MS FOREMAN AND MS JOURNEYMAN WERE REPLACING PIPING `T's ON THE SIZER IN THE WASH PLANT. THEY SUCCESSFULLY DISASSEMBLED (2) PIPE `T'S. WHILE DISASSEMBLING THE 3RD `T', A COMPRESSION PIPE CONNECTION FAILED. THIS CAUSED THE PIPE AND `T' TO FALL APPROXIMATELY (30'), STRIKING THE JOURNEYMAN ON TOP OF THE LEFT FOOT ABOVE THE STEEL TOE.