EE BRUISED HIS LEFT FOOT AFTER PERFORMING WORK ON #15 TRIPPED AT THE TOP OF THE R25 ROD MILL BLDG. HE WAS STEPPING DOWN FROM A FIXED METAL LADDER ON THE SIDE OF #15 TRIPPER. AS HE STEPPED OFF LADDER WITH LEFT FOOT, HE STEPPED ON EDGE OF NARROW DECK PLATE WHERE IT CONNECTS TO THE FLEXIBLE RUBBER SKIRTING MATERIAL. HIS FOOT ROLLED OFF THE EDGE.