Experiments were conducted on the inerting of magnesium dust with N-2, CO2, and Ar. Comparing the maximum explosion pressure, maximum rate of pressure rise, and limiting oxygen concentration with different inertants, it was determined that At is not the best inert gas under all conditions as commonly believed. N-2 was more effective than At as an inertant. CO2 provided more inerting effect than either At and N-2 in low magnesium dust concentrations, although explosibility was increased at higher dust concentrations. Both N-2 and CO2 as inerting agents showed higher LOC values than Ar. These results indicated that N-2 is a more economical inerting gas than At for the tested coarse magnesium dust. (C) 2009 Elsevier B.V. All rights reserved.