Air Pollution Control (2023)

Air Pollution Control

Title V Permit to Operate

Statement of Basis for Permit No V-SUIT-0029-2023.00

March 12, 2024

Northwest Pipeline LLC

La Plata B Compressor Station

Southern Ute Indian Reservation

La Plata County, Colorado

1. Facility Information

a. Location

The La Plata B Compressor Station, owned and operated by Northwest Pipeline LLC (Northwest) is located

within the exterior boundary of the Southern Ute Indian Reservation. The exact location is Section 35,

T34N, R9W, in La Plata County, at latitude North 37.14358 and longitude West -107.78723. The Mailing

address is:

Northwest Pipeline LLC

La Plata B Compressor Station

P.O. Box 58900

Salt Lake City, UT 84158

b. Contacts

Facility Contact:

Derek Forsberg

Environmental Specialist

Northwest Pipeline LLC

P.O. Box 58900

Salt Lake City, UT 84158

(801)-584-6748

Responsible Official:

Camilo Amezquita

VP/GM

Northwest Pipeline LLC

2800 Post Oak Blvd.

Houston, TX 77056

(713)-215-2524

c. Description of Operations

The La Plata B Compressor Station is a natural gas compression and transmission facility located in La

Plata County, Colorado. Natural gas is received at the station through a single inlet line from other gas

conditioning plants and then compressed at the station. The La Plata B Compressor Station uses two Solar

Taurus Model 60 T6502S Turbines to provide compression for Northwest Pipeline's mainline natural gas

pipeline system.

Auxiliary equipment at the compressor station includes a 565 bhp Reciprocating Engine (G001) driving

an emergency generator (IEU-01), 2.51 MMBtu/hr Boiler (IEU-1), 0.025 MMBtu/hr Space Heaters (Qty:

13) (IEU-2), .50 MMBtu/hr Catalytic Heater (IEU-3), 100 bbl Used Oil/Condensate Storage Tank (IEU4), and Process Piping & Equipment Leaks (IEU-5).

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d. List of All Units and Emission-Generating Activities

Northwest provided the information contained in Tables 1 and 2 in its Part 70 permit renewal application.

Table 1 lists emission units and emission generating activities, including any air pollution control devices.

Emission units identified as “insignificant” emitting units (IEUs) are listed separately in Table 2.

Emission

Unit ID

Table 1 – Emission Units

Northwest Pipeline LLC, La Plata B Compressor Station

Description

Control

Equipment

Solar Taurus 60 T6502S Natural Gas-Fired Simple Cycle Turbine

44.56 MMBtu/hr

P001

Serial No.

OHC11-T9506

Install Date:

11/01/1992

P002

Serial No.

OHG10-T5080

Install Date:

11/01/1992

Caterpillar 3412 SITA Natural Gas-Fired Emergency 4SRB Generator

600 Nameplate Rated HP

G001

Serial No.

7DB00769

Install Date:

None

None

06/01/1992

The Southern Ute Indian Tribe/State of Colorado Environmental Commission’s Reservation Air Code

allows sources to separately list in the permit application units or activities that qualify as “insignificant”

based on potential emissions below 2 tpy for all regulated pollutants that are not listed as hazardous air

pollutants (HAPs) under Section 112(b) of the Clean Air Act (CAA) and below 1,000 lbs. per year or the

de minimis level established under Section 112(g), whichever is lower, for HAP emissions

[RAC 2-106(4)(f); RAC 1-103(36) and (37)]. However, the application may not omit information needed

to determine the applicability of, or to impose, any applicable requirement, or to calculate the fee

[RAC 2-106(4)(f)]. Units that qualify as “insignificant” for the purposes of the Part 70 application are in

no way exempt from applicable requirements or any requirements of the Part 70 permit.

Northwest stated in its Part 70 permit renewal application that the emission units in Table 2, below, are

insignificant. The application provided calculations for heater/boiler emissions based on EPA’s AP-42

emission factors. Northwest provided sufficient information, including EPA Tanks 4.0.9d calculations, to

verify any emissions from liquids in the tanks were insignificant. This data supports Northwest’s claim that

these units qualify as insignificant.

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Table 2 – Insignificant Emission Units

Northwest Pipeline LLC, La Plata B Compressor Station

Emission Unit ID

Amount

Description

Size

Units

IEU-1

1

Sellers Water Heater

2.5

MMBtu/hr

IEU-2

13

Space Heaters for Personal Comfort

0.025

MMBtu/hr

IEU-3

1

Catalytic Heater for Chromatograph

0.5

MMBtu/hr

IEU-4

1

Used Oil / Condensate Tank

4,200

gal

IEU-5

5,580

Piping & Equipment Leaks (Fugitives)

N/A

N/A

e. Facility Construction and/or Permitting History

Prior to the promulgation of the Part 71 operating permit requirements, the La Plata B Compressor Station

had not been required to obtain any federal air quality control permits. However, the State of Colorado

issued air pollutant emission permits 91LP792-1 and 91LP792-2, which defined requirements for the two

turbine/duct burner units. The initial Part 71 permit for the La Plata B Compressor Station was issued on

November 19, 2003 (# V-SU-0029-00.00). The first permit renewal (# V-SU-0029-08.00) was issued in

June 2009. In November 2009, the permit went through an administrative amendment. The amendments

are reflected in permit # V-SU-0029-08.01. AQP issued an initial Part 70 permit, # V-SUIT-0029-2014.00

on June 2, 2014. Renewal permit, V-SUIT-0029-2019.00, was issued on April 29, 2019. Northwest

Pipeline, LLC (Northwest) transferred ownership of emission units B001 and B002, located at the La Plata

B Compressor Station (La Plata B), to Harvest Midstream Company. Northwest submitted an

administrative permit revision request to remove emission units B001 and B002 from the Title V permit for

La Plata B. The revision was completed February 11, 2021. A renewal permit, V-SUIT-0029-2023.00, was

issued on March 12, 2024. No pre-construction permits have been issued to this facility.

f. Potential to Emit

Under RAC 1-103(51), potential to emit (PTE) is defined as the maximum capacity of a stationary source

to emit a pollutant under its physical and operational design. Any physical or operational limitation on the

capacity of the source to emit a pollutant, including air pollution control equipment and restrictions on hours

of operation or on the type or amount of material combusted, stored, or processed, shall be treated as part

of its design if the limitation, or the effect it would have on emissions, is federally enforceable.

