A 64-square-foot chunk of concrete fell from the ceiling of the tube that connects Oakland to Alameda at around 6 p.m., a California Department of Transportation spokeswoman said.
The 2-inch-thick mass was not a structural piece of concrete, but an aesthetic one that a Caltrans employee noticed in the tube, Caltrans spokeswoman Lauren Wonder said.
Drivers trying to get into Alameda had to take Park Street or the Broadway tunnel, Wonder said.
