DAQ-2025-001102

DRAFT
2023 Regional SO2 Emissions and Milestone Report
Submitted [Date]

Wyoming
Nathan McNamara
Wyoming Department of Environmental Quality
Air Quality Division
200 West 17th Street, Suite 3
Cheyenne, Wyoming 82002
Phone: [phone]
[e-mail]
Utah
Glade Sowards
Utah Department of Environmental Quality
Division of Air Quality
195 North 1950 West
Salt Lake City, UT 84114-4820
Phone: [phone]
[e-mail]

New Mexico
Roslyn Higgin
New Mexico Environment Department
Air Quality Bureau
525 Camino de los Marquez, Suite 1
Santa Fe, NM 87505
Phone: [phone]
[e-mail]

Albuquerque-Bernalillo County
Allen Smith
City of Albuquerque
Environmental Health Department
Air Quality Program
P.O. Box 1293
Albuquerque, NM 87103
Phone: [phone]
[e-mail]

Executive Summary

ES-1

2023 Regional SO2 Emissions and Milestone Report
Executive Summary
Under Section 309 of the Federal Regional Haze Rule, nine western states, and tribes within those
states, have the option of submitting plans to reduce regional haze emissions that impair visibility at 16
Class I areas on the Colorado Plateau. Five states – Arizona, New Mexico, Oregon, Utah, and Wyoming –
and Albuquerque-Bernalillo County initially exercised this option by submitting plans to the
Environmental Protection Agency (EPA) by December 31, 2003. Oregon elected to cease participation in
the program in 2006 and Arizona elected to cease participation in 2010. The tribes were not subject to the
deadline and still can opt into the program at any time. Under the Section 309 plans, the three participating
states and Albuquerque-Bernalillo County have tracked the emissions of the applicable stationary sources
as part of the pre-trigger portion of the SO2 Milestone and Backstop Trading Program. The Western
Regional Air Partnership (WRAP) is assisting these states and county with the implementation and
management of the regional emission reduction program. As used in this document, “Section 309 states”
means New Mexico, Utah, Wyoming, and Albuquerque-Bernalillo County. (For CAA purposes, this report
treats Albuquerque-Bernalillo County as a state because it has authority under federal and state law to
administer the CAA separately from the rest of New Mexico).
As part of this program,
Section 309 states must submit
an annual Regional Sulfur
Dioxide (SO2) Emissions and
Milestone Report that compares
emissions to milestones. A
milestone is a maximum level
of annual emissions for a given
year. The states submitted the
first report in 2004 for the
calendar year 2003. Over the
course of the program, the states
have consistently stayed below
the milestones.
From 2003 to 2017
states compared the milestone
to a three-year average of SO2
emissions as required by their State Implementation Plans (SIP). The states’ SIPs require them to compare
the final 2018 regional milestone to 2018 emissions rather than the three-year average. The regional
milestone for 2018 is 141,849 tons. Section 309 of the Regional Haze Rule requires that states continue
showing compliance with the final 2018 milestone beyond the first Regional Haze implementation period.
In this document, the states report the 2023 adjusted emissions as required by Section 309 of the CAA. We
compared the adjusted 2023 emissions to the final 2018 milestone to determine whether the states continue
to meet the milestone. The adjustments to reported emissions were required to allow the basis of current
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50,000
100,000
150,000
200,000
250,000
300,000
350,000
20
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20
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3
20
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20
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7
20
0
9
20
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1
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S
O
2
SO2 Milestones and Emission TrendsNew Mexico, Utah, Wyoming, Albuquerque-Bernalillo
Three Year Average Milestone
Executive Summary

