The notice says Sunoco has not provided an immediate or long-term restoration plan to address the impacts.
The state DEP says Sunoco has one week to respond to a series of questions in the notice.
Drilling activity in the area has been suspended since the leaks earlier this month. The DEP continues to say they’ll hold Sunoco accountable to the full extent of the law.
Sunoco has also been hit with a $355,000 fine for violations related to the Mariner East II pipeline: unauthorized drilling fluid discharges into about a dozen streams, creeks, or waterways in eight counties across Pennsylvania, including Delaware County.