CHARLESTON, W.Va. (AP) — A hotly contested East Coast natural gas pipeline designed to carry gas from the Marcellus and Utica fields in Pennsylvania and Ohio was given the go-ahead Tuesday to start operating, six years after construction began.

The Federal Energy Regulatory Commission approved the 303-mile Mountain Valley Pipeline project across rugged mountainsides in West Virginia and Virginia over longstanding objections from environmental groups, landowners and some elected officials. Project developers told regulators on Monday that the pipeline was complete.

The $7.85 billion project has withstood weather delays, a maze of court and construction permit challenges and regulator scrutiny. It is designed to meet growing energy demands in the South and mid-Atlantic.

Congress ordered that all necessary permits be issued for the pipeline last year as part of a bipartisan bill to increase the debt ceiling. President Joe Biden signed the bill into law last June. Among the key votes for last year's sweeping legislation was U.S. Sen. Joe Manchin, a West Virginia independent. Manchin has called the pipeline “a crucial piece of energy infrastructure” that is good for global supply and American energy security.

Last July, the U.S. Supreme Court allowed the pipeline's construction to resume after a federal appeals court had blocked the work despite congressional approval.

Environmentalists object

Environmental groups argued that Congress overstepped its authority and have challenged the pipeline over its potential impact on endangered species. They also say it causes climate-altering pollution from greenhouse gases and contributes to erosion that will ruin soil and water quality. Part of the route includes national forest land.

“By allowing MVP to advance despite all these serious hazards, the system meant to protect our communities, land and water has failed,” Jessica Sims, the Virginia field coordinator for the environmental group Appalachian Voices, said in a statement.

An email sent to the pipeline operators wasn’t immediately returned Tuesday evening. On Monday, the operators told FERC in a filing that multiple shippers were prepared to start the flow of gas along the pipeline, “which further heightens the need to prompt authorization to meet market demands.”

First proposed in 2015, the pipeline's route includes 11 counties in West Virginia, six in Virginia and three compressor stations in West Virginia. It has been cited over the years for dozens of violations of environmental laws meant to control erosion and sedimentation.

Frustrated residents complained the pipeline altered pristine landscapes and muddied their clear springs that supply drinking water. In some places along the construction route, protesters locked themselves to heavy equipment or blocked access, bringing work to a temporary halt. In one Virginia county last year, heavy machinery was set on fire.

Failed test in May

After the pipeline operators initially asked FERC in April to issue the final authorization by May 23, a segment of pipe burst in southwestern Virginia on May 1 during pressurized water testing conducted to check for leaks and flaws. The damaged section was replaced and the operators investigated the cause of the incident.

The Montgomery County Board of Supervisors in Virginia asked FERC on May 13 to hold off placing the pipeline in service until safety testing and remediation was completed. Mountain Valley subsequently pushed back the targeted in-service date to early June due to the ongoing construction.

Virginia attorney and activist Jonathan Sokolow was among critics who claimed the pipeline was not ready to begin operations. He said Tuesday on the social platform X that no public information was available on the results of any pipeline inspections that have been done since April 1, including the area where the pipe burst.

In a phone call with FERC earlier on Tuesday, the Pipeline and Hazardous Materials Safety Administration, a unit of the U.S. Department of Transportation, said it had no objections if FERC were to authorize the pipeline operator’s request to begin service.

“We find that Mountain Valley has adequately stabilized the areas disturbed by construction and that restoration and stabilization of the construction work area is proceeding satisfactorily,” said Terry Turpin, director of FERC’s Office of Energy Projects, in a letter to the pipeline’s lead developer, Equitrans Midstream Corp, on Tuesday.

In March, Pittsburgh-based natural gas giant EQT Corp. announced an agreement to acquire Equitrans Midstream Corp. of Canonsburg, Pennsylvania, in an all-stock transaction.