New York State's Department of Environmental Conservation (DEC) is once again delaying a decision on whether to grant a permit for National Grid that would expand natural gas production at the Greenpoint Energy Center.

The state agency said Sunday — a day after its deadline passed — that it is waiting on the Public Service Commission to review National Grid’s request to install two vaporizers at the Brooklyn facility. These giant boilers would allow it to process more liquid natural gas during periods of large energy demand, but are also prone to leaking fumes. The DEC wants the commission to rule on whether the vaporizers are truly needed for “reliability purposes.”

The facility is located directly across from Cooper Park Houses, a NYCHA development, and the surrounding region is heavily burdened by air pollution. Activists claim that an expansion of the natural gas facility in Greenpoint is a violation of municipal environmental justice laws and state mandates to reduce fossil fuel dependency.

The move marks the seventh time this decision has been delayed since the permit was filed nearly three years ago. In the meantime, National Grid cannot begin construction. The DEC would not provide a new timeframe or deadline for the decision, stating, “The process is suspended subject to National Grid commencing and resolving the public proceeding before the PSC [Public Service Commission].”

The DEC said it granted the last extension in February to complete a review of more than 6,000 public comments that were submitted more than a year ago. But that announcement also came the day after local residents, elected officials and environmental groups gathered for a rally at the facility to protest against the permit.

The Public Service Commission told Gothamist via email that there is no timeframe for when and how its review will be conducted, even though the DEC’s final decision hinges on the PSC’s evaluation.

“The first step in the process will be for National Grid to submit a reliability needs and assessment to the PSC, which will then be followed up with an extensive opportunity for public review and comment before the PSC makes a determination,” said PSC spokesman James Denn. “There is no statutory deadline. The PSC’s review will be thoroughly conducted.”