ES-2
emission estimates to be comparable to the emissions monitoring or calculation method used in the most
recent base year inventory.
As presented in Table ES-1, the Section 309 states reported 41,420 tons of SO2 emissions for the
calendar year 2023. The total emissions increased to 50,767 tons of SO2 after adjusting to account for
changes in monitoring, calculation methods, and enforcement actions. The adjustments result in an
additional 9,347 tons of SO2 emissions.
Based on this adjusted annual emissions estimate, Section 309 states determined that emissions in
2023 were below the regional SO2 milestone for 2018. The states’ Section 309 plans contain provisions to
adjust the milestones to account for enforcement actions (to reduce the milestones where an enforcement
action identified that emissions in the baseline period were greater than allowable emissions). Based on
emissions data received from the states and plan requirements regarding adjustments to the milestones, no
enforcement action adjustment is required.
The plans also require that the annual report identify, first, changes in the total number of sources
from year to year and, second, significant changes in a source's emissions from year to year. The
significant emission changes from 2022 to 2023 are included in Section 6 of this report. A list of facilities
added to, or removed from, the list of subject sources in the original base year inventories is included in
Appendix B.
Table ES-1
Overview of 2023 Regional Milestones and Emissions for Section 309 Participating States
2018 Sulfur Dioxide Milestones
Regional 2018 Milestone* .......................................................................................................... 141,849 tons
Adjusted 2018 Milestone ............................................................................................................ 141,849 tons
2023 Sulfur Dioxide Emissions
Reported 2023 Emissions ............................................................................................................. 41,420 tons
Adjustments**
Emission Monitoring, Calculation Methods, and Enforcement Actions ...................... 9,347 tons
Adjusted 2023 Emissions (rounded number) ............................................................................. 50,767 tons
Comparison of Emissions to Milestone
2023 Adjusted Emissions .............................................................................................................. 50,767 tons
Adjusted Three-State 2018 Milestone ...................................................................................... 141,849 tons
Difference (Negative Value = Emissions < Milestone) ............................................................. -91,081 tons
2023 Emissions as Percent of 2018 Milestone .................................................................................... 35.8%
* See the Regional Milestones section of each state's 309 plan.
** See the Annual Emissions Report section of each state's 309 plan.
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2023 Regional SO2 Emissions and Milestone Report
1.0 Introduction
1.1 Background
Under Section 309 of the Federal Regional Haze Rule (40 CFR Part 51), nine western states, and
the tribes within those states, have the option of submitting State Implementation Plans (SIPs) to reduce
regional haze emissions that impair visibility at 16 Class I areas on the Colorado Plateau. Five states —
Arizona, New Mexico, Oregon, Utah, and Wyoming — and Albuquerque-Bernalillo County exercised
this option by submitting SIPs to the EPA by December 1, 2003. In October 2006, when EPA modified
Section 309, Oregon elected to cease participation in the SO2 Milestone and Backstop Trading Program
by not resubmitting SIP under 309. In 2010, Arizona elected to cease participation in the program. The
tribes were not subject to this deadline and still can opt into the program at any time.
Under the Section 309 SIPs, these three states and one local air agency have been tracking
emissions under the pre-trigger requirements of the SO2 Milestone and Backstop Trading Program since
2003. The Western Regional Air Partnership (WRAP) is assisting these states with the implementation
and management of this regional emission reduction program.
Under the milestone phase of the program, Section 309 states have established annual SO2
emissions targets (from 2003 to 2018). These voluntary emissions reduction targets represent reasonable
progress in reducing emissions that contribute to regional haze. If the participating sources fail to meet the
milestones through this voluntary program, then the states will trigger the backstop trading program and
implement a regulatory emissions cap for the states, allocate emissions allowances (or credits) to the
affected sources based on the emissions cap, and require the sources to hold sufficient allowances to
cover their emissions each year.
This report is the twenty-first annual report for the milestone phase of this program. The report
provides background on regional haze and the Section 309 program, the milestones established under the
program, and the emissions reported for 2023. Based on the last twenty years of data, the voluntary
milestone phase of the program is meeting its reasonable progress targets, and emissions are well below
the target levels.
What is Regional Haze?
Regional haze is air pollution that is transported long distances and reduces visibility in national
parks and wilderness areas across the country. Over the years, this haze has reduced the visual range from
145 kilometers (90 miles) to 24 – 50 kilometers (15 – 31 miles) in the East, and from 225 kilometers (140
miles) to 56 – 145 kilometers (35 – 90 miles) in the West. The pollutants that create this haze are sulfates,
nitrates, organic carbon, elemental carbon, and soil dust. Human-caused haze sources include industry,
motor vehicles, agricultural and forestry burning, and windblown dust from roads and farming practices.
What U.S. EPA Requirements Apply?
In 1999, the EPA issued regulations to address regional haze in 156 national parks and wilderness
areas across the country. EPA published these regulations in the Federal Register on July 1, 1999 (64 FR
35714). The goal of the Regional Haze Rule (RHR) is to prevent any future, and remedy any
existing, visibility impairment from anthropogenic air pollution in certain national parks and wilderness
2023 Milestone Report

