for its SIP.

Based on the estimated cost and visibility benefit from NOx and SO2 controls identified during 

the TCEQ’s four-factor analysis described below in Section B.2, the TCEQ estimated the costs 

and emission reductions of SO2 and NOx required to enable the Guadalupe Mountains and Big 

Bend to achieve the URP.

 
27

Table 13. Estimated emission reductions and cost to meet the URP35

Class I area

Additional 

Improvement Needed 

to meet URP (dv)

Approximate 

Additional Pollutant 

Reductions SO2 and 

NOx (tpy)

Estimated Cost of 

Additional 

Reductions

Big Bend 1.0 3,700,000 $6,500,000,000

Guadalupe 

Mountains 0.3 1,100,000 $1,900,000,000

The TCEQ states that these results emphasize the need for a better understanding of transport 

into Big Bend and the need for emission reductions in Mexico and Central America in order to 

make progress towards the goal of natural visibility conditions. 

EPA Findings

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 provide an informed and equitable 

decision making process to ensure a transparent process that would, among other things, 

guarantee 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.36

It appears that in estimating the emission reductions and costs to meet its URPs in Table 13, the

TCEQ used estimates of visibility benefits from an earlier draft of the Texas Regional Haze SIP. 

In that draft SIP, the TCEQ estimated the visibility benefit from a certain set of controls to be 

0.05 dv at each Class I area.37 Updating these calculations with TCEQ’s final estimation of the 

visibility benefit from the TCEQ control set of 0.16 dv at Big Bend and 0.22 dv at Guadalupe 

Mountains38 yields the following updated table. We note that using the EPA default values for 

the natural conditions would increase the estimated emission reductions needed and associated 

costs. Total projected emissions for 2018 are 625,068 tpy of SO2 and 525,174 tpy of NOx from 

all point sources. SO2 emissions from EGUs are projected to be approximately 350,000 tpy.

 

35 Table 10-9 of the Texas Regional Haze SIP

36

 64 FR 35733 (July 1, 1999).

37

“SIP Narrative comparison of changes from proposal to adoption” available at: 

http://www.tceq.texas.gov/assets/public/implementation/air/sip/haze/4HazeSIPcompare_rev.pdf

38

 see Table 10-6 of the Texas Regional Haze SIP
28

Table 14. EPA correction to TCEQ’s estimated emission reductions and cost to meet the URP

Class I area

Additional 

Improvement 

Needed to meet 

URP (dv)

Approximate 

Additional Pollutant 

Reductions SO2 and 

NOx (tpy)

Estimated Cost of 

Additional 

Reductions

Big Bend 1.0 1,100,000 $2,000,000,000

Guadalupe Mountains 0.3 250,000 $440,000,000

Errors in its calculation aside, we note that while the TCEQ has, in establishing its RPG, 

correctly followed the procedures for analyzing and determining the rate of progress needed to 

attain natural visibility conditions by the year 2064 consistent with the requirements of the 

Regional Haze Rule and our 2003 Tracking Progress Guidance,

39 we find that the TCEQ has 

calculated this rate of progress, and compared baseline visibility conditions to a flawed 

estimation of natural visibility conditions for the Big Bend and Guadalupe Mountains, as we 

describe in Section C.2 below. Therefore, we believe the record supports a finding that the 

TCEQs calculation of the URP needed to attain natural visibility conditions by 2064 does not 

meet the requirements under Section 51.308(d)(1)(i)(B). In addition, as we discuss in Section 

B.2, we note many problems with the TCEQ’s reasonable progress four factor analysis, which 

the TCEQ partially relied upon in consideration of the emission reduction measures needed to 

achieve the natural visibility conditions. For these reasons, we must also find that the record 

supports a finding that the TCEQ’s estimation of the emission reduction measures needed to 

achieve the URP for the period covered by the SIP does not meet the requirements under Section 

51.308(d)(1)(i)(B). 

B.4. Analysis of Reasonable Progress Goal: 40 CFR 51.308(d)(1)(ii)-(iii)

Section 51.308(d)(1)(ii) provides that for the period of the SIP, if Texas 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, 

Texas 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. 

In determining whether the Texas’ goals for visibility improvement provide for reasonable 

progress towards natural visibility conditions, the Administrator will evaluate the demonstrations 

developed by it pursuant to Section 51.308(d)(1)(i) and (d)(1)(ii).

State Submittal

Texas’ RPGs for the 20% worst days establish a slower rate of progress than the URP for Big 

Bend and the Guadalupe Mountains. The TCEQ calculated that under the rate of progress 

selected as reasonable, natural visibility conditions (as calculated by Texas) would not be 

 

39

 Guidance for Tracking Progress Under the Regional Haze Rule, EPA-454/B-03-004, September 2003.
29

attained at Big Bend until 2155 and at the Guadalupe Mountains until 2081. In Appendix 10-3 

of its regional haze SIP, the TCEQ includes calculations based on our default natural conditions, 

estimating attainment of natural visibility conditions at the Big Bend in 2215 and Guadalupe 

Mountains in 2167.

The TCEQ believes the RPGs it established for Big Bend and the Guadalupe Mountains on the 

20% worst days are reasonable, and that it is not reasonable to achieve the glide path in 2018. In 

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

of visibility impairment at these Class I areas (see Section 10.6. and Chapter 11 of the Texas 

Regional Haze SIP and Table 15 below). In considering the four reasonable progress factors 

under Section 51.308(d)(i)(A), as discussed in Section B.2, above, the TCEQ also took other 

factors into consideration in determining that it is not reasonable to achieve the glide paths in 

2018 and that the RPGs adopted by the state are reasonable. The TCEQ indicated that the ability 

to meet the URP or make additional progress towards reaching natural visibility conditions is 

impeded primarily by the following: the significant contribution of emissions from Mexico and 

other international sources; the uncertainty in the effect of CAIR; and the poor cost-effectiveness 

of additional reasonable point source controls. 

The TCEQ noted that the CENRAP PSAT analysis indicates that 52% of the impairment at Big 

Bend and 25% of the impairment at Guadalupe Mountains is from Mexico and further south. 

Substantial reductions in emissions from outside the United States are needed to meet the goal of 

natural visibility at the Texas Class I areas. As discussed in Section B.3, the TCEQ considered 

the URP and the emission reductions necessary to meet the URP in establishing the RPG.

Table 15. CENRAP’s PSAT Contribution to Visibility in the Texas Class I Areas on the Worst 

20% Days

Contribution by Area Big Bend (%) Guadalupe Mountains (%)

Texas 24.8 34.8

Mexico 26.7 16.5

Boundary Conditions 25.7 8.7

Other US 11.9 18.9

Miscellaneous 5.8 9.6

Neighboring States 5.1 11.5

In addition, with respect to reductions at Texas sources, the TCEQ noted a wide range of 

measures and programs in place in Texas that result in emission reductions that often go beyond 

federal requirements. Chapter 11 and Appendices 11-2 (Federal and Texas Programs Related to 

On-Road and Non-Road Mobile Sources) and 11-3 (Major Point Source NOx Rules and 

Reductions Promulgated in Texas Since 2000) detail additional rules and programs that minimize 

emissions that can cause or contribute to local and regional visibility impairment. In Section 

10.2 of the Texas regional haze SIP, the TCEQ identifies the following programs:

 Opacity limits on grandfathered facilities;

 Best Available Control Technology (BACT) requirements that typically go beyond 

EPA’s New Source Performance Standards (NSPS) for new and modified sources;
30

 Extensive NOx emission limits on existing and new sources including major, minor and 

area sources including some on a statewide basis;

 Texas Emissions Reduction Program (TERP), which provides financial incentives to 

accelerate the implementation of new, cleaner diesel engine technologies in on-road and 

non-road applications; and

 Air Check Texas Repair and Replacement Assistance Program, which provides financial 

incentives for scrapping older gasoline-powered on-road vehicles.

The TCEQ noted that the established RPGs reflect emissions reductions programs already in 

place, including CAIR, additional refinery SO2 reductions as a result of refinery consent decrees, 

Texas ozone SIP revisions, and the Texas Clean Air Act. It noted that the majority of the 

emissions reductions underlying the predicted visibility improvements are from the CAIR 

program or its eventual replacement. The TCEQ assumes that any replacement for CAIR will 

include interstate trading of emissions allowances and therefore there is uncertainty regarding 

how visibility will be improved at individual Class I areas. The TCEQ states that because 

emission allowances can be purchased by EGUs relatively close to the Texas Class I areas from 

EGUs far from the Texas Class I areas, the visibility improvement, may not be as great as 

predicted by the CENRAP’s modeling. Conversely, nearby EGUs may elect to control beyond 

their emission caps and sell emission allowances out of state, resulting in reduced emissions 

closer to the Texas Class I areas.

The TCEQ concluded that “given the significant impact from international emissions, the 

uncertainty in the impact of CAIR, and the poor cost-effectiveness of additional, reasonable 

point source controls, the TCEQ has determined that additional controls for regional haze are not 

appropriate at this time.” 40

EPA Findings

We agree that there is uncertainty regarding the size and location of reductions at Texas EGUs 

due to implementation of CAIR/CSAPR. While reductions at certain facilities within Texas 

would result in improvements in visibility conditions at the Texas Class I areas or Class I areas 

in other states, similar reductions at other facilities may have no impact on visibility conditions at 

the Class I area. Furthermore, reductions that are seasonal in nature due to decreased operation 

during the fall and/or winter reduce annual emissions, contribute towards CAIR/CSAPR 

compliance, but will not lead to improved visibility during the 20% worst days, which typically 

occur during the summer months. For example, in recent years the Monticello units have been 

shut down for several non-summer months, which has resulted in reduced annual emissions, 

while having no impact on summer time emissions or visibility impacts during the summer 

months. The CENRAP source apportionment results include the projected reductions due to 

CAIR compliance and show that even after these reductions, impacts from Texas points sources 

remain the most significant portion of the total visibility impairment with available controls at 

Big Bend and Guadalupe. Analysis of recent emissions from Texas EGUs shows that in many 

cases current emission levels are above those predicted in the 2018 CENRAP modeling. In fact, 

in the case of Martin Lake, current annual emissions are roughly twice those included in the 

 

40

 Section 10.7 of the Texas Regional Haze SIP
31

2018 modeling, and we are not aware of any upcoming controls or changes in operation to 

suggest that future actual emissions will decrease to those predicted levels. 

We also agree with the TCEQ’s conclusion that it is not reasonable to meet the URP for the 

Texas Class I areas for this planning period. We agree with the TCEQ that emissions and 

transport from Mexico and other international sources will limit the rate of progress achievable 

on the 20% worst days and that efforts to meet the goal of natural visibility by 2064 would 

require further emissions reductions not only within Texas, but also large emission reductions 

from international sources. 

We also note the more recent IMPROVE monitored data at the Big Bend and Guadalupe 

Mountains indicate that more progress than anticipated by the CENRAP modeling has 

occurred.41 The most recent five-year (2009-2013) average conditions for the 20% worst days is 

16.3 dv at Big Bend and 15.3 dv at Guadalupe Mountains. This is below the level anticipated in 

the CENRAP projection for 2018 of 16.6 dv for Big Bend and 16.3 dv for Guadalupe Mountains. 

We believe that this observed improvement from the baseline conditions is the result of 

meteorological conditions, reduction in the impacts from SO2 emissions, and a reduction in the 

impacts from coarse material. 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 goals for 2018 as calculated by us in Section VII.M of 

the Federal Register notice. As discussed above, emission reductions at some of the sources that 

impact visibility the most are still above the emission level projected in the model and we believe 

that cost-effective controls are likely available at these sources.

However, for the reasons we have discussed above, although we agree with the TCEQ that a rate 

of improvement necessary to attain natural visibility conditions by 2064 is not reasonable, we do 

not believe that the rate of improvement the TECQ has selected is reasonable, because we 

disagree with its four factor analysis and the analysis of emission measures needed to meet the 

URP. Therefore we believe the record supports a finding that the TCEQ’s RPGs for Big Bend 

and the Guadalupe Mountains do not meet the requirements under Section 51.308(d)(1)(ii). In so 

doing, we rely on the specific directive in Section 51.308(d)(1)(iii): “In determining whether the 

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

visibility conditions, the Administrator will evaluate the demonstrations developed by the State 

pursuant to paragraphs (d)(1)(i) and (d)(1)(ii) of this section.” We also find that visibility on the

20% best days will be better than Texas projects, given additional controls in our proposed FIP.

B.5. Reasonable Progress Goal To Be Considered by Administrator: 40 CFR 

51.308(d)(1)(v)

The language under Section 51.308(d)(1)(v) gives EPA authority to review a state’s RPG stating, 

“[t]he 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 Since it does not require a response from the state, it is not 

 

41

 Available at: http://vista.cira.colostate.edu/tss/
32

separately evaluated here.

B.6. Reasonable Progress State Consultation: 40 CFR 51.308(d)(1)(iv)

In developing each reasonable progress goal, Texas must consult with those states which may 

reasonably be anticipated to cause or contribute to visibility impairment in the mandatory Class I 

Federal area. In any situation in which Texas cannot agree with another such state or group of 

states that a goal provides for reasonable progress, Texas must describe in its submittal the 

actions taken to resolve the disagreement. In reviewing Texas’ SIP submittal, the Administrator 

will take this information into account in determining whether its goal for visibility improvement 

provides for reasonable progress towards natural visibility conditions.

State Submittal

Chapter 4, Appendix 4-1, Chapter 11

Pursuant to Section 51.308(d)(1)(iv), Texas consulted with other states which may reasonably be 

anticipated to cause or contribute to visibility impairment at its two Class I areas. The TCEQ 

held three conference calls in July, 2007 to which Arkansas, Kansas, Louisiana, New Mexico, 

and Oklahoma were invited. 

The TCEQ used CENRAP generated products, such as regional photochemical modeling results 

and visibility projections, and source apportionment modeling to assist in identifying 

neighboring states’ contributions to the visibility impairment at its Class I areas. Specifically, 

the TCEQ used the results from the CENRAP particulate matter source apportionment 

technology (PSAT) modeling to determine that New Mexico, Oklahoma, Kansas, and Louisiana 

contribute to visibility impairment at the Texas Class I areas. The TCEQ invited those states 

with a greater than 0.5 inverse megameter impact on one of its Class I areas to its consultations. 

Other participants that attended one or more of the calls included CENRAP, us, and the federal 

land managers. The TCEQ invited tribes in all of the CENRAP states to the consultation calls, 

but no tribes participated in the consultation on Big Bend and Guadalupe Mountains. These calls 

are summarized in Appendix 4-1 of the Texas regional haze SIP.

The first consultation call primarily addressed technical papers that discussed the natural 

conditions, the impacts of dust storms in Big Bend and the Guadalupe Mountains, our IPM 

emission projections, and the URP and RPGs for the Texas Class I areas. The second and third 

consultation calls consisted of discussions between the states and federal land managers 

regarding the dust storm technical papers. The TCEQ presented the URPs for its Class I areas, 

discussed controls that are in place in Texas, and its decision that no additional controls would be 

included in its regional haze SIP. The federal land managers suggested that the TCEQ revise the 

Prevention of Significant Deterioration (PSD) permit process to include FLM notification 

provisions. Texas committed to further consultations with the federal land managers to address 

their concerns about the Texas PSD program.

The TCEQ discussed the CENRAP PSAT modeling results with the attendees. It noted that the 

BRAVO study indicated that for SO4, which has the largest visibility impact of all pollutants at 
33

Big Bend, approximately 1/3 comes from Mexico, 1/3 from Texas, and 1/3 from the Midwest 

and South beyond Texas. It noted that these results are somewhat inconsistent with CENRAP 

PSAT modeling results, which indicate that slightly more than half of the visibility impairment at 

Big Bend comes from Mexico and other areas outside the U.S.

New Mexico and the federal land managers discussed that despite the Guadalupe Mountains in 

Texas and Carlsbad Caverns in New Mexico sharing the same monitor, these Class I areas 

appeared to have significantly different calculated natural visibility values, individually prepared 

by the two states.42 The federal land managers and we both expressed a desire to review the 

TCEQ’s natural visibility calculation.

The TCEQ concluded its consultations by noting that other states’ visibility impacts on Big Bend 

and the Guadalupe Mountains are relatively small. Texas sources are responsible for 25% and 

35% of the visibility impairment at Big Bend and the Guadalupe Mountains, respectively. 

Neighboring states combined contribute only 5% of the visibility impairment at Big Bend and 

11.5% at the Guadalupe Mountains. As a result of these consultations, the TCEQ did not request 

any additional reductions from other states.

Citing the source apportionment results and results of the BRAVO study, in Section 11.3 of the 

Texas regional haze SIP, Texas requests in its SIP that we initiate and pursue federal efforts to 

reduce impacts from international transport. Due to large contributions from international 

sources, the TCEQ concludes it will be impossible to reach natural conditions without significant 

reductions in Mexico and other countries, in parallel with reductions within Texas and the rest of 

the United States. The TCEQ notes that Class I areas in other states will also benefit from

reductions in emissions from international sources. We acknowledge that emissions from 

Mexico significantly impact the visibility at Big Bend and the Guadalupe Mountains. As we 

state in the Regional Haze Rule,43 “the EPA does not expect States to restrict emissions from 

domestic sources to offset the impacts of international transport of pollution. We believe that 

States should evaluate the impacts of current and projected emissions from international sources 

in their regional haze programs, particularly in cases where it has already been well documented 

that such sources are important.”

