Sunoco Pipeline L.P. has filed an amended application for its controversial Mariner East project it hopes will strengthen its case that the cross-state Marcellus Shale pipeline is exempt from local zoning restrictions.

The Philadelphia pipeline company filed new papers late Thursday with the Pennsylvania Public Utility Commission proposing to deliver propane from Western Pennsylvania to its Twin Oaks terminal in Delaware County. The filing became public Friday.

By delivering propane to Pennsylvania customers, the project would be subject to PUC tariff regulations as an intrastate pipeline. In its initial filing, the pipeline's only destination was Claymont, Del., making it an interstate pipeline.

Though Sunoco contends it has been a public utility corporation since 2002, the addition of the Twin Oaks delivery point would reinforce its argument that it qualifies as a Pennsylvania public utility and should be exempt from local zoning restrictions on 18 pump stations and 17 valve stations along its 299-mile route.

Sunoco's project has attracted fierce opposition in West Goshen Township, Chester County, where it proposes to build a pump station near Boot Road and U.S. 202 not far from a residential development.