The PTE for La Plata B Compressor Station was listed by Northwest in Forms “GIS”, “PTE”, and the

various forms “EMISS” of the Part 70 operating permit renewal application. Table 3 shows PTE data

broken down by each individual emission unit, as well as the total facility-wide PTE.

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Emission

Unit ID

Table 3 - Potential to Emit

Northwest Pipeline LLC, La Plata B Compressor Station

Regulated Air Pollutants

in tpy

NOX

VOC

SO2

PM10

CO

Lead

Total

HAPs

Largest

Single HAP

(CH2O)

GHGs

(CO2e mtpy)

P001

32.9

6.8

1.2

1.4

23.8

0.0

0.6

0.6

22,989

P002

32.9

6.8

1.2

1.4

23.8

0.0

0.6

0.6

22,989

G001

2.7

0.0

0.0

0.0

4.5

0.0

0.0

0.0

140.6

Total IEUs

1.3

0.6

0.1

0.1

1.1

0.0

0.1

0.1

423.1

69.8

14.2

2.5

2.9

53.2

0.0

1.3

1.3

46,542

2. Tribal Authority

La Plata B Compressor Station is located within the exterior boundaries of the Southern Ute Indian

Reservation and is thus within Indian Country as defined at 18 U.S.C. §1151. On March 2, 2012, the EPA

determined that the Southern Ute Indian Tribe of the Southern Ute Indian Reservation had met the

requirements of 40 CFR §70.4(b) for full approval to administer its Clean Air Act Title V, Part 70 Permitting

Program (Program). In concert with that Program approval, the EPA also found that the Tribe met the

requirements of Section 301(d)(2) of the CAA and 40 CFR §49.6 for treatment “in the same manner as a

state” for the purposes of issuing CAA Title V, Part 70 operating permits. The EPA promulgated its

approval of the Tribe’s applications on March 15, 2012 (77 FR 15267). The requirements of the Clean Air

Act Title V, Part 70 Permitting Program (Program) have been incorporated at Article II, Part 1 of the

Reservation Air Code. Therefore, the Southern Ute Indian Tribe is the appropriate governmental entity to

issue the Title V permit to this facility.

Reservation Air Code: The Reservation Air Code was adopted pursuant to the authority vested in the

Southern Ute Indian Tribe/State of Colorado Environmental Commission by (1) the Intergovernmental

Agreement Between the Southern Ute Indian Tribe and the State of Colorado Concerning Air Quality

Control on the Southern Ute Indian Reservation dated December 13, 1999, (2) tribal law (Resolution of

the Council of the Southern Ute Indian Tribe No. 00-09), (3) State law (C.R.S. § 24- 62-101), and (4) as

recognized in federal law (Act of October 18, 2004, Pub. L. No. 108-336, 118 Stat.1354).

NSPS and NESHAP Delegation: On September 6, 2013, the Southern Ute Indian Tribe received delegation

from the EPA to incorporate by reference into the Reservation Air Code and enforce certain subparts of

the new source performance standards (NSPS) and national emission standards for hazardous air pollutants

(NESHAP) under Sections 111 and 112 of the Clean Air Act, respectively (78 FR 40635). These NSPS

and NESHAP subparts generally apply to oil and gas operations within the exterior boundaries of the

Southern Ute Indian Reservation and were adopted, unchanged, into the Reservation Air Code as Parts 2

and 3.

Tribal Minor New Source Review Program: Minor sources of air pollution located within the Southern

Ute Indian Reservation exterior boundaries must comply with either the “Federal Implementation Plan for

Managing Air Emissions From True Minor Sources In Indian Country In The Oil And Natural Gas

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Production And Natural Gas Processing Segments Of The Oil And Natural Gas Sector” listed at 40 CFR

§49.101 – 105 or the “Federal Minor New Source Review Program In Indian Country” listed at 40 CFR

§49.151 – 164.

3. Applicable Requirements

The following discussion addresses a selection of the regulations from the Code of Federal Regulations

(CFR) at Title 40. Note that this discussion does not include the full spectrum of potentially applicable

regulations and is not intended to represent official applicability determinations. These discussions are

based on the information provided by Northwest Pipeline LLC in its Part 70 renewal permit application

and are only intended to present the information certified to be true and accurate by the Responsible

Official of this facility.

Tribal Minor New Source Review (TMNSR) – 40 CFR Part 49

EPA promulgated the federal rule “Review of New Sources and Modifications in Indian Country,”

otherwise known as the Tribal Minor New Source Review Rule (TMNSR), on July 1, 2011 (76 FR 38748).

