Incidents involving uncontrolled chemical reactions continue to result in injuries, fatalities, and economic loss and harm in industry. These incidents are often the result of not identifying or understanding the chemical reactivity hazards involved in storage, mixing, or processing operations. The chemical reactivity evaluation tool (RMT) and the Help Guide that accompanies it can be used as an aid in identifying and evaluating chemical reactivity hazards so that they may be effectively avoided or controlled. This paper will describe the RMT and demonstrate its use in identifying reactivity hazards in chemical storage, handling, and processing operations. The RMT and Help Guide are available as a free download from AIChE (www.aiche.org) and search RMR. (c) 2012 American Institute of Chemical Engineers Process Saf Prog, 2012