EE REPORTED ON 8-27-01 THAT HE HAD STRAINED HIS LOWER BACK ON 7-20-01, WHILE LIFTING AND STACKING PIPES AND STEEL ALONGSIDE OF THE WAREHOUSE. THE EE STATED HE DID NOT REALIZE HE HAD STRAINED H IMSELF UNTIL THAT EVENING AND NEXT MORNING. HE DID NOT THINK TI WAS SERIOUS SO HE DID NOT REPORT IT UNTIL HE WENT TO HIS DR. ON 8-27-01.