The US state of Pennsylvania has approved the restart of construction on the Mariner East 2 pipeline and allowed the adjoining Mariner East to resume operation. At the same time it slapped fines of $355,000 on the pipeline’s builders for polluting streams in Lancaster County and eight other counties.

In February, pipeline operator Sunoco was fined $12.6 million fine for several different violations. Mariner East 1 had been shut down since March after sinkholes opened in Chester County along the construction route.

An investigation by the Pennsylvania Public Utility Commission (PUC) determined that the sinkholes were caused by subsidence along that pipeline’s path. However, in recommending a restart, the commission said it did not believe the integrity of the Mariner East 1 pipeline had been compromised.

The Mariner East pipelines that cross southern Pennsylvania are designed to carry liquids from the Marcellus and Utica shale basins to a refinery at Marcus Hook near Philadelphia, for export to Europe and in future Asia. Ineos is one of the chief customers for US shale-derived ethane, which feeds its petrochemical and plastics production facilities at Grangemouth, Scotland, and Rafnes, Norway.

 Pennsylvania’s fines were for spillage of drilling fluids into wild trout streams, wetlands and streams. Drilling fluids were reportedly discharged into streams, a wetland adjacent to endangered bog turtle habitat and on the Middle Creek Wildlife Management Area.

Mariner East 2 has been vigorously opposed by US environmental groups and local residents, who have called for an end to its construction. They contend that it is dangerous because it is routed through densely populated neighborhoods.