EMPLOYEE CRAWLED UNDER T201 TANK TO CHECK AIR HOSE TO SOLIDS CONTROL VALVE. HIS FOOT SLIPPED AND HE FELT SOMETHING ""PULL"" IN HIS LOWER BACK. RESULTED IN RESTRICTED DUTY EFF. 11/08/04. EE WAS HOSPITALIZED 11/23/04 THRU 11/29/04 WITH SEVERE ALLERGIC REACTION TO MED. PRESCRIBED FOR INJURY. LTA. NOTIFIED BY EE OF ABSENCE 12/6/04.