DAQ-2025-005098

DAQE-AN130790015-25

{{$d1 }}

Dani Baldwin
MountainWest Pipeline, LLC
650 South Main Street, Suite 300
Salt Lake City, UT 84101
[e-mail]

Dear Ms. Baldwin:

Re: Approval Order: Administrative Amendment to Approval Order DAQE-AN130790006-12 for a
10-Year Review and Permit Updates
Project Number: N130790015

The attached Approval Order (AO) is issued pursuant to the Division of Air Quality conducting a 10-year
administrative review of this source and its respective AO. MountainWest Pipeline, LLC must comply
with the requirements of this AO, all applicable state requirements (R307), and Federal Standards.

The project engineer for this action is Stockton Antczak, who can be contacted at [phone] or
[e-mail]. Future correspondence on this AO should include the engineer's name as well as the
DAQE number shown on the upper right-hand corner of this letter.

Sincerely,

{{$s }}

Bryce C. Bird
Director

BCB:SA:jg

cc: TriCounty Health Department

195 North 1950 West • Salt Lake City, UT
Mailing Address: P.O. Box 144820 • Salt Lake City, UT 84114-4820
Telephone [phone] • Fax [phone] • T.D.D. [phone]
www.deq.utah.gov
Printed on 100% recycled paper
State of Utah

SPENCER J. COX
Governor
DEIDRE HENDERSON
Lieutenant Governor

Department of
Environmental Quality

Tim Davis
Executive Director

DIVISION OF AIR QUALITY
Bryce C. Bird
Director

October 14, 2025

STATE OF UTAH
Department of Environmental Quality
Division of Air Quality

{{#s=Sig_es_:signer1:signature}}
{{#d1=date1_es_:signer1:date:format(date, "mmmm d, yyyy")}}
{{#d2=date1_es_:signer1:date:format(date, "mmmm d, yyyy"):align(center)}}

APPROVAL ORDER
DAQE-AN130790015-25
Administrative Amendment to Approval Order
DAQE-AN130790006-12 for a 10-Year Review
And Permit Updates

Prepared By
Stockton Antczak, Engineer
[phone]
[e-mail]

Issued to
MountainWest Pipeline, LLC - Blind Canyon Compressor Station

Issued On
{{$d2 }}

Issued By

{{$s }}

Bryce C. Bird
Director
Division of Air Quality

October 14, 2025
TABLE OF CONTENTS

TITLE/SIGNATURE PAGE ....................................................................................................... 1
GENERAL INFORMATION ...................................................................................................... 3
CONTACT/LOCATION INFORMATION ............................................................................... 3
SOURCE INFORMATION ........................................................................................................ 3
General Description ................................................................................................................ 3
NSR Classification .................................................................................................................. 3
Source Classification .............................................................................................................. 3
Applicable Federal Standards ................................................................................................. 3
Project Description.................................................................................................................. 3
SUMMARY OF EMISSIONS .................................................................................................... 4
SECTION I: GENERAL PROVISIONS .................................................................................... 4
SECTION II: PERMITTED EQUIPMENT .............................................................................. 5
SECTION II: SPECIAL PROVISIONS ..................................................................................... 5
PERMIT HISTORY ..................................................................................................................... 7
ACRONYMS ................................................................................................................................. 8

DAQE-AN130790015-25
Page 3

GENERAL INFORMATION

CONTACT/LOCATION INFORMATION

Owner Name Source Name
MountainWest Pipeline, LLC MountainWest Pipeline, LLC - Blind Canyon Compressor Station

Mailing Address Physical Address
650 South Main Street, Suite 300 39.8479804992676 -110.205902099609
Salt Lake City, UT 84101 Myton, UT

Source Contact UTM Coordinates
Name: Dani Baldwin 567,933 m Easting
Phone: [phone],411,180 m Northing
Email: [e-mail] Datum NAD83
UTM Zone 12
SIC code 4922 (Natural Gas Transmission)

SOURCE INFORMATION
General Description
The MountainWest Pipelines, LLC - Blind Canyon Compressor Station is used to maintain pressure and
flow of natural gas through distribution pipelines for consumer use. This facility is located near Myton,
UT inside of Duchesne County. This location is in attainment for all criteria pollutants.

NSR Classification
10-Year Review

Source Classification
Located in Attainment Area
Duchesne County
Airs Source Size: B

Applicable Federal Standards
NSPS (Part 60), A: General Provisions
NSPS (Part 60), KKKK: Standards of Performance for Stationary Combustion Turbines
MACT (Part 63), ZZZZ: National Emissions Standards for Hazardous Air Pollutants for
Stationary Reciprocating Internal Combustion Engines

Project Description
A 10-year review to update contact information and requirement language.

DAQE-AN130790015-25
Page 4

SUMMARY OF EMISSIONS

The emissions listed below are an estimate of the total potential emissions from the source. Some
rounding of emissions is possible.

Criteria Pollutant Change (TPY) Total (TPY)
Carbon Monoxide 0 47.40
Nitrogen Oxides 0 39.84
Particulate Matter - PM10 0 2.47
Particulate Matter - PM2.5 0 2.47
Volatile Organic Compounds 0 32.82

Hazardous Air Pollutant Change (lbs/yr) Total (lbs/yr)
Acetaldehyde (CAS #75070) 0 123
Acrolein (CAS #107028) 0 218
Benzene (Including Benzene From Gasoline) (CAS #71432) 0 262
Ethyl Benzene (CAS #100414) 0 34
Formaldehyde (CAS #50000) 0 1192
Generic HAPs (CAS #GHAPS) 0 1140
Toluene (CAS #108883) 0 214
Xylenes (Isomers And Mixture) (CAS #1330207) 0 56
Change (TPY) Total (TPY)
Total HAPs 0 1.62

SECTION I: GENERAL PROVISIONS

I.1 All definitions, terms, abbreviations, and references used in this AO conform to those used in the UAC R307 and 40 CFR. Unless noted otherwise, references cited in these AO conditions refer to those rules. [R307-101]
I.2 The limits set forth in this AO shall not be exceeded without prior approval. [R307-401] I.3 Modifications to the equipment or processes approved by this AO that could affect the emissions covered by this AO must be reviewed and approved. [R307-401-1]
I.4 All records referenced in this AO or in other applicable rules, which are required to be kept by the owner/operator, shall be made available to the Director or Director's representative upon request, and the records shall include the two-year period prior to the date of the request. Unless otherwise specified in this AO or in other applicable state and federal rules, records shall be kept for a minimum of two (2) years. [R307-401-8]
I.5 At all times, including periods of startup, shutdown, and malfunction, owners and operators shall, to the extent practicable, maintain and operate any equipment approved under this AO, including associated air pollution control equipment, in a manner consistent with good air
pollution control practice for minimizing emissions. Determination of whether acceptable operating and maintenance procedures are being used will be based on information available to the Director which may include, but is not limited to, monitoring results, opacity observations,
review of operating and maintenance procedures, and inspection of the source. All maintenance performed on equipment authorized by this AO shall be recorded. [R307-401-4]
DAQE-AN130790015-25
Page 5

I.6 The owner/operator shall comply with UAC R307-107. General Requirements: Breakdowns. [R307-107] I.7 The owner/operator shall comply with UAC R307-150 Series. Emission Inventories. [R307-150]

SECTION II: PERMITTED EQUIPMENT
II.A THE APPROVED EQUIPMENT
II.A.1 Blind Canyon Compressor Station Line Booster Station II.A.2 Turbine T-1 One (1) Turbine Compressor engines Size Manufacture rating: 4540 hp Site rating: 3817 to 4822 hp Annual consumption: 314.32 MMSCF Subject to 40 CFR 60 Subpart KKKK
II.A.3 Turbine T-2 One (1) Turbine Compressor engines Size Manufacture rating: 4540 hp Site rating: 3817 to 4822 hp Annual consumption: 314.32 MMSCF Subject to 40 CFR 60 Subpart KKKK II.A.4 Generators G-1, 2 Two (2) Generators Size: 526 hp (each) Power: 370 kW Subject to 40 CFR 63 Subpart ZZZZ

SECTION II: SPECIAL PROVISIONS II.B REQUIREMENTS AND LIMITATIONS
II.B.1 Site Wide Requirements II.B.1.a Visible emissions from natural gas-operated equipment shall not exceed 10% opacity and any other stationary point or fugitive emission source associated with the source or with the control facilities shall not exceed 20% opacity. [R307-401]
II.B.1.a.1 Opacity observations of emissions from stationary sources shall be conducted in accordance with 40 CFR 60, Appendix A, Method 9. [R307-401] II.B.1.b The owner/operator shall operate only one (1) generator engine at any one time except during switching and testing. [R307-401]

