Sunoco Logistics Partners LP reported a small spill of ethane and propane from its Mariner East (ME) 1 pipeline earlier this month, saying on Friday that the system has been fixed.

Spokesperson Jeffrey Shields said an estimated 20 bbl of propane/ethane mixture leaked from the eight-inch diameter pipeline in New Morgan Borough in Berks County on April 1. A report was filed with the U.S. Coast Guard’s National Response Center. “Sunoco Logistics personnel responded, confirmed the release, shut down the pipeline and made the repair over the next several days,” Shields said. “There were no public safety impacts and all relevant agencies were notified.”

ME 1 entered full service last year to deliver ethane and propane from Western Pennsylvania to the Marcus Hook Industrial Complex near Philadelphia. The company is currently constructing the 350-mile ME 2 pipeline, which would deliver ethane, butane and propane from processing facilities in Ohio, Pennsylvania and West Virginia to Marcus Hook. That project has drawn the ire of environmental groups and concerned citizens.

It’s unclear what caused ME 1 to leak. Shields said an investigation is underway in cooperation with regulatory agencies. Pennsylvania Public Utility Commission spokesperson Nils Hagen-Frederiksen said the PUC’s pipeline safety team was alerted on April 1 and responded. The commission is conducting an investigation that’s being coordinated with the Pipeline and Hazardous Materials Safety Administration.

Sunoco began construction on ME 2 in February after it received key water-crossing and sedimentation permits from the state Department of Environmental Protection.

An appeal of those permits is pending before the state Environmental Hearing Board. The Clean Air Council, Delaware Riverkeeper Network and the Mountain Watershed Association filed the appeal, arguing that the project would cause “irreparable harm” to forests and water quality.

The company also said earlier this year that it would proceed with construction of a third Mariner East pipeline, which will run parallel to ME 2 and be installed shortly after that project is completed.