EE STATED THAT HE WAS STEPPING UP IN TO THE MOTOR GRADER (BLADE) WHEN HIS FOOT SLIPPED OFF LOWER STEP CAUSING HIM TO LOSE HIS BALANCE AND FALL TO THE GROUND. EE INJURED LOWER BACK. HE'S HAD A HISTORY OF BACK PROBLEMS, NOT JOB RELATED. HE'S HAD FIVE PRIOR BACK SURGERIES.