EE WAS TRYING TO MOVE CHAIN HOIST TO SOUTH. THE HOIST WAS TIGHT FROM DUST BUILDUP AND HARDENED MATERIAL ON THE RAIL. HE JERKED ON THE CHAIN & PULLED BOTH SHOULDERS, RT. SIDE WORSE THAN LEFT. DID NOT REQUEST TO SEE DR. UNTIL 4/29/03. WAS REFERRED TO ORTHOPEDIC SPECIALIST, AN MRI WAS PERFORMED AND REVEALED A ROTATOR CUFF TEAR ON THE RT. SURGERY PERFORMED ON 6/10/03.