HARRISBURG — More hearings were ordered Thursday on whether to exempt the construction of buildings around pump and valve-control stations from local zoning ordinances along a 300-mile pipeline to ship natural gas liquids from Marcellus Shale wells across southern Pennsylvania.

The Pennsylvania Public Utility Commission voted 4-1 in favor of the hearings to help decide whether the zoning exemptions sought by Sunoco Logistics are crucial to its Mariner East pipeline service.

In doing so, the commissioners rejected a July recommendation by two administrative law judges that went against Sunoco Logistics.

The two judges had recommended that the commission deny Sunoco Logistics’ request to exempt buildings to shelter 18 pump stations and 17 valve control stations from local zoning ordinances in 31 locations, each in a different municipality, along the planned ethane and propane pipeline.

Objections had been filed by the Clean Air Council, the Delaware Riverkeeper Network, the Concerned Citizens of West Goshen Township and the Mountain Watershed Association.

The propane service is to begin later this year, while the ethane service is to begin next year.

The pipeline is to originate in the southwestern Pennsylvania town of Houston amid the area’s Marcellus Shale drilling fields and end at the company’s distribution facilities in southeastern Pennsylvania’s Delaware County. The ethane and propane would be piped together and separated at the facilities.