DAQE-AN130790015-25
Page 6

II.B.2 Turbine Requirements II.B.2.a Emissions to the atmosphere at all times from the indicated emission point shall not exceed the
following rates and concentrations: Source: 4540 bhp Natural gas turbine compressor
Pollutant lb/hr CO 4.83
NOx 3.97 [R307-401]

II.B.2.b The owner/operator shall conduct any stack testing required by this AO according to the following conditions. [R307-401-8]
II.B.2.b.1 Notification At least 30 days prior to conducting a stack test, the owner/operator shall submit a source test
protocol to the Director. The source test protocol shall include the items contained in
R307-165-3. If directed by the Director, the owner/operator shall attend a pretest conference. [R307-165-3, R307-401-8]

II.B.2.b.2 Test Frequency The owner/operator shall conduct a stack test on each turbine for NOx and CO emissions within five (5) years after the date of the most recent stack test of the emission unit. The Director may require the owner/operator to perform a stack test at any time. [R307-165-2] II.B.2.b.3 Reporting
No later than 60 days after completing a stack test, the owner/operator shall submit a written
report of the results from the stack testing to the Director. The report shall include validated results and supporting information. [R307-165-5, R307-401-8]

II.B.2.c Standard Conditions A. Temperature - 68 degrees Fahrenheit (293 K) B. Pressure - 29.92 in Hg (101.3 kPa) C. Averaging Time - As specified in the applicable test method. [40 CFR 60 Subpart A, 40 CFR 63 Subpart A, R307-401-8]
II.B.2.c.1 Volumetric Flow Rate 40 CFR 60, Appendix A, Method 2; Method 19; or other EPA-approved testing method as
acceptable to the Director. [R307-401-8]

II.B.2.c.2 NOx 40 CFR 60, Appendix A, Method 7; Method 7E; or other EPA-approved testing method as acceptable to the Director. [R307-401-8]
II.B.2.c.3 CO
40 CFR 60, Appendix A, Method 10, or other EPA-approved testing method as acceptable to the
Director. [R307-401-8]

DAQE-AN130790015-25
Page 7

II.B.2.c.4 Calculations To determine mass emission rates (lb/hr, etc.) the pollutant concentration as determined by the appropriate methods above shall be multiplied by the volumetric flow rate and any necessary conversion factors determined by the Director, to give the results in the specified units of the emission limitation. [R307-401]
PERMIT HISTORY

This Approval Order shall supersede (if a modification) or will be based on the following documents: Supersedes AO DAQE-AN130790006-12 dated April 2, 2012

DAQE-AN130790015-25
Page 8

ACRONYMS

The following lists commonly used acronyms and associated translations as they apply to this document:

40 CFR Title 40 of the Code of Federal Regulations
AO Approval Order
BACT Best Available Control Technology
CAA Clean Air Act
CAAA Clean Air Act Amendments
CDS Classification Data System (used by Environmental Protection Agency to classify
sources by size/type)
CEM Continuous emissions monitor
CEMS Continuous emissions monitoring system
CFR Code of Federal Regulations
CMS Continuous monitoring system
CO Carbon monoxide
CO2 Carbon Dioxide
CO2e Carbon Dioxide Equivalent - Title 40 of the Code of Federal Regulations Part 98,
Subpart A, Table A-1
COM Continuous opacity monitor
DAQ/UDAQ Division of Air Quality
DAQE This is a document tracking code for internal Division of Air Quality use
EPA Environmental Protection Agency
FDCP Fugitive dust control plan
GHG Greenhouse Gas(es) - Title 40 of the Code of Federal Regulations 52.21 (b)(49)(i)
GWP Global Warming Potential - Title 40 of the Code of Federal Regulations Part 86.1818-
12(a)
HAP or HAPs Hazardous air pollutant(s)
ITA Intent to Approve
LB/YR Pounds per year MACT Maximum Achievable Control Technology MMBTU Million British Thermal Units NAA Nonattainment Area NAAQS National Ambient Air Quality Standards NESHAP National Emission Standards for Hazardous Air Pollutants NOI Notice of Intent
NOx Oxides of nitrogen
NSPS New Source Performance Standard
NSR New Source Review
PM10 Particulate matter less than 10 microns in size
PM2.5 Particulate matter less than 2.5 microns in size
PSD Prevention of Significant Deterioration
PTE Potential to Emit
R307 Rules Series 307
R307-401 Rules Series 307 - Section 401
SO2 Sulfur dioxide
Title IV Title IV of the Clean Air Act
Title V Title V of the Clean Air Act
TPY Tons per year
UAC Utah Administrative Code
VOC Volatile organic compounds

DAQE-

RN130790015 September 30, 2025 Dani Baldwin
MountainWest Pipeline, LLC 650 South Main Street Suite 300
Salt Lake City, UT 84101 [e-mail]
Dear Dani Baldwin, Re: Engineer Review - 10-Year Review and Permit Updates: Administrative Amendment to Approval Order DAQE-AN130790006-12 for a 10-Year Review Project Number: N130790015 The DAQ requests a company representative review and sign the attached Engineer Review (ER). This ER identifies all applicable elements of the New Source Review (NSR) permitting program. MountainWest Pipeline, LLC should complete this review within 10 business days of receipt. MountainWest Pipeline, LLC should contact Stockton Antczak at [phone] if there are questions
or concerns with the review of the draft permit conditions. Upon resolution of your concerns, please email Stockton Antczak at [e-mail] the signed cover letter. Upon receipt of the signed cover letter, the DAQ will prepare an Approval Order (AO) for signature by the DAQ Director. If MountainWest Pipeline, LLC does not respond to this letter within 10 business days, the project will move forward without source concurrence. If MountainWest Pipeline, LLC has concerns that cannot be
resolved and the project becomes stagnant, the DAQ Director may issue an Order prohibiting construction. Approval Signature _____________________________________________________________ (Signature & Date)
Mailing Address: P.O. Box 144820 • Salt Lake City, UT 84114-4820
Telephone [phone] • Fax [phone] • T.D.D. [phone]
www.deq.utah.gov
Printed on 100% recycled paper
Department of Environmental Quality
Tim Davis Executive Director DIVISION OF AIR QUALITY Bryce C. Bird Director
State of Utah
SPENCER J. COX Governor DEIDRE HENDERSON Lieutenant Governor

Engineer Review N130790015: MountainWest Pipeline, LLC- Blind Canyon Compressor station September 30, 2025 Page 1
UTAH DIVISION OF AIR QUALITY
ENGINEER REVIEW

SOURCE INFORMATION
Project Number N130790015 Owner Name MountainWest Pipeline, LLC Mailing Address 650 South Main Street
Suite 300 Salt Lake City, UT, 84101
Source Name MountainWest Pipeline, LLC- Blind Canyon Compressor station Source Location 39.8479804992676 -110.205902099609
Myton, UT UTM Projection 567,933 m Easting, 4,411,180 m Northing UTM Datum NAD83 UTM Zone UTM Zone 12 SIC Code 4922 (Natural Gas Transmission) Source Contact Dani Baldwin Phone Number [phone] Email [e-mail]
Billing Contact Dani Baldwin Phone Number [phone] Email [e-mail]
Project Engineer Stockton Antczak, Engineer Phone Number [phone]
Email [e-mail] Notice of Intent (NOI) Submitted March 10, 2025 Date of Accepted Application March 26, 2025

Engineer Review N130790015: MountainWest Pipeline, LLC- Blind Canyon Compressor station September 30, 2025 Page 2
SOURCE DESCRIPTION General Description
The MountainWest Pipelines, LLC - Blind Canyon Compressor Station is used to maintain pressure and flow of natural gas through distribution pipelines for consumer use. This facility is located near Myton, UT at 39°50'52.55" N 110°12'21.35" W inside of Duchesne County. This
location is in attainment for all criteria pollutants. NSR Classification: 10 Year Review Source Classification Located in an Attainment Area Duchesne County Airs Source Size: B Applicable Federal Standards
Project Proposal
Administrative Amendment to Approval Order DAQE-AN130790006-12 for a 10-Year Review Project Description A 10-year review to update contact information and requirement language. EMISSION IMPACT ANALYSIS
Emissions will remain unchanged as a result of the administrative amendment; therefore, modeling is not required. [Last updated July 1, 2025]

Engineer Review N130790015: MountainWest Pipeline, LLC- Blind Canyon Compressor station September 30, 2025 Page 3
SUMMARY OF EMISSIONS
The emissions listed below are an estimate of the total potential emissions from the source. Some rounding of emissions is possible.
Criteria Pollutant Change (TPY) Total (TPY)

Hazardous Air Pollutant Change (lbs/yr) Total (lbs/yr)
Change (TPY) Total (TPY)

Note: Change in emissions indicates the difference between previous AO and proposed modification.

