The minimum concentrations of xanthate dusts in air which will form explosive mixtures have been determined. Comparison with other dusts considered to be hazardous industrially indicates that xanthates of the lower alcohols should be classified as readily explosive. The explosive limit increases rapidly with particle size; dusts coarser than 150 mesh are relatively safe. Xanthate dusts are easily ignited and have very low ignition temperatures. Under conditions such that fine wood flour ignites at 540°C. the xanthates will ignite between 230°C. and 290°C.