The TMNSR rule applies to all new or modified industrial facilities in Indian country with a potential to

emit equal to or greater than the minor NSR thresholds, but less than the major source thresholds, which

are generally 100 to 250 tons per year (tpy). The minor NSR thresholds for attainment/unclassifiable areas

are displayed in the table below:

40 CFR 49.153 Minor NSR Thresholds

Minor NSR Thresholds for

Regulated NSR Pollutant

Attainment/Unclassifiable Areas in Tons Per

Year (TPY)

Carbon Monoxide (CO)

10

Nitrogen Oxides (NOx)

10

Sulfur Dioxide (SO2)

10

Volatile Organic Compounds (VOC)

5

PM10

5

PM2.5

3

Lead

0.1

Fluorides

1

Sulfuric Acid Mist

2

Hydrogen Sulfide (H2S)

2

Total Reduced Sulfur (including H2S)

2

Reduced Sulfur Compounds (including H2S)

2

Municipal Waste Combustor Emissions

10

Municipal Solid Waste Landfill Emissions

10

(measured as nonmethane organic compounds)

Starting August 30, 2011, all minor modifications at existing major NSR sources, requests for synthetic

minor limitations, and the transferring of synthetic minor limits from Part 71 permits into minor NSR

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permits became subject to the TMNSR rule. All true minor sources and minor modifications at existing

major sources constructed after August 30, 2011 were required to submit a registration form within 90 days

of beginning operation and obtain a permit if a general permit was available for that source category. No

general permit was available for sources in the oil and gas sector constructed or modified between August

30, 2011 and October 2, 2016 and these sources were only required to register with EPA.

On May 12, 2016, EPA finalized a Federal Implementation Plan (FIP) for true minor oil and gas sources in

Indian County. Beginning on October 3, 2016, all new and modified true minor oil and gas sources are

required to register with the EPA to obtain coverage under the FIP. Owners/operators also have the option

of apply to EPA for a source-specific permit instead of complying with the FIP, or EPA may determine that

a source-specific permit is necessary due to local or reservation-specific air quality concerns.

Future modifications at the Ignacio Gas Plant will be subject to the TMNSR rule; however, no TMNSR

permits have been issued to this facility at this time.

Prevention of Significant Deterioration (PSD) - 40 CFR 52.21

PSD is a preconstruction review requirement of the CAA that applies to proposed projects that are

sufficiently large (in terms of emissions) to be a “major” stationary source or “major” modification of an

existing stationary source. A new stationary source, or a modification to an existing minor stationary

source, is major if the proposed project has the potential to emit any pollutant regulated under the CAA in

amounts equal to or exceeding specified major source thresholds, which are 100 tpy for 28 listed industrial

source categories and 250 tpy for all other sources. PSD also applies to modifications at existing major

sources that cause a “significant net emissions increase” at that source. Significance levels for each

pollutant are defined in the PSD regulations at 40 CFR 52.21. A modification is a physical change or

change in the method of operation.

The La Plata B Compressor Station does not belong to any of the 28 listed source categories.

Therefore, the potential to emit threshold for determining PSD applicability for this source is 250

tpy. The La Plata B Compressor Station, the La Plata A Compressor Station (owned by

Transwestern Pipeline Company), and the Ignacio Gas Plant (owned by Harvest Midstream) are

considered by EPA Region 8 to be a single source for PSD permitting purposes.

The single source determination requires that the potential emissions from all components of the

source be aggregated when evaluating applicability of PSD. In addition, emissions netting

calculations must include emission increases and decreases from the entire source.

Although the La Plata B Compressor Station is a major PSD source (PTE of any one criteria

pollutant is greater than 250 tpy) as a result of the single source determination, a PSD review has

not been triggered at the La Plata B Compressor Station. Hence, Northwest Pipeline LLC has not

been required to obtain a PSD permit.

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New Source Performance Standards (NSPS)

40 CFR Part 60, Subpart A: General Provisions. This subpart applies to the owner or operator of any

stationary source that contains an affected facility, the construction or modification of which is commenced

after the date of publication of any standard in Part 60. The general provisions under Subpart A apply to

sources that are subject to the specific subparts of Part 60.

As explained below, the La Plata B Compressor Station contains affected facilities subject to the

provision of 40 CFR Part 60 Subpart GG. Therefore, the general provisions of Part 60 apply.

40 CFR Part 60, Subpart Dc: Standards of performance for Small Industrial-Commercial-Institutional

Steam Generating Units. This rule applies to steam generating units with a maximum design heat input

capacity of 100 MMBtu/hr or less, but greater than or equal to 10 MMBtu/hr.

According to Northwest, emission unit IEU-01 sellers water heater has a maximum design heat input

capacity of 2.51 MMBtu/hr. Therefore, Subpart Dc does not apply.

40 CFR Part 60, Subpart K: Standards of performance for Storage Vessels for Petroleum Liquids for which

Construction, Reconstruction, or Modification Commenced After June 11, 1973, and Prior to May 19, 1978.

This rule applies to storage vessels for petroleum liquids with a storage capacity greater than 40,000 gallons.

40 CFR Part 60, Subpart K does not apply to storage vessels for petroleum or condensate stored, processed,

and/or treated at a drilling and production facility prior to custody transfer.

According to Northwest, the La Plata B Compressor Station has no tanks with a storage capacity

greater than 40,000 gallons. Therefore, Subpart K does not apply.

40 CFR Part 60, Subpart Ka: Standards of Performance for Storage Vessels for Petroleum Liquids for which

Construction, Reconstruction, or Modification Commenced After May 18, 1978, and Prior to

June 23, 1984. This rule applies to storage vessels for petroleum liquids with a storage capacity greater

than 40,000 gallons. Subpart Ka does not apply to petroleum storage vessels with a capacity of less than

420,000 gallons used for petroleum or condensate stored, processed, or treated prior to custody transfer.

