A federal court has vacated yet another regulatory approval for the Atlantic Coast Pipeline (ACP) project, this time invalidating an air permit for a compressor station in Virginia.

A three-judge panel of the U.S. Court of Appeals for the Fourth Circuit ruled that the Virginia Air Pollution Control Board did not properly consider how the project might impact a minority community in Buckingham County. The court also found that regulators failed to adequately consider alternatives for the compressor station that could better mitigate environmental impacts.

“What matters is whether the board has performed its statutory duty to determine whether this facility is suitable for this site,” because of environmental justice “and potential health risks for the people of Union Hill. It has not,” the court wrote in its decision.

Environmental and community advocacy groups Friends of Buckingham and the Chesapeake Bay Foundation challenged the permit to site the project in historic Union Hill, which has a high population of African Americans whose ancestors established the community after the Civil War.

The Fourth Circuit determined that the air control board leaned too heavily on an incomplete record and did not make adequate findings about the population or the potential environmental impacts. Environmental justice reviews are typically conducted to determine whether a project will have a disproportionate impact on minority or low-income communities. The court also questioned why electric turbines were not considered for the compressor station instead of gas-fired turbines.

Under state law, regulators are required to consider environmental justice factors in approving a project. The court also noted that Gov. Ralph Northam’s administration in 2018 recommended suspending the permitting decision “pending further review of the station’s impacts on the health and the lives of those living in close proximity.”

The court vacated the permit and remanded it to the board.

The latest setback for ACP follows a series of regulatory and legal delays, a number of which have come at the Fourth Circuit. The project can’t move ahead until the court’s December 2018 ruling is resolved, which tossed approval to cross the Appalachian National Scenic Trail. That ruling could impact other natural gas infrastructure projects in the future.

The U.S. Supreme Court has agreed to hear ACP’s appeal of the decision in the coming months.

The 600-mile ACP would carry 1.5 Bcf/d of Appalachian gas through mountainous terrain from West Virginia to Virginia and North Carolina.