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areas. It contains strategies to improve visibility over the next six decades and requires states to adopt
implementation plans.
The EPA's RHR provides two paths to address regional haze. One is 40 CFR 51.308 (Section
308) and requires most states to develop long-term strategies out to the year 2064. States must show that
these strategies make "reasonable progress" in improving visibility in Class I areas inside the state and in
neighboring jurisdictions. The other is 40 CFR 51.309 (Section 309), and is an option for nine states —
Arizona, California, Colorado, Idaho, Nevada, New Mexico, Oregon, Utah, and Wyoming — and the 211
tribes located within these states to adopt regional haze strategies for the period from 2003 to 2018. These
strategies are based on recommendations from the Grand Canyon Visibility Transport Commission
(GCVTC) for protecting the 16 Class I areas on the Colorado Plateau. Adopting these strategies
constitutes reasonable progress until 2018. These nine western states and tribes can also use the same
strategies to protect the other Class I areas within their own jurisdictions.
The EPA revised the RHR on July 6, 2005 (70 FR 39104), and again on October 13, 2006 (71 FR
60612) in response to two legal challenges. The October 13, 2006 revisions modified Section 309 to
provide a methodology consistent with the Court's decision for evaluating the equivalence of alternatives
to Best Available Retrofit Technology (BART), such as the alternative Section 309 strategy based on the
GCVTC recommendations.
How Have the WRAP States Responded to EPA Requirements?
Of the nine states, and tribes within those states, that have the option under Section 309 of
participating in a regional strategy to reduce SO2 emissions, five states originally submitted Section 309
SIPs to EPA. These states were Arizona, New Mexico, Oregon, Utah, and Wyoming. In addition,
Albuquerque-Bernalillo County also submitted a Section 309 SIP. Due to legal challenges, EPA did not
approve the initial SIP submittals. EPA did, however, fully approve the regional milestone and backstop
trading program in 2012.
Oregon and Arizona have opted out of submitting a revised Section 309 SIP under the modified
RHR, which leaves three participating states and Albuquerque-Bernalillo County. To date, no tribes have
opted to participate under Section 309, and the other four states of the original nine opted to submit SIPs
under Section 308 of the RHR.
The following summarizes SO2 related elements of the Section 309 process for the participating
Section 309 states:
1. Section 309(d)(4)(i) requires SO2 milestones in the SIP and includes provisions for adjusting
these milestones, if necessary. The milestones must provide for steady and continuing emission
reductions through 2018 and greater reasonable progress than BART.
2. Section 309(d)(4)(iii) requires monitoring and reporting of stationary source SO2 emissions to
ensure the SO2 milestones are met. The SIP must commit to reporting to the WRAP as well as to
EPA.
3. Section 309(d)(4)(iv) requires that a SIP contain criteria and procedures for activating the trading
program within five years if an annual milestone is exceeded. A Section 309 SIP must also
require assessments of the state’s progress in 2013 and 2018.
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4. Section 309(d)(4)(vi)(A) requires that unless and until a revised implementation plan is submitted
in accordance with § 51.308(f) and approved by EPA, the implementation plan shall prohibit
emissions from covered stationary sources in any year beginning in 2018 that exceed the year
2018 milestone.
This report responds to Item 2, above, and provides the annual report that compares the 2023
emissions against the milestones for the states and city that have submitted Section 309 SIPs to EPA.
What Elements Must the Regional SO2 Emissions and Milestone Report Contain?
To facilitate compliance with the Section 309 SIPs, the WRAP has committed to compiling a
regional report on emissions for each year. In accordance with the SIPs, the WRAP will compile the
individual state emission reports into a summary report that includes:
1. Reported regional SO2 emissions (tons/year).
2. Adjustments to account for:
• Changes in emissions monitoring or calculation methods; or
• Enforcement actions or settlement agreements as a result of enforcement actions.
3. As applicable, average adjusted emissions for the last three years (which are compared to the
regional milestone). Per requirements in the Section 309 SIPs, it is understood that a single year
of emissions are used in the report beginning in 2018.
How Is Compliance with the SO2 Milestone Determined?
While the WRAP assists with the preparation of this report, each Section 309 state reviews the
information in the report and proposes a draft determination that the regional SO2 milestone is either met
or exceeded for that year. Each state submits the draft determination for public review and comment, in
accordance with its SIP.
1.2 Report Organization
This report presents the regional SO2 emissions and milestone information required by the 309
SIPs for the states that opted into the program. The report is divided into the following sections, including
two appendices:
• Reported SO2 Emissions in 2023;
• Emissions Adjustments Related to Monitoring Methodology or Enforcement Actions;
• 2023 Adjusted Emissions;
• Enforcement Milestone Adjustments;
• Quality Assurance (Including Source Change Information);
• Milestone Determination;
• Appendix A -- Facility Emissions and Emissions Adjustments; and
• Appendix B -- Changes to SO2 Emissions and Milestone Source Inventory.
2.0 Reported SO2 Emissions in 2023
The Section 309 SIPs require all stationary sources with reported emissions of 100 tons or more
per year in the year 2000, or any subsequent year, to report annual SO2 emissions. Table 1 summarizes
the annual reported emissions from applicable sources in each state. The 2023 reported SO2 emissions for
each applicable source are in Appendix A, Table A-1.
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Table 1. Reported 2023 SO2 Emissions by State
State Reported 2023 SO2 Emissions (tons/year)
Albuquerque-Bernalillo 87
New Mexico 905
Utah 5,046
Wyoming 35,382
TOTAL 41,420
3.0 Emissions Adjustments Related to Monitoring Methodology or
Enforcement Actions
The annual emissions reports for each state include proposed emissions adjustments to ensure
consistent comparison of emissions to the milestone. Each state adjusted the reported emissions levels so
that they are comparable to the levels that would result if the state used the same emissions monitoring or
calculation method used in the base year inventory (2006). The net impact throughout the region, because
of adjustments related to the monitoring methodology, is an increase of 1,342 tons from the reported 2023
emissions.
Utah adjusted the emissions from the Carbon Power Plant due to an enforcement action. As part of Utah’s
BART alternative for NOx, they required that the Carbon Power Plant shut down. Though there is an
actual emissions reduction of 8,005 tons of SO2 per year, the Utah Air Quality Board approved a
Commitment SIP stating that the emissions reductions from the closure will not be counted for both the
SO2 Milestone program and the BART alternative controls. Therefore, an additional 8,005 tons of SO2 are
included in the calculations for this milestone report. Table 2 summarizes the emissions adjustments made
for changes in monitoring methodology or enforcement actions.

