National Enforcement Investigations Center
Case Results - MarkWest
Clean Air Act Violations
Field Investigation & Analytical Support
NEIC's Support:
•	Forensics-based field
investigations and analytical
support under ISO/IEC:
17025, General
Requirements forthe
Competence ofTesting and
Calibration Laboratories
•	CAA expertise
•	Infrared (IR) camera
utilization
NEIC's Other Capabilities:
•	Statistical services
•	Toxicological expertise
•	CAA 112r, CWA EPCRA
and RCRA expertise
•	Training
NEIC'sfindings were instrumental in developingthe enforcement action, which allegedthat MarkWest had failed to
apply for, and comply with, the required permits and/or recordkeeping requirements underthe Clean Air Act (CAA)
and the Pennsylvania Air Pollution Control Act for venting activities that release VOC emissions. The case was
prosecuted by the U.S. Department of Justice (DOJ), and is the first environ mental case to recognize and address
the significant VOC emissions associated with pigging and other maintenance operations in shale gas formations.
Enforcement results: In April 2018, a settlement was reached with MarkWest resultingin:
•	$2.6 million in injunctive relief to install and operate technologies to reduce VOC emissions at MarkWest
facilities in western Pennsylvania and eastern Ohio
•	$610,000 civil penalty
•	$2.4 million to implementthree supplemental environmental projects to install and operate ambientair
monitoring stations, and the implementation of a technology for reducing VOC emissions
•	Emission reductions of 706 tons per year of VOCs and 91.5% annual emission reductions throughout the
natural gas collection system
How to obtain NEIC's support
NEIC provides environ mental fore nsics support for criminal and civil enforcement cases. If you would like more
information on NEICorto request laboratory analysis, toxicological support, an investigation, technical assistance,
or training from NEIC, please contact us at nei'c project requests@epa.gov. You may also contact your regional
enforcement coordinator for more information on requesting NEIC's support on civil projectsand EPA's CIDfor
supporton criminal projects.
NEIC | Denver Federal Center, Building 25 | Denver, Colorado | 303.462.9000
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Background: MarkWest and two of its subsidiaries (MarkWest Liberty Midstream
Resources, LLC and Ohio Gathering Company, LLC) operate facilities in eastern Ohio
and western Pennsylvania designed to gather and transport natural gas and natural
gas condensatesthrough pipelines. As part of regular maintenance activities,
MarkWest uses devices called "pigs" in pipe lines to remove debris and push through
accumulated liquids, in an operation known as "pigging." Pigging requiresthe
operatorto depressurizeand vent
pipe line gas from the equipment
designedto launch and receive
pigs.
NEIC's support: In July 2015, NEIC
investigators provided field
technical supportforan
investigation of a MarkWest
facility in McDonald, Pennsylvania.
NEIC investigators recorded
infrared (IR) videofootage of air
emissions at the pig launching/receiving station, and collected air canister, liquid
condensate, and soil samples for analysis at the NEIC laboratory. Chemical analysis
identified volatile organic compounds (VOCs) and light hydrocarbons in the air
samples.

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