Engineer Review N130790015: MountainWest Pipeline, LLC- Blind Canyon Compressor station September 30, 2025 Page 4
Review of BACT for New/Modified Emission Units BACT review regarding BACT
The source has not modified anything with this administrative amendment; therefore, a BACT Analysis was not required for this permit. [Last updated July 1, 2025]

SECTION I: GENERAL PROVISIONS

The intent is to issue an air quality AO authorizing the project with the following recommended conditions and that failure to comply with any of the conditions may constitute a violation of the AO. (New or Modified conditions are indicated as “New” in the Outline Label):
the UAC R307 and 40 CFR. Unless noted otherwise, references cited in these AO conditions refer to those rules. [R307-101]
emissions covered by this AO must be reviewed and approved. [R307-401-1]
the owner/operator, shall be made available to the Director or Director's representative upon request, and the records shall include the two-year period prior to the date of the request. Unless otherwise specified in this AO or in other applicable state and federal rules, records shall be kept for a minimum of two (2) years. [R307-401-8]
shall, to the extent practicable, maintain and operate any equipment approved under this AO,
including associated air pollution control equipment, in a manner consistent with good air pollution control practice for minimizing emissions. Determination of whether acceptable operating and maintenance procedures are being used will be based on information available
to the Director which may include, but is not limited to, monitoring results, opacity observations, review of operating and maintenance procedures, and inspection of the source. All maintenance performed on equipment authorized by this AO shall be recorded. [R307-
401-4]
[R307-107]
150]

Engineer Review N130790015: MountainWest Pipeline, LLC- Blind Canyon Compressor station September 30, 2025 Page 5
SECTION II: PERMITTED EQUIPMENT The intent is to issue an air quality AO authorizing the project with the following recommended conditions and that failure to comply with any of the conditions may constitute a violation of the
AO. (New or Modified conditions are indicated as “New” in the Outline Label):
II.A.1 Line Booster Station
Turbine T-1 One (1) Turbine Compressor engines Size Manufacture rating: 4540 hp Site rating: 3817 to 4822 hp Annual consumption: 314.32 MMSCF Subject to 40 CFR 60 Subpart KKKK
Turbine T-2 One (1) Turbine Compressor engines Size Manufacture rating: 4540 hp Site rating: 3817 to 4822 hp Annual consumption: 314.32 MMSCF Subject to 40 CFR 60 Subpart KKKK
Generators G-1, 2 Two (2) Generators
Size: 526 hp (each) Power: 370 kW Subject to 40 CFR 63 Subpart ZZZZ

SECTION II: SPECIAL PROVISIONS
The intent is to issue an air quality AO authorizing the project with the following recommended conditions and that failure to comply with any of the conditions may constitute a violation of the AO. (New or Modified conditions are indicated as “New” in the Outline Label):
II.B.1
II.B.1.a NEW other stationary point or fugitive emission source associated with the source or with the control facilities shall not exceed 20% opacity. [R307-401]
NEW with 40 CFR 60, Appendix A, Method 9. [R307-401]

Engineer Review N130790015: MountainWest Pipeline, LLC- Blind Canyon Compressor station September 30, 2025 Page 6
NEW switching and testing. [R307-401]
Turbine Requirements
NEW the following rates and concentrations:

Source: 4540 bhp Natural gas turbine compressor Pollutant lb/hr CO 4.83 NOx 3.97
[R307-401]
NEW The owner/operator shall conduct any stack testing required by this AO according to the following conditions. [R307-401-8]
NEW NotificationAt least 30 days prior to conducting a stack test, the owner/operator shall submit a source test protocol to the Director. The source test protocol shall include the items contained in R307-165-3. If directed by the Director, the owner/operator shall attend a pretest conference. [R307-165-3, R307-401-8]
NEW Test FrequencyThe owner/operator shall conduct a stack test on each turbine for NOx and CO emissions within five (5) years after the date of the most recent stack test of the emission unit. The Director may require the owner/operator to perform a stack test at any time. [R307-165-2]
NEW ReportingNo later than 60 days after completing a stack test, the owner/operator shall submit a written report of the results from the stack testing to the Director. The report shall include validated results and supporting information. [R307-165-5, R307-401-8]
NEW
Standard Conditions
A. Temperature - 68 degrees Fahrenheit (293 K) B. Pressure - 29.92 in Hg (101.3 kPa) C. Averaging Time - As specified in the applicable test method [40 CFR 60 Subpart A, 40 CFR 63 Subpart A, R307-401-8]
NEW Volumetric Flow Rate40 CFR 60, Appendix A, Method 2; Method 19; or other EPA-approved testing method as
acceptable to the Director. [R307-401-8]

Engineer Review N130790015: MountainWest Pipeline, LLC- Blind Canyon Compressor station September 30, 2025 Page 7
NEW NOx 40 CFR 60, Appendix A, Method 7; Method 7E; or other EPA-approved testing method as acceptable to the Director. [R307-401-8]
NEW CO40 CFR 60, Appendix A, Method 10 or other EPA-approved testing method as acceptable to the Director. [R307-401-8]
NEW
Calculations
To determine mass emission rates (lb/hr, etc.) the pollutant concentration as determined by the appropriate methods above shall be multiplied by the volumetric flow rate and any necessary conversion factors determined by the Director, to give the results in the specified units of the emission limitation. [R307-401]

Engineer Review N130790015: MountainWest Pipeline, LLC- Blind Canyon Compressor station September 30, 2025 Page 8
PERMIT HISTORY When issued, the approval order shall supersede (if a modification) or will be based on the
following documents:

REVIEWER COMMENTS
1.
As part of this 10-year review project, the following changes were made. Contact information was updated, UTM coordinates for the site were corrected, Opacity and stack testing language were updated, and general formatting of the permit was updated. [Last updated July 2, 2025]

Engineer Review N130790015: MountainWest Pipeline, LLC- Blind Canyon Compressor station September 30, 2025 Page 9
ACRONYMS The following lists commonly used acronyms and associated translations as they apply to this document:

DAQE-

RN130790015 September 30, 2025 Dani Baldwin MountainWest Pipeline, LLC 650 South Main Street Suite 300
Salt Lake City, UT 84101 [e-mail]
Dear Dani Baldwin, Re: Engineer Review - 10-Year Review and Permit Updates:
Administrative Amendment to Approval Order DAQE-AN130790006-12 for a 10-Year Review Project Number: N130790015
The DAQ requests a company representative review and sign the attached Engineer Review (ER). This ER identifies all applicable elements of the New Source Review (NSR) permitting program. MountainWest Pipeline, LLC should complete this review within 10 business days of receipt.
MountainWest Pipeline, LLC should contact Stockton Antczak at [phone] if there are questions or concerns with the review of the draft permit conditions. Upon resolution of your concerns, please email Stockton Antczak at [e-mail] the signed cover letter. Upon receipt of the signed cover letter, the DAQ will prepare an Approval Order (AO) for signature by the DAQ Director. If MountainWest Pipeline, LLC does not respond to this letter within 10 business days, the project will move forward without source concurrence. If MountainWest Pipeline, LLC has concerns that cannot be
resolved and the project becomes stagnant, the DAQ Director may issue an Order prohibiting construction.
Approval Signature _____________________________________________________________ (Signature & Date)

Mailing Address: P.O. Box 144820 • Salt Lake City, UT 84114-4820
Telephone [phone] • Fax [phone] • T.D.D. [phone]
www.deq.utah.gov
Printed on 100% recycled paper
Department of Environmental Quality
Tim Davis Executive Director DIVISION OF AIR QUALITY Bryce C. Bird Director
State of Utah
SPENCER J. COX Governor DEIDRE HENDERSON Lieutenant Governor

