Organic peroxides (OPs) are commonly used in many industrial fields as initiators, hardeners, or cross-linking agents of radical polymerization with unsaturated monomers. However, OPs contain the bivalent -O-O-structure which can incur exothermic decomposition that involves the splitting of the peroxide bond with a huge heat release and gas products that may cause an explosion under an uncontrollable upset. Differential scanning calorimetry (DSC) and thermal activity monitor III (TAM III) were used to analyze the thermal hazards and incompatibilities (H2SO4, NaOH, and Na2SO3) of cumene hydroperoxide (CHP), benzoyl peroxide (BPO), and dicumyl peroxide (DCPO). Dynamic and isothermal scanning tests were performed to compare the exothermic behaviors in a process. The thermokinetic data obtained via vent sizing package 2 (VSP2) were applied for evaluation, and the effects of thermal runaway hazard were compared for OPs conducted by acids and alkalis. These results are critically important in safer process design for producing and using OPs. (C) 2013 Elsevier B.V. All rights reserved.