This paper studies theoretically the heating and possible ignition of a layer of combustible dust on a hot surface. A new approach to this problem is the use of thermal conductivity equations for granular materials which have been developed by previous workers. The transient heat conduction equation with temperature-dependent distributed heat sources is solved numerically. In addition to the case of negligible reactant consumption, effects of reactant consumption on the heating behavior in dust layers are also considered. The results of computations are compared with experimental results obtained by other workers.