2023 Milestone Report

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Table 2. Adjustments for Changes in Monitoring Methodology or Enforcement Actions
State Source
Reported
2023 SO2
Emissions
(tons)
Adjusted
2023 SO2
Emissions
(tons)
Monitoring
Methodology
Adjustment
(tons)
Enforcement
Action
Adjustment
(tons) Description
UT Holcim-Devil's
Slide Plant 129 464 335 Now using CEM data
UT
PacifiCorp --
Carbon Power
Plant
0 8,005 8,005
An Utah Enforceable
Commitment SIP resolves
that SO2 emissions
reductions from the
closure of the Carbon
plant will not be counted
as part of achieving the
SO2 Milestones and as
part of the Alternative to
BART SIP for NOx.
Therefore, 8,005 tons of
SO2 are included in the
emissions totals.
UT
Chevron
Products Co. --
Salt Lake
Refinery
34 880 846
Increase in Adjusted SO2
Emissions is due to a
correction in the
calculation of Adjusted
SO2 Emissions. The
previous formula used to
calculate SO2 included
flowmeters and
engineering judgement
etc. The current formula
for calculating now
incorporates CEM data.
UT
Big West Oil
Company -
Flying J
Refinery
70 231 162 Now using CEM data
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4.0 2023 Adjusted Emissions
The SIPs require multi-year averaging of emissions from 2004 to 2017 for the milestone
comparison. From 2005 to 2017, states compare a three-year average (which includes the reporting year
and the two previous years) with the milestone. For this milestone report the SIPs require a comparison of
2023 emissions with the 2018 milestone. The adjusted emissions for 2023 are 50,767 tons. The following
report sections describe the adjusted milestone determination.
5.0 Enforcement Milestone Adjustments
The SIPs require that each state report on proposed milestone adjustments due to enforcement
actions, which affect baseline year emissions. The purpose of this adjustment is to remove emissions that
occurred above the allowable level in the baseline year from the baseline and the annual milestones. The
enforcement milestone adjustments require an EPA-approved SIP revision before taking effect. There
were no proposed enforcement actions related to milestone adjustments reported for 2023.
6.0 Quality Assurance
The states provided 2023 emissions data based on their state emissions inventories. States used
additional quality assurance (QA) procedures for this report to supplement the normal QA procedures the
states follow for their emissions inventories. First, each state submitted a source change report, and
second, the states compared their inventory data for utility sources against 40 CFR Part 75 Acid Rain
Program monitoring data.
6.1 Source Change Report
The SIPs require that this annual SO2 emissions and milestone report include a description of
source changes or exceptions report to identify the following:
• Any new sources that were not contained in the previous calendar year's emissions report, and an
explanation of why the sources are now included in the program.
• Identification of any sources that were included in the previous year's report and are no longer
included in the program, and an explanation of why this change has occurred.
• An explanation for emissions variations at any applicable source that exceeds ± 20% from the
previous year.
Appendix B provides a list of all sources added or removed from the program inventory in this
and previous reporting years.
Table 3 provides explanations for the emissions variations from applicable sources from 2022 –
2023 that are greater than 20%. Plants with variations greater than 20% but reported emissions of less
than 20 tons in both 2022 and 2023, are not included in Table 3. Information on these plants is provided
in Appendix A.
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Table 3. Sources with an Emissions Change of > ±20% from the Previous Year
State
County
FIPS
State
Facility
Identifier Plant Name
Reported
2022 SO2
Emissions
(tons)
Reported
2023 SO2
Emissions
(tons) % Change
Description Change > ±20%
2022 to 2023
NM 15 350150024 Agave Energy Co./Agave Dagger
Draw Gas Plant AI211 926 299 -68%
The decrease in emissions was related to reducing flaring
on the amine waste gas system. Redundant acid gas
injection compressors were put online at the plant to
ensure if one unit went down on an automated shutdown,
that the redundant unit would pick up the load and
continue injecting acid gas into the disposal well rather
than having the system overpressure and route to flare.
NM 15 350150002
Frontier Field Services /Empire Abo
Plant [Old name: Arco
Permian/Empire Abo Plant; BP
America Production] AI 191
142 186 31%
An increase in the volume of flared gas in 2023 versus
2022. The H2S content of the gas went down slightly in
2023, but the volumes were up 34%, resulting in an
overall 31% SO2 emissions increase.
NM 15 350150011 DCP Midstream/Artesia Gas Plant 21 35 67% Valve on the acid gas injection pump failure.
NM 25 350250035
DCP Midstream/Linam Ranch Gas
Plant [Old name: GPM GAS/LINAM
RANCH GAS PLANT]
36 10 -73% H2S concentration in the fuel gas was reduced in 2023.
NM 25 350250060
VERSADO GAS PROCESSORS,
LP/Eunice Gas Plant [Old name:
WARREN PETROLEUM/EUNICE
GAS PLANT] AI 609
150 87 -42% The reduction is due to less acid gas flaring year over year
at the Eunice Gas Plant.
NM 25 350250004 Frontier Field Services/Maljamar
Gas Planta 565 72 112 55%
The increase in production causes pipeline/field to run at
high pressure causing automated shutdown of equipment
leading to increased flaring.
NM 15 350150010 Navajo Refining Co/Artesia Refinery
AI 198 42 70 67%
The increase in SO2 TPY in 2023 was mainly due to flaring
events from unit shutdowns caused by planned TAR
(turnaround/shutdown), power outages, malfunctions,
and other maintenance activities.
NM 45 350450902
Public Service Co of New
Mexico/San Juan Generating
Station AI 1421
604 - -100% Plant shut down
NM 25 569 Regency Field Services/Jal #3 [Old
Name Southern Union Gas] /Jal #3 72 5 -93%
In late 2022 we installed redundant acid gas injection
compression which allowed for a significant reduction in
acid gas flaring.
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State
County
FIPS
State
Facility
Identifier Plant Name
Reported
2022 SO2
Emissions
(tons)
Reported
2023 SO2
Emissions
(tons) % Change
Description Change > ±20%
2022 to 2023
NM 25 350250061
Versado Gas Processors, LLC /
Monument Plant [Old name(s):
TARGA MIDSTREAM SERVICES LP,
WARREN
PETROLEUM/MONUMENT PLANT]
45 70 54%
Various equipment failures contributed to an increase of
acid gas with residue quality fuel being routed to the
flare.
NM 25 350250075 ConocoPhillips-Midland Office /
MCA Tank Battery No. 2AI 624 113 0 -100% The company made efforts to reduce emissions and
improve maintenance of the equipment.
NM 25 350250113
ConocoPhillips-Midland Office /
East Vacuum Liquid Recovery and
CO2 Plant
7 31 335% The plant experienced lower dips and bad weather that
caused the plant to go to flare.
UT 7 10096 Sunnyside Cogeneration Associates
-- Sunnyside Cogeneration Facility 472 362 -23%
The decrease in SO2 in 2023 is due to the plant being
offline for two months through September and most of
October.
UT 15 10237 PacifiCorp -- Hunter Power Plant 3,274 1,940 -41%
This facility was operating at lower loads than they maybe
ever have historically. The decrease in load is why we see
a decrease in SO2 emissions. Coal supply was an issue in
2023, in addition to Hunter and Huntington being
dispatched down to accommodate wind and solar loads.
UT 15 10238 PacifiCorp -- Huntington Power
Plant 2,518 1,057 -58%
This facility was operating at lower loads than they maybe
ever have historically. The decrease in load is why we see
a decrease in SO2 emissions. Coal supply was an issue in
2023, in addition to Hunter and Huntington being
dispatched down to accommodate wind and solar loads.
UT 27 10313 Graymont Western US Inc. -- Cricket
Mountain Plant 17 29 70%
The measured concentration during the 2023 stack test
was 4.36 lb/hr, which, while significantly below the limit at
93% compliance, represents an increase by a factor of six
from the 0.72 lb/hr measured in 2022.
UT 27 10327
Intermountain Power Service
Corporation -- Intermountain
Generation Station
1,667 848 -49%
The decrease in SO2 emissions at IPP was due to several
factors including changes in coal quality (a lower % sulfur
in the coal burned in 2023 than 2022) and a reduction in
load (IPP produced fewer megawatts/burned less coal in
2023 than in 2022).
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State
County
FIPS
State
Facility
Identifier Plant Name
Reported
2022 SO2
Emissions
(tons)
Reported
2023 SO2
Emissions
(tons) % Change
Description Change > ±20%
2022 to 2023
UT 35 10346 Kennecott Utah Copper Corp. --
Smelter & Refinery 642 430 -33%
The SO2 emissions decreased because the facility had an
extended shutdown last year. For about 4 months, the
facility didn’t smelt any copper, reducing the average SO2
emissions for the year.
WY 13 F000532 Contango Resources LLC -- Lost
Cabin Gas Plant 1,482 2,020 36%
The 2022 Train 3 Flare (FLR002) emissions decreased by
110% from 2021. Flaring from Bighorn wells prior to the
startup and difficulties during startup contributed
significantly to the 2021 flaring emissions. 2022 sulfur
tank emissions decreased by 40% from 2021. INC004
emissions decreased by 26% from 2021. Used lower
emission factor in 2022
WY 41 F000191 Hilcorp Energy Company -- Carter
Creek Gas Plant 152 379 150%
The 2022 SO2 emissions reflect a 313.13% increase as the
Plant experienced an Unavoidable Equipment
Malfunction event that spanned over several days, which
was documented with the WDEQ, in December 2022.
WY 23 F000329
Exxon Mobil Corporation --
Labarge Black Canyon Dehydration
Facility
63 0 -100%
Major SO2 contributing events for BC in 2022 were on
August 6th through August 8th. The highest volume event
occurred on August 8th, 2022, when a failed O-ring at the
facility led us to shut down and de-inventory to make
repairs. This single event accounted for 48.82 tons of SO2
which is 78% of the 62.7 tons of SO2 reported via the
Black Canyon SO2 Emissions Inventory. This unavoidable
equipment malfunction caused most of the piping
infrastructure to depressurize which led to elevated SO2
emissions.
WY 23 F000327 Exxon Mobil Corporation -- Shute
Creek Treating Facility 1,911 1,114 -42%
Major SO2 contributing events for the SCF were due to
variety of equipment malfunctions mainly at the end of
March, end of May, middle of August and end of
December. The highest volume event in 2022 occurred
on March 29th through April 1st due to the loss of
instrument air which caused a total plant shutdown and
resulted in 846.43
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State
County
FIPS
State
Facility
Identifier Plant Name
Reported
2022 SO2
Emissions
(tons)
Reported
2023 SO2
Emissions
(tons) % Change
Description Change > ±20%
2022 to 2023
WY 29 F000539 Merit Energy Company -- Oregon
Basin Gas Plant 263 344 31%
The SO2 emissions for our Oregon Basin field is all from
our flares. Our flares act as emergency control devices
when our VRUs go down for various reasons in the field.
Because they are emergency flares and not process flares,
this means that the volumes that can end up going to
them can vary significantly year to year. For instance, we
had a lot of issues with our Battery 3 south in 2022, and so
why the emissions increased so much. While at other
batteries, emissions decreased because of a lessening of
emergency situations. We do permit each of our facilities
to have an amount of VRU downtime (when we would be
flaring) for these emergency instances and we track these
volumes and emissions to ensure that we do not go over
the permitted amount.
WY 9 F000644 Pacificorp - Dave Johnston Plant 7,292 5,501 -25% Reduction in SO2 emissions correlate directly with the
overall operation hours and load of these units.
WY 1 F000832 University of Wyoming - Heat Plant 82 7 -92% SO2 emissions in 2022 were higher due to a scheduled
increase of coal consumption.
WY 56043 F026405 Contango Resources, LLC --
Worland Gas Plant (WMS) 34 42 23%
In 2022, there were more engine maintenance activities
required. Furthermore, there was a frozen discharge line
that required pigging. In 2022, there were multiple
maintenance and parts replacements for Units 1 and 2
throughout the year. Furthermore, the plant was shut
down and needed multiple attempts to be started back
up.

