The Atlantic Coast Pipeline (ACP) has hit a new obstacle—one that is giving environmental and racial justice advocates reason for cautious celebration.

On Friday (August 10), the Federal Energy Regulatory Commission (FERC) ordered Dominion Energy, ACP’s lead stakeholder, to stop all work on ACP until its ongoing permit problems are resolved. The pipeline, at completion, would be 600-miles long, spanning from West Virginia to North Carolina and carrying approximately 1.5 billion cubic feet of natural gas daily. As reported by ThinkProgress:

“Accordingly, allowing continued construction poses the risk of expending substantial resources and substantially disturbing the environment by constructing facilities that ultimately might have to be relocated or abandoned,” wrote Terry Turpin, director of FERC’s Office of Energy Projects, halting the pipeline in light of the permit decisions.

Southern Environmental Law Center attorney Greg Buppert, whose organization challenged the permits, said in a statement that FERC had made “the right decision” and said the agency should get to the bottom of Dominion Energy’s “over-blown and unsupported claims” of the public benefits the company has claimed the pipeline will bring.

Last week, the United States Court of Appeals for the Fourth Circuit vacated two permits for the pipeline, citing concerns that it would negatively impact endangered animals and public lands. ACP would run under waterways in Virginia, leading to a risk of spills and contamination.

Alongside environmental activists who oppose the ACP, racial justice groups have been key opponents to the pipeline. In May, the Virginia chapter of the National Association for the Advancement of Colored People (NAACP) sent a letter to the Virginia Department of Environmental Quality (DEQ). “Consideration under the U.S. Army Corps of Engineers is inadequate and grossly neglects to consider the magnitude of both projects and the massive disruptions to surrounding communities and the environment that will result,” the letter reads.

Prior to that, last February, the NAACP released a report, Fumes Across the Fence Line, which concluded that building the ACP through lower-income earning Eastern North Carolina counties would be detrimental to Black communities that would bear a disproportionate burden of air contamination and pollution. “African American and other environmental justice communities face heavy burdens because of the millions of pounds of hazardous emissions released by the oil and gas industry each year,” said the report.

Victories of the sort activists have enjoyed this summer in their efforts to stave off the construction of these pipelines are unusual, and pipeline opponents worry they may not hold out in the long term,” writes ThinkProgress, citing a recent investigation by ProPublica and The Charleston Gazette-Mail that asserts federal agencies tend to relax the rules to fast track permit approvals for pipelines.

Dominion Energy, in response to Friday’s stop work order, told The Washington Post it is working with FERC to resolve issues and “resume construction as soon as possible.”