EMPLOYEE WAS TROUBLESHOOTING THE PACKING AND LOADING PUMPMAN'S ALARM PANEL. THIS PANEL IS LOCATED IN AN ELECTRICAL ENCLOSURE AT THE VERY BOTTOM, ON THE BACK WALL OF THE ENCLOSURE. EMPLO YEE HAD TO BE ON HIS HANDS AND KNEES TO PERFORM THIS JOB. AT THE END OF THE JOB, EMPLOYEE COMPLAINED OF PAIN IN RIGHT KNEE. BECAME REPORTABLE ON9/10/01 WHEN HE STARTED TO MISS DUE TO SURGERY.