Quincy’s Conservation Commission has put the brakes on Boston’s Long Island bridge replacement project, with officials accusing Boston of “misleading” regulators by painting far too rosy a picture of its effects on the environment.

“They’re trying to do the least amount possible and avoid a more rigorous environmental review,” Quincy City Councilor William Harris told the Herald, saying Boston Mayor Martin J. Walsh’s administration is “misleading” Quincy and state environmental officials about the scope of the work the reconstruction of the bridge would require.

“I’m not going to respond to that,” Walsh told the Herald when asked about the accusations of deception.

Quincy’s Conservation Commission voted to deny Boston’s application for the bridge this week, the latest salvo between Boston and its immediate neighbor to the south in a bitter battle about the bridge. Walsh wants to rebuild the structure to the tune of $80 million and put a large drug-treatment center on the harbor island.

Christopher Walker, chief of staff for Quincy Mayor Thomas Koch, said his boss continues to adamantly oppose the bridge and plans to continue to fight the rebuilding process — and will take Boston to court if necessary.

“We’re prepared to argue vehemently that the city of Boston is grossly understating the environmental impact of new bridge,” Walker told the Herald.

Quincy’s government and residents have been in an uproar about Boston’s plans ever since Walsh announced them at the start of the year. The bridge, which carried traffic between Quincy’s Moon Island and Boston’s Long Island until 2014, was a bone of contention between the two cities for decades. When the bridge stood, it was only accessible by car through the winding roads of North Quincy and Squantum.

“The mayor of Boston decided not to listen to the people in the community,” said Harris, who represents the area and lives in the Squantum peninsula neighborhood.

Koch and other Quincy officials say they want Boston to use a ferry service from Boston land rather than the bridge from Quincy.

The bridge’s piers remain standing, with half inside Quincy city limits and the rest in Boston. Quincy helped sway its Conservation Commission’s mind by producing an expert who said the piers appear to be in much worse condition than Boston is claiming, and it would be “extremely unrealistic” to expect them to hold up for decades of bridge use.

“Those piers cannot be used to support a bridge,” Walker said.

Walsh said, “It’s an approach maybe that they’re using to prolong it a little bit, which is fine, but we’re still moving forward.”

The Conservation Commission has three weeks to write up its reasons for the denial, and then Boston has 10 days after that to decide on whether to appeal to the state Department of Environmental Protection.

“We’ll figure it out. I’m not sure of the next step on it yet,” Walsh said. “We’ll see. I’m not going to get into that.”

Boston’s Conservation Commission approved the project in May, a decision Quincy has appealed to the state DEP. The project would need a range of other local and state permits, including the blessing of Quincy’s planning board.

Quincy has taken other steps to try to head off the bridge, including banning commercial vehicles from the roads leading up to it.