Firefighters faced renewed challenges Saturday at a large Boyle Heights warehouse fire, where conditions remain highly complex as Mayor Karen Bass declared a local emergency to support response efforts. At a Saturday morning briefing, L.A. Fire Department officials described the facility as a 500,000-square-foot commercial building, which is used to store frozen foods. "The best way to describe this is like a giant cooler," said L.A. Fire Chief Jamie Moore, who added that the structure was