Pennsylvania has shut down highway projects because of the coronavirus emergency, but state regulators on Thursday rebuffed calls to halt construction of the contentious Mariner East pipeline project.

The Pennsylvania Public Utility Commission declined to interrupt construction of the pipeline expansion project, which transports natural gas liquids such as propane from the Marcellus Shale region across Pennsylvania to a terminal in Marcus Hook. The PUC, in a statement, said that project was exempt from Gov. Tom Wolf’s order Monday to shut down non-essential activity.

“As they are essential services, utilities are expected to continue operations, including construction projects, which are considered essential per the governor’s essential business guidance at this time,” the regulatory agency said in a statement.

But in the fast-changing world of the coronavirus, the PUC’s directive may already have been superseded by Wolf’s decision later on Thursday ordering a mandatory shutdown of all Pennsylvania businesses not considered “life-sustaining.” The businesses that must close as of 8 p.m. Thursday include all construction work, including “utility subsystem construction.”

State Sen. Andy Dinniman (D., Chester) called on the state on Wednesday to order the shutdown, saying the project was not essential and his constituents “are profoundly perplexed and alarmed” that construction continues.

"Not only will direct interaction during construction place skilled laborers at unnecessary risk of infection, but also the movement of these individuals throughout our communities only furthers the risk to all, including our essential workforce of medical professionals and first responders,” he wrote in a letter to Gladys Brown Dutrieuille, the PUC chair.

A pro-pipeline advocacy group, the Pennsylvania Energy Infrastructure Alliance, dismissed Dinniman’s call, saying the senator hoped the coronavirus emergency “will finally achieve what he has been unable to do: halt the construction of the legally permitted Mariner East pipeline network.”

Pipeline opponents have vigorously fought the Mariner East project on health and safety grounds, and state regulators have imposed several costly delays and millions of dollars in fines on the project’s sponsor, Energy Transfer LP and its Sunoco Pipeline subsidiary. But Energy Transfer says the project remains on course.

“The operations, construction and maintenance of our energy infrastructure — including pipelines and terminals — are essential to meeting the energy needs of Pennsylvania and the United States,” the company said in a statement this week. “That includes the reliable delivery of transportation fuels, home heating fuels and other energy demands as we navigate this unprecedented scenario.”

Energy Transfer says it has directed its employees and contractors to follow guidelines from the Centers for Disease Control and Prevention and the Occupational Safety and Health Administration to protect public health and safety while working within the project right-of-way. This includes implementing social distancing best practices, using good hygiene and infection control practices for workers, restricting visitor access to work sites, and requiring workers to stay home if they are sick.

While Mariner East construction continues, the project has not entirely escaped the impact of the coronavirus.

The Pennsylvania Department of Environmental Protection on Tuesday canceled three public hearings in April related to the permits because of concerns about the coronavirus. DEP also canceled an April 2 hearing on air quality plans at the Marcus Hook Industrial Complex, the Delaware River terminal that is the destination for much of the material supplied by the pipeline. The hearings were not rescheduled.

Gov. Wolf’s emergency order exempted all construction projects, not just utility projects, as essential services that were not required to shut down.

“Halting construction activity will do more harm than good for construction workers, community residents and the economy," said Stephen E. Sandherr, chief executive officer of the Associated General Contractors of America, in response to calls to suspend construction.

Nevertheless, much construction work has shut down across the state.

The Pennsylvania Department of Transportation has suspended all highway construction projects statewide, encompassing about 850 projects. “This decision was made to quickly minimize exposure for both PennDOT and private-sector employees,” Alexis Campbell, the agency’s spokeswoman, said Thursday in an email.

And Shell Pennsylvania Chemicals announced Wednesday that it was furloughing 8,000 workers building its giant ethane cracker project in Beaver County, one of the largest construction projects in the state. The decision came after local officials expressed concern about workers being transported to the site in crowded buses, and eating in common area.

Shell said it would install additional mitigation measures in line with CDC guidance. “Once complete, we will consider a phased ramp-up that allows for the continuation of safe, responsible construction activities,” it said in a statement.

This article was updated to include Gov. Wolf’s new order Thursday evening shutting down all non-life sustaining businesses.