Velarion Records

Clean Air Act stationary source · ICIS-AIR PA000732829

MARKWEST LIBERTY MIDSTREAM/WELLING COMP STA, Claysville, PA: Clean Air Act compliance record, inspections, violations, penalties

MARKWEST LIBERTY MIDSTREAM/WELLING COMP STA, at 165 CARLISLE RD, Claysville 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 filedMARKWEST LIBERTY MIDSTREAM/WELLING COMP STA
ICIS-AIR IDPA000732829
EPA facility registry ID110044801998
Operating statusOperating
Emissions classificationSynthetic minor source
Current violation status (ICIS-AIR high-priority violation field)No Violation Identified
Address165 CARLISLE RD, Claysville, PA 15323-1349
CountyWashington County
In a nonattainment countyYes (EPA Green Book)
Industry (NAICS)Oil and gas extraction (NAICS 2111)
SIC code1311
EPA region03

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/WELLING COMP STA 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

DateWhat EPA recordedAgencyPrograms
April 23, 2026PCE Off-SiteStateState Implementation Plan for National Primary and Secondary Ambient Air Quality Standards
June 3, 2025PCE Off-SiteStateState Implementation Plan for National Primary and Secondary Ambient Air Quality Standards
June 20, 2024PCE Off-SiteStateState Implementation Plan for National Primary and Secondary Ambient Air Quality Standards
August 31, 2023PCE Off-SiteStateState Implementation Plan for National Primary and Secondary Ambient Air Quality Standards
February 24, 2022PCE Off-SiteStateState Implementation Plan for National Primary and Secondary Ambient Air Quality Standards
February 17, 2022FCE On-SiteStateState Implementation Plan for National Primary and Secondary Ambient Air Quality Standards
June 29, 2021PCE Off-SiteStateState Implementation Plan for National Primary and Secondary Ambient Air Quality Standards
March 24, 2021PCE Off-SiteStateState Implementation Plan for National Primary and Secondary Ambient Air Quality Standards
September 3, 2020FCE On-SiteStateState Implementation Plan for National Primary and Secondary Ambient Air Quality Standards
April 28, 2020PCE Off-SiteStateState Implementation Plan for National Primary and Secondary Ambient Air Quality Standards
March 3, 2020PCE Off-SiteStateState Implementation Plan for National Primary and Secondary Ambient Air Quality Standards
May 30, 2019PCE Off-SiteStateState Implementation Plan for National Primary and Secondary Ambient Air Quality Standards
April 25, 2018FCE On-SiteStateState Implementation Plan for National Primary and Secondary Ambient Air Quality Standards
March 30, 2018PCE Off-SiteStateState Implementation Plan for National Primary and Secondary Ambient Air Quality Standards
April 21, 2017PCE Off-SiteStateState Implementation Plan for National Primary and Secondary Ambient Air Quality Standards
January 18, 2017PCE On-Site Monitoring/SamplingStateState Implementation Plan for National Primary and Secondary Ambient Air Quality Standards

Violations

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.

EPA’s violation history file holds no violation for ICIS-AIR PA000732829 since January 1, 2017.

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.

DateWhat EPA recordedAgencyPenalty, as filed
July 9, 2018Civil Judicial ActionU.S. EPA$385,000

Informal enforcement

EPA’s informal action file holds no notice or warning for ICIS-AIR PA000732829 since January 1, 2017.

Stack tests

DateWhat EPA recordedAgency
February 24, 2026PassState
February 26, 2025PassState
August 22, 2024PassState
July 18, 2024PassState
March 27, 2024PassState
February 27, 2024PassState
September 20, 2023PassState
August 3, 2023PassState
April 3, 2023PassState
February 28, 2023PassState
November 9, 2022PassState
September 27, 2022PassState
August 8, 2022PassState
April 4, 2022PassState
March 2, 2022PassState
October 21, 2021PassState
September 28, 2021PassState
August 9, 2021PassState
April 5, 2021PassState
March 2, 2021PassState
September 29, 2020PassState
September 8, 2020PassState
April 6, 2020PassState
March 5, 2020PassState
December 18, 2019PassState
October 4, 2019PassState
August 23, 2019PassState
April 9, 2019PassState
March 6, 2019PassState
October 2, 2018PassState
August 16, 2018PassState
April 10, 2018PassState
March 9, 2018PassState
October 3, 2017PassState
September 7, 2017PassState
April 18, 2017PassState
March 10, 2017PassState

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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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 110044801998 there.

Nearby on the register

Figures from EPA’s ICIS-AIR download, loaded September 14, 2026.

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