CINCINNATI (AP) -- A floor collapsed into a V shape Friday at the construction site of a new Ohio casino, sending workers sliding to the ground, leaving one worker with serious injuries and hurting at least a dozen others.
The collapse occurred shortly before 8 a.m. as a crew was pouring a section of concrete floor at the Horseshoe Casino Cincinnati site, Steve Rosenthal, of co-developer Rock Gaming LLC, said Friday. It came just weeks after a similar accident at a Cleveland casino with the same developers.
The male worker with serious injuries was downgraded from fair condition at a Cincinnati hospital Friday night, several hours after the collapse. Authorities had said earlier that there were no life-threatening injuries.
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.
"We've got men under a beam as well. We got to get this beam off of them."
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.
The man in serious condition is at Bethesda North, and the only worker from the collapse at the hospital, said Joe Kelley of the TriHealth system. The system's Good Samaritan Hospital treated and released two workers.
Ten workers were treated at University Hospital, said spokesman Matt Kramer, with seven released and three that stayed overnight for monitoring of non-life-threatening injuries.
Neither Kelley nor Kramer had details about the injuries.
Jo Ann Davidson, who chairs the Ohio Casino Control Commission, said she knew of one worker having a broken elbow and another, a broken hip.
Jessie Folmar, a spokeswoman for Cincinnati-based Messer Construction Co., said the company was trying to learn what happened.
"Our top priority is to ensure everyone at our jobsites can return home safely to their families at the end of each day," Messer's president and chief executive Tom Keckeis said in a statement. "We have stringent safety processes and protocols in place to ensure our jobsites remain safe and our structures secure."
Messer has a clean safety record with the Occupational Safety and Health Administration since 2006, according to information from the agency's database. Its last Ohio incident was that year, when it was penalized for four serious violations and paid a penalty of $3,125. One involved a lack of adequate fall protection for workers.
OSHA inspectors, as well as investigators from the state, were looking into the accident. The developers said work won't resume until the construction team and authorities say it is safe.
The collapse occurred on what will be the casino's second floor, said Jason Mullins, business manager for a union representing ironworkers on the project, but not the workers who were hurt. The framework was more than one-third complete, Mullins said.
Mullins said some of the union's workers were at the site and saw at least part of the collapse.
"They were shaken up, but they were not injured and they worked to help those who were," he said. "No one was underneath the floor, or there could have been lives lost."
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 on 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. "These are two different construction management companies, two different contractors, two different sites, two different areas."
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.
Davidson said she sees no link between the two accidents and does not believe casino construction is being rushed in Ohio.
"They're not working overtime shifts. Actually, they're on a regular work schedule, they have a well-known local construction company ... which has done significant work in the Cincinnati area," she said.
The commission plans to closely follow the investigation into the accident, she 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, an official with the company told an Ohio House panel at a hearing this week.
The casino is expected to attract 6 million visitors a year and create 1,700 jobs, said Lee Dillard, vice president of finance for the Horseshoe Casino Cleveland. It will feature three outward-facing restaurants, about 2,000 slot machines, 85 table games and a 31-table World Series of Poker room.
Casino development was touted during a statewide legalization campaign in 2009 for the immediate boost it would give to Ohio's economy, particularly through the temporary construction jobs needed to build the four new facilities in Cleveland, Cincinnati, Columbus and Toledo. According to a recent report from the Associated General Contractors of America, construction jobs rose in Ohio this past year - from 163,400 in December 2010 to 168,600 last month.
Nationwide, OSHA statistics show there were nearly 196,000 job-related injuries in 2010 in the construction industry, almost four injuries for every 100 fulltime workers. In Ohio, there were 21 fatal injuries in the construction industry in 2010, the agency said.