According to Northwest, the La Plata B Compressor Station has no tanks with a storage capacity

greater than 40,000 gallons. Therefore, Subpart Ka does not apply.

40 CFR Part 60, Subpart Kb: Standards of Performance for Volatile Organic Liquid Storage Vessels

(Including Petroleum Liquid Storage Vessels) for which Construction, Reconstruction, or Modification

Commenced After July 23, 1984. This rule applies to storage vessels with a capacity greater than or equal

to 75 cubic meters (~472 bbl).

According to Northwest, the La Plata B Compressor Station has no tanks with a capacity greater

than or equal to 75 m3 (~472 bbl or 19,813 gal) that are used to store volatile organic liquids.

Therefore, Subpart Kb does not apply.

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40 CFR Part 60, Subpart GG: Standards of Performance for Stationary Gas Turbines. This rule applies to

stationary gas turbines, with a heat input at peak load equal to or greater than 10.7 gigajoules per hour (10

MMBtu/hr), that commenced construction, modification, or reconstruction after October 3, 1977.

According to Northwest, turbine units P001 and P002 were each constructed after October 3, 1977;

each unit also has a heat input at peak load greater than 10 MMBtu/hr. Per 40 CFR 60.330, La

Plata B Compressor Station is subject to Subpart GG.

40 CFR Part 60, Subpart KKK: Standards of Performance for Equipment Leaks of VOC from Onshore

Natural Gas Processing Plants for which construction, reconstruction, or modification commenced after

January 20, 1984, and on or before August 23, 2011. This rule applies to compressors and other equipment

at onshore natural gas processing facilities. As defined in this subpart, a natural gas processing plant is any

processing site engaged in the extraction of natural gas liquids (NGLs) from field gas, fractionation of

mixed NGLs to natural gas products, or both. NGLs are defined as the hydrocarbons, such as ethane,

propane, butane, and pentane that are extracted from field gas.

According to Northwest, the La Plata B Compressor Station does not extract natural gas liquids

from field gas, nor does it fractionate mixed NGLs to natural gas products, and thus does not meet

the definition of a natural gas processing plant under this subpart. Therefore, Subpart KKK does

not apply.

40 CFR Part 60, Subpart LLL: Standards of Performance for SO2 emissions from Onshore Natural Gas

Processing for which construction, reconstruction, or modification commenced after January 20, 1984, and

on or before August 23, 2011. This rule applies to sweetening units and sulfur recovery units at onshore

natural gas processing facilities. As defined in this subpart, sweetening units are process devices that

separate hydrogen sulfide (H2S) and carbon dioxide (CO2) from a sour natural gas stream. Sulfur recovery

units are defined as process devices that recover sulfur from the acid gas (consisting of H2S and CO2)

removed by a sweetening unit.

According to Northwest, La Plata B Compressor Station does not perform sweetening or sulfur

recovery at the facility. Therefore, Subpart LLL does not apply

40 CFR Part 60, Subpart JJJJ: Standards of Performance for Stationary Spark Ignition Internal Combustion

Engines. This subpart establishes emission standards and compliance requirements for the control of

emissions from stationary spark ignition (SI) internal combustion engines (ICE) that commenced

construction, modification or reconstruction after June 12, 2006, where the SI ICE are manufactured on or

after specified manufacture trigger dates. The manufacture trigger dates are based on the engine type, fuel

used, and maximum engine horsepower.

For the purposes of this subpart, the date that construction commences is the date the engine is ordered by

the owner or operator (See 40 CFR 60.4230(a)).

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Table 4 – NSPS Subpart JJJJ Applicability Determination

Northwest Pipeline LLC, La Plata B Compressor Station

Unit

Serial No.

Unit Description

Fuel

Maximum

HP

Manufacture

Date

Commenced

Construction

Date

G001

7DB00769

Caterpillar 3412 SITA

Emergency 4SRB

Generator

Natural

Gas

600

1992

Prior to

6/12/2006

Trigger Date

for

Applicability –

Manufactured

on or After

7/1/2008

According to Northwest, the Caterpillar emergency generator (G001) was installed at the facility in

1992, and thus commenced construction prior to June 12, 2006. Therefore, the requirements of

Subpart JJJJ do not apply.

Should Northwest propose to install a stationary SI ICE at the La Plata B Compressor Station, which

is subject to Subpart JJJJ, Northwest will not be allowed to use the off-permit changes provision and

will be required to submit a minor permit modification application to incorporate Subpart JJJJ

requirements into the permit.

40 CFR Part 60, Subpart KKKK: Standards of Performance for Stationary Combustion Turbines. This rule

applies to stationary combustion turbines with a heat input at peak load equal to or greater than 10.7

gigajoules (10 MMBtu) per hour. This subpart establishes emission standards and compliance schedules

for the control of emissions from stationary combustion turbines that commenced construction,

modification, or reconstruction after February 18, 2005.

According to Northwest, the turbines operating at La Plata B Compressor Station (P001 and P002)

are affected units under this subpart; however, the turbines were constructed prior to February 18,

2005 and they have not been replaced with new units or modified after February 18, 2005.

Therefore, Subpart KKKK does not apply

40 CFR Part 60, Subpart OOOO: Standards of Performance for Crude Oil and Natural Gas Production,

Transmission and Distribution. This subpart establishes emission standards and compliance schedules for

the control of VOC and SO2 emissions from affected facilities that commence construction, modification

or reconstruction after August 23, 2011. Affected facilities under this subpart include gas wells,

compressors, pneumatic controllers, storage vessels, process unit equipment, and sweetening units.

