Environmental groups have asked the U.S. Court of Appeals for the Fourth Circuit to stay key federal authorizations for the Mountain Valley Pipeline (MVP) while the court reviews a broader challenge.

If the court grants a stay of the project’s Biological Opinion (BO) and Incidental Take Statement (ITS), MVP may be forced to suspend all construction across the entire 300-mile route. The approvals, issued by the U.S. Fish and Wildlife Service (USFWS) under the Endangered Species Act, are required for the 2 Bcf/d project’s federal certification.

MVP made a preemptive move last week to satisfy federal regulators and prevent a full work stoppage by voluntarily suspending some construction. The decision came days after the environmental groups, including Wild Virginia and the Sierra Club, asked the Fourth Circuit to review the BO and ITS. MVP halted construction activities where work could imperil federally listed species or risk modifying their habitats.

The Federal Energy Regulatory Commission agreed with the move and said only that construction the company has identified may not resume until it has permission from the Commission’s Office of Energy Projects.

In the petition to the Fourth Circuit, the environmental groups argued that the USFWS failed to protect the endangered Roanoke logperch. The groups also claimed that the agency didn’t set limits for the number of threatened or endangered bats that could be harmed or killed by the pipeline’s construction, an argument that caused problems for the similarly routed Atlantic Coast Pipeline (ACP).

The Fourth Circuit vacated ACP’s BO and ITS on two separate occasions, finding that USFWS failed to set clear limits for the project, which led to work stoppages.

ClearView Energy Partners LLC said on Thursday the court could make a decision to stay MVP’s authorization within a week given its reasoning on ACP. “We think there is reasonable risk that the Fourth Circuit could grant the stay in short order…solely on the basis of the Indiana bat issue without addressing the allegations related to risks to the Roanoke logperch and other concerns raised in the appeal filed earlier this month.”