Hazards evaluation was performed to investigate the thermal instability and incompatibility of tert-butyl hydroperoxide (TB HP) solution with various diluents. Two calorimeters, differential scanning calorimetry (DSC) and vent sizing package 2 (VSP2), are frequently used to characterize the inherent thermal hazards and adiabatic runaway features of organic peroxides. Through the thermal dynamic and isothermal scanning experiments, the enthalpy of energy-rich TBHP solutions to normalize various heats of decomposition was elucidated. The self-reactive rating of a runaway reaction can be characterized by the thermokinetic parameters, such as initial exothermic temperature (T-o), self-heating rate (dT center dot di(-1)), pressure rise rate (dP center dot di(-1)), pressure-temperature profiles, noncondensable pressure, etc. We also suggested using the isothermal tests of DSC combined with the kinetic data to evaluate the exothermic enthalpy and reaction aging time of aqueous TBHP. The novel finding was that aqueous TBHP with DSC and VSP2 was observed to possess intrinsic qualities leading to thermal explosion, with a sharp self-reactive rate and pressure rise under adiabatic conditions. In summary, the thermal hazards of aqueous TBHP may cause a catastrophe or large loss in operation, storing or transporting TBHP. This result also demonstrates that applying calorimetric methodology to classify the thermal hazards of organic peroxides is an alternative technology for research.