According to Northwest’s application, the La Plata B Compressor Station does not have any affected

facilities under the rule that commenced construction after August 23, 2011. Therefore, Subpart

OOOO does not apply.

40 CFR Part 60, Subpart OOOOa: Standards of Performance for Crude Oil and Natural Gas Facilities. This

subpart establishes emission standards and compliance schedules for the control of volatile organic

compounds (VOC) and sulfur dioxide (SO2) emissions from affected facilities in the crude oil and natural

gas production source category that commence construction, modification, or reconstruction after

September 18, 2015Affected facilities under this subpart include gas wells, compressors, pneumatic

9

controllers, pneumatic pumps, storage vessels, and the collection of fugitive emission components at well

sites and compressor stations.

According to Northwest’s application, the La Plata B Compressor Station is not a natural gas

processing plant and does not have gas wells, storage vessels, continuous-bleed pneumatic devices,

or compressors that have been constructed, modified, or reconstructed after September 18, 2015.

Therefore, Subpart OOOOa does not apply.

National Emission Standards for Hazardous Air Pollutants (NESHAP)

40 CFR Part 63, Subpart A: General Provisions. This subpart contains national emissions standards for

HAPs that regulate specific categories of sources that emit one or more HAP regulated pollutants under the

CAA. The general provisions under subpart A apply to sources that are subject to the specific subparts of

Part 63.

As explained below, the La Plata B Compressor Station is subject to 40 CFR Part 63, Subpart ZZZZ.

Therefore, the General Provisions of Part 63 apply as specified in the relevant subparts.

40 CFR Part 63, Subpart HH: National Emission Standards for Hazardous Air Pollutants from Oil and

Natural Gas Production Facilities. This subpart applies to the owners and operators of affected units located

at natural gas production facilities that are area or major sources of HAPs, and that process, upgrade, or

store natural gas prior to the point of custody transfer, or that process, upgrade, or store natural gas prior to

the point at which natural gas enters the natural gas transmission and storage source category or is delivered

to a final end user. The affected units are glycol dehydration units, storage vessels with the potential for

flash emissions, and the group of ancillary equipment, and compressors intended to operate in volatile

hazardous air pollutant service, which are located at natural gas processing plants.

Throughput Exemption

Those sources whose maximum natural gas throughput, as appropriately calculated per §63.760(a)(1)(i)

through (a)(1)(iii), is less than 18,400 standard cubic meters per day are exempt from the requirements of

this subpart.

Source Aggregation

Major source, as used in this subpart, has the same meaning as in §63.2, except that:

1)

Emissions from any oil and gas production well with its associated equipment and emissions from

any pipeline compressor station or pump station shall not be aggregated with emissions from other

similar units.

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2)

Emissions from processes, operations, or equipment that are not part of the same facility shall not

be aggregated.

3)

For facilities that are production field facilities, only HAP emissions from glycol dehydration units

and storage vessels with the potential for flash emissions shall be aggregated for a major source

determination.

Facility

For the purpose of a major source determination, facility means oil and natural gas production and

processing equipment that is located within the boundaries of an individual surface site as defined in Subpart

HH. Examples of facilities in the oil and natural gas production category include, but are not limited to:

well sites, satellite tank batteries, central tank batteries, a compressor station that transports natural gas to a

natural gas processing plant, and natural gas processing plants.

Production Field Facility

Production field facilities are those located prior to the point of custody transfer. The definition of custody

transfer (40 CFR 63.761) means the point of transfer after the processing/treating in the producing

operation, except for the case of a natural gas processing plant, in which case the point of custody transfer

is the inlet to the plant.

Natural Gas Processing Plant

A natural gas processing plant is defined in 40 CFR 63.761 as any processing site engaged in the extraction

of NGLs from field gas, or the fractionation of mixed NGLs to natural gas products, or a combination of

both. A treating plant or gas plant that does not engage in these activities is considered to be a production

field facility.

Major Source Determination for Production Field Facilities

The definition of major source in subpart HH (at 40 CFR 63.761) states, in part, that only emissions from

the dehydration units and storage vessels at production field facilities shall be aggregated when comparing

to the major source thresholds.

For facilities that are not production field facilities, HAP emissions from all HAP emission units shall be

aggregated.

Area Source Applicability

40 CFR Part 63, Subpart HH also applies to area sources of HAPs. An area source is a HAP source whose

total HAP emissions are less than 10 tpy of any single HAP or 25 tpy for all HAPs in aggregate. This

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subpart requires different emission reduction requirements for glycol dehydration units found at oil and gas

production facilities based on their geographical location.

Units located in densely populated areas (determined by the Bureau of Census) and known as urbanized

areas with an added 2-mile offset and urban clusters of 10,000 people or more, are required to have emission

controls. Units located outside these areas will be required to have the glycol recirculation pump rate

optimized or operators must document that uncontrolled annual actual benzene emissions are less than 0.9

megagrams (1,984 lbs.).

Any source that determines that it is not a major source but has actual emissions of 5 tons per year of a

single HAP or 12.5 tons per year of a combination of HAP (i.e. 50 percent of the major source thresholds),

shall update its major source determination within 1 year of the prior determination and each year thereafter,

using gas composition data measured during the preceding 12 months.

Applicability of Subpart HH to the La Plata B Compressor Station

According to Northwest, the La Plata B Compressor Station is not a natural gas production facility

and does not have any dehydration units. Therefore, Subpart HH does not apply.

