The company building a Cincinnati casino said worker safety remains a top priority as construction resumed Wednesday following last week\'s deck collapse. Thirteen people were injured when a second-floor deck collapsed as workers poured concrete for a floor, The Cincinnati Enquirer reported. The collapse occurred when a steel beam supporting sheet metal that the concrete was being poured onto broke away. Project manager Messer Construction Co. said in a statement that all parties involved in the resumption of construction have set worker safety as their top priority. However, the firm did not specify how it is improving safety procedures for the Horseshoe Casino or what caused Friday\'s accident. Cincinnati\'s chief building officer, Amit Ghosh, also declined to discuss possible causes of the collapse in a briefing before the city council. Investigators are looking at how many bolts were installed in the failed beam. The owner of a consulting firm said it is a common practice to erect steel without fully tightening all bolts to allow for adjustments. However, he added that those bolts should be tightened and inspected before any load -- such as a concrete floor -- is placed on the beams.