Fe-Mn-Al alloy steel was melted in a mass production tonnage arc furnace equipped with ladle refining facilities. The ingots were cracked and torn apart on hot rolling. Blue flames erupted from the cracks and became red. A white powder was observed adjacent to the cracks in ingots. The white powder was identified as magnesia. Concentrations of Mg and Ca were high in the centre of the ingot, implying the segregation of impurities. Quantitative elemental analysis and microstructural investigation revealed Mg, Si, Ca and S containing impurities and Cr, Mo and Si carbides were segregated within grain boundaries. The segregation was the main cause of ingot cracking. The 1600degreesC static cup test for carbon containing MgO-C refractories exhibited the reduction reaction, which raised the Mg concentration up to 0.017 wt% in Fe-Mn-Al alloy steel, whereas the pure MgO refractory cup test showed inertness to Fe-Mn-Al alloy. (C) 2003 Kluwer Academic Publishers.