Clean Air Act stationary source · ICIS-AIR OK0000004006300102
MARKWEST OKLAHOMA GAS CO LLC / WEST RELAY COMPESSOR STATION, Horntown, OK: Clean Air Act compliance record, inspections, violations, penalties
- OperatingOperating status
- Major sourceEmissions classification
- No Violation IdentifiedCurrent violation status, as filed
- 43Compliance evaluations since January 1, 2017
- 0High-priority violations since January 1, 2017
- 1Formal enforcement actions since January 1, 2017
MARKWEST OKLAHOMA GAS CO LLC / WEST RELAY COMPESSOR STATION, at 0.9 MI S OF E1330/N3840 RD, Horntown in Hughes County, Oklahoma, is an operating major source of air pollution on EPA’s ICIS-AIR register. EPA’s file records its current violation status (ICIS-AIR’s high-priority violation field) as “No Violation Identified”. The status and classification are as EPA’s facility file stood when Velarion loaded it (September 14, 2026); EPA’s free Detailed Facility Report on ECHO carries the source’s current standing, quarter by quarter.
Identity
| Facility as filed | MARKWEST OKLAHOMA GAS CO LLC / WEST RELAY COMPESSOR STATION |
|---|---|
| ICIS-AIR ID | OK0000004006300102 |
| EPA facility registry ID | 110067575822 |
| Operating status | Operating |
| Emissions classification | Major source |
| Current violation status (ICIS-AIR high-priority violation field) | No Violation Identified |
| Address | 0.9 MI S OF E1330/N3840 RD, Horntown, OK 74848 |
| County | Hughes County |
| In a nonattainment county | No (EPA Green Book) |
| Industry (NAICS) | Oil and gas extraction (NAICS 2111) |
| SIC code | 1311 |
| EPA region | 06 |
Cited to the EPA ICIS-AIR facility file (ECHO download).
Programs and pollutants
Velarion’s copy of EPA’s ICIS-AIR download does not include its program, pollutant and Title V certification files, so this page does not list the Clean Air Act programs MARKWEST OKLAHOMA GAS CO LLC / WEST RELAY COMPESSOR STATION is under or the pollutants it is permitted for. The programs each evaluation and violation below was recorded under are shown with it. EPA’s free Detailed Facility Report lists both.
Compliance evaluations
- 43Evaluations since January 1, 2017
- 3Full compliance evaluations
| Date | What EPA recorded | Agency | Programs |
|---|---|---|---|
| July 24, 2024 | FCE On-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards; Title V Permits |
| February 6, 2023 | FCE On-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards; Title V Permits |
| February 1, 2023 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards; Title V Permits |
| November 29, 2022 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards; Title V Permits |
| November 1, 2022 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards; Title V Permits |
| March 29, 2022 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards; Title V Permits |
| March 22, 2022 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards; Title V Permits |
| February 15, 2022 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards; Title V Permits |
| February 8, 2022 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards; Title V Permits |
| January 20, 2022 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards; Title V Permits |
| November 5, 2021 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards; Title V Permits |
| October 28, 2021 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards; Title V Permits |
| August 27, 2021 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards; Title V Permits |
| June 23, 2021 | FCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards; Title V Permits |
| June 9, 2021 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards; Title V Permits |
| January 12, 2021 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| October 19, 2020 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| September 28, 2020 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| August 19, 2020 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| January 7, 2020 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| November 26, 2019 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| September 24, 2019 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| August 22, 2019 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| June 5, 2019 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| May 8, 2019 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| May 8, 2019 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| April 8, 2019 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| January 24, 2019 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| January 15, 2019 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| December 12, 2018 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| September 26, 2018 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| September 19, 2018 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| August 15, 2018 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| June 18, 2018 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| February 27, 2018 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| November 20, 2017 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| September 26, 2017 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| September 21, 2017 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| August 16, 2017 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| July 31, 2017 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| July 10, 2017 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| June 29, 2017 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| February 15, 2017 | PCE Off-Site | State | MACT Standards (40 CFR Part 63); New Source Performance Standards; State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
Violations
- 6Violation determinations since January 1, 2017
- 0Of them high-priority
A high-priority violation (HPV) is the most serious class of Clean Air Act non-compliance an agency records; a federally reportable violation (FRV) is the next step down. Each row is one determination as EPA’s violation history files it.
