AFTER MAKING DELIVERY, DRIVER UNCOVERED 3""HOSE FROM STORAGE TANK. HE FAILED TO RELEAVE PRESSURE BY UNCOUPLING ONE SIDE AT A TIME, AS TRAINED 2 WEEKS PRIOR. ONCE UNCOUPLED THE HOSE FLEW BACK STRIKING HIM IN THE UPPER LIP CAUSING A DEEP LACERATION. HE SOUGHT IMMEDIATE TREATMENT BY PRIVATE TRANSPORTATION.