EE WAS HAND-TRIMMING BEDFORD COPING STONE - 36"" X 20"" X 2 1/4"". PIECES WERE ON FLOOR SITTING ON A PALLET (WEIGHT APPROX. 50 - 70 LBS). EE WAS LIFTING STONE FROM PALLET WITH BOTH HANDS TO WAIST HEIGHT. DURING LIFT HE FELT A ""POP"" IN HIS SHOULDER (LEFT). INCREASED PAIN IN L. SHOULDER FOLLOWING ""POP"" DURING ANY MOVEMENT - STOPPED WORKING AFTER IT WOULDN'T STOP HURTING.