EPA Findings

We reviewed the CENRAP PSAT data for the Texas Class I areas referred to during the 

consultation calls, as well as the technical papers discussed during those calls and the summary 

of the calls in Appendix 4-1 of Texas’ SIP submittal. Approximately half of the 2002 visibility 

impairment at Big Bend is due to Mexico and other international sources captured in the 

modeled boundary conditions, one quarter of the impairment is due to Texas sources and the 

remaining quarter is due to all the remaining sources combined, with the largest contributions in 

this group from the Eastern United States (2.5%) and Louisiana (2.8%). Examining only 

contributions due to point sources in 2002, Texas point sources contribute 10% of the total 

visibility impairment at Big Bend and Mexico point sources contribute 16.9%. The largest 

 

42

 Note that we discuss the difference between the natural visibility value calculated by New Mexico for Carlsbad 

Caverns and that calculated by Texas for the Guadalupe Mountains elsewhere in this TSD.

43

 64 FR 35736 (July 1, 1999).
34

impact from a nearby state is Louisiana at a little more than 2% contribution. All other nearby 

states contribute less than 1% to the total visibility impairment at Big Bend. The source 

apportionment results for 2018 projections at Big Bend show similar levels of contribution with a 

slight decrease in Texas and Eastern United States contributions. Mexico and other international 

sources contribute approximately one quarter of the visibility impairment and Texas contributes 

about one third of the visibility impairment at the Guadalupe Mountains in 2002. The next 

largest contributing source regions are New Mexico (7.3%, 4.7% from natural sources), Kansas 

(3.3%), the Eastern United States (3.2%), Western United States (3.0%), and Oklahoma (2.5%). 

Examining only contributions due to point sources in 2002, Texas point sources contribute 8.7% 

of the total visibility impairment and Mexico point sources contribute 6.8%. The largest impact 

from a nearby state is New Mexico at a little more than 1% contribution. All other nearby states 

contribute less than 1% to the total visibility impairment at Guadalupe Mountains. The source 

apportionment results for 2018 projections at Guadalupe Mountains show similar levels of 

contribution with a slight decrease in eastern United States contributions. PSAT results show an 

overwhelming contribution from international sources and Texas sources and the technical 

papers shared by Texas suggest that dust storms significantly impact a number of the worst 20% 

days at these Class I areas. See Section D.3 below, the CENRAP Modeling TSD, and the 

technical support document for the CENRAP modeling44 for additional discussion and PSAT 

modeling results for Big Bend and Guadalupe Mountains. 

We find that the TCEQ appropriately identified those states with the largest impacts on Texas 

Class I areas and invited them for consultation. We agree with Texas’ determination that it was 

reasonable not to request additional controls from other states at this time. Given the small 

contributions from individual nearby states, especially when only considering anthropogenic 

sources that can be easily controlled in comparison with the size of impacts from Texas sources 

and international sources, we find that it was reasonable for the TCEQ to have focused the 

analysis of additional controls on sources within Texas. We believe the record supports a finding

that Texas has satisfied the requirement under Section 51.308(d)(1)(iv) to consult with other 

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

two Class I areas. 

B.7. Reasonable Progress Goal Minimum: 40 CFR 51.308(d)(1)(vi)

Texas 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

The RPGs established by Texas 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 

 

44 Technical Support Document for CENRAP Emissions and Air Quality Modeling to Support Regional Haze SIP, 

included as Appendix 8-1 of the Texas regional haze SIP
35

reduction schedules that predate 2018, including the long-term strategies of Texas, Oklahoma, 

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

Oklahoma BART rule. 

EPA Findings

The TCEQ’s RPGs are based on the visibility improvement predicted by CENRAP’s modeling

projections to take place 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, we believe that the TCEQ’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 believe the record supports a finding that 

Texas’ submission meets the requirements of Section 51.308(d)(1)(vi) because its RPGs for the 

Guadalupe Mountains and Big Bend do not represent less visibility improvement than is 

expected to result from the implementation of other requirements of the CAA during this 

planning period. 

C. Baseline and Natural Visibility Conditions

Note: Section 51.308(d)(2)(ii) is not applicable since this SIP was submitted after 2003, and 

Section 51.308(d)(2)(iv)(B) is not applicable since this is the first SIP period.

C.1. Calculation of Baseline Conditions: 40 CFR 51.308(d)(2)(i)

For each of its mandatory Class I Federal areas tTexas must determine the baseline visibility 

conditions for the most impaired and least impaired days. The period for establishing baseline 

visibility conditions is 2000 to 2004. Baseline visibility conditions must be calculated, using 

available monitoring data, by establishing the average degree of visibility impairment for the 

most and least impaired days for each calendar year from 2000 to 2004. The baseline visibility 

conditions are the average of these annual values. For mandatory Class I Federal areas without 

onsite monitoring data for 2000–2004, Texas must establish baseline values using the most 

representative available monitoring data for 2000–2004, in consultation with the Administrator 

or his or her designee.

State Submittal

Chapter 5

As required by Section 51.308(d)(2)(i) of the Regional Haze Rule and in accordance with EPA’s 

2003 Natural Visibility Guidance,

45 the TCEQ calculated baseline visibility conditions for Big 

Bend and the Guadalupe Mountains. The baseline condition calculation begins with the 

calculation of light extinction for each day with monitoring data, using the IMPROVE equation. 

 

45

 Guidance for Estimating Natural Visibility Conditions Under the Regional Haze Rule, EPA-454/B-03-005, 

September 2003.
36

The IMPROVE equation sums the light extinction46 resulting from individual pollutants, such as 

sulfates and nitrates. As with the natural visibility conditions calculation, the TCEQ chose to use 

the new IMPROVE equation described below. 

The period for establishing baseline visibility conditions is 2000-2004, and baseline conditions 

must be calculated using available monitoring data, as required under Section 51.308(d)(2). The 

TCEQ averaged the data from 2001 through 2004 for Big Bend47 and calculated the baseline 

conditions at Big Bend to be 17.30 dv on the 20% worst days, and 5.78 dv on the 20% best days. 

In calculating the baseline conditions at the Guadalupe Mountains, the TCEQ averaged the 

visibility data for 2000-2004, and calculated the baseline conditions at the Guadalupe Mountains 

to be 17.19 dv on the 20% worst days, and 5.95 dv on the 20% best days. 

EPA Findings

Baseline conditions represent visibility for the best and worst days at the time the regional haze 

program is established. Baseline conditions are calculated using multiyear averaging of the 20 

percent of monitored days with the highest (most impaired, or worst days) and the 20 percent of 

monitored days with the lowest (least impaired, or best days) light extinction values, expressed in 

deciviews (dv), for the years 2000 through 2004. The Regional Haze Rule establishes the 

deciview (dv) as the principal metric for measuring visibility. See 70 FR 39104. A deciview is a 

uniform measure of light extinction caused by regional haze. This visibility metric expresses 

uniform changes in the degree of haze in terms of common increments across the entire range of

visibility conditions, from pristine to extremely hazy conditions. The deciview scale approaches 

zero for no visibility degradation and increases as visibility is degraded. The deciview scale was 

designed similar to the decibel scale for sound, so that equal changes in deciview are equally 

perceptible. The deciview is a useful measure for tracking progress in improving visibility, 

because each deciview change is an equal incremental change in visibility perceived by the 

human eye. Most people can detect a change in visibility of one deciview. Common current 

values in the west are 15 to 20 dv; common current values in the east are 25 to 30 dv. Visibility 

is also sometimes expressed in terms of the visual range, which is the greatest distance, in 

kilometers or miles, at which a dark object can just be distinguished against the sky.

The baseline is the starting point for this regional haze submittal, against which progress toward 

the national visibility goal is measured. Texas calculated its baseline conditions in accordance 

with our 2003 Natural Visibility Guidance48 , as required by the Regional Haze Rule. The 

baseline condition calculation begins with the calculation of light extinction, using the 

IMPROVE equation. The IMPROVE equation sums the light extinction resulting from 

individual pollutants, such as sulfates and nitrates 

 

46

 The amount of light lost as it travels over one million meters. The haze index, in units of deciviews (dv), is 

calculated directly from the total light extinction, bext expressed in inverse megameters (Mm-1), as follows: HI = 10 

ln(bext /10).

47

 The TCEQ determined that the fourth quarter of 2000 for Big Bend was not sufficiently complete for use in 

calculating a baseline average for regulatory purposes, as it had only ten complete days.

48

 Guidance for Estimating Natural Visibility Conditions Under the Regional Haze Program, EPA-454/B-03-005, 

September 2003.
37

In 2005 the IMPROVE Steering Committee made recommendations for a refined equation that 

modifies the terms of the original equation to account for the most recent data. 49 The purpose 

of this refinement is to provide more accurate estimates of the various factors that affect the 

calculation of light extinction. 

The new IMPROVE equation estimates additive extinction coefficients for each of several 

chemical constituents of particulate matter: sulfurous, nitrate, organic carbonaceous, elemental 

“light-absorbing” carbonaceous, fine soil, chlorine or chloride, and coarse matter. The equation 

also accounts for Rayleigh scattering of light and for deliquescence on sulfurous, nitrate, and 

chlorine or chloride particulates with an estimate of particle-bound water as a function of relative 

humidity. It reflects the most recent review of the science50 and it accounts for the effect of 

particle size distribution on light extinction efficiency of sulfate, nitrate, and organic carbon. It 

also adjusts the mass multiplier for organic carbon (particulate organic matter) by increasing it 

from 1.4 to 1.8. New terms are added to the equation to account for light extinction by sea salt 

and light absorption by gaseous nitrogen dioxide. Site-specific values are used for Rayleigh 

scattering (scattering of light due to atmospheric gases) to account for the site-specific effects of 

elevation and temperature. Separate relative humidity enhancement factors are used for small 

and large size distributions of ammonium sulfate and ammonium nitrate and for sea salt. The 

terms for the remaining contributors, elemental carbon (light-absorbing carbon), fine soil, and 

coarse mass terms, do not change between the original and new IMPROVE equations.

As with the natural visibility conditions calculation discussed below, the TCEQ chose to use the 

new IMPROVE equation. The choice between use of the old or the new equation for calculating 

the visibility metrics for each Class I area is made by the state in which the Class I area is 

located. TCEQ has chosen to use this new equation, referred to in the SIP as a “revised” 

approach, for calculating both the baseline and natural visibility conditions because it takes into 

account the most recent review of the science and because it is recommended by the IMPROVE 

Steering Committee.

The TCEQ calculated the baseline by first summing the light extinction (where the extinction 

 

49

 The IMPROVE program is a cooperative measurement effort governed by a steering committee composed of 

representatives from Federal agencies (including representatives from EPA and the federal land managers) and 

regional planning organizations. The IMPROVE monitoring program was established in 1985 to aid the creation of 

Federal and State implementation plans for the protection of visibility in Class I areas. One of the objectives of 

IMPROVE is to identify chemical species and emission sources responsible for existing anthropogenic visibility 

impairment. The IMPROVE program has also been a key participant in visibility-related research, including the 

advancement of monitoring instrumentation, analysis techniques, visibility modeling, policy formulation and source 

attribution field studies.

50The science behind the revised IMPROVE equation is summarized in appendix B.2 of the Oklahoma Regional

Haze submittal and in numerous published papers. See for example: Hand, J.L., and Malm, W.C.,2006, Review of 

the IMPROVE Equation for Estimating Ambient Light Extinction Coefficients - Final Report. March 2006. Prepared 

for Interagency Monitoring of Protected Visual Environments (IMPROVE), Colorado State University, Cooperative 

Institute for Research in the Atmosphere, Fort Collins, Colorado.

http://vista.cira.colostate.edu/improve/publications/GrayLit/016_IMPROVEeqReview/IMPROVEeqReview.htm; 

and Pitchford, Marc., 2006, Natural Haze Levels II: Application of the New IMPROVE Algorithm to Natural 

Species Concentrations Estimates. Final Report of the Natural Haze Levels II Committee to the RPO 

Monitoring/Data Analysis Workgroup. September 2006 

http://vista.cira.colostate.edu/improve/Publications/GrayLit/029_NaturalCondII/naturalhazelevelsIIreport.ppt
38

coefficient is expressed in Mm1) for sulfurous, nitrate, organic carbonaceous, elemental “lightabsorbing” carbonaceous, fine soil, chlorine or chloride, and coarse matter, using the following 

equation:

βext = βext S + βext NO3 + βext organic+ βext elemental+ βext SOil+ βext coarse+ βext Cl+ βext Rayleigh

The TCEQ then converted the total light extinction values to deciviews (dv), using the Haze 

Index (HI) equation:

HI (dv) = 10 ln[βext/(10 Mm -1)]

We have reviewed the TCEQ’s estimation of baseline visibility conditions at Big Bend and 

Guadalupe Mountains and the submittal supports a finding that Texas has satisfied the 

requirements of Section 51.308(d)(2)(i). 

C.2. Calculation of Natural Visibility Conditions: 40 CFR 51.308(d)(2)(iii)

For each mandatory Class I Federal area located within the state, the state must determine the 

natural visibility conditions for the most impaired and least impaired days. Natural visibility 

conditions must be calculated by estimating the degree of visibility impairment existing under 

natural conditions for the most impaired and least impaired days, based on available monitoring 

information and appropriate data analysis techniques.

Natural background visibility, as defined in our 2003 Natural Visibility Guidance51, is estimated 

by calculating the expected light extinction using default estimates of natural concentrations of 

fine particle components adjusted by site-specific estimates of humidity. Our guidance provides 

default natural conditions for the 20% worst and 20% best days for each Class I area based on 

the IMPROVE equation. As documented in our guidance, we allow states to use a “refined” 

approach or alternative approaches to the guidance defaults to estimate the values that 

characterize the natural visibility conditions of their Class I areas. Our guidance also states that 

states may wish to use a more refined approach to reduce uncertainty when baseline visibility is 

already near natural conditions or when there is marked seasonality. These alternative 

approaches can be implemented via alternative estimates of natural concentrations. One 

alternative approach is to develop and justify the use of alternative estimates of natural 

concentrations of fine particle components. Another option open to states is to use the “new 

IMPROVE equation” that was adopted for use by the IMPROVE Steering Committee in 

December 2005. The purpose of this refinement to the “old IMPROVE equation” was to provide 

more accurate estimates of the various factors that affect the calculation of light extinction. The 

default natural conditions in our 2003 guidance were updated by the Natural Haze Levels II 

Committee utilizing the new IMPROVE equation and included some refinements to the 

 

51

 Guidance for Estimating Natural Visibility Conditions Under the Regional Haze Program, EPA-454/B-03-005, 

September 2003.
39

estimates for the PM components.

52,53 These estimates are referred to as the “NCII” default 

natural visibility conditions.

State Submittal

Chapter 5, Appendix 5-2

The TCEQ chose to derive a “refined” estimate of natural visibility conditions rather than using 

the default NCII values. Chapter 5 of the Texas Regional Haze SIP and Appendix 5-2 provide 

calculations, methodologies, and a discussion of the reasons for the selection of the alternative 

methodology utilized by the TCEQ. In calculating natural visibility conditions, the TCEQ used 

the new IMPROVE equation and PM concentration estimates (i.e., the NCII values) for most 

components, but assumed that 100% of the fine soil and coarse mass concentrations in the 

baseline period should be attributed to natural causes and that the corresponding estimates in the 

NCII values should be replaced. The TCEQ has provided data54 that supports TCEQ’s 

conclusion that a large portion of dust impacting visibility at these Class I areas is likely due to 

natural sources. The TCEQ noted there is some uncertainty with these calculations in the amount 

of natural fine and coarse mass assumption. The TCEQ also stated that, to the extent its 

assumption that 100% of coarse mass and fine soil is natural is an overestimate, it expects that its

low organic carbon estimate will more than compensate for any errors in this assumption at this 

time. 

For the 20% worst days, the TCEQ calculated natural visibility conditions for Big Bend and the 

Guadalupe Mountains of 10.09 dv and 12.26 dv, respectively. For the 20% best days, the TCEQ 

calculated that natural visibility conditions for Big Bend and the Guadalupe Mountains of 2.19 

dv, and 2.10 dv, respectively. 

In response to FLM comments, the TCEQ also performed an additional calculation for the 20% 

worst days, assuming only 80% of fine soil and course mass as natural, in order to demonstrate 

the sensitivity of its approach to this assumption. Under this approach, the TCEQ estimated 

natural conditions to be 9.2 dv for the 20% worst days at Big Bend, compared to 10.09 dv using 

the assumption that 100% of fine soil and course mass is natural, and 7.16 dv using the NCII 

method. For the Guadalupe Mountains, the TCEQ’s estimate was 11.0 dv under the 80% 

assumption, compared with 12.26 dv under the 100% assumption and 6.65 dv using the NCII

method. These values are summarized below:

 

52

 Pitchford, Marc, 2006, Natural Haze Levels II: Application of the New IMPROVE Algorithm to Natural Species 

Concentrations Estimates. Final Report of the Natural Haze Levels II Committee to the RPO Monitoring/Data 

Analysis Workgroup. September 2006, available at: 

http://vista.cira.colostate.edu/improve/Publications/GrayLit/029_NaturalCondII/naturalhazelevelsIIreport.ppt.

