Building site collapse injures 13 in Cincinnati Fri Jan 27, 2012 12:17pm EST (Reuters) - A partial collapse at a Horseshoe casino construction site in Cincinnati injured at least 13 people on Friday, none of them critically, and all were accounted for, officials said. The cause of the collapse was undetermined, said Jennifer Spieser, a spokeswoman for the Cincinnati Fire Department. Most of the injured are construction workers, and all 13 were taken to hospitals, she said. "A single bay of the facility collapsed as concrete was being poured," Steve Rosenthal, a Rock Gaming LLC principal who is overseeing the design and construction of the project, said in a statement. All the workers were accounted for and were being treated at area hospitals, Rosenthal said. He could not confirm the extent of their injuries. The site has been secured and Rock Gaming planned to provide an update later Friday, Rosenthal said. The casino is being developed as a joint project between Rock Gaming LLC and Caesers Entertainment Corporation with plans to open in spring 2013. Caesers will manage the day-to-day operations. Reporting by David Bailey and Colleen Jenkins; Editing by Daniel Trotta