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6.2 Part 75 Data
Federal Acid Rain Program emissions monitoring data (required by 40 CFR Part 75) were used to
check reported power plant emissions.
Sources in the region subject to Part 75 emitted 67% of the region's reported emissions in 2023.
We compared Acid Rain Program power plant emission data from EPA's Clean Air Markets Program
Data website to plant totals reported by each state. The SIPs require the use of Part 75 methods for Part 75
sources. The reported emissions matched EPA's emission data except for three sources. The sources
whose reported emissions did not match EPA’s data are in Table 4. The difference between the Acid Rain
Program data and reported emissions for this report for sources in Wyoming is due to emissions factors
required by Wyoming Air Quality Standards and Regulations Chapter 14 Section 3 (d).
Table 4. Reported facility emissions that do not match information in the Acid Rain
Database
State Facility Name
Facility ID
(ORISPL) Year
2023 Acid
Rain Database
Emissions
(tons SO2)
2023
Reported
Emissions
(tons SO2)
WY Pacificorp -- Naughton Plant 4162 2023 1437 1,439
WY Pacificorp - Dave Johnston Plant 4158 2023 5500 5,501
WY Basin Electric -- Laramie River Station 6204 2023 6630 8,451

7.0 Milestone Determination
The Section 309 regional 2018 milestone is 141,849 tons SO2. The 2023 adjusted emissions are
50,767 tons SO2; therefore, the participating states met the 141,849 tons SO2 milestone.
8.0 Public Comments
New Mexico, Albuquerque-Bernalillo, Utah, and Wyoming each published a draft of this report
for public review and comment. The draft was also available on the WESTAR-WRAP website.
[Add summary of comments if any are received.]