53

 The second version of the natural haze level II estimates based on the work of the Natural Haze Levels II 

Committee is available at: 

http://vista.cira.colostate.edu/Docs/IMPROVE/Aerosol/NaturalConditions/NaturalConditionsII_Format2_v2.xls

54 Dust Storms as Natural Events for Regional Haze and Particulate Matter in West Texas (online: 

http://www.tceq.state.tx.us/implementation/air/sip/bart/haze_sip.html) ; “Investigation of Dust Emission Hotspots in 

Chihuahuan Desert Playa Basins” (Gill et al. 2005); Kavouras et al. (2007), “Classification of sources of 

atmospheric dust in Class I areas of the western United States”; Kavouras et al. (2006), “Assessment of the Principal 

Causes of Dust-Resultant Haze at IMPROVE Sites in the Western United States,”
40

Table 16. TCEQ Natural Visibility Calculations

Guadalupe Mountains Big Bend

20% Worst Days 20% Best Days 20% Worst Days 20% Best Days

100% fine soil 

and coarse mass 12.26 2.19 10.09 2.10

80% fine soil 

and coarse mass 11.0 Not calculated 9.2 Not calculated

NCII default 6.65 0.99 7.16 1.62

Ultimately, however, the TCEQ stated that it was including the 80% assumption for illustration 

purposes only and based its calculations of natural conditions on assuming that 100% coarse 

mass and fine soil assumption are due to natural sources. Similarly, the TCEQ did not utilize our 

default method to determine natural visibility conditions, but it did provide the default values for 

comparison (Appendix 5-2 of the Texas Regional Haze SIP). These different estimates of 

natural visibility conditions and the resulting calculated URP are depicted graphically in the 

figures prepared by TCEQ and reproduced below. 

Figure 4. Natural Condition and URP estimates for Big Bend
41

Figure 5. Natural Condition and URP estimates for the Guadalupe Mountains

EPA Findings 

Our default procedure has several acknowledged limitations. First, each chemical species can 

have one of only two possible background concentrations, one for the East and one for the West. 

Future efforts may provide for a larger number of geographic zones with differing 

concentrations. A second potential limitation is that the same approach is used for both naturaland anthropogenic-dominated species components; EPA guidance mentions the possibility of 

treating these separately. 

We agree that dust storms and other blown dust from deserts are a significant contributor to 

visibility impairment at the Texas Class I areas that may not be captured accurately by our 

default method. However, we find that the TCEQ has not adequately demonstrated that all 

coarse mass and fine soil measured in the baseline period can be attributed to 100% natural 

sources. Anthropogenic sources of coarse mass and fine soil in the baseline period could have 

included emissions associated with paved and unpaved roads, agricultural activity, and 

construction activities as well. We also note that the impact from dust at Big Bend is less certain 

than at Guadalupe Mountains and a different assumption may be appropriate in estimating 

natural conditions there. Given the significant uncertainty in the assumptions used in the Texas 

methodology and the demonstrated sensitivity to the assumption of 100% natural versus 80% 

soil and coarse mass from natural sources, we believe the record supports a finding that Texas’ 

calculation of the natural visibility conditions for the Big Bend and Guadalupe Class I areas does 

not meet the requirements under Section 51.308(d)(2)(iii). 

In its regional haze SIP, the TCEQ stated that it will continue to evaluate data, modeling, and any 

other sources of information in order to further improve its estimates. Furthermore, the TCEQ 

plans to work with us and the federal land managers to improve natural conditions estimates for 
42

future regional haze SIP revisions. We encourage these efforts.

As discussed in the Federal Register notice, we propose to rely on the default values that were 

used for every other Class I area in the country for our proposed FIP to address this deficiency in 

the Texas regional haze SIP, but we solicit comment on the acceptability of alternate estimates in 

the range between the EPA default estimates and Texas’ estimates. The federal land managers 

commented during the development of the Texas regional haze SIP that an assumption of 80% 

would be more reasonable than an assumption of 100%. We note that with any of the 

methodologies for calculating natural conditions discussed above, Texas’ Class I areas are not

projected to meet the URP in 2018 according to the CENRAP modeling and are not projected to 

meet the goal of natural visibility conditions by 2064.

C.3. Natural Visibility Impairment: 40 CFR 51.308(d)(2)(iv)(A)

For the first SIP addressing the requirements of 51.308(d) and (e) of this section, Texas must 

calculate the number of deciviews by which baseline conditions exceed natural visibility 

conditions for the most impaired and least impaired days. The natural visibility impairment is 

calculated by subtracting the natural visibility calculation from the baseline visibility calculation. 

State Submittal

Section 5-3.

As discussed in Section III.C.1 of this TSD, the TCEQ calculated the baseline conditions at its 

two Texas Class I areas on the 20 percent worst days and the 20 percent best days. Also 

discussed in Section III.C.2, the TCEQ calculated the natural visibility conditions for the 20 

percent worst days, and the 20 percent best days. Subtracting the natural visibility condition 

values from the baseline values results in the amount of visibility impairment. 

As summarized in Table 5-3 of its Regional Haze SIP (reproduced below as Table 17), the 

TCEQ calculates the number of deciviews by which baseline conditions exceed natural visibility 

conditions at the Big Bend and Guadalupe Mountains for the most impaired (20 percent worst) 

days and least impaired (20 percent best) days .
43

Table 17: Visibility Metrics for the Class I Areas in Texas

Estimate of Natural Visibility Conditions

Class I Area Haze Index (deciviews)

Most Impaired Least Impaired

Big Bend 10.09 2.19

Guadalupe Mountains 12.26 2.10

Baseline Visibility Conditions, 2000–2004

Class I Area Haze Index (deciviews)

Most Impaired Least Impaired

Big Bend 17.30 5.78

Guadalupe Mountains 17.19 5.95

Estimate of Extent Baseline Exceeds Natural Visibility Conditions

Class I Area Haze Index (deciviews)

Most Impaired Least Impaired

Big Bend 7.21 3.59

Guadalupe Mountains 4.93 3.85

EPA Findings

We have reviewed the TCEQ’s estimates of the natural visibility impairment at Big Bend and the 

Guadalupe Mountains and we find these estimates do not meet the requirements because this 

calculation depends on the TCEQ’s calculations for natural visibility conditions, which we also 

found do not meet the requirements for the reasons discussed in the previous section. See 

Section VII.L of the Federal Register notice for our calculation of visibility impairment based on 

the EPA default values (NC II). 

D. Long Term Strategy 40 CFR 51.308(d)(3).

Under Section 51.308(d)(3), Texas, as with each state listed in Section 51. 300(b)(3), must 

submit a LTS that addresses regional haze visibility impairment for each mandatory Class I area 

within the state and for each mandatory Class I area located outside the state which may be 

affected by emissions from the state. The LTS must include enforceable emissions limitations, 

compliance schedules, and other measures as necessary to achieve the reasonable progress goals 

established by the states having Class I areas.

There are a number of requirements a state must meet when establishing its long-term strategy. 

These requirements include: (1) states must consult with downwind states to develop 

coordinated management strategies that address regional haze visibility impairment;55 (2) where 

multiple states cause or contribute to visibility impairment in a Class I area, each state must 

demonstrate that it has put all measures necessary to obtain its share of emission reductions 

needed to meet the progress goal for the Class I area;56 and (3) each state must provide and 

 

55 Section 51.308(d)(3)(i)

56 Section 51.308(d)(3)(ii)
44

document the technical basis on which the state is relying to determine its share of emission 

reductions necessary to achieve reasonable progress for each Class I area it affects.57

Section 51.308(d)(3) of the Regional Haze Rule requires all states (both downwind and upwind) 

to “submit a long-term strategy that addresses regional haze visibility impairment for each 

mandatory Class I Federal area within the State and for each mandatory Class I Federal area 

located outside the State which may be affected by emissions from the State.”58 As explained in 

Section IV of the Federal Register notice, a state’s long-term strategy is inextricably linked to the 

RPGs.

D.1. Long Term Strategy State Consultation: 40 CFR 51.308(d)(3)(i)

Section 51.308(d)(3)(i) requires that where Texas has emissions that are reasonably anticipated 

to contribute to visibility impairment in any mandatory Class I Federal area located in another 

state or states, it must consult with the other state(s) in order to develop coordinated emission 

management strategies. Texas must consult with any other state having emissions that are 

reasonably anticipated to contribute to visibility impairment in any mandatory Class I Federal 

area within it.

State Submittal:

Chapter 4, Chapter 11

As detailed in Chapter 11.2.2, the TCEQ reviewed CENRAP modeling to assess how Texas 

emission might affect other state’s Class I areas and which Class I areas in other states might be 

impacted by Texas’ emissions. In Chapter 11.2.3 Texas reviews its impacts and 2018 impact 

reduction for Class I areas outside of Texas. The TCEQ’s review of the CENRAP PSAT 

modeling results were used to assess how Texas’ emissions might affect other states’ Class I 

areas. The results indicated that Texas’ emissions affect one or more Class I areas in New 

Mexico, Oklahoma, Colorado, Arkansas, Missouri, and Louisiana.59 Texas participated in 

consultation calls with Arkansas, Missouri, and Oklahoma and through letters with Arkansas, 

Colorado, Louisiana, Missouri, and New Mexico. 

Pursuant to the TCEQ’s review of impacts from Texas emissions and in response to comments 

from us and the federal land managers in March 2008, Texas wrote consultation letters to 

Arkansas, Missouri, Oklahoma, New Mexico, Louisiana, and Colorado to ask whether emission 

reductions projected in Texas by 2018 are sufficient to meet Texas’ apportionment of the impact 

reduction needed to meet the RPG for each Class I area in each state. Included with the letters 

were a discussion and data of the CENRAP Particulate Matter Source Apportionment 

Technology (PSAT) modeling determining the contribution from each Texas source area to 

visibility impairment at Class I areas in the given state. The TCEQ stated it participated fully in 

the analysis of this data, base period visibility impairment, natural visibility condition estimates, 

 

57 Section 51.308(d)(3)(iii)-(iv)

58

 40 C.F.R Section 51.308(d)(3).

59

 See Table 1 above for a summary of CENRAP source apportionment modeling results for Class I areas in other 

States impacted by emissions from sources in Texas.
45

and 2018 projections based on current and anticipated future state and federal controls. The 

PSAT modeling indicates that the probable impact of Texas sources will be reduced by 2018 in 

all of the affected Class I Areas due to the expected emissions reductions from current and 

planned controls. Also included with the consultation letter, where applicable, were area of 

influence (AOI) maps for each Class I area in the CENRAP states. Texas identified the 

significant point sources within each AOI and shared this information with nearby states during 

the consultation process (see Appendix 4-3). For reference purposes, the map showed the 

portions of Texas that are in the first and second order sulfate and nitrate areas of influence for 

the given Class I Area. The sulfur dioxide and nitrogen oxide sources shown on the map are 

Texas sources the TCEQ identified as high priority due to the fact that they have an emissions 

over distance equal to or greater than five (Q/D ≥ 5) for one or more of the Class I areas. Also 

included was a table of sources of particular interest to the affected Class I Area(s) due to their 

emissions and their positions within AOI.

The TCEQ also requested recipients of the letters to confirm they were not expecting any 

additional emission reductions from Texas sources. These letters and associated documents are 

included in Appendix 4-3 of the Texas Regional Haze SIP. Texas stated in the record that it had 

completed its consultation with Louisiana, Arkansas, Missouri, Oklahoma, and Colorado, and 

none of these states has asked it for further emission reductions to help the it meet its reasonable 

progress goals for its Class I area(s). Appendix 4-3 to the Texas regional haze SIP contains the 

official communications from these states to Texas. The following is a summary of the state-bystate review of Texas’ consultation under Section 51.308(d)(3)(i):

Colorado (Great Sand Dunes, Rocky Mountains) TCEQ sent Colorado a letter on March 25, 

2008 with information of impacts of Texas sources on Colorado Class I areas. On June 19, 2008, 

Colorado responded in a letter in which it presented its own impact analyses and stated that 

Texas sources are below the criteria identified in the Colorado SIP (based on regional 

apportionment modeling used to develop the Colorado SIP, PSAT.). In a June 24, 2008, letter, 

Colorado’s Department of Public Health and Environment responded that no further emissions 

reductions were requested of Texas at this time.

Louisiana (Breton). On November 29, 2007, the Louisiana Department of Environmental 

Quality (LDEQ) sent an email that stated it determined that emissions from Texas do not 

contribute to visibility impairment at Breton Wilderness Class I Area in Louisiana. LDEQ stated 

that it will continue to monitor all state and federal rules and control measures and will include 

the necessary emission factors in future modeling. TCEQ sent LDEQ a letter on March 25, 

2008, with information of impacts of Texas sources on Breton. 

New Mexico: (Carlsbad Caverns, Salt Creek, White Mountain, Wheeler Peak). On August 

8, 2008, TCEQ sent a letter to NMED. As of the date of the submission of the Texas regional 

haze SIP, New Mexico had not replied. New Mexico’s regional haze SIP provides additional 

clarification on its consultations. New Mexico acknowledges that the long-term strategies 

adopted by Colorado, Arizona, and Texas in their SIPs and approved by us will include emission 

reductions from a variety of sources that will reduce visibility impairment in New Mexico’s 
46

Class I areas.60

Missouri (Hercules-Glades, Mingo) and Arkansas (Caney Creek, Upper Buffalo). On 

August 26, 2007, Missouri and Arkansas invited states including Texas to a series of consultation 

calls concerning visibility at their four Class I areas. During these calls, a URP was developed 

for each Class I area in Arkansas and Missouri (Caney Creek and Upper Buffalo in Arkansas, 

and Hercules Glades and Mingo in Missouri). The participating states also determined that the 

projected 2018 CENRAP modeling and other findings based on existing and proposed controls 

arising from local, state, and federal requirements indicated that the two Class I areas in

Arkansas and the two Class I areas in Missouri are on the glidepath and are projected to meet the 

URP goals for the first implementation period ending in 2018. Arkansas Department of 

Environmental Quality (ADEQ) and Missouri Department of Natural Resources (MDNR) both 

determined that additional emissions reductions from other states were not necessary to address

visibility impairment at Caney Creek, Upper Buffalo, Hercules-Glades, and Mingo for the first

implementation period ending in 2018, and all states participating in its consultations agreed with 

this.

61

. The TCEQ sent Missouri and Arkansas letters on March 25, 2008, with information of 

impacts of Texas sources on Missouri and Arkansas Class I areas. On April 21, 2008, Missouri 

responded with a letter that stated it had reviewed the TCEQ analysis and attachments and they 

provided results generally consistent with the CENRAP and Missouri modeling and data analysis 

used in developing its plan. Missouri indicated at this time, that emissions reductions from 

Texas were adequate. In an April 21, 2008, letter, Missouri’s Department of Natural Resources 

responded that no further emissions reductions were requested of Texas. Arkansas responded on 

June 10, 2008. It concurred with the CENRAP PSAT modeling assessment, and those results 

were used to set Arkansas’ RPGs for its 2 Class I areas. Arkansas stated it was not depending on 

additional reductions at this time to meet its RPGs. In a June 10, 2008, letter, the ADEQ

responded that no further emissions reductions were requested of Texas.

Oklahoma (Wichita Mountains). The TCEQ attended Oklahoma’s three consultation calls 

held in August and September 2007. On August 3, 2007, ODEQ sent TCEQ a letter that noted 

the Wichita Mountains is not projected to be on its glide path and that, from “the work done 

through the CENRAP process, it is clear that Wichita Mountains suffers from significant 

anthropogenic impacts from Texas.” The letter requested that the ODEQ be able to comment on 

BACT determinations for Prevention of Significant Deterioration (PSD) sources that 

significantly impact the Wichita Mountains and requested that Class I impact reviews be

required for all proposed PSD sources within 300 kilometers of a Class I area. The letter cited 

several CAA visibility provisions related to PSD visibility requirements and the visibility 

transport requirement under Section 110 of the CAA. The ODEQ asked that the TCEQ “fully 

consider its comments” about applicable CAA provisions. In a response letter dated October 15, 

2007, the TCEQ agreed that the modeling shows Texas to be a “significant source of visibility 

impairing pollution on the Wichita Mountains.” The TCEQ agreed to notify the ODEQ, along 

with the relevant FLM, whenever modeling indicates that a proposed source significantly 

impacts Wichita Mountains. The TCEQ also responded to the ODEQ’s PSD comments on 

 

60 New Mexico Regional Haze SIP, Page 4 at: 

http://www.nmenv.state.nm.us/aqb/reghaz/documents/Proposed_RH_SIP_309g_03312011.pdf

61 See Appendix 4_3d of the Texas regional haze SIP for July 23, 2007, letter from ADEQ and MDNR to 

participants in the Central Class I Areas Consultation Process summarizing this series of consultation calls.
47

potential impacts of new and modified sources. The TCEQ did not agree to the ODEQ’s 300 

kilometer PSD review request, and cited the need for us to adopt significant impact levels for 

Class I reviews so that there is a consistent approach to requiring Class I reviews. During the 

interim, the TCEQ committed to working with the federal land managers on mutually acceptable 

criteria for determining when a proposed PSD source should conduct a Class I review. The 

TCEQ also stated, in conjunction with work being done through CENRAP, that there will be 

significant reductions in the next few years and visibility at Wichita Mountains would improve 

as a result of those reductions. 

