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SAN FRANCISCO (KTVU) -- The San Francisco City Attorney's Office on Tuesday served subpoenas to Millennium Partners, the developers of the luxury high-rise condo tower south of Market Street that is sinking and shifting.
City Attorney Dennis Herrera said he is looking for further evidence that Millennium developers knew the tower was sinking and didn't disclose that information to buyers who purchased condos in the building.
Executives with the tower said they will fully cooperate with the investigation, but they blamed the problem on the Transbay Joint Powers Authority, which is developing a transit hub next to the condo tower.
After weeks of silence, the project's founders lashed out at the TJPA for what they called "reckless behavior."
"The behavior here is so outrageous," said Chris Jeffries, founding partner of Millennium Partners, at a press conference at the Four Seasons Hotel Tuesday morning.
The tower's developers insist that even though the 58-story luxury tower has sunk more than 16 inches since construction, it is 100 percent safe and city approved.
Millennium officials say when the TJPA broke ground on the Transit Center next door, it compromised the foundation of the tower.
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"If you dig a 60 foot hole and de-water for six years and drop the water table by 20 feet, on a major high-rise structure, you're going to cause a problem," Jeffries said.
Engineers say de-watering is a process used for buildings erected in areas where the Tower and Transbay Terminal are located. That's because they are built on landfill and bay mud. They likened it to draining water out of coffee grounds to get a more stable consistency.
But engineers caution that when too much water is removed, the stability of other nearby structures is placed at risk.
"The amount of de-watering is staggering," said Peter Meier, an attorney for Millennium Partners. "[It's] up to 5 million gallons per month or 60 million gallons each year since 2011."
Millennium officials also say the TJPA has turned off the measuring devices on the water.
"To shift the blame exclusively to the Transbay Joint Powers Authority is a fiction, it defies and it defies fact," said Mark M. Gray, an attorney representing residents of Millennium Tower. A group of homeowners are pursuing a class action suit on their claims for “loss of value.”
Gray says developers should've anticipated the Transit Center excavation. "They should have designed a system that was anchored in bedrock that would have resisted the de-watering that they're now trying to use as an excuse," Gray said.
Millennium, as well as the Marriott Marquis are not anchored in bedrock 200 feet down, but rather 80 feet down into dense sand. Critics say it's an unstable, cost-cutting way to build.
But Millennium engineers say the other buildings are stable, adding that construction of the transit hub has caused the problem.
By KTVU reporter Tara Moriarty.