EE WAS IN THE PROCESS OF INSTALLING A 14"" FLANGEON A SECTION OF PIPE. HE WAS STRIKING THE FLANGEWITH A 3 LB. HAMMER TO POSITION IT IN PLACE. THEHAMMER STRUCK THE PIPE & LANCED UPWARD & STRUCK HIS LEFT THUMB, RESULTING IN A FRACTURE. NO TIMELOST OR WORK RESTRICTION.S