The TCEQ sent Oklahoma another consultation letter, dated March 25, 2008. In that letter, the 

TCEQ provides a detailed assessment, based on CENRAP modeling, of the impact of Texas 

sources on the visibility at the Wichita Mountains. Specifically, the letter contained information 

related to the 2002 visibility impacts and the 2018 projected visibility impacts from all source 

areas on the one Class I area in Oklahoma and the impacts apportioned to be from Texas’ 

sources. TCEQ indicated that CENRAP produced these results using particulate matter source 

apportionment technology (PSAT) modeling and relative response factors according to our

regional haze modeling guidance. The data were from the August 27, 2007, version of the PSAT 

tool that Environ produced for CENRAP. The TCEQ also provided a table of sources of 

particular interest to Wichita Mountains, identified by the TCEQ due to their emissions and 

location within the AOI, developed as part of the CENRAP planning process. This table 

included 2002 and 2018 projected annual emissions from CENRAP, as well as the sources 

distance from Wichita Mountains. The TCEQ concluded by requesting ODEQ’s concurrence on 

that assessment, and, “that your State is not depending on any additional reductions from Texas 

sources in order to meet your reasonable progress goal(s).” 

On May 12, 2008, the ODEQ responded to that letter and concurred with the “information in that 

letter.” The ODEQ stated that it developed its RPG through CENRAP deliberation. ODEQ’ 

stated that it does not anticipate reductions beyond those that Texas already planned to 

implement and upon which the CENRAP studies relied. However, the ODEQ stated that its 

RPG falls short of the uniform rate of improvement necessary to reach the default natural 

visibility conditions in 2064. The ODEQ stated that reaching its progress goal requires 

constraints on emissions from new, modified, and existing sources. Referring back to its August 

2007 letter, the ODEQ restated its request that the TCEQ perform an analysis of any new or 

modified PSD subject source within 300 km of the Wichita Mountains to conduct an analysis for 

its impact on the Wichita Mountains, following FLM guidance, as appropriate. It restated its

request to review BACT determinations for proposed sources projected to significantly 

contribute to visibility impairment at the Wichita Mountains. The TCEQ committed to provide 

the ODEQ the opportunity to comment on control determinations for Texas facilities that having 

the potential to significantly impair visibility at the Wichita Mountains. The ODEQ asked to be 

informed of actual emissions reductions achieved from CAIR. Please see our description of the 

Texas-Oklahoma consultations, based on the information in Oklahoma’s record, in our OK TSD 

and as summarized in Section VI.B.2 of the Federal Register notice for this proposed action, for 

additional consultation details.
48

EPA Findings:

Section 51.308(d)(3)(i) requires that Texas consult with other states if its emissions are 

reasonably anticipated to contribute to visibility impairment at that state’s Class I area(s), and 

that Texas consult with other states if those states’ emissions are reasonably anticipated to 

contribute to visibility impairment at Big Bend and Guadalupe Mountains. The TCEQ’s 

consultations with other states that impact Texas Class I areas are described and reviewed in 

Section B.6 above and Section V.C.5 of the Federal Register notice. 

During consultation, Colorado and Louisiana determined that Texas impacts on their Class I 

areas were not significant enough to warrant additional controls for this planning period. Based 

on the 2018 CENRAP projections, Missouri and Arkansas62 established RPGs for their Class I 

areas that provide for a slightly greater rate of improvement in visibility than needed to attain the 

URP, and determined that the projected emission reductions included in the model were 

adequate, and that it was not reasonable to request additional controls from Texas at this time. 

The record supports a finding that these consultations are acceptable.

The CENRAP source apportionment modeling indicates that Texas emissions, particularly SO2

emissions from point sources, impact a number of Class I areas outside of Texas. Texas SO2

emissions are projected in 2018 to have the largest visibility impacts, in terms of both absolute 

contribution to extinction and percent contribution to total extinction, at the Wichita Mountains 

in Oklahoma.63 As we discuss above, both the ODEQ and the TCEQ agreed that sources in 

Texas significantly impact the visibility at the Wichita Mountains in Oklahoma, and that the 

impacts from point sources in Texas is several times greater than the impact from Oklahoma’s 

own point sources. Furthermore, the ODEQ asserted in its consultations with the TCEQ, and 

elsewhere in its regional haze SIP, that it would not be able to reach natural visibility by 2064 

without additional reductions from Texas sources. During consultations, the ODEQ specifically 

requested additional information on controls identified through the CENRAP process that were 

cost-effective and had the potential to result in visibility improvements due to their location and 

size. In addition, the ODEQ had information that other sources with existing controls still have a 

large potential to impact visibility and should be analyzed for control upgrades. 

Ultimately, however, Texas determined that no additional controls at its sources were warranted 

during the first planning period to help achieve reasonable progress at the Wichita Mountains, 

and Oklahoma did not specifically request any additional reductions from Texas sources. As a 

result, Oklahoma set RPGs for the Wichita Mountains that do not reflect any reasonable 

emission reductions from Texas beyond those that will be achieved by compliance with other 

requirements of the CAA. During the notice-and-comment period on Oklahoma’s proposed SIP, 

several commenters criticized Oklahoma for not requesting additional reductions from Texas. 

They argued that without such reductions, Oklahoma would not make reasonable progress 

toward the national goal at the Wichita Mountains. In responding to these comments, Oklahoma 

acknowledged that sources in Texas had significant impacts on visibility in the Wichita 

 

62

 We note, however, that we disapproved Arkansas’ RPGs because it did not perform an adequate four-factor 

analysis of their own sources and because we disapproved BART determinations in the State. See 76 FR 64186 

(October 17, 2011).

63 See Tables 25 and 26 and Figure 10 below in Section D.3.
49

Mountains, but maintained that it did not have the regulatory authority to require emission 

reductions in other states. Oklahoma asserted that only Texas and we could require such 

reductions. We believe that the technical analysis developed by Texas (See Section B.2. for a 

description and our review of the technical analysis developed by Texas to evaluate controls for 

Texas sources) did not provide the information necessary to identify reasonable reductions from 

its sources, and inform consultations in order to develop coordinated management strategies with 

Oklahoma. As a result, we believe that Texas did not incorporate those potential reasonable 

reductions into its long-term strategy and those reductions were not included in the reasonable 

progress goal established by Oklahoma for Wichita Mountains. Consequently, we believe the 

submittal supports a finding that TCEQ did not adequately address the requirement in Section

51.308(d)(3)(i) to “consult with the other state(s) in order to develop coordinated emission 

management strategies.” 

D.2. Share of Reductions in Other States’ Progress Goals: 40 CFR 51.308(d)(3)(ii)

Section 51.308(d)(3)(ii) requires that if Texas emissions cause or contribute to impairment in 

another state’s Class I area, it must demonstrate that it has included in its regional haze SIP all 

measures necessary to obtain its share of the emission reductions needed to meet the progress 

goal for that Class I area. Section 51.308(d)(3)(ii) also requires that since Texas participated in a 

regional planning process, it must ensure it has included all measures needed to achieve its 

apportionment of emission reduction obligations agreed upon through that process. As we state 

in the Regional Haze Rule, Texas’ commitment to participate in CENRAP bind it to secure 

emission reductions agreed to as a result of that process, unless it proposes a separate or 

supplemental process and performs its consultations on the basis of that process.

State Submittal:

Chapter 4, Chapter 11

As stated elsewhere, Texas relied on implementation of existing and ongoing control measures 

for their LTS, consistent with the CENRAP projections for Texas emissions relied upon in 

establishing the RPGs on the member states. 

EPA Findings

As mentioned in Section IV of the Federal Register notice, the control measures in an upwind 

state’s long term strategy should be sufficient to obtain its share of reductions needed to meet an 

approved, or approvable, progress goal in a downwind state’s SIP. In this instance, the 

CENRAP technical analysis was sufficient to demonstrate that Texas as a whole, and particular 

source categories such as EGU point sources, had a significant impact on the visibility at the 

Wichita Mountains and other Class I areas. The analysis also estimated that large emission 

reductions could be achieved at some of these sources by implementing potentially cost-effective 

controls. For example, Alpine Geophysics64 estimated the cost of SO2 controls at the two units 

at Big Brown to be approximately $1,500/ton. They also projected that these controls would 

 

64 CENRAP contracted with Alpine Geophysics to conduct an evaluation of possible additional point-source add-on 

controls for sources in CENRAP States. See Section B.2 for more information. 
50

achieve greater than 40,000 tpy in SO2 emission reductions. Alpine Geophysics estimated the 

cost of SO2 controls at two units at Monticello to be approximately $1,850/ton. They also 

projected that these controls would achieve greater than 35,000 tpy in SO2 emission reductions. 

The TCEQ recognized that some aspects of CENRAP’s technical analysis were limited and 

therefore attempted to supplement that analysis, which it used as the technical basis for both its 

reasonable progress and long-term strategy demonstrations, as we describe in Section V.C of the 

Federal Register notice. As it states with regard to the development of its long-term strategy on 

page 10-4 of its regional haze SIP, “[t]he TCEQ used the control strategy analysis completed by 

the CENRAP as the starting point for the analysis of additional controls.” In fact, the TCEQ 

went beyond the CENRAP analysis by contemplating additional controls, applying a lower costeffectiveness threshold and estimating the visibility benefit from the identified control set. The 

TCEQ incorporated this supplemental analysis in the development of its RPG and its long-term 

strategy. It used this analysis to inform its decision not to control any additional sources, 

including those that impact the visibility at the Wichita Mountains and other Class I areas in 

other states. 

However, we believe the technical analysis developed by CENRAP and supplemented by the 

TCEQ did not provide the information needed to evaluate the reasonableness of controls on those 

sources with the largest potential to impact visibility at the Wichita Mountains.65 We believe this 

information was critical for ODEQ to use in setting the RPG and critical for TCEQ when

determining its fair share of reductions. 

We find that Texas did not develop an adequate technical basis to inform consultations with 

Oklahoma and to identify reasonable reductions from its sources. As a result, we find that Texas 

did not incorporate those reasonable reductions into its long-term strategy. Texas’ “share of the 

emission reductions needed to meet the progress goal” for the Wichita Mountains was not 

properly established because of the inadequacies in its technical analyses, which compromised

its consultations with Oklahoma. For these reasons we believe the record supports a finding that 

TCEQ did not adequately meet the requirement in Section 51.308(d)(3)(ii).

D.3. Technical Basis for the Long Term Strategy: 40 CFR 51.308(d)(3)(iii) – (iv)

Section 51.308(d)(3)(iii) requires that Texas document the technical basis, including modeling, 

monitoring and emissions information, on which it is relying to determine its apportionment of 

emission reduction obligations necessary for achieving reasonable progress in each mandatory 

Class I Federal area it affects. It may meet this requirement by relying on technical analyses 

developed by the regional planning organization and approved by all state participants. Texas 

must identify the baseline emissions inventory on which its strategies are based. The baseline 

emissions inventory year is presumed to be the most recent year of the consolidated periodic 

emissions inventory.

Section 51.308(d)(3)(iv) requires that Texas identify all anthropogenic sources of visibility 

impairment considered by it in developing its long-term strategy. Texas should consider major 

and minor stationary sources, mobile sources, and area sources.

 

65 See Section B.2. for a detailed description and our review of the CENRAP and TCEQ analyses.
51

The TCEQ addressed the requirements of Sections 51.308(d)(3)(iii) – (iv) mainly by relying on 

technical analyses developed by CENRAP and approved by all state participants, but it also 

performed an additional analysis building upon the work of the regional planning organization in 

order to evaluate additional controls, as described in Section B.2 above and Section V.C.2 of the 

Federal Register notice. The emissions inventory used in the regional haze technical analyses 

was developed by CENRAP with assistance from Texas. The 2018 emissions inventory was 

developed by projecting 2002 emissions and applying reductions expected from federal and state

regulations affecting the emissions of the visibility-impairing pollutants NOx, PM, SO2, and 

VOCs. By analogy, with regard to development of the long-term strategy, the BART Guidelines 

direct states to exercise judgment in deciding whether VOCs and NH3 impair visibility in their 

Class I area(s).66 CENRAP performed modeling sensitivity analyses, which demonstrated that 

anthropogenic emissions of VOC and NH3 do not significantly impair visibility in the CENRAP 

region. Therefore, Texas did not consider NH3 among visibility-impairing pollutants and did not 

further evaluate NH3 and VOC emissions sources for potential controls under BART or 

reasonable progress.

State Submittal

D.3.a. Emission Inventory

D.3.a.i. Texas’ 2002 Emission Inventory

The TCEQ and CENRAP developed an emission inventory for five inventory source 

classifications: point, area, non-road and on-road mobile sources, and biogenic sources for the 

baseline year of 2002. Texas’ 2002 emissions inventory provides estimates of annual emissions 

for haze producing pollutants by source category, based on information in Section 7.0 of Texas’

regional haze SIP.

Methodologies used in developing the 2002 emissions inventory are documented in Appendix 7-

1 of the Texas regional haze SIP and the technical support document for the CENRAP emission 

inventory development. 67 See the CENRAP Modeling TSD for a summary and our review of 

how the 2002 emissions inventory was constructed. State, tribal, and local agencies submitted 

information to the national emissions inventory for 2002 which formed the basis of the CENRAP 

emissions inventory. A CENRAP contractor supplemented this inventory with non-point source 

inventories developed for CENRAP. These CENRAP-specific inventories addressed agricultural 

and prescribed burning, on-road and non-road mobile sources, agricultural tilling and livestock 

dust, and agricultural ammonia. The Texas point sources are defined as industrial, commercial, 

or institutional sites that meet the reporting requirements of 30 Texas Administrative Code 

(TAC) §101.10. Permitted point sources in Texas are required to submit annual emissions 

inventories. The reported data are drawn from TCEQ’s computer-based State of Texas Air 

Retrieval system (STARS). This data, along with similar data available from other states make 

the basis of the point source inventory. A CENRAP contractor provided further refinement of 

the information. Emissions from area sources are typically estimated on a source category or 

 

66

 70 FR 39114 (July 6, 2005). 

67 Technical Support Document for CENRAP Emissions and Air Quality Modeling to Support Regional Haze SIP, 

included as Appendix 8-1 of the Texas regional haze SIP
52

group basis. The area source inventory includes data from the EPA 2002 NEI and inventories 

prepared by TCEQ, CENRAP and other CENRAP states. Sonoma Technology prepared 

additional inventories of prescribed burning, agricultural dust, and soil agricultural ammonia for 

the CENRAP region.68 The TCEQ also prepared an inventory of oil and gas production area 

sources based on county-level production data and emission estimates for gasoline distribution, 

dry cleaning and wildfires. The Western Regional Air Partnership (WRAP) provided an oil and 

gas production inventory for states within the WRAP that included a number of states in the 

CENRAP modeling domain. These emissions were consolidated by Pechan and CEP.69 A 

CENRAP contractor consolidated the area-source inventories from these various inventory 

sources, conducted additional quality assurance, and worked with the TCEQ to revise this 

consolidated inventory. Another CENRAP contractor removed selected sources from the 

consolidated area inventories to process them as separate subcategories to allow specialized 

processing to facilitate particulate source apportionment within the Comprehensive Air Quality 

Model with extensions (CAMx) model. 

The TCEQ notes that the area source SO2 emissions used by the CENRAP in their modeling are 

significantly higher than the 15,633 tons per year (tpy) reported by the TCEQ for 2002. The 

difference is industrial and residential coal combustion which was erroneously included in the 

CENRAP inventory. Texas determined that CENRAP’s modeled emissions estimates are not 

expected to significantly impact visibility estimates for 2018 because of the relatively small 

contribution from these Texas sources on Class I areas. 70

To enhance accuracy of transportable dust estimates, the contractor also applied road and 

fugitive dust transport factors71 to appropriate area source emissions. The TCEQ and CENRAP 

developed the on-road mobile source emissions inventory for 2002 with contractor support on a 

county basis. For Texas counties, county-level Highway Performance Monitoring System 

(HPMS) annual average VMT data were used. CENRAP contractors used our NONROAD 

model to prepare and develop broad emissions estimates for the non-road mobile source 

inventory generated the non-road emissions inventory. A CENRAP contractor ran our Biogenic 

Emissions Inventory System 3 (BEIS3) model to generate a biogenic emissions inventory. 

 

68 Reid, S.B. et al. 2004. Emission Inventory Development for Mobile Sources and Agricultural Dust Sources for 

the Central States. Sonoma Technology, Inc. 

(http://cenrap.sonomatech.com/CENRAP_Mobile/FinalReport.pdf).; Reid, S.B et al. 2004. 

Research and Development of Planned Burning Emission Inventories for the Central States Regional Air 

Planning Association. Sonoma Technology, Inc. 

(http://cenrap.sonomatech.com/CENRAP_PlannedBurnData/FinalReport.pdf).; Coe, D.L. and 

S.B. Reid. 2003. Research and Development of Ammonia Emission Inventories for the Central States Regional 

Air Planning Association. Sonoma Technology, Inc. 

