CINCINNATI, Ohio (WWJ) – A partial collapse at a casino construction site in Cincinnati has sent 13 people to the hospital with injuries. The casino is being developed by Caesar’s Entertainment and Detroit-based Rock Gaming, a group headed by Quicken Loans founder Dan Gilbert.

A spokesperson for Rock Gaming said the floor collapsed as concrete was being poured.

READ MORE: Police Seek Detroit Man Accused Of Fatally Shooting Cousin

Cincinnati Fire Chief Richard Braun described the scene when firefighters arrived.

“It looked like, the first floor, they were pouring the flooring and one of the beams gave way and the flooring came down,” said Braun. “Fortunately, there was nobody underneath it. But the workers that were working on top, they actually road the floor down at it collapsed.”

READ MORE: Police: Woman Walking On I-75 In Troy With 55-Gallon Drum On Head Arrested

“It was very muddy … complicated just a little bit,” he said. “We even had to make a makeshift bridge just to get across to them.”

Braun said, at first inspection, there didn’t seem to be any broken bones. But he said they quickly put the hurt workers on to stretchers and rushed them to the hospital.

MORE NEWS: City Targets Packard Plant, Other Old Industry Sites To Improve Detroit Neighborhoods

A garage at another casino under construction in Cleveland partially collapsed last month, but no one was hurt.  That site is also being developed by Rock Gaming.