As pipelines go, the Eastern Panhandle Expansion Project isn’t much. It would run just 3.5 miles, north to south, traversing one of the narrowest parts of western Maryland.

But there’s no small controversy around this project. It would involve tunneling deep under the Potomac River — drinking water source for the Washington metropolitan area and other smaller communities upriver — to carry natural gas from Pennsylvania to growing communities in West Virginia.

Environmental groups have been campaigning for months against the “Potomac Pipeline,” as they call it, citing concerns about the potential harm to drinking water and the river. Activists recently trained their criticism on Maryland state regulators, accusing them of neglecting their responsibilities to protect the environment by not conducting a more thorough review of the project’s impact. They even urged people to boycott a public meeting the state Department of the Environment held Monday night to collect comments on the project.

“They’re not looking at cumulative impacts on drinking water in the Potomac [or at] all the cumulative impacts on forests and sedimentation,” said Mike Tidwell, executive director of the Chesapeake Climate Action Network. “They’re being very narrowly focused.”

By not exercising its authority to do a broader and deeper analysis of all of the project’s potential impacts, Tidwell argued, Maryland is ceding responsibility for environmental protection to federal agencies, which have a history of approving pipeline projects.

The pipeline has been proposed by TransCanada, based in Calgary, Canada, which operates extensive networks of gas and oil pipelines across North America. The 8-inch diameter line under the Potomac would provide 47,500 dekatherms of gas daily to Morgan County in West Virginia’s Eastern Panhandle. It’s intended to “increase supply options and system reliability, thereby reducing the risk of interruptions” to the company’s customers.

A TransCanada fact sheet says the project “will be constructed to stringent federal standards for safety and the environment” and that it will undergo a “thorough review” by the Federal Energy Regulatory Commission. Queries emailed to the company received no response. The company’s fact sheet says it hopes to begin construction in April and put the line in service by October.

To go forward, the project also needs a permit from the U.S. Army Corps of Engineers and a water quality certification from the MDE. Under Section 401 of the Clean Water Act, the state has veto authority over the project if it’s deemed harmful to the state’s waters.

MDE spokesman Jay Apperson referred questions about the pipeline to a fact sheet the state agency prepared, which says that the Corps is processing the company’s permit application under a “general permit” that covers smaller projects like this. The state gave a blanket water quality certification to all projects covered by that general permit.

“Generally, projects covered by [the general permit] do not require a project-specific 401 Water Quality Certification,” the fact sheet says. “However, ongoing review continues.”

So many people turned out on Dec. 19 for the public informational hearing on the project that many did not get a chance to speak. The MDE scheduled the hearing to continue Jan. 22 in Hancock and extended the public comment period until Thursday (Jan. 25).

Apperson noted that “issues raised in verbal hearing testimony and written comments will be considered and addressed in a final decision.”

But activists say they’ve become convinced that state officials are effectively “running out the clock” on the project. Under the Clean Water Act, Maryland has one year from the time a project seeks federal approval to exert state authority to conduct its own water quality review, or it loses that right. Columbia Gas Transmission, a TransCanada company, filed its application in March 2017. Tidwell said there’s precious little time left now for the MDE to conduct its own review for a water quality certification.

The MDE fact sheet says there are 23 existing pipelines across the Potomac and its North Branch. For this project, the company intends to use “horizontal directional drilling” to lay the pipeline 114 feet beneath the river, and the clay that would be used in drilling is nontoxic. Excavation, grading and vegetation removal would collectively impact about three-fifths of an acre of wetlands, wetland buffer, stream and floodplain areas, the fact sheet says.

But activists say the MDE review looks only at the relatively small disturbance of wetlands and waterways, while ignoring other significant concerns about the project, including the possibility that the pipeline could run through unstable karst geology, raising risks of breaks in the line or the contamination of groundwater.

The nearest public water supply intake is 30 miles downriver, for the city of Hagerstown, the MDE fact sheet notes. The town of Hancock, 1.4 miles east of the pipeline’s route, relies on groundwater for its drinking water supply, but the project would be outside the wellhead protection area for the town, according to the MDE. Information supplied by the Maryland Geological Survey indicates that “the presence of karst geology in the area is not definite,” according to the fact sheet, though a part of the pipeline alignment does cross a rock formation with “modest” potential for containing karst.

Tidwell acknowledged that having a state conduct its own water quality certification analysis is no assurance the project won’t pass environmental muster. Virginia’s Department of Environmental Quality conducted its own review before the Virginia Water Control Board gave the green light for two much larger projects in that state, the Atlantic Coast and Mountain Valley pipelines. The state’s approval of each is now being challenged in court by environmental groups.

“It doesn’t guarantee anything,” Tidwell said of a more detailed review, “but what it does do is help advocates like me — and all groups concerned about the environment and water — to be heard.”