69 Pechan and CEP. 2005. Consolidation of Emissions Inventories (Schedule 9; Work Item 3). E.H. Pechan and 

Associates, Inc. and Carolina Environmental Program (CEP), University of North Carolina(UNC), 

(http://www.cenrap.org/html/projects.php?mode=subcatdownload&id=50); Pechan and CEP. 2005. Refinements 

of CENRAP’s 2002 Emissions Inventories (Schedule 9; Work Item 3). E.H. Pechan and Associates, Inc. and 

CEP, UNC. (http://www.dnr.mo.gov/env/apcp/docs/appendixh-3.pdf)

70 See page 7-1 of the Texas Regional Haze SIP

71

 Using Methodology to Estimate the Transportable Fraction of Fugitive Dust Emissions for Regional and Urban 

Scale Air Quality Analyses, Thompson G. Pace, US EPA (8/3/2005 Revision), available at 

http://www.epa.gov/ttn/chief/emch/dustfractions/transportable_fraction_080305_rev.pdf
53

Texas’ 2002 emissions inventory is summarized in Tables 18 and 19:

Table 18. Texas’ 2002 Emissions Inventory (tons/year)

CO NOx SO2 TOG72 PM2.5 PM10 NH3

Area 908,407 280,811 111,853 1,163,549 347,490 1,552,824 380,057

Point 498,467 600,725 821,961 207,695 46,789 80,947 2,609

Non-road 

mobile 1,210,158 242,551 21,828 148,952 15,089 15,556 56

On-road 

mobile 4,098,391 664,163 18,814 309,707 11,275 15,476 21,599

Total 6,715,423 1,788,250 974,457 1,829,902 420,642 1,664,803 404,321

Table 19. Texas’ 2002 Biogenic Emissions Inventory (tons/year)

Biogenic NOx CO VOC

184,896 755,941 4,033,760

D.3.a.ii. Texas’ 2018 Emission Inventory

In general, the TCEQ used a combination of our Economic Growth Analysis System (EGAS 5), 

our mobile emissions factor model (MOBILE 6), our off-road emissions factor model 

(NONROAD), and the IPM for electric generating units. 73 

More specifically, CENRAP developed emissions for five inventory source classifications: point, 

area, non-road and on-road mobile sources, and biogenic sources. CENRAP used its 2002 

emission inventory, described above, to estimate emissions in 2018. CENRAP contractors, with 

input from us, compiled the growth and control assumptions and factors used to estimate pointsource emissions in 2018 from the inventory for 2002. This included EGUs, internal combustion 

engines and other non-EGU point sources. CENRAP states provided data for the area source and 

non-road mobile emissions inventory for 2018, to which a CENRAP contractor applied area 

source growth and control factors. Similarly, CENRAP states provided data for the emissions 

inventory for 2018, to which a CENRAP contractor applied source growth and control factors for 

locomotives, aircraft, and commercial marine vessels. These control factors accounted for 

federal standards for commercial marine vessels and locomotives. For the remaining non-road 

mobile categories, the contractor ran our NONROAD 2004 model for 2018. This accounted for 

estimated growth in equipment populations and incorporated anticipated effects of most final 

federal standards, including the Tier 4 compression-ignition engine standards and the exhaust 

emissions standards for large spark-ignition engines, compression-ignition marine engines, and 

land-based recreational engines. The TCEQ and CENRAP also developed the on-road mobile 

 

72

 TOG is total organic gas, which includes total hydrocarbons.

73 Appendix 7-2 of the Texas regional haze SIP: Integrated Planning Model Projections of Electric Generating Unit 

Emissions for the Regional Haze State Implementation Plan
54

source emissions inventory for 2018 with contractor support. Biogenic emissions were held 

constant from the 2002 emission inventory.

All control strategies expected to take effect prior to 2018 are included in the projected emission 

inventory. See the CENRAP Modeling TSD for a summary and our review of how the 2018 

emissions inventory was constructed. Texas’ 2018 emissions inventory is summarized in Table 

20, based on information in Section 7.0 of the Texas regional haze SIP.

Table 20. Texas’ 2018 Emissions Inventory

CO NOx SO2 TOG74 PM2.5 PM10 NH3

Area 899,497 274,663 114,138 1,420,681 354,712 1,557,089 562,379

Point 542,128 525,174 625,068 283,290 80,577 121,733 6,790

Non- Road 1,921,674 167,451 6,988 119,855 10,588 11,498 239

On-Road 2,710,631 148,387 2,925 125,234 5,337 5,337 32,191

Total 6,073,930 1,115,676 749,119 1,949,060 451,214 1,695,657 601,598

Methodologies used in developing the 2018 emissions inventory are documented in Appendix 7-

1 of the Texas regional haze SIP and the technical support document for the CENRAP emission 

inventory development. CENRAP and the TCEQ used this and other state’s 2018 emission 

inventories to construct visibility projection modeling for 2018.

D.3.b. Visibility Projection Modeling

Chapter 8

Chapter 8 of the Texas regional haze SIP discuss the modeling methods and protocol used by the 

TCEQ and CENRAP in developing the assessment. Chapter 7 describes the baseline and 2018 

emission inventories used by the TCEQ. A detailed description and discussion of the model 

selection, modeling protocol, quality assurance, performance evaluation, emission inventory 

development and data used in the regional haze analysis can be found in the CENRAP Modeling 

TSD and references therein. A short summary is provided below:

CENRAP performed modeling for the regional haze long-term strategy for its member states, 

including Texas. The modeling analysis is a complex technical evaluation that began with 

selection of the modeling system. CENRAP used the following modeling system:

 Meteorological Model: The Pennsylvania State University/National Center for 

Atmospheric Research (PSU/NCAR) Mesoscale Meteorological Model (MM5) is a 

non-hydrostatic, prognostic meteorological model routinely used for urban- and 

regional- scale photochemical, PM2.5, and regional haze regulatory modeling studies.

 

74 TOG is total organic gas, which includes total hydrocarbons.
55

 Emissions Model: The Sparse Matrix Operator Kernel Emissions (SMOKE) 

modeling system generates hourly gridded speciated emission inputs of mobile, nonroad mobile, area, point, fire and biogenic emission sources for photochemical grid 

models.

 Air Quality Model: Our Models-3/ Community Multiscale Air Quality (CMAQ) 

modeling system is a photochemical grid model capable of addressing ozone, PM, 

visibility and acid deposition at a regional scale. The photochemical model selected 

for this study was CMAQ version 4.5. It was modified through CENRAP with a 

module for Secondary Organics Aerosols (SOA) in an open and transparent manner 

that was also subjected to outside peer review. The Comprehensive Air Quality 

Model with extensions (CAMx) Version 4.40 model, applied using similar options as 

used by CMAQ, was used as a secondary corroborative model. CAMx was also 

utilized with its Particulate Source Apportionment Technology (PSAT) tool to 

provide source apportionment of predicted nitrate and sulfate aerosol concentrations. 

CMAQ and CAMx modeling of regional haze in the CENRAP region for 2002 and 2018 was 

carried out on a grid of 36x36 kilometer (km) cells that covers the continental United States, 

portions of Canada and Mexico, and portions of the Atlantic and Pacific Oceans along the east 

and west coasts. Selection of a representative period of meteorology is crucial for evaluating 

baseline air quality conditions and projecting future changes in air quality due to changes in 

emissions of visibility-impairing pollutants. CENRAP conducted an in-depth analysis which 

resulted in the selection of the entire year of 2002 (January 1-December 31) as the best period of 

meteorology available for conducting the modeling. The CENRAP states’ modeling, described 

in Section 8 of the Texas Regional Haze SIP, was developed consistent with our guidance.75,76

CENRAP examined the model performance of the regional modeling for the areas of interest 

before determining whether the CMAQ model results were suitable for use in the regional haze 

assessment of the LTS and for use in the modeling assessment. The 2002 modeling efforts were 

used to evaluate air quality/visibility modeling for a historical episode—in this case, for calendar 

year 2002—to demonstrate the suitability of the modeling systems for subsequent planning, 

sensitivity, and emissions control strategy modeling. Model performance evaluation is 

performed by comparing output from model simulations with ambient air quality data for the 

same time period to determine whether the model’s performance is sufficiently accurate to 

justify using the model for simulating future conditions. In keeping with the objective of the 

CMAQ modeling platform, the air quality model performance was evaluated using graphical and 

statistical assessments based on ambient measurements of PM species, gas-phase species and wet 

deposition from various monitoring networks and databases for the 2002 base year. CENRAP 

 

75

 Guidance on the Use of Models and Other Analyses for Demonstrating Attainment of Air Quality Goals for 

Ozone, PM2.5, and Regional Haze, (EPA-454/B-07-002), April 2007, located at 

http://www.epa.gov/scram001/guidance/guide/final-03-pm-rh-guidance.pdf

 Emissions Inventory Guidance for Implementation of Ozone and Particulate Matter National Ambient Air 

Quality Standards (NAAQS) and Regional Haze Regulations, August 2005, updated November 2005 (“our

Modeling Guidance”), located at http://www.epa.gov/ttnchie1/eidocs/eiguid/index.html, EPA-454/R-05-001

76

 Modeling protocol for the CENRAP 2002 Annual Emissions and Air Quality Modeling, included as Appendix 8-

2 of the Texas Regional Haze SIP.
56

used a diverse set of statistical parameters from our Modeling Guidance to stress and examine 

the model and modeling inputs. Once CENRAP determined the model performance to be 

acceptable, it used the model to determine the 2018 RPGs using the current and future year air 

quality modeling predictions, and compared the RPGs to the URP. The modeling assessment 

predicts future levels of emissions and visibility impairment used to support the LTS and to 

compare predicted, modeled visibility levels with those on the URP. The results of CENRAP’s 

visibility projection modeling are discussed in the section that follows and in the CENRAP 

Modeling TSD.

77

 

Visibility impairment in Class I areas is the result of local air pollution as well as transport of 

regional pollution across long distances. CENRAP used CAMx with its Particulate Source 

Apportionment Technology (PSAT) tool to provide source apportionment by geographic region 

and major source category. A PSAT Visualization Tool was developed that can be used by 

states, Tribes and others to generate displays of the contributions of source regions and 

categories to visibility impairment for the average of the worst 20 percent and best 20 percent 

days at each CENRAP and nearby Class I areas.78 The pollutants causing the highest levels of 

light extinction are associated with the sources causing the most visibility impairment. 

D.3.b.i. Sources of Visibility Impairment in Big Bend National Park

Tables 21 and 22 summarize the modeled contributions to total extinction at Big Bend for each 

source category and species for 2002 and 2018, respectively.79 Visibility impairment at Big 

Bend in 2002 on the worst 20% days is largely due to SO4 from point sources that contributes 

17.7 Mm-1of the total extinction of 47.79 Mm-1. The largest contributions of SO4 come from 

Texas (5.50 Mm-1 from all source categories), boundary conditions outside the modeling domain 

(5.82 Mm-1) and Mexico (8.28 Mm-1). Overall, the largest source region contributions to 

visibility impairment in 2002 are from Mexico (12.75 Mm-1), Texas (11.87 Mm-1), and outside 

the modeling domain (12.27 Mm-1).

In 2018, Texas, Mexico and sources outside the modeling domain are projected to continue to 

contribute the most to visibility impairment at Big Bend. The 2018 projection shows the total 

extinction at Big Bend for the worst 20% days is estimated to be 44.06 Mm-1, a reduction of 

approximately 8% from 2002 levels. Anticipated reductions of SO4 emissions primarily from 

point sources in Texas, the Eastern United States, Indiana, Illinois, Kansas, Alabama and Ohio 

will account for a decrease of 2.73 Mm-1 in total light extinction (1.55 Mm-1decrease from Texas 

point sources). Even with these expected reductions in SO4 emissions from point sources in 

2018, extinction due to point sources will continue to be the highest contributor to visibility 

impairment on the worst 20% days, accounting for over one third of the total extinction. 

 

77

 See the Technical Support Document for CENRAP Emissions and Air Quality Modeling to Support Regional 

Haze SIP, included as Appendix 8-1 of the Texas Regional Haze SIP for further detail on the modeling analyses 

performed by CENRAP.

78 Data downloaded from http://www.cenrap.org/html/projects.php. And available in the docket for this action as 

CENRAP_PSAT_Tool_ENVIRON_Aug27_2007.mdb

79

 The species contributing to visibility extinction at Big Bend and Guadalupe Mountains, shown on Tables 21, 22, 

23 and 24, are the following: sulfate (SO4), nitrate (NO3), primary organic aerosols (POA), elemental carbon (EC), 

soil dust, and coarse mass (CM). These species’ precursors are SO2, NOx, and in some cases, NH3 and VOCs.
57

Visibility impairment from all Texas sources will decrease by 1.90 Mm-1, primarily due to 

expected reductions from point sources. Figure 6 below shows the CENRAP 2018 projection 

PSAT results in percent contribution to total extinction for each source region and each source 

type. Figure 7 shows the percent contribution to total extinction from point sources in each 

source region. 80

Table 21. Projected light extinction for 20% worst days at Big Bend Wilderness Area in 2002 

(Mm-1)

Total1 Point Natural On-Road Non-Road Area

SO4 26.10 17.70 0.02 0.28 0.45 1.82

NO3 2.05 0.55 0.33 0.36 0.23 0.30

POA 5.81 0.10 0.08 0.04 0.09 0.83

EC 2.12 0.01 0.03 0.10 0.32 0.45

SOIL 2.54 0.28 1.14 0.01 0.00 1.00

CM 7.03 0.02 5.52 0.00 0.07 1.23

Sum 47.79 18.66 7.12 0.80 1.16 5.63

1Totals include contributions from boundary conditions and secondary organic matter but 

exclude contribution from Rayleigh scattering 

Table 22. Projected light extinction for 20% worst days at Big Bend Wilderness Area in 2018 

(Mm-1)

Total1 Point Natural On-Road Non-Road Area

SO4 23.00 15.15 0.01 0.04 0.20 1.84

NO3 1.99 0.63 0.38 0.12 0.16 0.35

POA 5.61 0.14 0.06 0.02 0.08 0.67

EC 1.81 0.02 0.02 0.02 0.23 0.29

SOIL 2.54 0.32 1.13 0.01 0.00 0.97

CM 7.03 0.02 5.42 0.00 0.07 1.33

Sum 44.06 16.27 7.03 0.20 0.74 5.46

1Totals include contributions from boundary conditions and secondary organic matter but 

exclude contribution from Rayleigh scattering 

 

80 Data downloaded from http://www.cenrap.org/html/projects.php. And available in the docket for this action as 

CENRAP_PSAT_Tool_ENVIRON_Aug27_2007.mdb
58

Figure 6. 2018 projected percent contribution from all sources at Big Bend
59

Figure 7. 2018 projected percent contribution from point sources at Big Bend

D.3.b.ii. Sources of Visibility Impairment in Guadalupe Mountains National Park

Tables 23 and 24 summarize the contributions to total extinction at Guadalupe Mountains for 

each source category and species for 2002 and 2018, respectively. Visibility impairment at

Guadalupe Mountains in 2002 on the worst 20% days is largely due to SO4 from point sources 

and course material from natural and area sources. The largest contributions of SO4 come from 

Texas (4.28 Mm-1 from all source categories), boundary conditions outside the modeling domain 

(1.90 Mm-1) and Mexico (3.21 Mm-1). Overall, the largest source region contributions to 

visibility impairment in 2002 are from Texas (16.62 Mm-1), New Mexico (3.49 Mm-1), Mexico 

(7.90 Mm-1), and source outside the modeling domain (4.16Mm-1). 

In 2018, sulfate and course material from Texas, Mexico, New Mexico and sources outside the 

modeling domain are projected to continue to contribute the most to visibility impairment at the 

Guadalupe Mountains. The 2018 projection shows the total extinction at the Guadalupe 

Mountains for the worst 20% days is estimated to be 44.32Mm-1, a reduction of approximately 

7% from 2002 levels. Anticipated reductions of SO4 emissions primarily from point sources in 

Texas, the Eastern United States, Indiana, Alabama and Ohio will account for a decrease of 2.02 

Mm-1 in total light extinction (0.68 Mm-1decrease from Texas point sources). Even with these 
60

expected reductions in SO4 emissions from point sources in 2018, extinction due to point sources 

will still be a significant contributor to visibility impairment on the worst 20% days, accounting 

for over one fourth of the total extinction. Visibility impairment from all Texas sources will 

decrease by 1.29 Mm-1, primarily due to expected reductions from point sources. Figure 8 below 

shows the CENRAP 2018 projection PSAT results in percent contribution to total extinction for 

each source region and each source type. Figure 9 shows the percent contribution to total 

extinction from point sources in each source region. 81

Table 23. Projected light extinction for 20% worst days at Guadalupe Mountains in 2002 (Mm-1)

Total1 Point Natural On-Road Non-Road Area

SO4 15.94 12.10 0.02 0.22 0.33 1.36

NO3 3.67 1.09 0.40 0.79 0.55 0.52

POA 2.75 0.24 0.19 0.10 0.16 1.61

EC 1.19 0.01 0.04 0.15 0.34 0.51

SOIL 4.37 0.41 1.29 0.02 0.00 2.41

CM 16.04 0.19 7.75 0.02 0.39 6.60

Sum 47.80 14.05 9.68 1.31 1.76 13.00

1Totals include contributions from boundary conditions and secondary organic matter but 

exclude contribution from Rayleigh scattering 

Table 24. Projected light extinction for 20% worst days at Upper Guadalupe Mountains in 2018 

(Mm-1)

Total1 Point Natural On-Road Non-Road Area

SO4 13.65 10.11 0.02 0.03 0.10 1.40

NO3 3.32 1.18 0.44 0.27 0.37 0.65

POA 2.38 0.29 0.15 0.05 0.13 1.30

EC 0.86 0.02 0.04 0.04 0.23 0.37

SOIL 4.37 0.51 1.29 0.02 0.00 2.31

CM 16.02 0.20 7.69 0.03 0.38 6.65

Sum 44.32 12.31 9.62 0.43 1.22 12.68

1Totals include contributions from boundary conditions and secondary organic matter but 

exclude contribution from Rayleigh scattering 

 

81 Data downloaded from http://www.cenrap.org/html/projects.php. And available in the docket for this action as 

CENRAP_PSAT_Tool_ENVIRON_Aug27_2007.mdb
61

Figure 8. 2018 projected percent contribution from all sources at Guadalupe Mountains 
62

Figure 9. 2018 projected percent contribution from point sources at Guadalupe Mountains 

D.3.b.iii. Texas’ Contribution to Visibility Impairment in Class I Areas Outside the State

CAMx PSAT results were also utilized to evaluate the impact of Texas emission sources in 2002 

and 2018 on visibility impairment at Class I areas outside of the state. Texas sources are 

modeled to have contributions to the Class I areas in a number of nearby states. Tables 25 and 

26 summarize the contribution from Texas emissions of sulfate, nitrate and total visibility

degradation at nearby states’ Class I areas for the 20% worst days in 2002 and 2018, as modeled 

by CENRAP and shown in Section 11.2 of the Texas regional haze SIP,

82 and compares them to 

the total extinction due to all emissions of sulfate and nitrate from all source regions. The 

contributions from Texas sources on total visibility impairment decreases from 2002 to 2018 at 

all impacted Class I areas shown in the tables below. Texas’ impacts on other Class I areas in 

these nearby states are less than the impacts for the areas that are shown in the tables below for 

each state. Figure 10 below is constructed from the data in Table 26.

