EE WAS STANDING AT A FIRST AID CABINET GETTING A BAND AID. ANOTHER EE WAS BACKING HIS FORKLIFT TO GET IN POSITION TO PICK UP A LOAD OF BAGGED PRODUCT. HE PROCEEDED TO BACK UP WHILE THE GATE OF A PROPANE TANK HOLDER WAS OPEN (ABOUT 2 1/2 FT IN LENGTH). THE GATE STRUCK THE EE IN THE BACK CAUSING A DEEP BRUISE.