The Chester County prosecutor, amping up pressure on Sunoco’s Mariner East pipeline, said on Tuesday his office plans to sue the $5.1 billion project as a public nuisance.

Chester County District Attorney Thomas P. Hogan notified the pipeline’s owner, Energy Transfer LP, that his office plans to file a civil nuisance action in 60 days unless the company corrects several problems, including exposed underground pipes and leaks, or “inadvertent returns,” of drilling fluid during the pipeline’s construction.

Most of the incidents mentioned by the DA were already cited in 98 violations notices filed by the Pennsylvania Department of Environmental Protection (DEP) against the cross-state project, which aims to carry Marcellus Shale natural gas liquids by several underground pipelines to Sunoco’s export terminal in Marcus Hook.

Energy Transfer, in a statement, said it believes it was already “well on our way" to resolving the issues cited by the district attorney.

“To that end, we have completed all required remediation as a result of inadvertent returns or other construction related discharges from the Mariner East 2 project in Chester County consistent with our approved permits,” the company said. "We also have resolved associated claims with the DEP through agreed upon consent agreements. In addition, the company is under an order issued by the DEP to cover any exposed areas of pipes, including the two pipes in Chester County, which is subject to a schedule of work.”

The civil action is the latest legal swat Chester County has taken against the giant project, including a suit filed in April by the county commissioners seeking to block construction of two new pipelines.

Hogan’s office in December announced a criminal investigation of the project, which resulted in charges being filed last month against two local constables who were moonlighting as security agents on the project.

The criminal investigation is still ongoing, said Michael G. Noone, the first assistant district attorney. He said the nuisance lawsuit represents the DA’s effort to use every tool at its disposal to ensure the safety of the community.

“This step will force Energy Transfer to begin to right their wrongs and fix these problems,” Noone said.