In this study, Minimum Ignition Energy (MIE) and Minimum Explosible Concentration (MEC) of L-isoleucine and glycine powder with two different particle size distributions were experimentally investigated. The experimental results showed that the values of MIE and MEC of L-isoleucine powder were lower than those of glycine powder. The pyrolysis and the combustible products of glycine and L-isoleucine powders were measured. The results showed that a number of flammable and combustible materials are formed during the pyrolysis of L-isoleucine, although few flammable compounds are generated during the pyrolysis of glycine due to polymerization. This result indicated that the L-isoleucine powder has a high risk of dust explosion as compared to the glycine powder. Consequentially, an appropriate risk assessment for the L-isoleucine powder with fine particles is necessary in the powder handle processes. (C) 2019 Elsevier B.V. All rights reserved.