 On June 29 , 2003 , the deadliest porch collapse in United States history occurred in Chicago . An overloaded balcony collapsed during a party in an apartment building , killing thirteen people and seriously injuring fifty @-@ seven others . The ensuing investigation was highly critical of the way the balcony was built , finding a large number of errors in its construction which ultimately resulted in the collapse . However , the building 's owner continues to blame overcrowding on the balcony for its complete structural failure , although he has taken steps to strengthen the balconies at his properties to prevent a recurrence of the disaster . The accident resulted in sweeping inspections of similar structures across Chicago , with 1 @,@ 260 cases being actioned by the city authorities . 
