After failing to persuade a judge to halt construction of the 350-mile Mariner East 2 pipeline, three environmental groups on Tuesday encouraged activists to remain vigilant as they continued to appeal the state permits allowing the cross-state Marcellus Shale pipeline.

The Clean Air Council, Delaware Riverkeeper Network and Mountain Watershed Association on Tuesday expressed disappointment that a Pennsylvania Environmental Hearing Board judge declined to halt construction while a full review of the state water permits could be completed. The pipeline's operator, Sunoco Logistics Partners, said it is moving forward on the $2.5 billion project, which terminates in Marcus Hook.

Alex Bomstein, a Clean Air Council attorney, said all landowners should be invited to a pre-construction meeting with Sunoco, and urged opponents to report any violations to the Department of Environmental Protection.