The Mariner East 1 pipeline has been allowed to resume ferrying natural gas liquids from southwestern Pennsylvania across the state, but two pipelines under construction along the same route remain on hold.

Three out of five Public Utility Commission members voted Thursday to reverse in part a scathing decision issued by a PUC judge last month that suspended the existing pipeline from operating and that halted construction of Mariner East 2 and 2X lines in West Whiteland, Chester County.

The petition for an immediate halt to all three lines was brought by state Sen. Andrew Dinniman, a Chester County Democrat who has a case before the same judge raising legal questions about the pipelines.

The judge’s decision last month was based on her finding that there is an imminent and irreversible danger to allowing the pipelines to proceed while the underlying case is litigated.

Sunoco immediately appealed the order to the PUC, whose own staff had found that Mariner East 1 was safe to operate.

“I wholeheartedly agree with the [judge] that the risk of physical injury or death because of unsafe construction is catastrophic,” Commissioner Gladys Brown wrote in her motion, which passed.

“However, these is also a very real harm to the public economically in the continued shutdown of [Mariner East 1], which plays an important role in local, state and the national economy,” she added, citing an extensive brief filed by natural gas company Range Resources and redacted testimony by a Range executive calculating the financial damage to the oil and gas company from shutdowns. Range is a major shipper on the Mariner East pipeline.

In supporting the suspension of work on the Mariner East 2 and 2X pipelines in West Whiteland, the commission ordered Sunoco to provide more information in the next 20 days, including its inspection and testing protocols, emergency response plans and safety training for employees.

Commissioners John Coleman and Norman Kennard voted against the motion because it didn’t go far enough: They thought that in addition to reinstating the Mariner East pipeline, the commission should have cleared the path for construction of the new pipelines in West Whiteland.

They stressed how much time PUC pipeline staff has spent evaluating the construction project — 76 inspection days in 2017 alone — and said the PUC may not even be the right agency to address concerns about things like water contamination. That responsibility falls to the state Department of Environmental Protection, they said.

Further, they claimed the judge’s fear about Sunoco using unqualified welders on a project in Texas two years ago — the Texas pipeline subsequently failed — has “no relevance to a finding of immediate harm” from construction in Pennsylvania.

“To date our pipeline safety experts have not reported any safety issues that warrant halting of construction of ME2 or ME2X,” Mr. Coleman said. He then repeated the statement slowly, with emphasis.

The decision to keep construction on hold may not be a huge blow to Sunoco, which said in its legal briefs that it doesn’t plan to restart activity in West Whiteland until July. Before it can resume, Sunoco needs to get certain approvals from the Department of Environmental Protection.

Sunoco’s Mariner East 2 pipelines have racked up dozens of environmental violations and caused a series of spills during a process known as horizontal directional drilling, where a tunnel is drilled under a feature such as a road or a stream to prevent damage on the surface.

In West Whiteland, the activity caused sinkholes in March unearthing a portion of the Mariner East 1 pipeline. That prompted the PUC to order the pipeline shut down to evaluate its integrity. It resumed operation in early May, only to be stopped again a few weeks later with the judge’s order.

Environmental groups that celebrated the PUC decision Thursday downplayed the resumption of service on Mariner East 1.

“The threats posed by Sunoco’s Mariner East project do not end at the West Whiteland Township line,” said Joseph Minott, executive director of Clean Air Council. “Communities should continue bringing their concerns to the Commission,”

Several townships across Pennsylvania have appealed to the PUC and the judge in the case, some fighting against Sunoco and some fervently in favor of it.

“[T]his work needs to continue without delay,” urged Brian Merdian, supervisor at Sewickley Township in Westmoreland County, who said the revenue from the gas industry has kept people employed and tax increases at bay.

“Sunoco has been a welcomed addition to our community not only with their project, but also with how they have conducted their business and also by generously donating to our local fire departments,” Mr. Berdian wrote.

Meanwhile, the company, which is owned by Energy Transfer Partners, has been ducking blows in a number of other venues, including a recent decision by the U.S. Supreme Court not to hear an appeal from a Lebanon County landowner who challenged Sunoco’s use of eminent domain for the Mariner East 2 pipeline.

Earlier this week, Delaware Riverkeeper Network filed a lawsuit against Sunoco in U.S. District Court for the Eastern District of Pennsylvania, alleging the company has been illegally discharging its drilling fluids into streams without a permit.

Anya Litvak: alitvak@post-gazette.com or 412-263-1455.

First Published: June 14, 2018, 5:25 p.m.