Appendix A

A-1
Appendix A

Table A-1
2023 Reported and Adjusted Emissions for Sources Subject to
Section 309 -- Regional Haze Rule
State County
FIPS
State
Facility
Identifier
ORIS Plant Name Plant
SIC
Plant
NAICS
Reported
2023 SO2
Emissions
(tons)
Adjusted
2023 SO2
Emissions
(tons)
2023 General
New Monitoring
Calculation
Method
Adjustment
(tons)
ABQ 1 3500100008 GCC Rio Grande Inc. - Portland Cement
Manufacturer 3241 327310 87 87 0
NM 15 350150024 Agave Energy Co./Agave Dagger Draw Gas
Plant AI211 1311 21112 299 299 0
NM 15 350150002
Frontier Field Services /Empire Abo Plant
[Old name: Arco Permian/Empire Abo Plant;
BP America Production] AI 191
1321 21113 186 186 0
NM 15 350150011 DCP Midstream/Artesia Gas Plant 1321 211112 35 35 0
NM 25 350250044 DCP Midstream/Eunice Gas Plant [Old name:
GPM GAS EUNICE GAS PLANT] AI 595 1321 21113 - - 0
NM 25 350250035
DCP Midstream/Linam Ranch Gas Plant [Old
name: GPM GAS/LINAM RANCH GAS
PLANT]
1321 21113 10 10 0
NM 15 350150138 Duke -- Magnum/Pan Energy -- Burton Flats 1321 211112 - - 0
NM 15 350150285 Duke Energy/Dagger Draw Gas Plant 1321 211112 - - 0
NM 25 350250060 609
VERSADO GAS PROCESSORS, LP/Eunice
Gas Plant [Old name: WARREN
PETROLEUM/EUNICE GAS PLANT] AI 609
1321 21113 87 87 0
Appendix A

A-2
State County
FIPS
State
Facility
Identifier
ORIS Plant Name Plant
SIC
Plant
NAICS
Reported
2023 SO2
Emissions
(tons)
Adjusted
2023 SO2
Emissions
(tons)
2023 General
New Monitoring
Calculation
Method
Adjustment
(tons)
NM 25 350250004 Frontier Field Services/Maljamar Gas Plant aI
565 1321 21113 112 112 0
NM 31 350310008
Western Refining Southwest Inc-Gallup
Refinery {Old names: Western
Refinery/Ciniza Refinery (Gallup) and GIANT
REFINING/CINIZA] AI 888
2911 236220 - - 0
NM 25 350250007 Davis Gas Processing/Denton Plant AI 568 1311 21113 - - 0
NM 15 350150008
OXY USA WTP Limited Partnership - Indian
Basin Gas Plant [Old Name -Marathon
Oil/Indian Basin Gas Plant] --AI197
1321 211112 - - 0
NM 15 350150010 Navajo Refining Co/Artesia Refinery AI 198 2911 32411 70 70 0
NM 45 350450902 2451 Public Service Co of New Mexico/San Juan
Generating Station AI 1421 4911 221112 - - 0
NM 7 350070001 Raton Pub. Service/Raton Power Plant 4911 221112 - - 0
NM 25 569 Regency Field Services/Jal #3 [Old Name
Southern Union Gas] /Jal #3 1321 21113 5 5 0
NM 25 350250051 Versado Gas Processors, LP/Eunice South
Gas Plant 1321 211112 - - 0
NM 25 350250061
Versado Gas Processors, LLC / Monument
Plant [Old name(s):TARGA MIDSTREAM
SERVICES LP, WARREN
PETROLEUM/MONUMENT PLANT]
1321 21113 70 70 0
NM 25 350250063
Versado Gas Processors, LLC/Saunders Plant
[Old name(s): TARGA MIDSTREAM
SERVICES, LP, WARREN
PETROLEUM/SAUNDERS PLANT]
1321 21113 - - 0
Appendix A

A-3
State County
FIPS
State
Facility
Identifier
ORIS Plant Name Plant
SIC
Plant
NAICS
Reported
2023 SO2
Emissions
(tons)
Adjusted
2023 SO2
Emissions
(tons)
2023 General
New Monitoring
Calculation
Method
Adjustment
(tons)
NM 31 350310032 87 Tri-State Gen & Transmission/Escalante
Station 4911 221112 - - 0
NM 45 350450247 CCI San Juan, LLC /San Juan River Gas Plant 1321 21113 - - 0
NM 45 350450023
Western Refining Southwest Inc./Bloomfield
Products Terminal [Old name: GIANT
INDUSTRIES/BLOOMFIELD REF] AI 1156
2911 42471 0 0 0
NM 25 350250075 ConocoPhillips-Midland Office / MCA Tank
Battery No. 2AI 624 1311 21113 0 0 0
NM 25 350250113 ConocoPhillips-Midland Office / East
Vacuum Liquid Recovery and CO2 Plant 1311 21112 31 31 0
UT 29 10007 Holcim-Devil's Slide Plant 3241 327310 129 464 335
UT 37 10034
Green Ventures, LLC (was Paradox
Midstream LLC CCI Paradox Midstream LLC
and Patara Midstream LLC and EnCana Oil &
Gas (USA) Incorporated and Tom Brown
Incorporated) - Lisbon Natural Gas
Processing Plant
2911 211120 0 0 0
UT 7 10081 3644 PacifiCorp -- Carbon Power Plant 4911 221112 0 8,005 8,005
UT 7 10096 Sunnyside Cogeneration Associates --
Sunnyside Cogeneration Facility 4911 221112 362 362 0
UT 11 10119 Chevron Products Co. -- Salt Lake Refinery 2911 324110 34 880 846
UT 11 10122 Big West Oil Company - Flying J Refinery 2911 324110 70 231 162
UT 11 10123 Holly Refining and Marketing Co. -- Phillips
Refinery 2911 324110 12 12 0
Appendix A

