EE WAS SCALING 3/4 BLOWDOWN PIT USING JACKHAMMER. A PIECE OF SCALE BROKE LOOSE AND THE EE LOST CONTROL OF THE JACKHAMMER. EE FELT PAIN IN LOWER BACK. HE WAS TREATED BY MEDICAL DEPT. HE RECEIVE D PHYSICAL THERAPY ON 6/21/01. EE IS NOT LOSING ANY TIME, BUT IS ON WORK RESTRICTIONS. EE WORKED 8 HOUR SHIFT ON 6/21, WENT HOME & UNABLE TO MOVE WHILE BATHING; ADMITTED TO HOSPITAL; RELEASED