Drying is an especially hazardous operation. To make this operation safer, it is critical to understand the hazards associated with decomposition, fire, and explosion including worst-case scenarios resulting from operational and control failures. This article describes the tests and standards required to prevent accidents when handling bulk powders and dusts. The outcome of these tests and standards is to quantify the risks for normal and upset conditions and to implement adequate safeguards to prevent accidents. (C) 2012 American Institute of Chemical Engineers Process Saf Prog, 2012