 

82 See Appendix E of the Technical Support Document for CENRAP Emissions and Air Quality Modeling to Support 

Regional Haze SIP, included as Appendix 8-1 of the Texas Regional Haze SIP for PSAT modeling results
63

Table 25. Contribution from Texas Emissions to Visibility Impairment (Mm-1) at Class I areas 

on 20% Worst Days in 2002

Sulfate Nitrate Total

Class I area State Texas

Total, all 

source 

areas Texas

Total, all 

source 

areas Texas

Total, all 

source 

areas

Salt Creek New Mexico 4.79 16.75 3.05 11.15 13.41 52.50

White Mountain New Mexico 2.78 10.51 0.53 3.05 7.40 32.91

Wheeler Peak New Mexico 0.76 5.27 0.22 1.64 1.85 21.96

Wichita Mountains Oklahoma 13.98 49.12 7.89 23.72 28.15 100.03

Great Sand Dunes Colorado 0.66 5.84 0.02 1.94 1.25 27.88

Rocky Mountains Colorado 0.30 7.69 0.08 5.17 0.58 32.13

Caney Creek Arkansas 11.55 87.05 1.49 13.78 14.89 133.93

Upper Buffalo Arkansas 4.41 83.18 0.27 13.30 5.19 131.79

Hercules-Glades Missouri 3.48 87.94 2.56 17.91 6.59 140.05

Mingo Missouri 0.69 102.52 1.18 27.24 2.01 159.83

Breton Louisiana 3.55 96.83 0.15 8.29 4.20 123.99
64

Table 26. Contribution from Texas Emissions (Mm-1) to Visibility Impairment at Class I areas 

on 20% Worst Days in 2018

Sulfate Nitrate Total

Class I area State Texas

Total, 

all 

source 

areas Texas

Total, all 

source 

areas Texas

Total, all 

source 

areas

Salt Creek New Mexico 3.50 13.75 2.43 9.81 10.24 46.67

White Mountain New Mexico 2.37 8.92 0.47 2.68 6.22 29.80

Wheeler Peak New Mexico 0.79 5.00 0.19 1.48 1.59 20.80

Wichita Mountains Oklahoma 9.68 33.33 6.08 18.10 20.79 75.56

Great Sand Dunes Colorado 0.65 5.32 0.02 1.83 1.11 26.77

Rocky Mountains Colorado 0.30 6.52 0.06 4.28 0.51 29.41

Caney Creek Arkansas 7.24 48.95 0.83 7.57 9.74 85.84

Upper Buffalo Arkansas 2.74 45.38 0.18 9.22 3.38 86.16

Hercules-Glades Missouri 2.51 50.63 1.51 12.35 4.45 92.49

Mingo Missouri 0.53 54.45 0.64 19.14 1.28 99.24

Breton Louisiana 2.66 68.63 0.16 8.20 3.23 94.06
65

Figure 10. Projected 2018 total extinction and Texas contribution at Class I areas in Texas and 

other states

EPA Findings:

We find that the record supports a finding that the TCEQ’s 2002 and 2018 emission inventory 

are acceptable and that Texas has satisfied the requirement of Section 51.308(D)(3)(iv) regarding 

identifying all anthropogenic sources of visibility impairment considered by it in developing its 

long-term strategy, and that it considered major and minor stationary sources, mobile sources, 

and area sources. 

However, as we discuss in Section IV.C. of the Federal Register notice for this proposed action, 

given the plain language of the CAA, we believe Section 51.308(d)(3)(iii) requires states to 

consider the four factors used in determining reasonable progress in developing the technical 

basis for both their own Class I areas and downwind Class I areas.. This documentation is 

necessary so that the interstate consultation process can proceed on an informed basis, and so 

that downwind states can properly assess whether any additional upwind emission reductions are 

necessary to achieve reasonable progress at their Class I areas. Therefore, in determining its 
66

long-term strategy under Section 51.308(d)(3)(iii), we believe that Texas had an obligation to 

conduct an appropriate technical analysis, and demonstrate through that technical analysis 

(required under (d)(3)(ii)), that it provided its fair share of emissions reductions to Oklahoma. In 

addition, we believe that Texas was required through consultation under Section 51.308(d)(3)(i) 

to provide a reasoned technical analysis, on which it based its long-term strategy, to Oklahoma. 

The regulations further provide that:

The State must document the technical basis, including modeling, monitoring and 

emissions information, on which the State is relying to determine its apportionment of 

emission reduction obligations necessary for achieving reasonable progress in each 

mandatory Class I Federal area it affects. States may meet this requirement by relying on 

technical analyses developed by the regional planning organization and approved by all 

State participants.83

Thus, States may meet this requirement by relying on reasonable progress four-factor analyses 

and associated technical documentation prepared by a regional planning organization on behalf 

of its member States, to the extent that such analyses and documentation were conducted. If the 

technical analysis performed by the regional planning organization was missing, flawed, or 

incomplete, it could not be solely relied upon by a state when developing or documenting the 

technical basis of its long-term strategy. The technical data prepared through the regional 

planning organization process is typically designed to inform the member states of their 

apportionment of the visibility impact at Class I areas, project future visibility conditions, and to 

provide high-level information on potential control strategies to inform consultations and the 

four-factor analysis necessary to establish RPGs. These analyses may require additional 

refinements by the states in development of their regional haze SIPs to address impacts and 

potential controls of specific sources or source categories. As we discuss in Sections V.C., and 

V.E.2 of the Federal Register notice, the TCEQ recognized that some aspects of CENRAP’s 

technical analyses were limited because it supplemented that analysis with its own. It used this 

analysis to inform its decision not to control any additional sources, including those that impact 

the visibility at the Wichita Mountains and other Class I areas in other states. For the reasons 

discussed at length in Section V.C.2 of the Federal Register notice and Section B.2 above, we 

believe this analysis was inadequate and did not provide the information necessary to determine 

the reasonableness of controls at those sources in Texas that significantly impact visibility at the 

Wichita Mountains or other Class I areas. Based on CENRAP data and information shared 

during consultations, included in the record, the ODEQ and the TCEQ had evidence of some 

potential controls at certain EGUs in Northeast Texas that were estimated to be cost-effective 

even according to the TCEQ’s own cost threshold and would result in large emission reductions 

within the source type and region with the largest projected impacts at Wichita Mountains. The 

ODEQ and the TCEQ were also aware of additional large emission sources in Texas that should 

have been further evaluated for potential controls. Although both the ODEQ and the TCEQ had 

abundant evidence that Texas coal fired EGUs had a significant impact on the visibility at 

Oklahoma and Texas Class I areas, the development of this technical information by either party

did not progress to the point where the impacts of individual sources could be determined or to 

the point where the information on cost-effective controls identified for some sources could be 

refined from a high level state. 

 

83 40 C.F.R. Section 51.308(d)(3)(iii).
67

Consequently, we find that the record supports a finding that Texas did not adequately address 

the requirements in Section 51.308(d)(3)(iii) to “document the technical basis, including 

modeling, monitoring and emissions information, on which the state is relying to determine its 

apportionment of emission reduction obligations necessary for achieving reasonable progress in 

each mandatory Class I Federal area it affects.” 

To determine whether additional controls were reasonable in Texas, we believed it necessary to 

undertake a cost/control and visibility analysis which is presented in our FIP TSD. In the FIP 

TSD, we provide detailed information concerning which sources within Texas are the largest 

contributors to the visibility degradation at the Wichita Mountains and at other Class I areas, and 

which sources we believe have cost-effective controls. 

D.4. Consideration of Long Term Strategy Factors: 40 CFR 51.308(d)(3)(v)

As required by Section 51.308(d)(3)(v), Texas must consider, at a minimum, the following 

factors in developing its long-term strategy:

(A) Emission reductions due to ongoing air pollution control programs, including 

measures to address RAVI; 

(B) Measures to mitigate the impacts of construction activities; 

(C) Emissions limitations and schedules for compliance to achieve the reasonable 

progress goal; 

(D) Source retirement and replacement schedules;

(E) Smoke management techniques for agricultural and forestry management 

purposes including plans as currently exist within the state for these purposes;

(F) Enforceability of emissions limitations and control measures; and 

(G) The anticipated net effect on visibility due to projected changes in point, area, and 

mobile source emissions over the period addressed by the long-term strategy.

State Submittal:

Chapter 11

Texas’ long-term strategy incorporates emission reductions due to a number of ongoing air 

pollution control programs. This includes enforceable emissions limitations, compliance 

schedules, administrative orders, the issuance and enforcement of permits limiting emissions 

from all known major sources in Texas state rules which specifically limit targeted emissions 

sources and categories, and several other ongoing air pollution control programs. The TCEQ has 

promulgated rules in order to administer these programs. These rules govern the TCEQ’s 

permitting process, including PSD and BACT requirements, and implementation of federal 

requirements. The TCEQ also has promulgated rules that limit emissions in order to comply 

with the NAAQS, which have ancillary benefits of visibility improvements. Other air pollution 

control programs, including federal mobile emissions programs, the Clean Air Interstate Rule, 

Maximum Achievable Control Technology, and Refinery Consent Decrees are implemented by 

TCEQ, have similar ancillary benefits of visibility improvements. 
68

The TCEQ addresses the long term strategy LTS factors in 40 CFR 51.308(d)(3)(v)(A)-(G) as 

follows:

D.4.a. Reductions due to ongoing air pollution programs

The Texas long-term strategy incorporates emission reductions due to a number of ongoing air 

pollution control programs, which are summarized below. 

Clean Air Interstate Rule (CAIR)

Texas implements CAIR. See the Federal Register notice for this proposed action for a 

discussion of CAIR and the Cross State Air Pollution Rule (CSAPR). 

Mobile Source Emissions

Texas implements a number of federal and state rules related to mobile source emissions, which 

are summarized in Appendix 11-2 of the Texas Regional Haze SIP, and include:

• Federal Phase II reformulated gasoline Dallas-Fort Worth and HoustonGalveston-Brazoria.

• Tier 2 vehicle emission standards and federal low-sulfur gasoline

• National low emissions vehicle standards (NLEV)

• Heavy-duty diesel standards

• Lawn and garden equipment

• Tier 2 heavy-duty diesel equipment

• Locomotive engine standards

• Compression ignition standards for vehicles and equipment

• Recreational marine engine standards

• Texas Vehicle Inspection and Maintenance Programs

• The Low Income Vehicle Repair Assistance, Retrofit, and Accelerated Vehicle 

Retirement Program

Point Source NOx Emissions

Texas implements some major point sources NOx rules, which are summarized in Appendix 11-

3 of the Texas Regional Haze SIP, and include:

• Texas Senate Bill 7, which required emission reductions at EGUs built before 

Texas BACT emission control requirements went into effect in 1972. This bill 

required a 50% reduction in NOx from 1997 levels and a 25% reduction in SO2 

for 1997 levels by May 1, 2003 at grandfathered EGUs.

• NOx emission reductions related to ozone SIP revisions for the HoustonGalveston-Brazoria area, Beaumont-Port Arthur area, Austin, Northeast Texas, 

and East Texas. 
69

Miscellaneous Programs

• SO2 reductions under EPA refinery consent decrees

• Texas Low Emissions Diesel (TxLED) Program to reduce pollutants from diesel 

engines

• Texas Emissions Reduction Plan (TERP) to reduce NOx and PM emissions by 

encouraging older road and non-road engine replacement.

• Rules to control opacity and sulfur emissions, such as 30 TAC Chapters 111 and 

112.

• Texas Best Available Control Technology (BACT ). 

The TCEQ states that the FLMs for Big Bend and Guadalupe Mountains, or other Class I areas 

that are impacted by emissions from Texas sources, have not identified any Reasonably 

Attributable Visibility Impairment (RAVI) caused by Texas sources. Consequently, Texas does 

not have any measures in place or a requirement to implement RAVI. 

D.4.b. Measures to mitigate the impacts of construction activities

Section 51.308(d)(3)(v)(B) requires that Texas consider measures to mitigate the impacts of 

construction activities in developing its long-term strategy. The TCEQ notes that State Rule 30 

TAC 111.145, Construction and Demolition, requires precautions to control dust emissions from 

construction operations and other activities.84 It also notes that water pollution control 

requirements to prevent pollution from storm runoff and mud and dirt tracked from construction 

sites reduces the amount of fine soil material suspended in the air from traffic in these areas. The 

TCEQ determined that no additional measures were needed to mitigate the impacts of 

construction activities for purposes of visibility improvement.

D.4.c. Emissions limitations and schedules for compliance

Section 51.308(d)(3)(v)(C) requires that in developing its long-term strategy, Texas consider 

emissions limitations and schedules of compliance to achieve the RPGs. No newly adopted 

source specific measures were identified to achieve the RPGs established by Texas. The TCEQ 

determined that implementation of existing and ongoing control measures are adequate to 

achieve the RPGs established by it and other CENRAP states. 

D.4.d. Source retirement and replacement schedules

Section 51.308(d)(3)(v)(D) requires that Texas consider source retirement and replacement 

schedules in developing its long-term strategy. Retirement and replacement schedules were 

taken into account, to the extent possible, when developing inputs for the IPM that was used in 

the CENRAP modeling analysis. Units that the TCEQ knew were going to be shut down under 

enforceable actions at the time the modeling was performed were removed from the future year 

emission inventory. 

 

84

 Approved into the SIP on January 18, 1994, at 59 FR 02532.
70

D.4.e. Smoke management techniques 

Section 51.308(d)(3)(v)(E) requires that Texas consider smoke management techniques for 

agricultural and forestry management purposes in developing its long-term strategy. The TCEQ 

examined the data and modeling for the worst 20% days at Big Bend and the Guadalupe 

Mountains and determined that smoke from agricultural burning and wildfires in Texas are not a 

large contributor to visibility impairment at these Class I areas. The TCEQ also determined that 

agricultural burning and wildfires in Texas are not significant contributors to visibility 

impairment at Class I areas in nearby states. Because of the relatively low contribution of smoke 

from Texas to visibility impairment, Texas decided that certifying a smoke management plan as 

part of this SIP revision was unnecessary. The Texas Forest Service (TFS) coordinates fire and 

smoke management issues in Texas and have developed a voluntary plan under which all land 

managers in Texas, including the National Park Service, inform the TFS prior to performing 

prescribed burns. Texas also has an outdoor burning rule (30 TAC Chapter 111, subchapter B)85

that includes requirements for allowable prescribed burning. Texas counties also have the 

authority to prohibit open burning in times of drought. Appendix 11-1 of the Texas Regional 

Haze SIP provides information on the following smoke management plans and the outdoor 

burning rule:

 Texas Wildfire Protection Plan 

 Texas Forest Service Smoke Management System 

 30 TAC Chapter 111, Subchapter B: Outdoor Burning 

 Big Bend National Park Fire Management Plan 

 Guadalupe Mountains National Park Fire Management Plan 

 Big Thicket National Preserve Fire Management Plan 

 Lyndon B. Johnson National Historical Park Fire Management Plan 

 Padre Island National Seashore Fire Management Plan 

 San Antonio Missions National Historical Park Fire Management Plan.

The TCEQ found that the current rules, policies, and plans (including smoke management plans 

of the NPS and other federal agencies) are adequate to meet the long-term strategy. 

D.4.f. Enforceability of emissions limitations and control measures

Section 51.308(d)(3)(v)(F) requires that Texas ensure the enforceability of emission limitations 

and control measures used to meet RPGs. The TCEQ has rules in place to ensure the 

enforceability of its emission limitations. This includes rules that govern TCEQ’s permitting 

process for major and minor sources, Prevention of Significant Deterioration (PSD) provisions, 

and BACT. The TCEQ has the authority to issue permits to all major and minor point sources in 

Texas, as they are currently defined at 30 TAC Ch. 116. Each permit must contain enforceable 

limitations on emissions of various defined pollutants, including those which cause or contribute 

to regional haze at the Texas Class I areas and Class I areas in other states. The TCEQ included 

information describing their legal authority and applicable laws in the submitted Texas regional 

haze SIP following the executive summary. 

 

85

 Approved into the SIP on April 28, 2009, at 74 FR 19144.
71

D.4.g. The anticipated net effect on visibility due to projected changes in emissions

Section 51.308(d)(3)(v)(G) requires that in developing its long-term strategy, Texas consider the 

anticipated net effect on visibility due to projected changes in point, area, and mobile source 

emissions over the period addressed by the long-term strategy. In developing its regional haze 

SIP, the TCEQ relied on the CENRAP’s 2018 modeling projections. As described above, 

CENRAP used its 2002 emissions inventory as the starting point for its 2018 emissions 

inventory. The 2018 emissions inventory was designed to capture the anticipated changes in 

point, area, and mobile sources emissions over the period addressed by the long-term strategy. 

