A floor collapsed into a V shape Friday at the construction site of a new casino, sending workers sliding to the ground and leaving at least a dozen with broken bones, bumps or bruises.
Authorities said there were no life-threatening injuries in the collapse at the Horseshoe Casino Cincinnati site, which came just weeks after a similar accident at a Cleveland casino with the same developer.
The collapse occurred shortly before 8 a.m. as a crew was pouring a section of concrete floor, Steve Rosenthal, of casino co-developer Rock Gaming LLC, said Friday.
Shouts could be heard on a 911 call right after the collapse as the caller told the dispatcher "we've got one guy that's in desperate position."
"There's about 20 guys just fell through the floor pour. You've got to get down here as quick as possible. They fell about 15, 20 foot. Hurry," he said.
Rosenthal told reporters at a news conference that it was too soon to determine what caused the collapse.
Fire Chief Richard Braun, who was one of the first on the scene after the collapse, said that a beam supporting the floor "sheared away" and the floor came down while the workers were on top of it.
"They basically rode the V down," Braun said. No one was underneath the 60-foot-by-60-foot section of floor.
The injured were sent to hospitals with what appeared to be mostly bruises and bumps, and possibly some broken bones, the fire chief said. All workers were accounted for, according to Rosenthal.
By dinnertime Friday, all but three of the workers had been treated and released.
Jessie Folmar, a spokeswoman for Cincinnati-based Messer Construction Co., said the company was trying to learn what happened.
The casino is being developed by Rock Gaming in partnership with Caesar's Entertainment. The same team is behind a casino project in downtown Cleveland where a garage partially collapsed Dec. 16. A 60-foot-by-60-foot second-level section of the parking deck gave way while concrete was being poured. No one was injured.
There is "absolutely zero connection" between the collapse in Cincinnati and the accident in Cleveland, Rosenthal said.
Rock Gaming spokeswoman Jennifer Kulczycki said the concrete work being done Friday was "a regularly scheduled pour."
"There was absolutely no acceleration of the work schedule," Rosenthal said.
Horseshoe Casino Cincinnati is a $400 million development under construction in the northeast corner of the city's center and is expected to open in spring 2013.