EE PLACED AN EXTENSION LADDER ON A SMOOTH CONCRETE SURFACE AND BEGAN CLIMBING THE LADDER TO TIGHTEN BOLTS, WHEN HE WAS 3' OFF THE GROUND, THE LADDER SLIPPED OUT FROM UNDER HIM AND HE FELL 3', LANDING HEAVILY ON HIS LEFT FOOT, SPRAINING HIS ANKLE. CLAY-LIKE MATERIAL UNDER THE LADDER ON THE CONCRETE CAUSED THE LADDER TO SLIP. HE WAS EXAMINED AT THE HOSPITAL RELEASED