9/30/2025

Engineer Review N130790015: MountainWest Pipeline, LLC- Blind Canyon Compressor station September 30, 2025 Page 1
UTAH DIVISION OF AIR QUALITY
ENGINEER REVIEW

SOURCE INFORMATION
Project Number N130790015 Owner Name MountainWest Pipeline, LLC Mailing Address 650 South Main Street Suite 300 Salt Lake City, UT, 84101 Source Name MountainWest Pipeline, LLC- Blind Canyon Compressor station Source Location 39.8479804992676 -110.205902099609
Myton, UT UTM Projection 567,933 m Easting, 4,411,180 m Northing
UTM Datum NAD83 UTM Zone UTM Zone 12 SIC Code 4922 (Natural Gas Transmission)
Source Contact Dani Baldwin Phone Number [phone]
Email [e-mail] Billing Contact Dani Baldwin Phone Number [phone] Email [e-mail] Project Engineer Stockton Antczak, Engineer Phone Number [phone]
Email [e-mail] Notice of Intent (NOI) Submitted March 10, 2025
Date of Accepted Application March 26, 2025

Engineer Review N130790015: MountainWest Pipeline, LLC- Blind Canyon Compressor station September 30, 2025 Page 2
SOURCE DESCRIPTION General Description
The MountainWest Pipelines, LLC - Blind Canyon Compressor Station is used to maintain pressure and flow of natural gas through distribution pipelines for consumer use. This facility is located near Myton, UT at 39°50'52.55" N 110°12'21.35" W inside of Duchesne County. This
location is in attainment for all criteria pollutants. NSR Classification:
10 Year Review Source Classification
Located in an Attainment Area Duchesne County Airs Source Size: B
Applicable Federal Standards
Project Proposal
Administrative Amendment to Approval Order DAQE-AN130790006-12 for a 10-Year Review Project Description
A 10-year review to update contact information and requirement language. EMISSION IMPACT ANALYSIS
Emissions will remain unchanged as a result of the administrative amendment; therefore, modeling is not required. [Last updated July 1, 2025]

Engineer Review N130790015: MountainWest Pipeline, LLC- Blind Canyon Compressor station September 30, 2025 Page 3
SUMMARY OF EMISSIONS The emissions listed below are an estimate of the total potential emissions from the source. Some rounding of emissions is possible.
Criteria Pollutant Change (TPY) Total (TPY)
Hazardous Air Pollutant Change (lbs/yr) Total (lbs/yr)
Change (TPY) Total (TPY)

Note: Change in emissions indicates the difference between previous AO and proposed modification.

Engineer Review N130790015: MountainWest Pipeline, LLC- Blind Canyon Compressor station September 30, 2025 Page 4
Review of BACT for New/Modified Emission Units BACT review regarding BACT
The source has not modified anything with this administrative amendment; therefore, a BACT Analysis was not required for this permit. [Last updated July 1, 2025]

SECTION I: GENERAL PROVISIONS

The intent is to issue an air quality AO authorizing the project with the following recommended conditions and that failure to comply with any of the conditions may constitute a violation of the AO. (New or Modified conditions are indicated as “New” in the Outline Label):

the UAC R307 and 40 CFR. Unless noted otherwise, references cited in these AO conditions refer to those rules. [R307-101]
emissions covered by this AO must be reviewed and approved. [R307-401-1]
the owner/operator, shall be made available to the Director or Director's representative upon request, and the records shall include the two-year period prior to the date of the request. Unless otherwise specified in this AO or in other applicable state and federal rules, records
shall be kept for a minimum of two (2) years. [R307-401-8]
shall, to the extent practicable, maintain and operate any equipment approved under this AO,
including associated air pollution control equipment, in a manner consistent with good air pollution control practice for minimizing emissions. Determination of whether acceptable operating and maintenance procedures are being used will be based on information available
to the Director which may include, but is not limited to, monitoring results, opacity observations, review of operating and maintenance procedures, and inspection of the source. All maintenance performed on equipment authorized by this AO shall be recorded. [R307-
401-4]
[R307-107]
150]

Engineer Review N130790015: MountainWest Pipeline, LLC- Blind Canyon Compressor station September 30, 2025 Page 5
SECTION II: PERMITTED EQUIPMENT The intent is to issue an air quality AO authorizing the project with the following recommended conditions and that failure to comply with any of the conditions may constitute a violation of the
AO. (New or Modified conditions are indicated as “New” in the Outline Label):
II.A.1 Line Booster Station
Turbine T-1 One (1) Turbine Compressor engines
Size Manufacture rating: 4540 hp Site rating: 3817 to 4822 hp Annual consumption: 314.32 MMSCF
Subject to 40 CFR 60 Subpart KKKK
Turbine T-2 One (1) Turbine Compressor engines
Size Manufacture rating: 4540 hp Site rating: 3817 to 4822 hp Annual consumption: 314.32 MMSCF
Subject to 40 CFR 60 Subpart KKKK
Generators G-1, 2 Two (2) Generators
Size: 526 hp (each) Power: 370 kW Subject to 40 CFR 63 Subpart ZZZZ

SECTION II: SPECIAL PROVISIONS
The intent is to issue an air quality AO authorizing the project with the following recommended conditions and that failure to comply with any of the conditions may constitute a violation of the AO. (New or Modified conditions are indicated as “New” in the Outline Label):
II.B.1
II.B.1.a NEW other stationary point or fugitive emission source associated with the source or with the control facilities shall not exceed 20% opacity. [R307-401]
NEW with 40 CFR 60, Appendix A, Method 9. [R307-401]

Engineer Review N130790015: MountainWest Pipeline, LLC- Blind Canyon Compressor station September 30, 2025 Page 6
NEW switching and testing. [R307-401]
Turbine Requirements
NEW the following rates and concentrations:
Source: 4540 bhp Natural gas turbine compressor Pollutant lb/hr CO 4.83 NOx 3.97
[R307-401]
NEW The owner/operator shall conduct any stack testing required by this AO according to the following conditions. [R307-401-8]
NEW NotificationAt least 30 days prior to conducting a stack test, the owner/operator shall submit a source test
protocol to the Director. The source test protocol shall include the items contained in R307-165-3. If directed by the Director, the owner/operator shall attend a pretest conference. [R307-165-3, R307-401-8]
NEW Test FrequencyThe owner/operator shall conduct a stack test on each turbine for NOx and CO emissions within five (5) years after the date of the most recent stack test of the emission unit. The
Director may require the owner/operator to perform a stack test at any time. [R307-165-2]
NEW ReportingNo later than 60 days after completing a stack test, the owner/operator shall submit a written
report of the results from the stack testing to the Director. The report shall include validated results and supporting information. [R307-165-5, R307-401-8]
NEW
Standard Conditions
A. Temperature - 68 degrees Fahrenheit (293 K) B. Pressure - 29.92 in Hg (101.3 kPa) C. Averaging Time - As specified in the applicable test method [40 CFR 60 Subpart A, 40 CFR 63 Subpart A, R307-401-8]
NEW Volumetric Flow Rate40 CFR 60, Appendix A, Method 2; Method 19; or other EPA-approved testing method as acceptable to the Director. [R307-401-8]

Engineer Review N130790015: MountainWest Pipeline, LLC- Blind Canyon Compressor station September 30, 2025 Page 7
NEW NOx 40 CFR 60, Appendix A, Method 7; Method 7E; or other EPA-approved testing method as acceptable to the Director. [R307-401-8]
NEW
CO
40 CFR 60, Appendix A, Method 10 or other EPA-approved testing method as acceptable to the Director. [R307-401-8]
NEW
Calculations
To determine mass emission rates (lb/hr, etc.) the pollutant concentration as determined by the appropriate methods above shall be multiplied by the volumetric flow rate and any necessary conversion factors determined by the Director, to give the results in the specified units of the
emission limitation. [R307-401]

Engineer Review N130790015: MountainWest Pipeline, LLC- Blind Canyon Compressor station September 30, 2025 Page 8
PERMIT HISTORY When issued, the approval order shall supersede (if a modification) or will be based on the
following documents:

REVIEWER COMMENTS
1.
As part of this 10-year review project, the following changes were made. Contact information was updated, UTM coordinates for the site were corrected, Opacity and stack testing language were updated, and general formatting of the permit was updated. [Last updated July 2, 2025]

Engineer Review N130790015: MountainWest Pipeline, LLC- Blind Canyon Compressor station September 30, 2025 Page 9
ACRONYMS The following lists commonly used acronyms and associated translations as they apply to this document:

Stockton Antczak <[e-mail]>
SIGNED Blind Canyon Updated Review
1 message
Baldwin, Dani <[e-mail]>Tue, Sep 30, 2025 at 1:11 PM
To: Stockton Antczak <[e-mail]>
Hi Stockton,
I did see the email clarifying the Blind Canyon site is not in the ozone non-attainment area.
The review has been completed. The permit looks great. The attached document has been
signed.
Thank you,
Dani
Dani Baldwin | She/Her/Hers | What’s This? | Williams
Environmental Specialist | Western Interstates
Cell: [phone] | 650 South Main Street, Suite 300, Salt Lake City, UT 84101
Williams.com | Facebook | X | LinkedIn | YouTube | Instagram | Newsroom
If you have received this message in error, please reply to advise the sender of the error and then immediately delete this
message.