EPA Finding:

For the reasons describe above in this section, we find the following:

We believe that the record supports a finding that Texas has satisfied Section 51.308(d)(3)(v)(A), 

regarding the consideration of emission reductions due to ongoing air pollution control 

programs, including measures to address reasonably attributable visibility impairment.

We believe that the record supports a finding that Texas has satisfied Section 51.308(d)(3)(v)(B), 

regarding measures to mitigate the impacts of construction activities.

We believe the record supports a finding that Texas has not satisfied this requirement under 

Section 51.308(d)(3)(v)(C), regarding emissions limitations and schedules for compliance to 

achieve the RPGs for Big Bend and the Guadalupe Mountains. Please see the technical 

discussion we present in Section B and Section V.C. of the Federal Register notice regarding the 

development of the Texas RPGs, as the TCEQ applied the same technical basis to the 

development of its long-term strategy. As with its RPGs, we believe the record supports a 

finding that this analysis is inadequate as it does not provide the information necessary to 

determine the reasonableness of controls at those sources in Texas that significantly impact 

visibility at the Wichita Mountains.

We believe the record supports a finding that Texas has satisfied Section 51.308(d)(3)(v)(D), 

regarding sources retirement and replacement schedules.

We believe the record supports a finding that Texas has satisfied Section 51.308(d)(3)(v)(E), 

regarding smoke management techniques for agricultural and forestry management purposes 

including plans as currently exist within the state for these purposes.

We believe the record supports a finding that Texas has satisfied Section 51.308(d)(3)(v)(F), 

regarding the enforceability of emissions limitations and control measures.

As we discuss in Section E, we believe the record supports a finding that the TCEQ has met its

obligation to develop a statewide inventory of emissions, including future projected emissions. 

We believe that these projected changes in emissions were adequately implemented in 

CENRAP’s 2018 modeling, and therefore believe the record supports a finding that Texas has 
72

satisfied Section 51.308(d)(3)(v)(G).

E. Monitoring Strategy/Other SIP Requirements 40 CFR 51.308(d)(4)

Texas must submit with the SIP a monitoring strategy for measuring, characterizing, and 

reporting of regional haze visibility impairment that is representative of all mandatory Class I 

Federal areas within it. This monitoring strategy must be coordinated with the monitoring 

strategy required in Section 51.305 for reasonably attributable visibility impairment. 

Compliance with this requirement may be met through participation in the Interagency 

Monitoring of Protected Visual Environments network. The SIP must also provide for the 

following: 

(i) The establishment of any additional monitoring sites or equipment needed to 

assess whether reasonable progress goals to address regional haze for all 

mandatory Class I Federal areas within Texas are being achieved.

(ii) Procedures by which monitoring data and other information are used in 

determining the contribution of emissions from within Texas to regional haze 

visibility impairment at mandatory Class I Federal areas both within and outside 

the state.

(iii) For a state with no mandatory Class I Federal areas, procedures by which 

monitoring data and other information are used in determining the contribution of 

emissions from within the state to regional haze visibility impairment at 

mandatory Class I Federal areas in other states.

(iv) The SIP must provide for the reporting of all visibility monitoring data to the 

Administrator at least annually for each mandatory Class I Federal area in the 

state. To the extent possible, Texas should report visibility monitoring data

electronically.

(v) A statewide inventory of emissions of pollutants that are reasonably anticipated to 

cause or contribute to visibility impairment in any mandatory Class I Federal area. 

The inventory must include emissions for a baseline year, emissions for the most 

recent year for which data are available, and estimates of future projected 

emissions. The state must also include a commitment to update the inventory 

periodically.

(vi) Other elements, including reporting, recordkeeping, and other measures, 

necessary to assess and report on visibility.

State Submittal

Chapter 6 and 7

As Section 51.308(d)(4) notes, compliance with this requirement may be met through 
73

participation in the IMPROVE network, which applies to the monitors at the Big Bend and

Guadalupe Mountains. The TCEQ stated its intention to rely on the IMPROVE network for 

complying with the regional haze monitoring requirement in our Regional Haze Rule for the 

current and future regional haze implementation periods. The primary monitoring network for 

regional haze in CENRAP is the Interagency Monitoring of Protected Visual Environments 

(IMPROVE) network. FLMs responsible for Class I areas joined us in 1985 in response to the 

1977 CAA Amendments to form the IMPROVE Program. The IMPROVE Steering Committee 

consists of representatives from the FLMs, us, and regional-state agencies At the direction of the 

National Park Service, the Cooperative Institute for Research in the Atmosphere, at Colorado 

State University’s Foothills Campus in Fort Collins, Colorado, maintains the network plan on the 

IMPROVE Internet Web site.86 The primary objectives of the IMPROVE Web site are to 

provide federal, state, and air quality regulatory agencies as well as the general public access to 

IMPROVE data, data products, and metadata fully describing the IMPROVE database, including 

characteristics and history of all network sites. The website allows users to query data, review 

reports, and communicate with different members of the IMPROVE Program.

Section 51.308(d)(4)(i) requires the establishment of any additional monitoring sites or 

equipment needed to assess whether reasonable progress goals to address regional haze for all 

mandatory Class I Federal areas within the state are being achieved. Section 51.308(d)(4)(ii) 

requires that TCEQ establish procedures by which monitoring data and other information are 

used in determining the contribution of emissions from within Texas to regional haze visibility 

impairment at mandatory Class I Federal areas both within and outside the state. The IMPROVE 

program provides an IMPROVE monitor at each of the two Class I areas in Texas, Big Bend and 

Guadalupe Mountains. Because of their location, the monitors are appropriate for determining 

progress in reducing visibility impairment in the Texas Class I areas. The monitoring strategy 

relies on continuation of IMPROVE monitoring at these sites. The TCEQ plans to continue to 

participate in the IMPROVE network through the financial support of the EPA. The IMPROVE 

monitoring program is national in scope, and other states have similar monitoring and data 

reporting procedures, ensuring a consistent and robust monitoring data collection system. 

Section 51.308(d)(4)(iv) requires that the SIP must provide for the reporting of all visibility 

monitoring data to the Administrator at least annually for each mandatory Class I Federal area in 

the state. To the extent possible, Texas should report visibility monitoring data electronically. 

Section 51.308(d)(4)(vi) also requires that TCEQ provide for other elements, including reporting, 

recordkeeping, and other measures, necessary to assess and report on visibility. Again, Texas’

participation in the IMPROVE network ensure the monitoring data is reported at least annually 

and is available for download from the site referenced above.

Section 51.308(d)(4)(v) requires that TCEQ maintain a statewide inventory of emissions of 

pollutants that are reasonably anticipated to cause or contribute to visibility impairment in any 

mandatory Class I Federal area. The inventory must include emissions for a baseline year, 

emissions for the most recent year for which data are available, and estimates of future projected 

emissions. The TCEQ must also include a commitment to update the inventory periodically. 

Please refer to Section D.3, above, where we discuss how the TCEQ has constructed its emission 

inventory. The TCEQ discusses updating the Texas statewide emissions inventories periodically 

 

86

 http://vista.cira.colostate.edu/improve/
74

and review periodic emissions information from other states and future emissions projections in 

Section 6.5, Chapter 7 and Appendix 7-1 of the Texas Regional Haze SIP. Texas also presents 

the 2005 emission inventory, the most recent data available at the time of SIP submittal, in 

Appendix 7-1.

EPA Findings

We find that the submittal supports a finding that Texas has satisfied the requirements of section 

51.308(d)(4).

F. Best Available Retrofit Technology (BART) Requirements: 40 CFR 51.308(e)

F.1. Identification and Analysis of BART: 40 CFR 51.308(e)(1) – (4)

Best Available Retrofit Technology (BART) requirements for regional haze visibility 

impairment. Texas must submit a SIP containing identifying all potential BART eligible 

sources, determine if sources screen out or are subject to BART and include emission limitations 

representing BART and schedules for compliance with BART for each BART eligible source 

that may reasonably be anticipated to cause or contribute to any impairment of visibility in any 

mandatory Class I Federal area, unless it demonstrates that an emissions trading program or 

other alternative will achieve greater reasonable progress toward natural visibility conditions.

The evaluation of whether the Texas Regional Haze SIP contains “adequate emission limitations 

representing BART and schedules for compliance with BART for each BART eligible source 

that may reasonably be anticipated to cause or contribute to any impairment of visibility in any 

mandatory Class I Federal area” is conducted within different modeling approaches to screen 

groups or individual sources as further discussed in the BART TSD for each BART eligible 

source based on visibility impacts. 

State Submittal and EPA Findings

Texas promulgated, and submitted, rule sections that add engineering and control requirements 

for BART on certain affected sources. Texas’s BART rules are codified at 30 TAC 116.1500 –

116.1540 and were included in the TX RH SIP in Appendix 9-2. The rules establish definitions, 

applicability, exemptions, BART, and exemption from BART to implement the requirements of 

40 CFR 51.308(e).

We propose to approve the provisions in Texas’s BART rules at 30 Tex. Admin. Code (TAC) 

116.1500 – 116.1540, with the exception of 30 TAC 116.1510(d). Please refer to the BART 

TSD for a detailed explanation of the TCEQ’s BART analyses submittal and our analysis of it. 

In summary, we find that:

 Texas has satisfied Section 51.308(e)(1)(i), regarding the identification of all BARTeligible sources within the state.

 Texas has satisfied Section 51.308(e)(1)(ii), regarding the determination of BART.

 Sections 51.308(e)(1)(iii) – (v), regarding alternatives to BART emission limits, the 
75

installation of BART not later than 5 years from approval, and the maintenance of BART 

control equipment, do not apply, since no sources were determined to be subject to 

BART.

 Sections 51.308(e)(2) – (3) concerning the use of a trading program or other alternative to 

BART are not applicable to this SIP.

 We propose a FIP to replace Texas’s reliance on CAIR in 30 TAC 116.1510(d) with 

reliance on CSAPR. See below, in our BART TSD and the Federal Register notice for 

detailed explanation of Texas’ reliance on CAIR for SO2 and NOx BART for BARTeligible EGUs under Section 51.308(e)(4)

We propose to approve Texas’ determination of which sources in the State are BART-eligible. 

We also propose to approve Texas’ determination that none of the State’s BART-eligible nonEGUs are subject to the BART requirements because they are not reasonably anticipated to cause 

or contribute to visibility impairment in any Class I areas. We propose to approve the provisions 

in Texas’s BART rules at 30 Tex. Admin. Code (TAC) 116.1500 – 116.1540, with the exception 

of 30 TAC 116.1510(d), which relies on CAIR. With respect to EGUs, we previously issued a 

limited disapproval of the Texas regional haze SIP due to Texas’ reliance on CAIR to satisfy the 

BART requirements. This action does not impact the limited disapproval.

F.1.1 40 CFR 51.308(e)(1)(i)

Texas must submit a SIP containing a list of all BART-eligible sources within the State.

Note: This section is intended to cover the general question of whether the state identified which 

sources were subject to BART. Subsequent sections treat this determination in more detail.

State Submittal

Texas’s BART rule, 30 TAC 116.1500 and 116.1510, and companion definitions related to the 

BART rule, implement the BART requirements of our regional haze rule 51.308(e)(1)(i). The 

Texas BART rule sets out the criteria for identifying BART-eligible sources and incorporates by 

reference the guidelines contained in Appendix Y to 40 C.F.R. Part 51. TCEQ identified sources 

that were BART eligible if they: belonged to one of twenty-six industry source categories (see list 

below); did not operate before 7 August 1962 but were in existence on 7 August 1977. The final 

test for inclusion is based on potential to emit 250 tons per year or more of any visibilityimpairing pollutant in 51.308(e)(1)(i). TCEQ determined that the visibility-impairing pollutants 

in Texas include sulfur dioxide (SO2), nitrogen oxides (NOx), volatile organic compounds 

(VOCs), and particulate matter (PM10 and PM2.5). As a result of CENRAP modeling, TCEQ 

concluded that ammonia was not a significant visibility-impairing pollutant. TCEQ did not have 

a good database of sources with potential emissions, so they relied on the annual emission data 

that point sources provide on actual emissions and identified sources as BART eligible if actual 

emissions were 80% or more of the 250 tpy threshold. TCEQ also used a distance threshold from 

EPA’s two model plants and modified the 50km/500tpy and 100km/1000 tpy. TCEQ used the 

distance of each county to a Class I to determine whether to include a source on the BART 

eligible list. TCEQ used actual emissions and 80% of the applicable threshold test. If the Class 

I area was less than 500 km from the county they used a 200 tpy actual emissions threshold, 500 

– 1000 km they used a 400 tpy actual emissions threshold, and for beyond a 1000 km they used 
76

800 tpy actual emissions threshold. While TCEQ’s use of actuals differs with the use of potential 

emissions, we think the use of 80% and the model plant thresholds is acceptable and conclude 

that TCEQ has adequately identified all BART eligible sources. TCEQ initially determined 

which sources were BART eligible by screening its emissions inventory database to identify 

major facilities with emission units in one or more of the BART categories:

1. Fossil-fuel fired steam electric plants of more than 250 million British thermal 

units (BTU) per hour heat input,

2. Coal cleaning plants (thermal dryers),

3. Kraft pulp mills,

4. Portland cement plants,

5. Primary zinc smelters,

6. Iron and steel mill plants,

7. Primary aluminum ore reduction plants,

8. Primary copper smelters,

9. Municipal incinerators capable of charging more than 250 tons of refuse per day,

10. Hydrofluoric, sulfuric, and nitric acid plants,

11. Petroleum refineries,

12. Lime plants,

13. Phosphate rock processing plants,

14. Coke oven batteries,

15. Sulfur recovery plants,

16. Carbon black plants (furnace process),

17. Primary lead smelters,

18. Fuel conversion plants,

19. Sintering plants,

20. Secondary metal production facilities,

21. Chemical process plants,

22. Fossil-fuel boilers of more than 250 million BTUs per hour heat input,

23. Petroleum storage and transfer facilities with a capacity exceeding 300,000 

barrels,
77

24. Taconite ore processing facilities,

25. Glass fiber processing plants, and

26. Charcoal production facilities.

TCEQ then sent surveys to all the identified sources to obtain or confirm pertinent data and 

information. These emissions units comprise the “BART-eligible sources” listed in Table 2 of 

the TX BART TSD. 

EPA Findings

We propose to approve that TCEQ has adopted regulations to meet and implement the 

requirements of 40 CFR 51.308(e)(1)(i). We find that TCEQ has adequately identified all BARTeligible sources within the State. For full details and our review see Section B of the TX BART 

TSD. 

F.1.2 40 CFR 51.308(e)(1)(ii)

A determination of BART for each BART-eligible source in Texas that emits any air pollutant 

which may reasonably be anticipated to cause or contribute to any impairment of visibility in any 

mandatory Class I Federal area. All such sources are subject to BART. 

State Submittal

Texas’s BART rule, 30 TAC 116.1500, 116.1510 and 116.1520, and companion definitions 

related to the BART rule, implement the BART requirements of our regional haze rule

51.308(e)(1)(ii). Chapter 9 of TCEQ’s SIP included TCEQ’s analysis of all the BART eligible 

sources visibility impacts at Class I areas in Texas and surrounding states. TCEQ used a number 

of different approaches that included CAMx or CALPUFF modeling to assess the impacts and 

determined that all sources were below the screening level and did not cause or contribute to 

impairment of visibility in any mandatory Class I area and thus were screened out from full 

BART applicability/analysis.

EPA Findings

We propose to approve that TCEQ has adopted regulations to meet and implement the 

requirements of 40 CFR 51.308(e)(1)(ii). We find that TCEQ has adequately screened out all 

BART-eligible sources within the State. For full details and our review see Sections C, D, E, and 

F of the TX BART TSD. 

BART Determination: 40 CFR 51.308(e)(1)(ii)(A) 

The determination of BART must be based on an analysis of the best system of continuous 

emission control technology available and associated emission reductions achievable for each 

BART-eligible source that is subject to BART within the State. In this analysis, the State must 

take into consideration the technology available, the costs of compliance, the energy and nonair 

quality environmental impacts of compliance, any pollution control equipment in use at the 

source, the remaining useful life of the source, and the degree of improvement in visibility which 
78

may reasonably be anticipated to result from the use of such technology.

State Submittal

TCEQ did not identify any BART eligible sources that required a BART determination.

EPA Findings

We concur with TCEQ’s conclusions.

BART for Larger Fossil Fuel Power Plants: 40 CFR 51.308(e)(1)(ii)(B)

The determination of BART for fossil-fuel fired power plants having a total generating capacity 

greater than 750 megawatts must be made pursuant to the guidelines in appendix Y of this part 

(Guidelines for BART Determinations under the Regional Haze Rule).

State Submittal

TCEQ screening of primary PM2.5 emissions did not identify any BART eligible sources that 

required a BART determination under this provision. 

EPA Findings

We concur with TCEQ’s conclusions.

De Minimis BART: 40 CFR 51.308(e)(1)(ii)(C)

Texas is not required to make a determination of BART for SO2 or for NOx if a BART-eligible 

source has the potential to emit less than 40 tons per year of such pollutant(s), or for PM10 if a 

BART-eligible source has the potential to emit less than 15 tons per year of such pollutant.