40 CFR Part 63, Subpart HHH: National Emission Standards for Hazardous Air Pollutants from Natural

Gas Transmission and Storage Facilities. This subpart applies to natural gas transmission and storage

facilities that transport or store natural gas prior to entering the pipeline to a local distribution company or

to a final end user, and that are a major source of hazardous air pollutant (HAP) emissions. Natural gas

transmission means the pipelines are used for long distance transport (excluding processing).

According to Northwest, the La Plata B Compressor Station is a natural gas transmission facility,

but it does not operate a glycol dehydration unit, nor does it have HAP emissions in excess of the

major source thresholds of 10 tpy of a single HAP or 25 tpy of HAPs in aggregate. Therefore,

Subpart HHH does not apply.

40 CFR Part 63, Subpart YYYY: National Emission Standards for Hazardous Air Pollutants from Stationary

Combustion Turbines. This rule establishes national emission limitations and work practice standards for

HAPs emitted from stationary combustion turbines. An affected source includes any stationary combustion

turbine located at a major source of HAP emissions.

Stationary Combustion Turbine:

Stationary combustion turbines are defined in §63.6175 as all equipment, including but not limited to the

turbine, the fuel, air, lubrication and exhaust gas systems, control systems (except emissions control

equipment), and any ancillary components and sub-components comprising any simple cycle stationary

combustion turbine, any regenerative/recuperative cycle stationary combustion turbine, the combustion

turbine portion of any stationary combined cycle steam/electric generating system. Stationary means that

the combustion turbine is not self-propelled or intended to be propelled while performing its function.

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Stationary combustion turbines do not include turbines located at a research or laboratory facility, if

research is conducted on the turbine itself and the turbine is not being used to power other applications at

the research or laboratory facility.

Major Source:

Major Source for purposes of this subpart has the same meaning as provided in 40 CFR 63.2 with the

exception that emissions from any oil or gas exploration or production well (with its associated equipment)

and emissions from any pipeline compressor station or pump station shall not be aggregated with emissions

from other similar units, to determine whether such emission points or station are major sources, even when

emission points are in a contiguous are or under common control.

Applicability of Subpart YYYY to the La Plata B Compressor Station

The La Plata B Compressor station is not a major source of HAPs as determined from the

requirements of this rule. Therefore, Subpart YYYY does not apply

40 CFR Part 63, Subpart ZZZZ (RICE MACT): National Emission Standards for Hazardous Air

Pollutants for Stationary Reciprocating Internal Combustion Engines (RICE). This rule establishes

national emission limitations and operating limitations for HAPs emitted from stationary spark-ignition

reciprocating internal combustion engines (SI RICE) and stationary compression ignition reciprocating

internal combustion engines (CI RICE).

For the purposes of this standard, construction or reconstruction is as defined in §63.2.

Summary of Applicability to Engines at Major Sources of HAPs

Major HAP Sources

Engine Type

Horse Power Rating

New / Existing

Applicability Trigger Date

SI RICE – All

≥ 500 HP

New

On or After:

12/19/2002

SI RICE – 4SRB

> 500 HP

Existing

Before:

12/19/2002

SI RICE – All1

≤ 500 HP

New

On or After:

6/12/2006

1

SI RICE – All

≤ 500 HP

Existing

Before:

6/12/2006

CI RICE – All2

≥ 500 HP

New

On or After:

12/19/2002

CI RICE – Non-Emergency

> 500 HP

Existing

Before:

12/19/2002

CI RICE – All2

≤ 500 HP

New

On or After:

6/12/2006

2

CI RICE – All

≤ 500 HP

Existing

Before:

6/12/2006

1. All includes emergency RICE, limited use RICE, RICE that burn land fill or digester gas, 4SLB, 2SLB, and 4SRB.

2. All includes emergency RICE and limited use RICE

1

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Summary of Applicability to Engines at Area Sources of HAPs

Area HAP Sources

Engine Type

Horse Power Rating

New / Existing

Applicability Trigger Date

SI RICE – All1

All HP

New

On or After:

6/12/2006

1

SI RICE – All

All HP

Existing

Before:

6/12/2006

CI RICE – All2

All HP

New

On or After:

6/12/2006

2

CI RICE – All

All HP

Existing

Before:

6/12/2006

1. All includes emergency RICE, limited use RICE, RICE that burn land fill or digester gas, 4SLB, 2SLB, and 4SRB.

2. All includes emergency RICE and limited use RICE

Table 4 – Applicability of 40 CFR 63, Subpart ZZZZ to the La Plata B Compressor Station

Unit

Serial

Number

Unit Description

Fuel

Site Rated

HP

G001

7DB00769

Caterpillar 3412 SITA

Emergency 4SRB Generator

Natural

Gas

Commenced Construction,

Reconstruction, or

Modification Date

565

Prior to 06/12/2006

According to Northwest, La Plata B Compressor station is an area source as defined in Subpart

ZZZZ. Unit G001 is a four-stroke rich-burn (4SRB) emergency generator engine > 500 HP

constructed before June 12, 2006 and has not been reconstructed since this date. Therefore, G001

is considered existing emergency stationary RICE, and is subject to the area source

requirements for existing emergency RICE of Subpart ZZZZ

40 CFR Part 63, Subpart DDDDD (Boiler MACT (for major sources): National Emission Standards for

Hazardous Air Pollutants for Major Sources: Industrial, Commercial, and Institutional Boilers and Process

Heaters. This rule establishes national emission limitations and work practice standards for HAPs emitted

from new and existing industrial boilers, institutional boilers, commercial boilers, and process heaters that

are located at major sources of HAPs, as defined by 40 CFR 64.7575. Boilers or process heaters that

combust natural gas for fuel or have a maximum designed heat input capacity less than 10 MMBtu/hr are

subject to work practice standards in lieu of emission limits. For the purposes of this subpart, an affected

unit is an existing unit if it was constructed prior to June 4, 2010.

