Another Upper East Side Democratic club is taking a pass on the mayor’s race, citing a lack of sufficient opposition from the candidates to the city’s plans to build a marine waste transfer station at East 91st Street.

The East Side Democrats voted not to endorse in the mayor’s race Sunday, following on a similar decision by the Lenox Hill Democratic Club last week. Presidents from both clubs said the plan to build the garbage facility weighed heavily on their choices.

The Lenox Hill Democrats were poised to back Council Speaker Christine Quinn, but instead opted to withhold their endorsement. Ms. Quinn is the only mayoral candidate who is a fervent supporter of the East 91st Street facility, which she sees as part of the environmental justice movement. But her rivals, some of whom had voted with Ms. Quinn for the Solid Waste Management Plan that included the transfer station only to later criticize it, had not promised to abandon the plan, East Side Democrats President Betsy Feist said.

“There was not a major candidate that had pledged not to go ahead and build that” facility, Ms. Feist said. “It just led to a decision that the best thing to do was not to endorse.”

David Menegon, president of the Lenox Hill Democrats, said Ms. Quinn had the inside track on his group’s support, but her support for the garbage station was too much to overlook.

“A lot of people were leaning toward Christine Quinn and her ability to run the city,” he said. “But that one issue really prevented people from endorsing her. That’s probably the most important issue on the Upper East Side.”

Comptroller John Liu and Public Advocate Bill de Blasio, who had both recently expressed skepticism about the East 91st Street project, also were passed over for endorsements by the clubs. Mr. Menegon noted that both officials voted in favor of the project when they were in the City Council. Former Comptroller Bill Thompson has also voiced uncertainty about the plan, but has not called for its outright reversal.

Only former MTA Chairman Joe Lhota has come out publicly against the proposed facility, vowing to nix the project if elected. But Mr. Lhota is a Republican, and not eligible for endorsement from the two UES Democratic clubs.

The Bloomberg administration is pushing the project forward on the premise that each borough should process at least some of its own garbage. For years, trash transfer stations were concentrated in manufacturing zones in the outer boroughs, subjecting nearby residents to heavy truck traffic and air pollution. But Upper East Siders say the location chosen for the plant is inappropriate because it is too close to a heavily used recreational space. An independent analysis found that the city would save hundreds of millions of dollars by canceling the project and trucking the trash elsewhere to be prepared for shipment to landfills. But the administration has continued to defend the plan in the courts, which have consistently deemed it proper and legal.

“Chris Quinn has been consistent and unequivocal on this issue,” said a spokesman for her campaign. “She believes it’s every borough’s responsibility, not just communities of color, to do their fair share handling municipal waste. While some people in this race flip-flop, pander and duck, Christine Quinn remains firmly committed to a waste management plan for New York City where every community does its part.”

As it happens, Ms. Quinn’s predecessor as speaker, Gifford Miller, represented the Upper East Side in the council and strongly opposed siting a transfer station there. His position helped poison his relationship with Mayor Michael Bloomberg. When Mr. Miller ran for mayor in 2005, he finished a distant fourth in the Democratic primary, behind Fernando Ferrer, Anthony Weiner and Virginia Fields.

Read on Crain’s New York.