From: Stockton Antczak <[e-mail]>
Sent: Tuesday, September 30, 2025 10:34 AM
To: Baldwin, Dani <[e-mail]>
Subject: [EXTERNAL] Blind Canyon Updated Review
Dani,
I assume you saw the other email clarifying that the Blind Canyon site is not in the ozone non-attainment area. Attached is
my updated review with your comments addressed.
Thanks,
Stockton
--
Stockton J. Antczak | Permitting Engineer | Major New Source Review
385-306-6724 (cell)
9/30/25, 1:55 PM State of Utah Mail - SIGNED Blind Canyon Updated Review
https://mail.google.com/mail/u/0/?ik=15596fcb07&view=pt&search=all&permthid=thread-f:1844717312397849345&simpl=msg-f:1844717312397849345 1/2
195 North 1950 West, Salt Lake City, UT 84116
Blind Canyon CS RN130790015 2025-9-30 SIGNED.pdf
305K
9/30/25, 1:55 PM State of Utah Mail - SIGNED Blind Canyon Updated Review
https://mail.google.com/mail/u/0/?ik=15596fcb07&view=pt&search=all&permthid=thread-f:1844717312397849345&simpl=msg-f:1844717312397849345 2/2
Stockton Antczak <[e-mail]>
SLEIS ozone MWP Comments for 10-Year Review of Blind Canyon Site
5 messages
Baldwin, Dani <[e-mail]>Tue, Sep 30, 2025 at 8:38 AM
To: Stockton Antczak <[e-mail]>
Cc: Elizabeth Slade <[e-mail]>, Catherine Williams <[e-mail]>
Hi Stockton,
My recollection is the SLEIS team added it to our annual emissions tool one year. But I may be
wrong. I have cc'd my regular contacts.
The SLEIS ID is Blind Canyon Compressor Station (13079).
Thanks,
Dani
Dani Baldwin | She/Her/Hers | What’s This? | Williams
Environmental Specialist | Western Interstates
Cell: [phone] | 650 South Main Street, Suite 300, Salt Lake City, UT 84101
Williams.com | Facebook | X | LinkedIn | YouTube | Instagram | Newsroom
If you have received this message in error, please reply to advise the sender of the error and then immediately delete this
message.

From: Stockton Antczak <[e-mail]>
Sent: Tuesday, September 30, 2025 8:33 AM
To: Baldwin, Dani <[e-mail]>
Subject: [EXTERNAL] Re: ozone MWP Comments for 10-Year Review of Blind Canyon Site

***CAUTION! EXTERNAL SENDER*** STOP. ASSESS. VERIFY!! If suspicious, STOP and click the Phish Alert Button
Dani,
Do you know who originally reached out to you about being in a non-attainment area? I'm pretty sure you aren't but I want
to check with them to see if maybe they have information I don't.
Thanks,
Stockton
On Wed, Sep 24, 2025 at 2:31 PM Stockton Antczak <[e-mail]> wrote:
Dani,
It looks like those coordinates are for your Vernal Compressor Station, Site ID 10756 and AO number DAQE-
AN107560012-24. That site is definitely inside the Uinta ozone non-attainment area. Perhaps that is where the
9/30/25, 1:55 PM State of Utah Mail - SLEIS ozone MWP Comments for 10-Year Review of Blind Canyon Site
https://mail.google.com/mail/u/0/?ik=15596fcb07&view=pt&search=all&permthid=thread-f:1844700161421758928&simpl=msg-f:184470016142175892…1/7
confusion is? I plan to ask about how accurate our maps on our website are so that I can give you a more definite
answer on whether the blind canyon site is in the NAA or not.
Thanks,
Stockton
On Wed, Sep 24, 2025 at 2:23 PM Baldwin, Dani <[e-mail]> wrote:
Hi Stockton,
I remember a very old question or email about the facilities location in the permit. Can you
please map the old 2012 UTM coordinates (yellow) and see if that is why the Division told me
Blind Canyon was ozone non-attainment?
If we are not required to report then I need to document the confusion.
Has the DAQ's ozone map (blue in your screenshot) changed since CY2021 (we reported in
2022)?
Thanks.
OLD 2012 issued permit
UTM coordinates: 641, 178 m Basting, 4,492,17 1 m Northing, UTM Zone 12
NEW 2025 draft

UTM Projection 567,933 m Easting, 4,411,180 m Northing
UTM Datum NAD83
UTM Zone UTM Zone 12
Dani
Dani Baldwin | She/Her/Hers | What’s This? | Williams
Environmental Specialist | Western Interstates
Cell: [phone] | 650 South Main Street, Suite 300, Salt Lake City, UT 84101
Williams.com | Facebook | X | LinkedIn | YouTube | Instagram | Newsroom
If you have received this message in error, please reply to advise the sender of the error and then immediately delete this
message.

From: Stockton Antczak <[e-mail]>
Sent: Wednesday, September 24, 2025 1:16 PM
To: Baldwin, Dani <[e-mail]>
Subject: [EXTERNAL] Re: MWP Comments for 10-Year Review of Blind Canyon Site

***CAUTION! EXTERNAL SENDER*** STOP. ASSESS. VERIFY!! If suspicious, STOP and click the Phish Alert Button
Dani,
9/30/25, 1:55 PM State of Utah Mail - SLEIS ozone MWP Comments for 10-Year Review of Blind Canyon Site
https://mail.google.com/mail/u/0/?ik=15596fcb07&view=pt&search=all&permthid=thread-f:1844700161421758928&simpl=msg-f:184470016142175892…2/7
Sorry I sent you the review with so many edits to be made. I was able to update my review based on your comments
and it is attached to this email.
In regard to #4 above, from what I can find, the blind canyon site is a few miles outside the Uinta Basin ozone non-
attainment area. I checked using both the interactive map and non-attainment area locator tool on the DAQ website.
Attached is a screenshot from the non-attainment locator tool. The pin is the blind canyon facility, the blue area is the
non-attainment area.
For #5, "THE APPROVED EQUIPMENT" Is standard for all permits so I have left it as is.
For #7 I chose to replace Questar with "the owner/operator." We tend to avoid putting owner names in permits
because it leads to situations like this where we miss changing it.
Let me know if you have any further comments.
Thanks,
Stockton
On Wed, Sep 24, 2025 at 10:59 AM Baldwin, Dani <[e-mail]> wrote:
Hi Stockton,
Thank you for the opportunity to review the draft AO. Here are the comments for your
consideration. Please let me know if you have any questions regarding this request for
changes.
1. Please update the date of the letter before I have the RO sign it since the letter says
MWP has 10 days to sign. The letter is dated September 3.
2. Please update the email to [e-mail]
a. Both Williams emails work but I prefer Dani to keep contact consistency.
3. Please update our mailing address:
a. MountainWest Pipeline, LLC, 650 South Main Street, Suite 300, Salt Lake City,
Utah 84101
4. Please confirm Utah’s Administrative Code (UAC) R307-150-9. It is my understanding
that Blind Canyon Compressor Station is within the designated ozone nonattainment
area. Therefore, Blind Canyon Compressor Station is required to submit an Annual
Ozone Emission Statement.
a. Therefore Page 2, General Description should be updated with a sentence
about ozone: “This location is in nonattainment for ozone.”
5. Suggestion: for Page 5, THE APPROVED EQUIPMENT remove THE as a
grammatical edit.
6. Suggestion: Page 5, II.A.4, change “horse power” to “hp” as a grammatical edit.
7. Please replace “Questar” and replace with “MountainWest Pipeline” on page 6
(II.B.1.b)
8. Please remove the period after 3.97. on page 6 (II.B.2.a)
9. Should Page 6, II.B.2.b, Test Frequency, have a reference of R307-165-2 instead
R307-401-8?
10. Suggestion: Page 6, II.B.2.c.1, Volumetric Flow Rate – Please revise the language to
be similar to the NOx and CO conditions.
9/30/25, 1:55 PM State of Utah Mail - SLEIS ozone MWP Comments for 10-Year Review of Blind Canyon Site
https://mail.google.com/mail/u/0/?ik=15596fcb07&view=pt&search=all&permthid=thread-f:1844700161421758928&simpl=msg-f:184470016142175892…3/7
a. 40 CFR 60, Appendix A, Method 2; Method 19; or other EPA-approved testing
method as acceptable to the Director. [R307-401-8]
11. Could you please add a condition (e.g., II.B.2.c.5, Test Notification) “MountainWest
Pipeline shall notify the director of the date, time and place of stack testing no less
than 30 days, before conducting a stack test, and provide a copy of the source test
protocol to the director. [R307-165-3]“
12. Could you please add a condition (e.g., II.B.2.c.6, Test Report) “MountainWest
Pipeline shall submit a written report of the results from the stack testing to the director
no later than 60 days after completion of the stack testing. The report shall include
validated results and supporting information. [R307-165-5]”
Dani
Dani Baldwin | She/Her/Hers | What’s This? | Williams
Environmental Specialist | Western Interstates
Cell: [phone] | 650 South Main Street, Suite 300, Salt Lake City, UT 84101
Williams.com | Facebook | X | LinkedIn | YouTube | Instagram | Newsroom
If you have received this message in error, please reply to advise the sender of the error and then immediately delete this
message.

