WHILE TIGHTENING BOLTS ON CS-37 SPOOL PULLED MUSCLE IN LOWER BACK. THE DATE OF HIS INJURY HE JUST SAID HE FELT PAIN. ON 4/25/00 IT WAS BROUGHT TO OUT KNOWLEDGE HE WAS GIVEN MEDS AND SENT HOME FOR HIS INJURY BECAME BORE SEVERE. AT THIS TIME THE INJURY BECAME A DEGREE 3.