EMPLOYEE BENT OVER AND LIFTED APPROX 4 STACKS OF EMPTY CODE B MOD BAGS OUT OF A NEARLY EMPTY BOX. HE PUT THEM ON THE BAG SHELF ON THE LEFT HAND SIDE OF THE SCREW PACKER. THE SHELF IS ABOUT EYE LEVEL. HE FELT PAIN IN HIS BACK AFTER HE PUTTHE BAGS ON THE SHELF.