U.S. federal energy regulators on July 19 denied Williams Co. Inc.’s (NYSE: WMB) request to rehear an earlier decision on the Constitution natural gas pipeline finding New York environmental regulators were able to deny a water permit for the project.

The U.S. Federal Energy Regulatory Commission (FERC) said it decided not to rehear its decision in January that determined the New York Department of Environmental Conservation (DEC) had not waived its authority to issue a water quality certification for Constitution under the Clean Water Act.

Several analysts said they were expecting FERC to grant Williams more time to complete the long-delayed project that would transport gas from Pennsylvania to New York, noting this would likely be the last time Commissioner Rob Powelson would be voting before he leaves FERC in August.

Williams had asked FERC for more time to complete the project, which it has not started, because the DEC denied the company’s request for water quality certification.

Officials at Williams, the lead partner seeking to build Constitution, were not immediately available for comment.

FERC approved construction of Constitution in December 2014 and gave the company until December 2016 to complete the project. After Williams’ appeals of the New York water permit denial, FERC gave the company until December 2018 to complete the project.

Williams has argued that New York waived its authority to decide on the water quality certification by failing to act within a reasonable period.

Williams filed with the DEC for the water permit in August 2013. The company withdrew and resubmitted that application twice, both times at the DEC’s request.

In April 2016, the DEC denied Williams’ application. Williams appealed that denial in federal court all the way to the Supreme Court, which declined to review the judgment of the appeals court. The appeals court concluded it lacked jurisdiction and upheld New York state’s decision.

If built, the 125-mile (201-km) pipeline would transport 0.65 billion cubic feet per day (bcf/d) of gas. New York consumes about 3.6 bcf/d.

When Williams proposed building Constitution in 2013, it estimated it would cost about $683 million and enter service in 2016. Delays have boosted that estimate to as high as $875 million, according to local newspapers.

Williams said it would take 10 to 12 months to build the pipeline after it receives the necessary approvals.

Constitution is owned by subsidiaries of Williams, Cabot Oil & Gas (NYSE: COG), Duke Energy Corp. (NYSE: DUK) and WGL Holdings.