Stanford University Medical Center officials scored a major victory two weeks ago, when Palo Alto approved a dramatic expansion of Stanford's hospital facilities.

These celebrations were temporarily halted Monday night, when Stanford found itself facing a protest from a nearby day care center -- an unexpected development that threatens to delay the historic project.

Dozens of parents and children from the Stanford Arboretum Children's Center gathered at City Hall Monday night to demand that the city reconsider its approval of the Renewal Project-- Stanford's $5 billion effort that includes reconstruction of Stanford Hospital & Clinics, an expansion of the Lucile Packard Children's Hospital and renovations to various Stanford School of Medicine buildings.

After four years of negotiations and 97 public hearings, the City Council voted 8-0 on June 6 to approve the project, which would add about 1.3 million of new development to the city.

The day care center is located on Quarry Road near Hoover Pavilion, which is one of the first facilities scheduled for renovation, according to Stanford. A new parking garage is planned for the site.

The city planned to hold a "second reading" on the Stanford project Monday night -- a largely procedural vote that would officially grant the medical center the green light. But after day care parents railed about the noise and pollution from construction, Stanford asked the council to delay the vote so that it could address their concerns. After hearing from about a dozen parents (whose comments were punctuated by gurgling and crying from the younger audience members), the council agreed and postponed its vote to July 11.

City Manager James Keene characterized the latest hurdle to Project Renewal as a dispute between Stanford Hospital and the day care center. He said it would be "premature" for the city to take a stance on the dispute, though he said delaying the vote to allow for a resolution would be appropriate.

"The second reading of the ordinance has been postponed and until that takes place, there is no project and there is no ability to proceed on any of these matters," Keene said.

Mark Tortorich, Stanford Hospital's vice president for design and construction, told the council Monday that Stanford believes that the environmental analysis for the project is accurate but that hospital officials agreed to work with the parents to address their concerns.

"We made a commitment to them, if they give us some time, to work with them to work mutually with them to address their concerns," Tortorich said.

Tortorich said Stanford learned just last week that day care officials did not alert parents about the construction project. But some parents argued that the problem was not in outreach but in Stanford's environmental analysis.

"We don't believe this is a communication problem," said Melissa Michelson, one of many parents who attended. "We believe this is Stanford not taking adequate concern for our children.

"We have several parents willing to lie in front of bulldozers if necessary."

Stanford geophysics professor Simon Klemperer, whose child attends the day care, also argued that the hospital's construction could have negative impacts on Arboretum's children. Klemperer had issued a statement earlier in the day expressing anger at what Arboretum parents characterized as a "last-minute announcement of a Stanford Hospital construction project that endangers their children."

The planned parking garage would be located 38 feet from Arboretum Children's Center, he said.

Klemperer, who was one of many parents who attended the meeting, said that the Environmental Impact Report for the project failed to consider a number of serious construction impacts, including noise and pollution levels. Work on the parking lot, he said, could harm the day care center's 140 children, particularly those with asthma and allergies.

"Because these children are so young, their airways are still in development," he said in a statement. "They may not have adequate defenses against high concentration of toxic airborne substances."

Stanford Hospital countered with its own statement Monday maintaining that its environmental analysis is valid and that construction would not impact the children's health. It cited an independent consultant who "confirmed that project construction will not pose significant health risks to children at the Center."

"Based on breathing rates and other exposure factors specific to infants and children, and using the most conservative assumptions that the child care facilities would provide no air filtration, windows would be open, and children would spend substantial time outdoors, the risk assessors have determined that health risks to children would be less than 20 percent of the level that the Bay Area Air Quality Management District considers to be significant," hospital officials said in a statement.

Hospital officials are now considering various options for assuaging the parents' concerns, including providing off-site child-care facilities during construction and providing "opportunities for other child-care services." They are expected to hold meeting with parents in the next month.

Council members thanked the parents for attending the meeting and agreed that delaying the vote is the best way to bring forth a resolution.

"I think this is the clearest step we can take to show that we heard their concerns," Vice Mayor Yiaway Yeh said.