The Alexandria City Council, in an acrimonious six-hour hearing Saturday, refused to change the zoning that would allow the local housing authority to replace 15 antiquated but historic public housing units with 53 new units.

The council, forced by a citizens’ petition to approve the change with a supermajority vote, failed to get the six votes needed, thus rejecting the housing authority’s 11th-hour request to pass the rezoning and defer a vote on the project. A late effort to demonstrate that the council members support increasing affordable housing was met with derision by one member.

While Mayor Allison Silberberg (D) said the decision should encourage the housing authority to try again in six months, its chief executive said it was uncertain if it would. “We expended a considerable amount of money to develop these plans. We can’t do that again,” said Roy Priest, chief executive of the Alexandria Redevelopment and Housing Authority. “I don’t want to leave the residents in those units for another year — I don’t know now where we will put them.”

The 74-year-old Ramsey Homes, built by the federal government to house African American defense workers during World War II, have long passed their use-by date. There is no air-conditioning nor are there dishwashers, the heating is inadequate, the units are not accessible to people in wheelchairs, and when one tenant does her laundry, the sink in the adjacent unit backs up, residents told the council.

But replacing the four mustard-colored concrete buildings with new units catering to moderate- and low-income residents would require a more dense development to be eligible for financing and low-income tax credits, ARHA officials said. Historic preservation advocates urged preservation of at least a portion of the project. Neighbors complained that the project removed too much open space.

Although long civic hearings are not unusual in the Alexandria council chambers, the anger that erupted from the elected officials on the dais was remarkable.

Furious that ARHA waited to ask for a deferment of its special-use permit until 4:30 p.m. Friday, council members questioned whether ARHA was trying to game the system by getting a rezoning without saying exactly what it would build on the site — or whether it would sell the property to a private developer.

ARHA officials insisted that they could not do that without the approval of both the city council and the U.S. Department of Housing and Urban Development, which has a say in the property’s disposition.

But years of acrimony between the two bodies spilled over, with members of both groups accusing the other of failure to share information and plans.

“We gave very explicit instructions five months ago, and a lot of time has passed,” said council member Paul Smedberg (D). “This is utterly frustrating. . . . And if you care so much about residents, what about the maintenance of these units over time?”

Council member John Taylor Chapman (D), who grew up in public housing, said that preservationists were not only trying to retain segregated and substandard housing but also asking families to continue to live there.

He also assailed the mayor for meeting with the city manager and the ARHA chief executive without informing council members, including those working on the issue. When Silberberg defended herself, calling the meeting “a prerogative of the seat,” Chapman said she missed his point.

“It’s not about you working with [ARHA’s chief]. It’s about you working with us — this is a jointly run government,” Chapman said.

“Your anger toward me in this situation, I say with all due respect, is misplaced,” she said.

Vice Mayor Justin Wilson (D) derided Silberberg’s effort to pass a limited approval of a change in the master plan, which she said would “send a signal” that the council supports affordable housing.

“You are amending the allowable housing from 30 to 63 units here. That’s all you’re doing,” Wilson said.