According to Northwest’s application, the La Plata B Compressor Station is not a major source as

defined in this subpart. Therefore, Subpart DDDDD does not apply.

40 CFR Part 63, Subpart JJJJJJ (Boiler MACT (for area sources)): National Emission Standards for

Hazardous Air Pollutants for Area Sources: Industrial, Commercial, and Institutional Boilers. This rule

establishes national emission standards and operating limitations for HAPs emitted from new and existing

industrial boilers, institutional boilers, as defined in §63.11237, and commercial boilers that are fueled by

coal, biomass, or oil and are located at area sources of HAPs, as defined in §63.2, except for as specified in

§63.11195. For the purposes of this subpart, an affected unit is an existing unit if it was constructed prior

to June 4, 2010.

According to Northwest’s application, these units have been removed and are no longer under

Northwest’s Ownership . Therefore, Subpart JJJJJJ does not apply.

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Compliance Assurance Monitoring (CAM) Rule

40 CFR Part 64: Compliance Assurance Monitoring Provisions. According to 40 CFR 64.2(a), the CAM

rule applies to each Pollutant Specific Emission Unit (PSEU) at a major source that is required to obtain a

Part 70 or Part 71 permit if the unit satisfies all of the following criteria:

1)

The unit is subject to an emission limitation or standard for the applicable regulated air pollutant

other than an emissions limitation or standard that is exempt under §64.2(b)(1);

Ҥ64.2(b)(1): Exempt emission limitations or standards. The requirements of this part shall not

apply to any of the following emission limitations or standards:

(i)

(ii)

(iii)

(iv)

(v)

(vi)

Emission limitations or standards proposed by the Administrator after November 15, 1990

pursuant to Section 111 or 112 of the Act;

Stratospheric ozone protection requirements under Title VI of the Act;

Acid Rain Program requirements pursuant to Sections 404, 405, 406, 407(a), 407(b) or 410

of the Act;

Emissions limitations or standards or other applicable requirements that apply solely under

an emissions trading program approved or promulgated by the Administrator under the Act

that allows for trading emissions with a source or between sources;

An emissions cap that meets the requirements specified in §70.4(b)(12) or §71.6(a)(13)(iii)

of this chapter;

Emission limitations or standards for which a Part 70 or 71 permit specifies a continuous

compliance determination method, as defined in §64.1.”

Ҥ64.1: Continuous compliance method means a method, specified by the applicable standard or

an applicable permit condition, which:

(1) Is used to determine compliance with an emission limitation or standard on a continuous basis,

consistent with the averaging period established for the emission limitation or standard; and

(2) Provides data either in units of the standard or correlated directly with the compliance limit.”

2)

The unit uses a control device to achieve compliance with any such limit or standard; and

3)

The unit has pre-control device emissions of the applicable regulated pollutant that are equal to or

greater than 100% of the amount, in tons per year, required for a source to be classified as a major

source.

According to Northwest, the CAM rule does not apply to any of the units at the La Plata B

Compressor Station because neither of the PSEUs at the station use add on controls to achieve

emission limits, and the pre-controlled emissions for each unit are less than the major source

threshold. Therefore, CAM does not apply.

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Chemical Accident Prevention Program

40 CFR Part 68: Chemical Accident Prevention Provisions. This rule applies to stationary sources that

manufacture, process, use, store, or otherwise handle more than the threshold quantity of a regulated

substance in a process. Regulated substances include 77 toxic and 63 flammable substances which are

potentially present in the natural gas stream entering the facility and in the storage vessels located at the

facility. The quantity of a regulated substance in a process is determined according to the procedures

presented under §68.115. §68.115(b)(l) and (2)(i) indicate that toxic and flammable substances in a mixture

do not need to be considered when determining whether more than a threshold quantity is present at a

stationary source if the concentration of the substance is below one percent by weight of the mixture.

§68.115(b)(2)(iii) indicates that prior to entry into a natural gas processing plant, regulated substances in

naturally occurring hydrocarbon mixtures need not be considered when determining whether more than a

threshold quantity is present at a stationary source. Naturally occurring hydrocarbon mixtures include

condensate, field gas, and produced water.

According to Northwest, the La Plata B Compressor Station does not use or store any regulated

substances listed in 112(r) of the Clean Air Act that is above the threshold quantity. Therefore, the

facility is not subject to the requirement to develop and submit a risk management plan.

Stratospheric Ozone and Climate Protection

40 CFR Part 82, Subpart F: Air Conditioning Units. According to Northwest, no maintenance, service,

repair or disposal of any equipment containing Class I or Class II refrigerants chlorofluorocarbons (CFCs))

occurs at La Plata B Compressor Station. However, if Northwest were to engage in any of the afore

mentioned activities it must comply with the standards of part 82, Subpart F for recycling and emissions

reduction if they service, maintain, or repair the air conditioning units in any way or if they dispose of the

units.

40 CFR Part 82, Subpart H: Halon Fire Extinguishers. According to Northwest, there are no halon fire

extinguishers at La Plata B Compressor Station. However, should Northwest obtain any halon fire

extinguishers, then it must comply with the standards of 40 CFR Part 82, Subpart H for halon emissions

reduction, if it services, maintains, tests, repairs, or disposes of equipment that contains halon or uses such

equipment during technician training. Specifically, Northwest would be required to comply with 40 CFR

Part 82 and submit an application for a revision to this Title V permit.