From: Stockton Antczak <[e-mail]>
Sent: Tuesday, September 23, 2025 10:29 AM
To: Baldwin, Dani <[e-mail]>
Subject: [EXTERNAL] 10-Year Review of Blind Canyon Site

***CAUTION! EXTERNAL SENDER*** STOP. ASSESS. VERIFY!! If suspicious, STOP and click the Phish Alert Button
Dani,
Here is a copy of my 10-year review for the Blind Canyon site. Please take a look at it and let me know if you have
any questions or concerns.
Thanks,
Stockton
--
Stockton J. Antczak | Permitting Engineer | Major New Source Review
385-306-6724 (cell)
195 North 1950 West, Salt Lake City, UT 84116
9/30/25, 1:55 PM State of Utah Mail - SLEIS ozone MWP Comments for 10-Year Review of Blind Canyon Site
https://mail.google.com/mail/u/0/?ik=15596fcb07&view=pt&search=all&permthid=thread-f:1844700161421758928&simpl=msg-f:184470016142175892…4/7
Catherine Williams <[e-mail]>Tue, Sep 30, 2025 at 9:25 AM
To: "Baldwin, Dani" <[e-mail]>
Cc: Stockton Antczak <[e-mail]>, Elizabeth Slade <[e-mail]>
Hi Dani and Stockton,
Here's a screenshot of the location info in SLEIS:
The UTM's match what I see as the most recent AO in TEMPO, DAQE-AN130790006-
12. SLEIS converts the UTM's to lat/longs, which I plugged into the NAA area map,
which shows 13079 is in the Uinta Basin Ozone Moderate Nonattainment Area:
Let me know if you have different info that would change the status. Thanks!
[Quoted text hidden]
Stockton Antczak <[e-mail]>Tue, Sep 30, 2025 at 9:39 AM
To: Catherine Williams <[e-mail]>
Cc: "Baldwin, Dani" <[e-mail]>, Elizabeth Slade <[e-mail]>
Catherine,
I think there is some confusion with the site coordinates. The coordinates shown in the screenshot you sent are for the
Vernal Compressor Station, Site ID 10756. I think there was some confusion a while ago when the permits were last
updated and the incorrect coordinates were assigned to the Blind Canyon site. I am currently working on a 10-year review
that is updating these coordinates. The correct coordinates for the Blind Canyon site are as follows:
Lat/Long: 39.8479804992676, -110.205902099609
UTM: 567,933 m Easting, 4,411,180 m Northing
Here is a screenshot of the site plotted next to the Uinta ozone NAA.
9/30/25, 1:55 PM State of Utah Mail - SLEIS ozone MWP Comments for 10-Year Review of Blind Canyon Site
https://mail.google.com/mail/u/0/?ik=15596fcb07&view=pt&search=all&permthid=thread-f:1844700161421758928&simpl=msg-f:184470016142175892…5/7
If the NAA area locator tool is a definitive source to see if a source is in a NAA or not, can we say that this site is definitely
not in the ozone NAA and remove the owner's responsibility for submitting the annual reports for this site?
Thanks,
Stockton
[Quoted text hidden]
Catherine Williams <[e-mail]>Tue, Sep 30, 2025 at 10:01 AM
To: Stockton Antczak <[e-mail]>
Cc: "Baldwin, Dani" <[e-mail]>, Elizabeth Slade <[e-mail]>
Okay, great. I'm glad you are getting the correct coordinates! Yes, I agree the NAA area
locator tool is the definitive source for if a facility is in the NAA. I updated the
coordinates in SLEIS and removed the annual reporting requirement. So, Dani, this
facility only has to report every three years now. Thanks!
[Quoted text hidden]
Baldwin, Dani <[e-mail]>Tue, Sep 30, 2025 at 10:42 AM
To: Catherine Williams <[e-mail]>
Cc: Elizabeth Slade <[e-mail]>, Stockton Antczak <[e-mail]>
Great thanks Catherine.
Dani
Dani Baldwin | She/Her/Hers | What’s This? | Williams
Environmental Specialist | Western Interstates
Cell: [phone] | 650 South Main Street, Suite 300, Salt Lake City, UT 84101
Williams.com | Facebook | X | LinkedIn | YouTube | Instagram | Newsroom
If you have received this message in error, please reply to advise the sender of the error and then immediately delete this
message.

9/30/25, 1:55 PM State of Utah Mail - SLEIS ozone MWP Comments for 10-Year Review of Blind Canyon Site
https://mail.google.com/mail/u/0/?ik=15596fcb07&view=pt&search=all&permthid=thread-f:1844700161421758928&simpl=msg-f:184470016142175892…6/7
From: Catherine Williams <[e-mail]>
Sent: Tuesday, September 30, 2025 10:01 AM
To: Stockton Antczak <[e-mail]>
Cc: Baldwin, Dani <[e-mail]>; Elizabeth Slade <[e-mail]>
Subject: [EXTERNAL] Re: SLEIS ozone MWP Comments for 10-Year Review of Blind Canyon Site

[Quoted text hidden]
9/30/25, 1:55 PM State of Utah Mail - SLEIS ozone MWP Comments for 10-Year Review of Blind Canyon Site
https://mail.google.com/mail/u/0/?ik=15596fcb07&view=pt&search=all&permthid=thread-f:1844700161421758928&simpl=msg-f:184470016142175892…7/7
Stockton Antczak <[e-mail]>
ozone MWP Comments for 10-Year Review of Blind Canyon Site
3 messages
Baldwin, Dani <[e-mail]>Wed, Sep 24, 2025 at 2:23 PM
To: Stockton Antczak <[e-mail]>
Hi Stockton,
I remember a very old question or email about the facilities location in the permit. Can you please
map the old 2012 UTM coordinates (yellow) and see if that is why the Division told me Blind
Canyon was ozone non-attainment?
If we are not required to report then I need to document the confusion.
Has the DAQ's ozone map (blue in your screenshot) changed since CY2021 (we reported in
2022)?
Thanks.
OLD 2012 issued permit
UTM coordinates: 641, 178 m Basting, 4,492,17 1 m Northing, UTM Zone 12
NEW 2025 draft

UTM Projection 567,933 m Easting, 4,411,180 m Northing
UTM Datum NAD83
UTM Zone UTM Zone 12
Dani
Dani Baldwin | She/Her/Hers | What’s This? | Williams
Environmental Specialist | Western Interstates
Cell: [phone] | 650 South Main Street, Suite 300, Salt Lake City, UT 84101
Williams.com | Facebook | X | LinkedIn | YouTube | Instagram | Newsroom
If you have received this message in error, please reply to advise the sender of the error and then immediately delete this
message.

