EE WAS REPLACING THE HIGH PRESSURE FITTING ON THE AC COMPRESSOR ON A CAT 16H GRADER. ON HIS WAY DOWN THE LADDER HE MISJUDGED HIS LAST FOOT PLACEMENT FALLING BACKWARDS HITTING THE BACK OF HIS HEAD ON THE CONCRETE FLOOR. THIS RESULTED IN A LACERATION ON THE BACK OF HIS HEAD. HE WAS TREATED AND RELEASED FROM THE PALMETTO GENERAL HOSPITAL.