Mandatory Greenhouse Gas Reporting

40 CFR Part 98: This rule requires sources above certain emission thresholds to calculate, monitor, and

report greenhouse gas emissions. The requirements of 40 CFR Part 98 and CAA §307(d)(1)(V), the CAA

authority under which 40 CFR Part 98 was promulgated, however, need not be included in a tribal-issued

Part 70 permit because those requirements are not included in the definition of “applicable requirement” in

either 40 CFR Part 70 or RAC 1-103(11). Although the rule is not an applicable requirement under 40 CFR

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Part 70 or the RAC, the source is not relieved from the requirement to comply with the rule separately from

compliance with its Part 70 operating permit. It is the responsibility of each source to determine whether

Part 98 is applicable and to comply, if necessary.

4. Public Participation

a. Public Notice

Per RAC §2-109, all Part 70 draft operating permits shall be publicly noticed and made available for public

comment. Public notice is given by publication in a newspaper of general circulation in the area where the

source is located or in a state publication designed to give general public notice, to persons on a mailing list

developed by the Tribe, including those who request in writing to be on the list, and by other means if

necessary to assure adequate notice to the affected public. If an interested person would like to be added to

the Tribe’s mailing list to be informed of future actions on permits issued by the Tribe, please send your

name and address:

by United State Postal Service to:

by any other delivery service to:

Southern Ute Indian Tribe

Environmental Programs Department

Part 70 Program

PO Box 737 MS #84

Ignacio, Colorado 81137

Southern Ute Indian Tribe

Environmental Programs Department

Part 70 Program

398 Ouray Drive

Ignacio, Colorado 81137

Public notice for the draft permit was published in the Durango Herald and the Southern Ute Drum on

November 22, 2023, in order to provide opportunity for public comment on the draft permit and the

opportunity to request a public hearing.

b. Opportunity for Comment

Members of the public were given an opportunity to review a copy of the draft permit prepared by the Tribe,

the application, the statement of basis for the draft permit, and all supporting materials for the draft permit.

Copies of these documents were on the Southern Ute Air Quality Division webpage at

https://www.southernute-nsn.gov/justice-and-regulatory/epd/air-quality/, and at:

Southern Ute Indian Tribe

Environmental Programs Department

Air Quality Division

71 Mike Frost Way

Ignacio, Colorado 81137

All documents were available for review at the Southern Ute Indian Tribe’s Environmental Programs

Department office Monday through Friday from 9:00 a.m. to 4:00 p.m. (excluding holidays).

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Any interested person was given the opportunity to submit written comments on the draft Part 70 operating

permit during the public comment period. The Tribe has considered and addressed comments in making a

final decision on the permit. The Tribe keeps a record of the commenters and of the issues raised during

the public participation process.

Anyone, including the applicant, who believed any condition of the draft permit was inappropriate, could

raise all reasonably ascertainable issues and submit all arguments supporting his or her position by the close

of the public comment period. Any supporting materials submitted must have been included in full and

may not have been incorporated by reference, unless the material had already been submitted as part of the

administrative record in the same proceeding or consisted of Environmental Commission, tribal, state or

Federal statutes and regulations, EPA documents of general applicability, or other generally available

reference material.

c. Opportunity to Request a Hearing

A person may submit a written request for a public hearing to the Part 70 Permit Contact at the addresses

listed above, by stating the nature of the issues to be raised at the public hearing. Based on the number of

hearing requests received, the Tribe will hold a public hearing whenever it finds there is a significant degree

of public interest in a draft operating permit. The Tribe will provide public notice of the public hearing. If

a public hearing is held, any person may submit oral or written statements and data concerning the draft

permit.

d. Public Petitions to the Administrator

In the event the Administrator of the United States Environmental Protection Agency does not object to

issuance of the permit, on the basis that it would not be in compliance with applicable requirements, within

its 45-day review period, any person may then petition the Administrator within 60 days after the expiration

of the Administrator’s 45-day review period to make such objection. Any such petition must be based only

on objections to the permit that were raised with reasonable specificity during the public comment period

unless the petitioner demonstrates that it was impracticable to raise such objections within such period, or

unless the grounds for such objections arose after such period. If the administrator objects to a permit as a

result of this petition, the Tribe shall not issue the permit until the Administrator’s objection has been

resolved, except that a petition for review does not stay the effectiveness of a permit or its requirements if

the permit was issued after the end of the 45-day review period and before the Administrator’s objection.

e. Appeal of Permits

Within 60 days after the Tribe’s final permit action, an applicant, any person who filed comments on the

draft permit or participated in the public hearing, and any other person who could obtain judicial review of

that action under applicable law, may appeal to the Environmental Commission in accordance with RAC

2-109(8) and the Commission’s Procedural Rules.

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Petitions for administrative review of final permit actions can be filed after the deadline designated by the

Commission only if they are based solely on grounds arising after the deadline for administrative review

has passed. Such petitions shall be filed no later than 60 days after the new grounds for review arise. If the

final permit action being challenged is the Tribe’s failure to take final action, a petition for administrative

review may be filed any time before the Tribe denies or issues the final permit.

f. Notice to Affected States/Tribes

As required by RAC § 2-108, the following entities were notified of the public comment period:

•

•

•

•

•

•

•

State of Colorado, Department of Public Health and Environment

State of New Mexico, Environment Department

Ute Mountain Ute Tribe, Environmental Programs Department

Navajo Tribe, Navajo Nation EPA

Jicarilla Tribe, Environmental Protection Office

National Park Service, Air Resources Division, Denver, CO

U.S. Department of Agriculture, United States Forest Service, Rocky Mountain

Region

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