Citing adverse impacts at a horizontal directional drill (HDD) site in southeastern Pennsylvania, the state’s Department of Environmental Protection (DEP) has ordered Sunoco Pipeline LP to reroute part of its Mariner East (ME) system.

Mariner East

Sunoco will need to “take all steps necessary, including the submission of appropriate applications and supporting materials for permit amendments,” to implement a 1.1-mile reroute of its ME system around the “HDD-290” site in Upper Uwchlan Township, Chester County, PA, according to an administrative order issued Friday by the DEP.

Last month, Sunoco spilled 8,000 gallons of drilling fluid and caused a 15-foot-wide, 8-foot-deep subsidence at the site, adversely impacting wetlands, two tributaries to the Marsh Creek Lake and the lake...