The Bureau of Mines has investigated fumes generated by selected welding electrodes used in mines in order to help determine their relative health hazard potential. Fumes were generated and collected in an enclosed chamber for subsequent generation rate and chemical constituent determination. Shielded metal arc electrodes from the following groups were tested: aws types e308-16 and e310- 16 stainless steel, ecocr-a co-cr hardfacing alloy, enici-ni, a mn- cr buildup alloy, e7018 carbon steel, and e11018-m low-alloy steel. Flux-cored wire electrodes of this last group also were tested. Fume generation rates and the chemical composition of the fumes were measured. From these data, exposure indices were determined, which give a relative measure of the health hazards potential of using the electrodes. The effect of welding onto buildup alloy layers on the fume composition also was examined for five of the higher alloy groups.