The Pennsylvania Department of Environmental Protection (DEP) and Gov. Tom Wolf on Friday responded to public concerns about horizontal directional drilling (HDD) operations for the Mariner East (ME) 2 pipeline project, which have resulted in several releases of drilling mud and well water contamination in the southeast part of the state.

“I have heard concerns directly from local legislators, including in-person meetings where they have shared concerns of their constituents, along with residents who have written and called my office,” Wolf said. “I have directed DEP to do what they are legally able and feel is appropriate to ensure the operator is held accountable to addressing these incidents and taking additional steps to prevent similar incidents from occurring.”

Construction on the project began in February after the DEP issued key water quality permits. The agency said Friday that it has issued four notices of violation to Sunoco. One consent order and agreement has been executed with a penalty of $87,600 for a violation that impacted a wetland area next to a highway in Cumberland County. The violations are related to fluid releases during HDD operations.

“With so much concern about the ME 2 pipeline, the public needs to know that DEP is taking its oversight and regulatory enforcement role seriously,” said agency Secretary Patrick McDonnell. “This project has raised questions about public health and the health of the environment, and it is important to be transparent about the issues that have arisen over the course of the construction.”

Red flags were raised about project construction after more than a dozen families in Chester County reported losing water pressure and murky water in an area about 30 miles west of Philadelphia where HDD was underway. It’s believed drilling mud — a mix of non-toxic bentonite clay and water — affected groundwater and private water wells in the area. Sunoco has since agreed to connect those families to public water supplies and pay the expenses.

On Wednesday, environmental groups challenging the company’s state permits before the Environmental Hearing Board released documents from the DEP detailing more than 61 spills that have been reported by Sunoco during construction activities. In the meantime, Democratic and Republican lawmakers from suburban Philadelphia have sent letters to the DEP and Wolf asking that construction be stopped until their concerns are addressed.

While a company spokesman could not be reached on Friday to comment about the administration’s response, Sunoco has responded at nearly every turn, saying its use of HDD has significantly reduced impacts on the environment. It has also noted that permit applications approved by the state for the project require compliance with an Inadvertent Return Contingency Plan, which it has followed to help contain releases. DEP reiterated that on Friday. The company has also said that drilling mud and groundwater returns are not unexpected during HDD, while the DEP said Friday that they are not expected to “have any lasting effects on impacted waters” in the state.

Sunoco is a subsidiary of Energy Transfer Partners LP, which also has recently drawn public scrutiny over both the Dakota Access Pipeline and for alleged environmental violations in Ohio during construction of its Rover Pipeline project.

DEP said a detailed list of incidents related to ME 2 construction would be released soon on its website and updated weekly thereafter. The 350-mile pipeline would transport ethane, butane and propane from Ohio, Pennsylvania and West Virginia to the Marcus Hook Industrial Complex near Philadelphia for domestic and international distribution.