Barclay Damon announces a significant victory on behalf of client Transcontinental Gas Pipe Line Company LLC (Transco), a subsidiary of Williams Companies Inc., after the US Court of Appeals for the Second Circuit upheld the New York State Department of Environmental Conservation’s (NYSDEC) issuance of a Clean Water Act Water Quality Certification for the Northeast Supply Enhancement project. The decision was issued by a panel composed of Circuit Judges Steven J. Menashi and Sarah A. L. Merriam and District Judge John P. Cronan, sitting by designation, in Raritan Baykeeper, Inc., et al. v. New York State Department of Environmental Conservation, No. 25-2938.
Yvonne Hennessey, chair of Barclay Damon’s Environmental Practice Area and co-leader of the Oil & Gas and Linear Infrastructure Teams, led the team of Barclay Damon attorneys that represented Transco before the Second Circuit, which included Andrew Carroll, counsel, and Dan Krzykowski, associate.
The Northeast Supply Enhancement project will upgrade Transco’s pipeline infrastructure in Pennsylvania, New Jersey, and offshore New York and New Jersey to deliver an additional 400,000 dekatherms per day of capacity – enough energy to serve the equivalent of 2.3 million homes – to customers in New York City and on Long Island. Related litigation over other state and federal approvals for the project continues in the Third and DC Circuits.
“This decision confirms what we’ve argued from the start: NYSDEC’s 2025 certification was the product of a thorough, technical review that directly addressed the concerns underlying its prior denials,” said Hennessey. “We’re pleased the court recognized the strength of the agency’s record and the rigor of the safeguards built into this certification.”
A coalition of environmental organizations—including Raritan Baykeeper, Food & Water Watch, Natural Resources Defense Council, Sierra Club, Surfrider Foundation, and Protectors of Pine Oak Woods—had petitioned the Second Circuit to vacate the NYSDEC’s November 2025 certification, arguing the agency failed to justify reversing its 2020 denial of the project and improperly permitted Transco to submit certain compliance plans after certification. The Second Circuit rejected both challenges, finding that the NYSDEC’s 2025 approval directly and adequately addressed the issues raised in NYSDEC’s prior denial. The court also confirmed that the certification’s compliance plans, which require NYSDEC review and approval before construction begins, satisfy Section 401 of the Clean Water Act, given the certification’s binding water quality limits, continuous monitoring requirements, defined construction windows, and independent third-party monitor with stop-work authority.
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