Environmentalists are celebrating a federal appeals court ruling on Friday that reaffirmed New York State's decision to block a 124-mile natural gas pipeline project.

"Today's ruling confirms the independent authority and responsibility of states to protect their waterbodies from natural gas pipelines that carve through and degrade critical watersheds."

—Moneen Nasmith, Earthjustice

"This project would have been bad news for New York waters and communities, and the court's decision will help ensure that important waterways in the state, including the Hudson River and Schoharie Creek, will be protected," said Riverkeeper president Paul Gallay.

The U.S. Court of Appeals for the Second Circuit ruled that the New York State Department of Environmental Conservation (NYSDEC) had the authority to deny a Clean Water Act permit to four companies planning to construct the Constitution Pipeline, which would have carried fracked gas from Pennsylvania to Eastern New York State.

The pipeline—which would have crossed waterways 251 times and run through more than 80 acres of wetlands—received initial approval from the Federal Energy Regulatory Commission (FERC), the federal agency that regulates interstates pipeline projects. However, it was blocked by NYSDEC last year, when the state agency determined the gas companies had not provided enough information to ensure that the pipeline would comply with state water quality standards.

The companies argued in court that FERC's approval preempted any state-level decision, but the court's three-judge panel determined "NYSDEC is responsible for evaluating the environmental impacts of a proposed pipeline on New York waterbodies in light of the state's water quality standards," and upheld the agency's decision to prevent the pipeline.

"The collective efforts of individuals and local, regional, and national groups—including terrific legal representation by Earthjustice—prevented the pipeline from plowing through our communities and damaging our waterways," said Wes Gillingham of Catskill Mountainkeeper, which along with Earthjustice, Riverkeeper, and Sierra Club, helped to defend NYSDEC's decision in court.

The ruling is being lauded as a win for state regulatory agencies to deny construction projects because of environmental impact concerns, even if they have federal approval.

"Today's ruling confirms the independent authority and responsibility of states to protect their waterbodies from natural gas pipelines that carve through and degrade critical watersheds," said Earthjustice attorney Moneen Nasmith.

Echoing Nasmith's remarks, Roger Downs of Sierra Club's Atlantic Chapter said: "With today's ruling, the Court of Appeals has affirmed the rights of states to reasonably protect their water resources from oversized infrastructure projects that run roughshod over states' natural resources." Downs also praised New York Gov. Andrew Cuomo and Attorney General Eric Schneiderman for defending NYSDEC's decision to halt pipeline.

"New York must be able to do what's necessary to protect our environment—and we're glad that the court agreed," Schneiderman said in a statement. "It would be unacceptable for a pipeline—or any project—to pollute our waters and undermine New Yorkers' health and water resources. Today's decision marks a major win for New Yorkers, and for the state's right to take the actions necessary to protect the public and our environment."

Those celebrating the decision were optimistic that it could help to set a precedent for challenges to other proposed pipeline projects around the United States.

"This is not just a victory for the people impacted along the pipeline route," said Gillingham, "but gives hope across the country for people facing the onslaught of oil and gas infrastructure."