A-4
State County
FIPS
State
Facility
Identifier
ORIS Plant Name Plant
SIC
Plant
NAICS
Reported
2023 SO2
Emissions
(tons)
Adjusted
2023 SO2
Emissions
(tons)
2023 General
New Monitoring
Calculation
Method
Adjustment
(tons)
UT 15 10237 6165 PacifiCorp -- Hunter Power Plant 4911 221112 1,940 1,940 0
UT 15 10238 8069 PacifiCorp -- Huntington Power Plant 4911 221112 1,057 1,057 0
UT 27 10311 Materion Natural resources - Delta Mill (was
Brush Resources) 1099 212299 4 4 0
UT 27 10313 Graymont Western US Inc. -- Cricket
Mountain Plant 1422 212312 29 29 0
UT 27 10327 6481 Intermountain Power Service Corporation --
Intermountain Generation Station 4911 221112 848 848 0
UT 35 10335 Tesoro West Coast -- Salt Lake City Refinery 2911 324110 18 18 0
UT 35 10346 Kennecott Utah Copper Corp. -- Smelter &
Refinery 3331 331410 430 430 0
UT 35 10572 Kennecott Utah Copper Corp. -- Power
Plant/Lab/Tailings Impoundment 1021 212230 0 0 0
UT 43 10676 Utelite Corporation -- Shale processing 3295 212325 110 110 0
UT 49 10790 Brigham Young University -- Main Campus 8221 611310 1 1 0
WY 11 F021196 American Colloid Mineral Co -- Colony East
& West Plants 1459 212325 0 0 0
WY 5 F020818 56609 Basin Electric -- Dry Fork Station 4911 22112 887 887 0
WY 31 F000085 6204 Basin Electric -- Laramie River Station 4911 221112 8,451 8,451 0
Appendix A

A-5
State County
FIPS
State
Facility
Identifier
ORIS Plant Name Plant
SIC
Plant
NAICS
Reported
2023 SO2
Emissions
(tons)
Adjusted
2023 SO2
Emissions
(tons)
2023 General
New Monitoring
Calculation
Method
Adjustment
(tons)
WY 3 Big Horn Gas Proc -- Big Horn/Byron Gas
Plant 1311 22121 - - 0
WY 5 F030139
4150,
7504,
55479,
56596,
56319
Neil Simpson Complex - includes WYGEN I,
WYGEN II, WYGEN III, Neil Simpson I, and
Neil Simpson II
4911 22112 1068 1068 0
WY 45 4151 Black Hills Corporation - Osage Plant 4911 22112 - - 0
WY 13 F022325 Contango Resources LLC -- Bighorn 10-5
(Formerly Bighorn Wells) 1300 21111 0 0 0
WY 13 F000532 Contango Resources LLC -- Lost Cabin Gas
Plant 1311 211111 2,020 2,020 0
WY 41 F000191 Hilcorp Energy Company -- Carter Creek Gas
Plant 1311 211111 379 379 0
WY 37 Chevron USA -- Table Rock Field 1300 21111 - - 0
WY 37 Chevron USA -- Table Rock Gas Plant
(Formerly Anadarko E&P Co LP) 1321 211111 - - 0
WY 41 W000001 Northshore Exploration & Production --
Whitney Canyon/Carter Creek Wellfield 1300 21111 - - 0
WY 37 F000349 Genesis Alkali Wyoming LP -- Westvaco
Facility 2812 327999 2,045 2,045 0
WY 13 W000002 Devon Energy Production Co., L.P. -- Beaver
Creek Gas Field 1300 21111 - - 0
WY 13 F000058 Denbury Onshore LLC -- Beaver Creek
Compressor Station 1311 211111 0 0 0
Appendix A

A-6
State County
FIPS
State
Facility
Identifier
ORIS Plant Name Plant
SIC
Plant
NAICS
Reported
2023 SO2
Emissions
(tons)
Adjusted
2023 SO2
Emissions
(tons)
2023 General
New Monitoring
Calculation
Method
Adjustment
(tons)
WY 23 F000329 Exxon Mobil Corporation -- Labarge Black
Canyon Dehydration Facility 1300 21111 0 0 0
WY 23 F000327 Exxon Mobil Corporation -- Shute Creek
Treating Facility 1311 211111 1,114 1,114 0
WY 43 F026405 Hiland Partners, LLC -- Hiland Gas Plant 1321 48621 - - 0
WY 21 F030136 Holly Frontier Cheyenne Refining--
Cheyenne Renewable Diesel Facility 2911 32411 0 0 0
WY 29 F000539 Merit Energy Company -- Oregon Basin Gas
Plant 1321 211112 344 344 0
WY 29 W000004 Merit Energy Company -- Oregon Basin
Wellfield 1300 21111 - - 0
WY 37 F000827
North Shore Exploration & Production -
Brady Gas Plant (formerly Merit Energy
Company)
1321 211112 - - 0
WY 29 F026274 Vaquero Big Horn, LLC - Shoshone Unit
Battery 211112 - - 0
WY 29 F026853 Vaquero Big Horn, LLC - Frannie Unit Battery
No 1 211112 - - 0
WY 29 F001075 Vaquero Big Horn, LLC - Cody Unit Battery 211112 - - 0
WY 29 F001076 Vaquero Big Horn, LLC - Frannie 2 Battery 211112 - - 0
WY 41 W000003 Merit Energy Company -- Whitney Canyon
WellField 1300 21111 - - 0
WY 41 F000053 North Shore Exploration & Production --
Whitney Facility 1311 211111 1 1 0
Appendix A

