A thorough, in-depth understanding of the reactive nature of chemical processing operations is the first step to accomplishing the reduction of risks of these operations to a tolerable level. This understanding may be obtained through a laboratory evaluation using recognized and accepted process safety testing technologies as well as the conventional process hazards analysis. A systematic process safety testing program characterizes the reactive nature of both the desired and undesired chemistry. These data are needed to define the critical limits of temperature, pressure, power output, concentration, and dosing rates of processes involving reactive chemicals. The minimum basic data are the variation of energy (or power), temperature and pressure as a function of time, and reaction mass composition. The realistic use of these data requires an understanding of both the limitations of some laboratory data for scale-up and acceptable safety margins for industrial size operations. This paper will briefly review the current regulatory environment for chemical process safety, describe the integration of various calorimetric test techniques, and illustrate the use of data from isothermal differential scanning, and adiabatic calorimetry for improving process safety. An example, taken from the investigation of an accident involving the reaction between an amine and chlorine-substituted derivative. demonstrates the use of calorimetric data in understanding the origin and progress of the accident. Suggestions for how to improve process safety, based on the calorimetric information are also presented.