EE WAS KNOCKED OFF A LADDER BY A FALLING CEMENT CHUNK. (EE WAS ON FREE-STANDING LADDER UNDER SILO, CLEANING DISCHARGE CHUTE. EE FELL APPROX. 2' AND HIT HIS SHOULDER AGAINST SUPPORT WALL OF SILO, CAUSING INJURY. FIRST AID ONLY - X RAY NEGATIVE; NO PRESCRIPTION DRUGS GIVEN.)