Clean Air Act stationary source · ICIS-AIR PA000707674
MARKWEST LIBERTY MIDSTREAM & RESOURCES/HOUSTON GAS PLT, Washington, PA: Clean Air Act compliance record, inspections, violations, penalties
- OperatingOperating status
- Synthetic minor sourceEmissions classification
- No Violation IdentifiedCurrent violation status, as filed
- 26Compliance evaluations since January 1, 2017
- 1High-priority violations since January 1, 2017
- 5Formal enforcement actions since January 1, 2017
MARKWEST LIBERTY MIDSTREAM & RESOURCES/HOUSTON GAS PLT, at 800 WESTERN AVE, Washington in Washington County, Pennsylvania, is an operating synthetic minor 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”. Washington County is on EPA’s Green Book list of areas that do not meet a national air quality standard. 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 LIBERTY MIDSTREAM & RESOURCES/HOUSTON GAS PLT |
|---|---|
| ICIS-AIR ID | PA000707674 |
| EPA facility registry ID | 110046247138 |
| Operating status | Operating |
| Emissions classification | Synthetic minor source |
| Current violation status (ICIS-AIR high-priority violation field) | No Violation Identified |
| Address | 800 WESTERN AVE, Washington, PA 15301-8655 |
| County | Washington County |
| In a nonattainment county | Yes (EPA Green Book) |
| Industry (NAICS) | Oil and gas extraction (NAICS 2111) |
| SIC code | 1321 |
| EPA region | 03 |
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 LIBERTY MIDSTREAM & RESOURCES/HOUSTON GAS PLT 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
- 26Evaluations since January 1, 2017
- 2Full compliance evaluations
| Date | What EPA recorded | Agency | Programs |
|---|---|---|---|
| June 11, 2026 | FCE On-Site | State | State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| April 18, 2026 | PCE Off-Site | State | State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| June 28, 2025 | PCE Off-Site | State | State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| May 28, 2024 | PCE Off-Site | State | State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| July 12, 2023 | PCE Off-Site | State | State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| April 6, 2023 | PCE On-Site Monitoring/Sampling | State | State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| March 30, 2023 | PCE On-Site Monitoring/Sampling | State | State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| May 6, 2022 | PCE Off-Site | State | State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| May 2, 2022 | PCE On-Site Monitoring/Sampling | State | State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| January 5, 2022 | PCE On-Site Monitoring/Sampling | State | State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| January 4, 2022 | PCE Off-Site | State | State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| April 19, 2021 | PCE Off-Site | State | State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| April 15, 2021 | FCE On-Site | State | State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| February 16, 2021 | PCE Off-Site | State | State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| November 23, 2020 | PCE Off-Site | State | State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| November 13, 2020 | PCE On-Site Monitoring/Sampling | State | State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| April 9, 2020 | PCE Off-Site | State | State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| February 24, 2020 | PCE Off-Site | State | State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| January 8, 2020 | PCE On-Site Monitoring/Sampling | State | State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| June 25, 2019 | PCE Off-Site | State | State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| December 20, 2018 | PCE On-Site Monitoring/Sampling | State | State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| July 9, 2018 | PCE Off-Site | State | State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| May 3, 2018 | PCE On-Site Monitoring/Sampling | State | State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| March 29, 2018 | PCE Off-Site | State | State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| October 13, 2017 | PCE On-Site Monitoring/Sampling | State | State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| April 26, 2017 | PCE Off-Site | State | State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
Violations
- 2Violation determinations since January 1, 2017
- 1Of 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 |
|---|---|---|---|
| August 1, 2023 | HPV day-zero determination | State | State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
| November 17, 2021 | Earliest FRV determination | State | State Implementation Plan for National Primary and Secondary Ambient Air Quality Standards |
Enforcement and penalties
5 formal enforcement actions since January 1, 2017, 3 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 18, 2023 | Administrative Order | State | $0 |
| September 6, 2021 | Administrative Order | State | $5,200 |
| January 8, 2019 | Civil Judicial Action | U.S. EPA | $385,416 |
| January 8, 2019 | Administrative Order | State | $76,350 |
| July 9, 2018 | Administrative Order | State | $0 |
Informal enforcement
| Date | What EPA recorded | Agency |
|---|---|---|
| August 1, 2023 | Notice of Violation | State |
| January 14, 2022 | Notice of Violation | State |
| February 16, 2021 | Notice of Violation | State |
| November 23, 2020 | Notice of Violation | State |
Stack tests
- 1Stack tests since January 1, 2017
- 0Recorded as failed
| Date | What EPA recorded | Agency |
|---|---|---|
| September 22, 2022 | 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 110046247138 there.
Nearby on the register
- Air-emissions sources in Washington County
- Every source record in Washington County, A to Z
- Air-emissions sources in Pennsylvania
- Every source record in Pennsylvania, A to Z
Figures from EPA’s ICIS-AIR download, loaded September 14, 2026.