VICTIM & CO-WORKER WERE REPLACING A 14"" PLASTIC WATER PIPE. THE WRAP-AROUND COUPLING WAS TIGHT & THEY COULDN'T GET THE CONNECTION BOLTS STARTED. THEY LEFT THE AREA TO RETRIEVE A PRY BAR. UPON RETURNING TO THE WORK SITE, THE CO-WORKER FOUND THE VICTIM LAYING ON THE PLANT FLOOR BLEEDING FROM A LACERATION TO HIS HEAD. THE VICTIM CAN'T RECALL WHAT OCCURRED, THERE WAS NO EYE WITNESS.