Environmental groups dropped their appeals of 20 permits issued to Sunoco Pipeline LP's Mariner East 2 liquids pipeline project after reaching a settlement with the Pennsylvania Department of Environmental Protection.

The agency in a July 27 statement touted the agreement with the Clean Air Council, Mountain Watershed Association and Delaware Riverkeeper Network as a "significant validation" of the permits, which were not changed.

The state agency was "pleased that we were able to reach an amicable agreement with the appellants, resolving all claims related to the issuance of these permits while incorporating new processes to ensure that future pipeline projects learn from the mistakes made by Sunoco in implementing this project," Patrick McDonnell, the state's secretary of environmental protection, said in the statement.

The department agreed to continue to develop and apply additional enhanced procedures for environmental protection associated with the construction of natural gas pipelines.

"From the outset, Sunoco has maintained that the permits issued for the construction of [the projects] were properly and lawfully issued by [the Pennsylvania Department of Environmental Protection] and fully protective of the environment," Sunoco spokeswoman Lisa Dillinger said in an emailed statement.

In February, the Pennsylvania regulator assessed $12.6 million in fines in a settlement of various environmental infractions.

The project would deliver 354,000 barrels per day of ethane, propane and butane from western Pennsylvania, West Virginia and Ohio to a marine export terminal in Marcus Hook, Pa.

Sunoco Pipeline is an affiliate of Energy Transfer Partners LP.