From: Stockton Antczak <[e-mail]>
Sent: Wednesday, September 24, 2025 1:16 PM
9/30/25, 1:55 PM State of Utah Mail - ozone MWP Comments for 10-Year Review of Blind Canyon Site
https://mail.google.com/mail/u/0/?ik=15596fcb07&view=pt&search=all&permthid=thread-f:1844178214903070760&simpl=msg-f:184417821490307076…1/4
To: Baldwin, Dani <[e-mail]>
Subject: [EXTERNAL] Re: MWP Comments for 10-Year Review of Blind Canyon Site

***CAUTION! EXTERNAL SENDER*** STOP. ASSESS. VERIFY!! If suspicious, STOP and click the Phish Alert Button
Dani,
Sorry I sent you the review with so many edits to be made. I was able to update my review based on your comments and
it is attached to this email.
In regard to #4 above, from what I can find, the blind canyon site is a few miles outside the Uinta Basin ozone non-
attainment area. I checked using both the interactive map and non-attainment area locator tool on the DAQ website.
Attached is a screenshot from the non-attainment locator tool. The pin is the blind canyon facility, the blue area is the non-
attainment area.
For #5, "THE APPROVED EQUIPMENT" Is standard for all permits so I have left it as is.
For #7 I chose to replace Questar with "the owner/operator." We tend to avoid putting owner names in permits because it
leads to situations like this where we miss changing it.
Let me know if you have any further comments.
Thanks,
Stockton
On Wed, Sep 24, 2025 at 10:59 AM Baldwin, Dani <[e-mail]> wrote:
Hi Stockton,
Thank you for the opportunity to review the draft AO. Here are the comments for your
consideration. Please let me know if you have any questions regarding this request for changes.
1. Please update the date of the letter before I have the RO sign it since the letter says MWP
has 10 days to sign. The letter is dated September 3.
2. Please update the email to [e-mail]
a. Both Williams emails work but I prefer Dani to keep contact consistency.
3. Please update our mailing address:
a. MountainWest Pipeline, LLC, 650 South Main Street, Suite 300, Salt Lake City,
Utah 84101
4. Please confirm Utah’s Administrative Code (UAC) R307-150-9. It is my understanding
that Blind Canyon Compressor Station is within the designated ozone nonattainment
area. Therefore, Blind Canyon Compressor Station is required to submit an Annual
Ozone Emission Statement.
a. Therefore Page 2, General Description should be updated with a sentence about
ozone: “This location is in nonattainment for ozone.”
5. Suggestion: for Page 5, THE APPROVED EQUIPMENT remove THE as a grammatical
edit.
6. Suggestion: Page 5, II.A.4, change “horse power” to “hp” as a grammatical edit.
7. Please replace “Questar” and replace with “MountainWest Pipeline” on page 6 (II.B.1.b)
8. Please remove the period after 3.97. on page 6 (II.B.2.a)
9. Should Page 6, II.B.2.b, Test Frequency, have a reference of R307-165-2 instead R307-
401-8?
9/30/25, 1:55 PM State of Utah Mail - ozone MWP Comments for 10-Year Review of Blind Canyon Site
https://mail.google.com/mail/u/0/?ik=15596fcb07&view=pt&search=all&permthid=thread-f:1844178214903070760&simpl=msg-f:184417821490307076…2/4
10. Suggestion: Page 6, II.B.2.c.1, Volumetric Flow Rate – Please revise the language to be
similar to the NOx and CO conditions.
a. 40 CFR 60, Appendix A, Method 2; Method 19; or other EPA-approved testing
method as acceptable to the Director. [R307-401-8]
11. Could you please add a condition (e.g., II.B.2.c.5, Test Notification) “MountainWest
Pipeline shall notify the director of the date, time and place of stack testing no less than 30
days, before conducting a stack test, and provide a copy of the source test protocol to the
director. [R307-165-3]“
12. Could you please add a condition (e.g., II.B.2.c.6, Test Report) “MountainWest Pipeline
shall submit a written report of the results from the stack testing to the director no later
than 60 days after completion of the stack testing. The report shall include validated
results and supporting information. [R307-165-5]”
Dani
Dani Baldwin | She/Her/Hers | What’s This? | Williams
Environmental Specialist | Western Interstates
Cell: [phone] | 650 South Main Street, Suite 300, Salt Lake City, UT 84101
Williams.com | Facebook | X | LinkedIn | YouTube | Instagram | Newsroom
If you have received this message in error, please reply to advise the sender of the error and then immediately delete this
message.

From: Stockton Antczak <[e-mail]>
Sent: Tuesday, September 23, 2025 10:29 AM
To: Baldwin, Dani <[e-mail]>
Subject: [EXTERNAL] 10-Year Review of Blind Canyon Site

***CAUTION! EXTERNAL SENDER*** STOP. ASSESS. VERIFY!! If suspicious, STOP and click the Phish Alert Button
Dani,
Here is a copy of my 10-year review for the Blind Canyon site. Please take a look at it and let me know if you have any
questions or concerns.
Thanks,
Stockton
--
Stockton J. Antczak | Permitting Engineer | Major New Source Review
385-306-6724 (cell)
9/30/25, 1:55 PM State of Utah Mail - ozone MWP Comments for 10-Year Review of Blind Canyon Site
https://mail.google.com/mail/u/0/?ik=15596fcb07&view=pt&search=all&permthid=thread-f:1844178214903070760&simpl=msg-f:184417821490307076…3/4
195 North 1950 West, Salt Lake City, UT 84116
Stockton Antczak <[e-mail]>Wed, Sep 24, 2025 at 2:31 PM
To: "Baldwin, Dani" <[e-mail]>
Dani,
It looks like those coordinates are for your Vernal Compressor Station, Site ID 10756 and AO number DAQE-
AN107560012-24. That site is definitely inside the Uinta ozone non-attainment area. Perhaps that is where the confusion
is? I plan to ask about how accurate our maps on our website are so that I can give you a more definite answer on
whether the blind canyon site is in the NAA or not.
Thanks,
Stockton
[Quoted text hidden]
Stockton Antczak <[e-mail]>Tue, Sep 30, 2025 at 8:33 AM
To: "Baldwin, Dani" <[e-mail]>
Dani,
Do you know who originally reached out to you about being in a non-attainment area? I'm pretty sure you aren't but I want
to check with them to see if maybe they have information I don't.
Thanks,
Stockton
[Quoted text hidden]
9/30/25, 1:55 PM State of Utah Mail - ozone MWP Comments for 10-Year Review of Blind Canyon Site
https://mail.google.com/mail/u/0/?ik=15596fcb07&view=pt&search=all&permthid=thread-f:1844178214903070760&simpl=msg-f:184417821490307076…4/4
Stockton Antczak <[e-mail]>
MWP Comments for 10-Year Review of Blind Canyon Site
3 messages
Baldwin, Dani <[e-mail]>Wed, Sep 24, 2025 at 10:59 AM
To: Stockton Antczak <[e-mail]>
Hi Stockton,
Thank you for the opportunity to review the draft AO. Here are the comments for your
consideration. Please let me know if you have any questions regarding this request for changes.
1. Please update the date of the letter before I have the RO sign it since the letter says MWP
has 10 days to sign. The letter is dated September 3.
2. Please update the email to [e-mail]
a. Both Williams emails work but I prefer Dani to keep contact consistency.
3. Please update our mailing address:
a. MountainWest Pipeline, LLC, 650 South Main Street, Suite 300, Salt Lake City, Utah
84101
4. Please confirm Utah’s Administrative Code (UAC) R307-150-9. It is my understanding that
Blind Canyon Compressor Station is within the designated ozone nonattainment area.
Therefore, Blind Canyon Compressor Station is required to submit an Annual Ozone
Emission Statement.
a. Therefore Page 2, General Description should be updated with a sentence about
ozone: “This location is in nonattainment for ozone.”
5. Suggestion: for Page 5, THE APPROVED EQUIPMENT remove THE as a grammatical edit.
6. Suggestion: Page 5, II.A.4, change “horse power” to “hp” as a grammatical edit.
7. Please replace “Questar” and replace with “MountainWest Pipeline” on page 6 (II.B.1.b)
8. Please remove the period after 3.97. on page 6 (II.B.2.a)
9. Should Page 6, II.B.2.b, Test Frequency, have a reference of R307-165-2 instead R307-
401-8?
10. Suggestion: Page 6, II.B.2.c.1, Volumetric Flow Rate – Please revise the language to be
similar to the NOx and CO conditions.
a. 40 CFR 60, Appendix A, Method 2; Method 19; or other EPA-approved testing
method as acceptable to the Director. [R307-401-8]
11. Could you please add a condition (e.g., II.B.2.c.5, Test Notification) “MountainWest Pipeline
shall notify the director of the date, time and place of stack testing no less than 30 days,
before conducting a stack test, and provide a copy of the source test protocol to the director.
[R307-165-3]“
9/30/25, 1:54 PM State of Utah Mail - MWP Comments for 10-Year Review of Blind Canyon Site
https://mail.google.com/mail/u/0/?ik=15596fcb07&view=pt&search=all&permthid=thread-f:1844165422377315363&simpl=msg-f:184416542237731536…1/4
12. Could you please add a condition (e.g., II.B.2.c.6, Test Report) “MountainWest Pipeline shall
submit a written report of the results from the stack testing to the director no later than 60
days after completion of the stack testing. The report shall include validated results and
supporting information. [R307-165-5]”
Dani
Dani Baldwin | She/Her/Hers | What’s This? | Williams
Environmental Specialist | Western Interstates
Cell: [phone] | 650 South Main Street, Suite 300, Salt Lake City, UT 84101
Williams.com | Facebook | X | LinkedIn | YouTube | Instagram | Newsroom
If you have received this message in error, please reply to advise the sender of the error and then immediately delete this
message.

