Twelve workers were injured Friday morning when a building partially collapsed at an Oakland construction site near downtown, city officials said. No workers were seriously injured in the collapse, which took place around 9:30 a.m. at the construction site at 3093 Broadway, said Oakland Fire Battalion Chief Ian McWhorter. Some of the workers were taken to hospitals strictly as a precaution, while most of the injuries were bruises and back strains, he added. Workers were pouring wet concrete to build the second floor of what was to become a parking garage when part of the structure collapsed around them, McWhorter said. When police and firefighters arrived, they found some of the workers hanging from the scaffolding while others were up to their knees in wet concrete. Construction and fire crews used planks and plywood so they could reach the trapped workers without themselves becoming submerged. Abraham walked out and saw workers coming down from the roof and emergency personnel pulling up to the scene. Ezaud Duran, safety inspector for Cen Cal Plastering, said he was working at the other end of the site when he heard a “sound like a boom,” followed by people screaming. Inspectors from Cal/OSHA, the state’s workplace safety regulator, and a building engineer from the city of Oakland were at the site shortly after the accident. The state inspectors “will be looking at the scene, talking to witnesses, speaking with the contractors and looking at safety plans and such,” said Peter Melton, a Cal/OSHA spokesman in Oakland. The seven-story building is slated to include 435 apartments and 24,000 square feet of retail space, as well as 472 parking stalls on the first and second floors, and 266 bicycle parking spaces. The corner of the building, which is preserved as a historical showroom from the Chevy dealership, is being integrated into the new structure.