READ: Chester County joins lawsuit against Sunoco over Mariner East construction
Delaware County District Attorney Kat Copeland says the two offices are teaming up to investigate allegations of misconduct by Energy Transfer Partners, Sunoco, and pipeline construction and other activity surrounding the project.
Meanwhile, Pa. Sen. Tim Kearney, who represents Delaware County and part of Chester County, is calling for a moratorium on the project until safety protocols are set up.
Mariner East 2 is a 350-mile stretch of Sunoco's current Mariner East pipeline system. The project has been plagued with leaks, sinkholes and safety issues since it began. It is also the focus of a grand jury investigation in Chester County.
READ: Grand jury is impaneled to hear testimony on Mariner East pipelines