A fire broke out before dawn on San Francisco’s Fisherman’s Wharf and destroyed a warehouse. Fire officials said no injuries have been reported Saturday morning and firefighters are making multiple searches to ensure no one was inside the building on Pier 45. They said the warehouse is typically unoccupied at night. The fire tore through the warehouse, sending thick smoke over the waterfront and causing its walls to collapse. At one point, it threatened to spread to a historic World War II-era ship that docks by Pier 45, but officials said firefighters successfully saved the vessel. The cause of the fire is under investigation.