From: Stockton Antczak <[e-mail]>
Sent: Tuesday, September 23, 2025 10:29 AM
To: Baldwin, Dani <[e-mail]>
Subject: [EXTERNAL] 10-Year Review of Blind Canyon Site

***CAUTION! EXTERNAL SENDER*** STOP. ASSESS. VERIFY!! If suspicious, STOP and click the Phish Alert Button
Dani,
Here is a copy of my 10-year review for the Blind Canyon site. Please take a look at it and let me know if you have any
questions or concerns.
Thanks,
Stockton
--
Stockton J. Antczak | Permitting Engineer | Major New Source Review
385-306-6724 (cell)
195 North 1950 West, Salt Lake City, UT 84116
Stockton Antczak <[e-mail]>Wed, Sep 24, 2025 at 1:16 PM
To: "Baldwin, Dani" <[e-mail]>
Dani,
Sorry I sent you the review with so many edits to be made. I was able to update my review based on your comments and
it is attached to this email.
9/30/25, 1:54 PM State of Utah Mail - MWP Comments for 10-Year Review of Blind Canyon Site
https://mail.google.com/mail/u/0/?ik=15596fcb07&view=pt&search=all&permthid=thread-f:1844165422377315363&simpl=msg-f:184416542237731536…2/4
In regard to #4 above, from what I can find, the blind canyon site is a few miles outside the Uinta Basin ozone non-
attainment area. I checked using both the interactive map and non-attainment area locator tool on the DAQ website.
Attached is a screenshot from the non-attainment locator tool. The pin is the blind canyon facility, the blue area is the non-
attainment area.
For #5, "THE APPROVED EQUIPMENT" Is standard for all permits so I have left it as is.
For #7 I chose to replace Questar with "the owner/operator." We tend to avoid putting owner names in permits because it
leads to situations like this where we miss changing it.
Let me know if you have any further comments.
Thanks,
Stockton
[Quoted text hidden]
2 attachments
Screenshot 2025-09-24 113918.png
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Baldwin, Dani <[e-mail]>Wed, Sep 24, 2025 at 1:56 PM
To: Stockton Antczak <[e-mail]>
Hi Stockton,
Here are a few more comments. 🙂 I need to look more into the Ozone map and the facility
coordinates. A few years ago, the Division told me Blind Canyon was Ozone non-attainment, and
that we needed to submit an annual report in SLEIS.
1. Please update our mailing address on the cover letter page and page 1 to the following
address:
a. MountainWest Pipeline, LLC, 650 South Main Street, Suite 300, Salt Lake City, Utah
84101
2. Could you please remove condition II.B.2.b.2, Test Notification? Condition II.B.2.b.1, Test
Notification above is identical to II.B.2.b.2.
3. Suggestion: Page 6, II.B.2.c.1, Volumetric Flow Rate – Please revise the reference from 40
CFR +0 to 40 CFR 60.
Thanks for making these changes.
Dani
Dani Baldwin | She/Her/Hers | What’s This? | Williams
Environmental Specialist | Western Interstates
Cell: [phone] | 650 South Main Street, Suite 300, Salt Lake City, UT 84101
Williams.com | Facebook | X | LinkedIn | YouTube | Instagram | Newsroom
9/30/25, 1:54 PM State of Utah Mail - MWP Comments for 10-Year Review of Blind Canyon Site
https://mail.google.com/mail/u/0/?ik=15596fcb07&view=pt&search=all&permthid=thread-f:1844165422377315363&simpl=msg-f:184416542237731536…3/4
If you have received this message in error, please reply to advise the sender of the error and then immediately delete this
message.

From: Stockton Antczak <[e-mail]>
Sent: Wednesday, September 24, 2025 1:16 PM
To: Baldwin, Dani <[e-mail]>
Subject: [EXTERNAL] Re: MWP Comments for 10-Year Review of Blind Canyon Site

[Quoted text hidden]
9/30/25, 1:54 PM State of Utah Mail - MWP Comments for 10-Year Review of Blind Canyon Site
https://mail.google.com/mail/u/0/?ik=15596fcb07&view=pt&search=all&permthid=thread-f:1844165422377315363&simpl=msg-f:184416542237731536…4/4
Stockton Antczak <[e-mail]>
Blind Canyon Compressor Station Question
2 messages
Stockton Antczak <[e-mail]>Wed, Sep 3, 2025 at 11:20 AM
To: [e-mail]
Danell,
My name is Stockton Antczak. Jacob changed positions at the DEQ so I have taken over working on the 10-year review
for the Blind Canyon Compressor Station. Sorry for the delay on this, I ran into some confusion with another nearby
source that I was working on and it took some time to resolve. I just have a quick question about which federal standards
are applicable to some of the equipment at the Blind Canyon Compressor Station. While compliance was reviewing my
10-year review of the site, they asked if the compressors are applicable to 40 CFR 60 Subpart OOOO, and if the two
generators are applicable to 40 CFR 63 Subpart ZZZZ. If you could let me know if these pieces of equipment are subject
to those subparts I would appreciate it. Once I hear back from you it shouldn't take very long for me to send over my
engineering review for you to look over.
Thanks,
Stockton
--
Stockton J. Antczak | Permitting Engineer | Major New Source Review
385-306-6724 (cell)
195 North 1950 West, Salt Lake City, UT 84116
Baldwin, Dani <[e-mail]>Wed, Sep 3, 2025 at 11:32 AM
To: Stockton Antczak <[e-mail]>
Hi Stockton,
The 2 turbine compressors are NOT applicable to 40 CFR 60 (NSPS) Subpart OOOO,
OOOOa, or OOOOb.
The turbines are applicable to NSPS Subpart KKKK for emissions testing.
The two generator engines are applicable to 40 CFR 63 (NESHAP) Subpart ZZZZ and are
considered "Remote Engines" under ZZZZ.
The engines are NOT applicable to NSPS Subpart JJJJ.
Regards,
Dani
Dani Baldwin | She/Her/Hers | What’s This? | Williams
Environmental Specialist | MountainWest Pipeline
Cell: [phone] | 650 South Main Street, 3rd Floor, Salt Lake City, UT 84101
Williams.com | Facebook | X | LinkedIn | YouTube | Instagram | Newsroom
9/30/25, 1:54 PM State of Utah Mail - Blind Canyon Compressor Station Question
https://mail.google.com/mail/u/0/?ik=15596fcb07&view=pt&search=all&permthid=thread-a:r8364145097317333594&simpl=msg-a:r-723435576062365…1/2
If you have received this message in error, please reply to advise the sender of the error and then immediately delete this
message.

From: Stockton Antczak <[e-mail]>
Sent: Wednesday, September 3, 2025 11:20 AM
To: Baldwin, Dani <[e-mail]>
Subject: [EXTERNAL] Blind Canyon Compressor Station Question
[Quoted text hidden]
9/30/25, 1:54 PM State of Utah Mail - Blind Canyon Compressor Station Question
https://mail.google.com/mail/u/0/?ik=15596fcb07&view=pt&search=all&permthid=thread-a:r8364145097317333594&simpl=msg-a:r-723435576062365…2/2



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