| Date | What EPA recorded | Agency | Programs |
|---|---|---|---|
| September 4, 2024 | Earliest FRV determination | State | MACT Standards (40 CFR Part 63); State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| May 7, 2023 | Earliest FRV determination | State | State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards; Title V Permits |
| September 21, 2021 | Earliest FRV determination | State | New Source Performance Standards |
| June 9, 2021 | Earliest FRV determination | State | New Source Performance Standards |
| June 19, 2020 | Earliest FRV determination | State | New Source Performance Standards |
| June 5, 2018 | Earliest FRV determination | State | State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
Enforcement and penalties
1 formal enforcement actions since January 1, 2017, 1 of them with a penalty filed above zero. Each penalty is shown as EPA’s formal action file states it; “Not stated” means the file gives no figure, and $0 is a disclosed zero.
| Date | What EPA recorded | Agency | Penalty, as filed |
|---|---|---|---|
| January 8, 2024 | Administrative Order | State | $1,575 |
Informal enforcement
| Date | What EPA recorded | Agency |
|---|---|---|
| September 6, 2024 | Notice of Violation | State |
| June 6, 2023 | Notice of Violation | State |
Stack tests
- 56Stack tests since January 1, 2017
- 0Recorded as failed
The newest 50 of 56.
| Date | What EPA recorded | Agency |
|---|---|---|
| May 29, 2025 | Pass | State |
| November 14, 2024 | Pass | State |
| November 14, 2024 | Pass | State |
| November 14, 2024 | Pass | State |
| November 14, 2024 | Pass | State |
| August 29, 2024 | Pass | State |
| December 11, 2023 | Pass | State |
| December 1, 2023 | Pass | State |
| November 30, 2023 | Pass | State |
| November 30, 2023 | Pass | State |
| September 12, 2023 | Pass | State |
| January 19, 2023 | Pass | State |
| December 14, 2022 | Pass | State |
| April 5, 2022 | Pass | State |
| April 5, 2022 | Pass | State |
| January 19, 2022 | Pass | State |
| December 13, 2021 | Pass | State |
| October 20, 2021 | Pass | State |
| October 13, 2021 | Pass | State |
| October 13, 2021 | Pass | State |
| October 12, 2021 | Pass | State |
| March 12, 2021 | Pass | State |
| September 11, 2020 | Pass | State |
| September 4, 2020 | Pass | State |
| September 4, 2020 | Pass | State |
| July 8, 2020 | Pass | State |
| July 8, 2020 | Pass | State |
| February 12, 2020 | Pass | State |
| October 17, 2019 | Pass | State |
| October 17, 2019 | Pass | State |
| September 4, 2019 | Pass | State |
| July 9, 2019 | Pass | State |
| July 9, 2019 | Pass | State |
| July 9, 2019 | Pass | State |
| July 9, 2019 | Pass | State |
| May 28, 2019 | Pass | State |
| February 8, 2019 | Pass | State |
| October 24, 2018 | Pass | State |
| September 17, 2018 | Pass | State |
| August 10, 2018 | Pass | State |
| August 9, 2018 | Pass | State |
| August 9, 2018 | Pass | State |
| August 9, 2018 | Pass | State |
| February 6, 2018 | Pass | State |
| October 27, 2017 | Pass | State |
| October 25, 2017 | Pass | State |
| September 12, 2017 | Pass | State |
| August 9, 2017 | Pass | State |
| August 8, 2017 | Pass | State |
| August 8, 2017 | Pass | State |
Cited to the EPA ICIS-AIR evaluation, violation, stack test and enforcement files (ECHO download), events dated January 1, 2017 or later as loaded; up to 50 rows of each shown, newest first.
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How we handle your data → Privacy
EPA publishes a free Detailed Facility Report for every source on ECHO: its compliance status quarter by quarter, its evaluations, and its violations, enforcement actions and penalties. EPA also sends free notices of new inspections and enforcement actions through ECHO Notify; enter EPA facility registry ID 110067575822 there.
Nearby on the register
- Air-emissions sources in Hughes County
- Every source record in Hughes County, A to Z
- Air-emissions sources in Oklahoma
- Every source record in Oklahoma, A to Z
Figures from EPA’s ICIS-AIR download, loaded September 14, 2026.