EE ASSEMBLED SCAFFOLD LADDER TO LEAN AGAINST I-BEAM AND CLIMBED DOWN. THE LADDER STARTED TO BEND - EE GRABBED ONTO I-BEAM JUST AS LADDER COLLAPSED. EE HUNG FROM I-BEAM THEN FELL FROM APPROX. 15 FEET TO LOWER LEVEL. EE LANDED STRIKING LEFT HAND AGAINST LADDER RESULTING IN DISLOCATED JOINTS.