A quick and inexpensive method to facilitate product control in assuring safe chemicals management in transportation and storage is introduced. Product safety measures related to large quantities of reactive chemicals require frequent measurements of thermal activity (TA) at low temperature in order to control the potential for contamination, etc., that can accelerate the reaction rate. The fast thermal activity interpreter (FTAI) instrument is designed to monitor chemical systems undergoing gaseous decomposition reactions with the capability of interpreting TAs of the order of 1mu W/g or a self beat rate of the order of 10(-5)degreesC min(-1). Recognizing the need for frequent sampling, the FTAI takes about 1 h to run an analysis. The FTAI concept provides an easy means for determining activation energies and rate laws of gaseous decomposition reactions at ambient temperature conditions and is also well suited to measure material oxidation or corrosion reaction rates involving oxygen consumption. (C) 2004 American Institute of Chemical Engineers Process.