A-7
State County
FIPS
State
Facility
Identifier
ORIS Plant Name Plant
SIC
Plant
NAICS
Reported
2023 SO2
Emissions
(tons)
Adjusted
2023 SO2
Emissions
(tons)
2023 General
New Monitoring
Calculation
Method
Adjustment
(tons)
WY 1 F000587 Mountain Cement Company -- Laramie
Cement Plant 3241 23571 133 133 0
WY 37 F000584 P4 Production, L.L.C. -- Rock Springs Coal
Calcining Plant 3312 331111 690 690 0
WY 9 F000644 4158 Pacificorp - Dave Johnston Plant 4911 221112 5,501 5,501 0
WY 37 F000645 8066 Pacificorp -- Jim Bridger Plant 4911 221112 6,668 6,668 0
WY 23 F000647 4162 Pacificorp -- Naughton Plant 4911 221112 1,439 1,439 0
WY 5 F000646 6101 Pacificorp -- Wyodak Plant 4911 221112 1,803 1,803 0
WY 37 F000746 Simplot Phosphates LLC -- Rock Springs
Fertilizer Complex 2874 325312 550 550 0
WY 7 F000758 HF Sinclair Parco Refining LLC -- HF Sinclair
Parco Refining LLC 2911 32411 94 94 0
WY 25 F000531 HF Sinclair Casper Refining LLC -- Casper
Refinery 2911 32411 26 26 0
WY 37 F000765 American Soda LLC -- Green River Soda Ash
Plant 1474 325181 41 41 0
WY 37 F000361 TATA Chemicals (Soda Ash) Partners-- Green
River Works (formerly General Chemical) 1474 327999 1,592 1,592 0
WY 15 F000389 The Western Sugar Cooperative --
Torrington Plant 2063 311313 - - 0
WY 37 F000803 Genesis Alkali Wyoming, LP -- Granger Soda
Ash Plant 1474 212391 5 5 0
Appendix A

A-8
State County
FIPS
State
Facility
Identifier
ORIS Plant Name Plant
SIC
Plant
NAICS
Reported
2023 SO2
Emissions
(tons)
Adjusted
2023 SO2
Emissions
(tons)
2023 General
New Monitoring
Calculation
Method
Adjustment
(tons)
WY 1 F000832 University of Wyoming - Heat Plant 8221 61131 7 7 0
WY 29 F000060 Contango Resources, LLC -- Elk Basin Gas
Plant 1311 211111 479 479 0
WY 56043 F026405 Contango Resources, LLC -- Worland Gas
Plant (WMS) 1321 211112 42 42 0
WY 45 F000980 Wyoming Refining Company -- Newcastle
Refinery 2911 32411 4 4 0

B-1
Appendix B

Table B-1
Sources Added to the SO2 Emissions and Milestone Report Inventory
State
County
FIP Code
State
Facility ID Facility Name
Report
Year of
Change
UT 043 10676 Utelite Corporation -- Shale processing 2003
WY 011 0002 American Colloid Mineral Company -- East Colony 2003
WY 011 0003 American Colloid Mineral Company -- West Colony 2003
WY 037 0014 Chevron USA (previously owned by Anadarko E&P Company LP) -- Table
Rock Gas Plant
2003
WY 005 0146 Black Hills Corporation -- Wygen 1 2003
WY 041 0002 BP America Production Company -- Whitney Canyon Well Field 2003
WY 013 0009 Burlington Resources -- Bighorn Wells 2003
WY 037 0177 Chevron USA -- Table Rock Field 2003
WY 041 0008 Chevron USA -- Whitney Canyon/Carter Creek Well field 2003
WY 013 0008 Devon Energy Corp. -- Beaver Creek Gas Plant 2003
WY 035 0001 Exxon Mobil Corporation -- Labarge Black Canyon Facility (also identified as
Black Canyon Dehy Facility)
2003
WY 013 0007 Devon Energy Corp. -- Beaver Creek Gas Field 2004
WY 005 0225 Cheyenne Light, Fuel and Power (a subsidiary of Black Hills Corporation) --
Wygen II
2008
WY 005 0281 Black Hills Corporation – Wygen III 2010
WY 005 0045 Basin Electric – Dry Fork Station 2011
NM 025 350250075 ConocoPhillips-Midland Office / MCA Tank Battery No. 2 2013
NM 025 350250113 ConocoPhillips-Midland Office / East Vacuum Liquid Recovery and CO2
Plant
2013
ABQ*
NM 001 3500100008 GCC Rio Grande Inc. - Portland Cement Manufacturer 2018
* ABQ NM is Albuquerque-Bernalillo County.

B-2
Table B-2
Sources Removed from the SO2 Emissions and Milestone Report Inventory
State
County
FIP Code
State
Facility ID Facility Name
1998
Baseline
Emissions
(tons/year) Reason for Change
Report
Year of
Change
WY 043 0001 Western Sugar Company --
Worland 154 Emissions did not meet 100
TPY program criteria. 2003
WY 017 0006 KCS Mountain Resources --
Golden Eagle 942 Emissions did not meet 100
TPY program criteria. 2003
WY 003 0017 KCS Mountain Resources --
Ainsworth 845 Closed since 2000. 2003
WY 017 0002 Marathon Oil -- Mill Iron 260 Emissions did not meet 100
TPY program criteria. 2003
UT 049 10796 Geneva Steel -- Steel
Manufacturing Facility 881 Plant is shut down and
disassembled. 2004
WY 023 0001 Astaris Production -- Coking
Plant 1,454 Plant is permanently shut
down and dismantled. 2004
ABQ*
NM 001 00145 Southside Water
Reclamation Plant 120 Not subject to program
after baseline revisions. ** 2008
NM 023 350230003 Phelps Dodge Hidalgo
Smelter 16,000 Facility is permanently
closed. 2008
NM 017 350170001 Phelps Dodge Hurley
Smelter/Concentrator 22,000 Facility is permanently
closed. 2008
WY 003 00012 Big Horn Gas Processing –
Bighorn/Byron Gas Plant 605 Facility is permanently
closed and dismantled. 2011

* ABQ NM in Albuquerque-Bernalillo County.
** 1998 baseline emissions were based on the facilities' potential to emit (PTE), and not actual emissions. Actual
annual emissions have always been below 100 tons. Once the year 2006 baseline became effective, this facility
was removed from the inventory.