Large amounts of powders are being handled in industrial activities, and these are facing static electrification that might lead to dust explosion or fire. Therefore, it is important to know about the static electrification in detail in the powder handling processes to prevent the hazards.The authors investigated the static electrification characteristics such as the relation between the powder charge and dust concentration, transportation velocity, transportation distance, etc., using pneumatic transportation system. Also, the influences of spark duration time, ignition energy and feeding ratio of the ignition energy to initiate the dust explosion were investigated because there is a potential risk of dust explosion due to the static electrification.From the results of the experiments, the information on the static electrification and the ignition of the dust cloud was obtained. This would contribute to maintain safe operation of the powder handling, especially pneumatic transportation, by regulating the transport conditions. (C) 2003 Elsevier B.V. All rights reserved.