Sunoco Pipeline LP, a subsidiary of Energy Transfer Partners (ETP), has been fined $319,000 for violating environmental regulations pertaining to its Mariner East pipeline system, which is the latest among $13.5 million in penalties assessed on the controversial project in numerous counties of Pennsylvania since 2017.

The Pennsylvania Department of Environmental Protection announced last week that Sunoco had signed two consent agreements to settle complaints that it violated the Clean Streams Law and Dam Safety and Encroachment Act in 2017 and 2018. The company was cited for unauthorized discharges of drilling fluids, consisting of bentonite clay and water, while conducting horizontal drilling in 10 counties to excavate underground pathways for its pipeline. It was also cited for accelerated erosion and sedimentation at sites in Cumberland County in 2017.

Sunoco’s $5.1 billion Mariner East system consists of two adjacent pipelines that transport natural gas liquids, such as propane, from Western Pennsylvania and Ohio to an export terminal in Marcus Hook. Construction of the third Mariner East pipeline is nearly completed, and it is expected to go into service by the end of the year.