Explosion characteristics of micron-size conveyor rubber dust were determined employing a normal 20 L stainless steel orbicular chamber and two types of modified 1.2-L Hartmann tubes. Maximum explosion pressure (P-max), maximum rate of pressure rise (dP/dt)(max), and minimum explosion concentration (MEC) were tested in the spherical chamber. The results indicated that the explosion severity of conveyor rubber powders is weaker than some common dust, such as coal, magnesium, and aluminum dust. However, conveyor rubber dust is a kind of combustible dust. Furthermore, the explosion severity increased as the particle size decreased from 120 to 48 mu m. The MEC decreased from 90 to 30 g/m(3) on decreasing particle size from 120 to 48 mu m. Moreover, the MEC of conveyor rubber dust was 30, 50 and 90 g/m(3) for the particle size of 48, 75, and 120 mu m. The minimum ignition energy (MIE) was measured by two types of modified 1.2-liter Hartmann tubes. The results indicated that particle size and dust concentration had influences on MIE. However, the MIE of conveyor rubber dust was much higher than 10 mJ. Accordingly, conveyor rubber dust cannot be ignited by collision, friction, and attrition. The experimental data presented could be useful for process plants that manufacturing conveyor rubber to evaluate explosibility of their conveyor rubber powders and propose/design adequate safety measures. (C) 2016 Elsevier Ltd. All rights reserved.