While placing concrete on the second floor of a future seven-story mixed use building in Oakland, California, the concrete forms suddenly gave way, sending around 20 workers 10 to 15 feet below with the wet concrete. News reports explain the job site went into a panic, understandably so, and co-workers rushed to the scene to help.
Thankfully, the 12 workers that had to be transported to the hospital only suffered minor injuries, including sprains and bruising, but the injuries could have been much worse. As is good practice, nobody was below the forms during the concrete placement above.
People in nearby businesses recalled the collapse sounding like bombs going off, according to SF Gate. In order to get to some of the trapped workers, plywood and wood planks had to be put on top of the wet concrete for fear the rescuers would get stuck in the quicksand like material. Oakland Fire Department Battalion Chief Ian McWhorter was pleased with the teamwork between the co-workers and the firefighters called to the scene, telling ABC7 that, "It was a great rescue between us and them.”
An aerial photo of the collapsed formwork is below:
While many of the workers above fell down to the wet concrete below, many were left hanging from the steel rebar that managed to stay suspended. Someone on site captured cell phone footage of several workers dangling, which you can watch below.
Cal/OSHA was on site starting their investigation shortly after the incident. It's not yet clear what caused the collapse. Both the General Contractor and concrete sub have received Cal/OSHA safety violations within the past 5 years, according to ABC7.