A proposed 47-story condominium tower — which also would be the long-awaited permanent home of the Mexican Museum — faces the prospect of a lawsuit from residents of the Four Seasons on Market Street who want to stop it from casting a pall on sunny Union Square.
The 510-foot tower would be built at 706 Mission St. by developer Millennium Partners. At that height, it would drop shadows on the southeast corner of Union Square during part of the morning, according to a group calling itself Friends of Yerba Buena Gardens.
That’s enough darkness to violate a voter-approved city law limiting shadows on public parks, and enough to provide grounds to sue if the developer does not agree to build shorter, according to businessman Matthew Schoenberg, the group’s president and one of the roughly 80 Four Seasons residents who oppose the tower.
“You can’t keep shadowing Union Square,” said Schoenberg, who stressed that he and his neighbors “are fully supportive” of the Mexican Museum — and aren’t opposed to the condo tower, either, as long as it’s only 351 feet.
The 510-foot tower is already shorter than the 550-foot tower first proposed, according to documents on file with the Planning Department.
Sean Jeffries, Millennium Partners’ vice president, could not be reached for comment Wednesday.
Developers have to get a special height exemption for a tower taller than 350 feet, and that legislation is expected to go before the Board of Supervisors on June 4.
Schoenberg and his group have already attempted to block the project with an unsuccessful appeal of the environmental impact report.
The Planning Commission and Recreation and Park Department could sign off on the project — and rule the shadow issue is not substantial — as soon as today.
But if construction is approved on a tower taller than 351 feet, Schoenberg and his group will sue, he said Wednesday.
There’s also a chance someone — whom Schoenberg would not reveal — could bankroll a ballot initiative, similar to the referendum that has ensnared a condo proposal at 8 Washington St. along The Embarcadero, Schoenberg said.