State Submittal

TCEQ utilized these minimum emission levels in screening of sources. No sources were 

identified as subject to BART analysis, so this provision was not utilized. 

EPA Findings

We concur with TCEQ’s conclusions.

F.1.3 Design, Equipment, or Work Practice BART: 40 CFR 51.308(e)(1)(iii)

Texas’s BART rule, did not include this specific provision.

State Submittal

Not Applicable - TCEQ did not prescribe a design, equipment, work practice, or other 

operational standard, or combination thereof, as BART.
79

EPA Findings

Not Applicable.

F.1.4 Installation of BART: 40 CFR 51.308(e)(1)(iv) – (v)

Each source subject to BART must (1) install and operate BART as expeditiously as practicable, 

but in no event later than 5 years after approval of the SIP revision, and (2) maintain the control 

equipment required by this subpart and establish procedures to ensure such equipment is 

properly operated and maintained.

State Submittal

Texas’s BART Rule, 30 TAC 116.1530(a), requires that “each BART-eligible source subject to 

BART shall install and operate BART no later than five years after EPA approves the Texas

Regional Haze SIP.” 30 TAC 116.1530(b) of the RH SIP requires that sources shall obtain 

appropriate permits before installing BART controls. 

EPA Findings

We propose to approve that TCEQ has adopted regulations to meet and implement the 

requirements of 40 CFR 51.308(e)(1)(iv)-(v). We note that TCEQ did not find any sources 

subject to BART. We find that TCEQ has demonstrated it has the authority and enforceable 

mechanisms in place to ensure each source subject to BART will (1) install and operate BART as 

expeditiously as practicable, but in no event later than 5 years after approval of the SIP revision, 

and (2) maintain the control equipment required by this subpart and establish procedures to 

ensure such equipment is properly operated and maintained.

F.2 Alternate Emission Trading Program: 40 CFR 51.308(e)(2)-(3)

Texas’s BART rule, did not include this specific provision.

State Submittal

Not Applicable.

EPA Findings

Not Applicable.

F.3. CAIR for BART: 40 CFR 51.308(e)(4)

Texas also promulgated, and submitted, rule sections that add engineering and control 

requirements for BART on certain affected sources. Texas’s BART rules are codified at 30 TAC 

116.1500 – 116.1540. The rules establish definitions, applicability, exemptions, BART, and 

exemption from BART. On September 22, 2006, we provided substantive comments on Texas’ 
80

proposed BART rules.87 In its final adoption of the rules, the TCEQ adequately addressed all of 

our comments. However, at the time of our comments, CAIR had not yet been vacated by the 

D.C. Circuit. One provision in Texas’s BART rule, 30 TAC 116.1510(d), provides an exemption 

from BART based on CAIR. Specifically, it states “BART-eligible electric generating units 

participating in the Clean Air Interstate Rule Trading Program are not subject to the requirements 

of Section 116.1520 or Section116.1530 of this title for NOX and SO2.”88 We have already 

issued a limited disapproval of the Texas regional haze SIP for its reliance on CAIR. However, 

we determined that CSAPR provides for greater reasonable progress towards the national goal 

than would BART and Texas is included in CSAPR for NOX and SO2. Therefore, our proposed 

FIP to replace reliance on CAIR with reliance on the trading programs of CSAPR as an 

alternative to BART includes a FIP to replace Texas’s reliance on CAIR in 30 TAC 116.1510(d) 

with reliance on CSAPR.

Our proposed regional haze FIP relies on the already promulgated CSAPR FIP for Texas at 40 

CFR 52.2283-84 to satisfy the BART requirement for SO2 and NOx emissions from EGUs. We 

more fully explained the basis for our limited disapproval in that rulemaking and are not taking 

comment on our limited disapproval of Texas’ regional haze SIP in this action.

Background - Our Prior Limited Disapproval of Texas’ Regional Haze SIP Concerning 

CAIR

In 2005, we promulgated CAIR, which required 28 States and the District of Columbia to reduce 

emissions of SO2 and NOX that significantly contribute to, or interfere with maintenance of, the 

1997 NAAQS for ozone and PM2.5.

89

 Also in 2005, we determined that States could rely on 

CAIR to meet certain requirements of the Regional Haze Rule.90 In particular, we amended our 

regulations to provide that States participating in the CAIR cap-and-trade programs under 40 

CFR part 96 pursuant to an EPA-approved CAIR SIP or States that remain subject to a CAIR 

FIP in 40 CFR part 97 need not require affected BART-eligible EGUs to install, operate and 

maintain BART for emissions of SO2 and NOX.91 A number of States, including Texas, relied 

on CAIR in their regional haze SIPs as an alternative to BART for EGU emissions of SO2 and 

NOX and as an element of their long-term strategy. 

Following our determination in 2005 that States could rely on CAIR in their regional haze SIPs, 

the D.C. Circuit Court of Appeals ruled on several petitions challenging CAIR and remanded 

CAIR to us.92 We issued a new rule in 2011 to replace CAIR.93 The Cross-State Air Pollution 

Rule (CSAPR), which replaced CAIR, also requires a number of States to improve air quality by 

reducing SO2 and NOX emissions that cross State lines and significantly contribute to ozone 

and/or fine particulate pollution in other States. We amended our regulations in 2012 to allow 

CSAPR to serve as an alternative to SO2 and NOX BART for EGUs in States in the CSAPR 

 

87

 See Letter from Thomas Diggs, EPA, to Lola Brown, TCEQ (Sept. 22, 2006), attachment W-16 in the TCEQ’s 

March 19, 2009, SIP submittal.

88

 30 TAC 116.1510(d). 

89

 70 FR 25162 (May 12, 2005). 

90

 70 FR 39104 (July 6, 2005). 

91

 40 CFR 51.308(e)(4) (Aug. 6, 2012). 

92 North Carolina v. EPA, 531 F3d 896; modified by 550 F.3d 1176 (D.C. Cir. 2008).

93

 76 FR 48208 (Aug. 8, 2011).
81

region.94 In that same rulemaking, we also finalized a limited disapproval of the regional haze 

SIPs of 14 States, including Texas. Although at the time that we completed our limited 

disapproval of these SIPs, CAIR remained in place pursuant to an order of the D.C. Circuit, we 

explained that as CAIR had been remanded, it remained in place temporarily. We also finalized 

FIPs replacing reliance on CAIR with reliance on CSAPR as an alternative to BART for several 

States but not for Texas.95 We more fully explained the basis for our limited disapproval in that 

rulemaking and are not taking comment on our limited disapproval of Texas’ regional haze SIP 

in this action. 

F.4. Reasonable Progress and BART: 40 CFR 51.308(e)(5)

After a state has met the requirements for BART or implemented emissions trading program or 

other alternative measure that achieves more reasonable progress than the installation and 

operation of BART, BART-eligible sources will be subject to the requirements of paragraph (d) 

of this section, regarding reasonable progress and LTS, in the same manner as other sources.

State Submittal

As described in Section B above, the TCEQ analyzed a number of sources for additional 

reductions under Section 51.308(d), including Texas EGUs that have met the BART 

requirements through participation in CAIR. Texas determined that no source subject to BART 

should be further controlled for reasonable progress or LTS.

EPA Findings

For the reasons we have discussed in the Sections above and in other TSDs, we find that TCEQ 

did not adequately address certain portions of Section 51.308(d), in part, because we do not 

believe the affected BART sources were properly analyzed for inclusion within Texas’ LTS and 

hence its RPGs and Oklahoma’s RPG.

F.5 BART: 40 CFR 51.308(e)(6)

Any BART-eligible facility subject to the requirement under paragraph (e) of this section to 

install, operate, and maintain BART may apply to the Administrator for an exemption from that 

requirement. An application for an exemption will be subject to the requirements of 

§51.303(a)(2)-(h).

Note: This provision of the regional haze rule was not used by TCEQ in the preparation of its 

RH SIP.

G. 2018 Regional Haze SIP Revision: 40 CFR 51.308(f)

Each state identified in Section 51. 300(b)(3),which includes Texas, must revise and submit its 

regional haze SIP revision to EPA by July 31, 2018 and every ten years thereafter. In each SIP 

 

94

 77 FR 33642 (June 7, 2012). 

95

 77 FR 33642, 33643. (June 7, 2012)
82

revision, Texas must evaluate and reassess all of the elements required in paragraph (d) of this 

section, taking into account improvements in monitoring data collection and analysis techniques, 

control technologies, and other relevant factors. In evaluating and reassessing these elements, 

Texas must address the following: 

(1) Current visibility conditions for the most impaired and least impaired days, and 

actual progress made towards natural conditions during the previous 

implementation period. The period for calculating current visibility conditions is 

the most recent five year period preceding the required date of the SIP submittal 

for which data are available. Current visibility conditions must be calculated 

based on the annual average level of visibility impairment for the most and least 

impaired days for each of these five years. Current visibility conditions are the 

average of these annual values.

(2) The effectiveness of the LTS for achieving reasonable progress goals over the 

prior implementation period(s); and 

(3) Affirmation of, or revision to, the reasonable progress goal in accordance with the 

procedures set forth in paragraph (d)(1) of this section. If Texas established a 

RPG for the prior period which provided a slower rate of progress than that 

needed to attain natural conditions by the year 2064, it must evaluate and 

determine the reasonableness, based on the factors in paragraph (d)(1)(i)(A) of 

this section, of additional measures that could be adopted to achieve the degree of 

visibility improvement projected by the analysis contained in the first SIP 

described in paragraph (d)(1)(i)(B) of this section.

State Submittal

TCEQ acknowledged this requirement in Chapter 12 of their Regional Haze SIP.

H. Five Year Progress Report: 40 CFR 51.308(g)

Each state identified in Section 51. 300(b)(3), which includes Texas, must submit a report to the 

Administrator every 5 years evaluating progress towards the reasonable progress goal for each 

mandatory Class I Federal area located within it and in each mandatory Class I Federal area 

located outside it which may be affected by emissions from within it. The first progress report is 

due 5 years from submittal of the initial SIP addressing paragraphs (d) and (e) of this section. 

The progress reports must be in the form of SIP revisions that comply with the procedural 

requirements of Section 51.102 and Section 51.103. Periodic progress reports must contain at a 

minimum the following elements: 

(1) A description of the status of implementation of all measures included in the SIP 

for achieving reasonable progress goals for mandatory Class I Federal areas both 

within and outside Texas.

(2) A summary of the emissions reductions achieved throughout Texas through 
83

implementation of the measures described in paragraph (g)(1) of this section.

(3) For each mandatory Class I Federal area within Texas, it must assess the 

following visibility conditions and changes, with values for most impaired and 

least impaired days expressed in terms of 5-year averages of these annual values.

(i) The current visibility conditions for the most impaired and least impaired 

days; 

(ii) The difference between current visibility conditions for the most impaired 

and least impaired days and baseline visibility conditions; 

(iii) The change in visibility impairment for the most impaired and least 

impaired days over the past 5 years; 

(4) An analysis tracking the change over the past 5 years in emissions of pollutants 

contributing to visibility impairment from all sources and activities within Texas. 

Emissions changes should be identified by type of source or activity. The 

analysis must be based on the most recent updated emissions inventory, with 

estimates projected forward as necessary and appropriate, to account for 

emissions changes during the applicable 5-year period.

(5) An assessment of any significant changes in anthropogenic emissions within or 

outside Texas that have occurred over the past 5 years that have limited or 

impeded progress in reducing pollutant emissions and improving visibility.

(6) An assessment of whether the current SIP elements and strategies are sufficient to 

enable Texas, or other states with mandatory Federal Class I areas affected by 

emissions from it, to meet all established reasonable progress goals.

(7) A review of Texas’ visibility monitoring strategy and any modifications to the 

strategy as necessary.

State Submittal

The TCEQ acknowledged this requirement in Chapter 12 of their Regional Haze SIP. TCEQ 

submitted the first five-year report in March 2014. We are not including our analysis of this SIP 

within this proposed action.

I. Existing SIP Adequacy Determination: 40 CFR 51.308(h)

At the same time Texas is required to submit any 5-year progress report to us in accordance with 

paragraph (g) of this section, it must also take one of the following actions based upon the 

information presented in the progress report: 

(1) If Texas determines that the existing SIP requires no further substantive revision 
84

at this time in order to achieve established goals for visibility improvement and 

emissions reductions, it must provide to the Administrator a negative declaration 

that further revision of the existing SIP is not needed at this time. 

(2) If Texas determines that the SIP is or may be inadequate to ensure reasonable 

progress due to emissions from sources in another state(s) which participated in a 

regional planning process, it must provide notification to the Administrator and to 

the other state(s) which participated in the regional planning process with the 

states. Texas must also collaborate with the other state(s) through the regional 

planning process for the purpose of developing additional strategies to address the 

plan’s deficiencies. 

(3) Where Texas determines that the SIP is or may be inadequate to ensure 

reasonable progress due to emissions from sources in another country, it shall 

provide notification, along with available information, to the Administrator. 

(4) Where Texas determines that the SIP is or may be inadequate to ensure 

reasonable progress due to emissions from sources within the state, the state shall 

revise its SIP to address the plan’s deficiencies within one year. 

State Submittal

TCEQ acknowledged this requirement in Chapter 12 of its Regional Haze SIP. TCEQ submitted

the first five-year report required by Section 51.308(g) March 2014. We are not including our 

analysis of this SIP within this proposed action.

J. Federal Land Manager Coordination: 40 CFR 51.308(i)

(1) By November 29, 1999, TCEQ must identify in writing to the Federal Land Managers the 

title of the official to which the Federal Land Manager of any mandatory Class I Federal 

area can submit any recommendations on the implementation of this subpart including, 

but not limited to: 

(i) Identification of impairment of visibility in any mandatory Class I Federal area(s); 

and

(ii) Identification of elements for inclusion in the visibility monitoring strategy 

required by Section 51.305 and this section.

(2) Texas must provide the Federal Land Manager with an opportunity for consultation, in 

person and at least 60 days prior to holding any public hearing on a SIP (or plan revision) 

for regional haze required by this subpart. This consultation must include the opportunity 

for the affected Federal Land Managers to discuss their: 

(i) Assessment of impairment of visibility in any mandatory Class I Federal area; and 
85

(ii) Recommendations on the development of the reasonable progress goal and on the 

development and implementation of strategies to address visibility impairment.

(3) In developing any SIP (or plan revision), Texas must include a description of how it 

addressed any comments provided by the Federal Land Managers. 

(4) The SIP (or SIP revision) must provide procedures for continuing consultation between 

Texas and Federal Land Manager(s) on the implementation of the visibility protection 

program required by this subpart, including development and review of SIP revisions and 

5-year progress reports, and on the implementation of other programs having the 

potential to contribute to impairment of visibility in mandatory Class I Federal areas.

State Submittal

Chapter 4, Appendix 2-2, Appendix 4-3(g)

Under Section 51.308(i)(2), Texas was obligated to provide the Park Service with an opportunity 

for consultation, in person and at least 60 days prior to holding a public hearing on its regional 

haze SIP. In practice, state environmental agencies have usually provided all federal land 

managers – the Forest Service, the Park Service, and the Fish and Wildlife Service, copies of 

their regional haze SIP, as the federal land managers collectively have reviewed these regional 

haze SIPs. The TCEQ followed this practice and sent its draft of this implementation plan 

revision to the federal land manager staff. The federal land managers were provided a comment 

period of from November 16, 2007, through January 16, 2008. Their comments were provided 

to the public 30 days prior to the public hearing, which the federal land managers were notified 

of, and which occurred on February 19, 2008. 

Section 51.308(i)(3) requires that the TCEQ provide in its regional haze SIP a description of how 

it addressed any comments provided by the federal land managers. The TCEQ has provided that 

information in Appendix 2-2 of its regional haze SIP.

Lastly, Section 51.308(i)(4) specifies the regional haze SIP must provide procedures for 

continuing consultation between the state and federal land managers on the implementation of 

the visibility protection program required by Section 51.308, including development and review 

of implementation plan revisions and 5-year progress reports, and on the implementation of other 

programs having the potential to contribute to impairment of visibility in the mandatory Class I 

Federal areas. 

The TCEQ acknowledges the requirement that FLMs must be consulted in the following 

instances: development and review of implementation plan revisions; review of five-year 

progress reports; and development and implementation of other programs that may contribute to 

impairment of visibility in Class I areas in Section 4.1 of the Regional Haze SIP. 

EPA Findings

Big Bend National Park and Guadalupe Mountains National Park are managed by the National 
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Park Service, which is the Federal Land Manager (FLM) for this Class I area. Although the 

FLMs are very active in participating in the RPOs, the Regional Haze Rule grants the FLMs a 

special role in the review of the Regional Haze SIPs. We view both the FLMs and the state 

environmental agencies as our partners in the regional haze process.

We acknowledge that Section 51.308(i)(1) has been satisfied by all states via communication 

prior to this SIP. 

We find that the TCEQ has satisfied the requirements of Section 51.308(i)(2)-(3) by providing 

the FLMs with an opportunity for consultation, in person and at least 60 days prior to holding 

any public hearing on its Regional Haze SIP, and the TCEQ has addressed the FLM comments in 

its SIP. 

We find that TCEQ has satisfied Section 51.308(i)(4) by acknowledging the requirement to 

continue consultation between it and the FLMs on the implementation of the visibility protection 

program required by Section 51.308(i), including development and review of SIP revisions and 

5-year progress reports, and on the implementation of other programs having the potential to 

contribute to impairment of visibility in mandatory Class I Federal areas.