Azobisisobutyronitrile (AIBN) is extensively utilized as an initiator and foaming agent in polymerization processes. Upon thermal decomposition, AIBN releases toxic nitrogen gas and organic cyanides, posing significant hazards. This study investigates its thermal stability and associated risks using TG-MS, DSC, and ARC methodologies. The decomposition process comprises two stages: crystalline phase transition followed by simultaneous solid-phase melting and decomposition. Mass loss occurs across three temperature ranges: preheating (< 86 °C), rapid decomposition (86–133 °C), and subsequent decomposition (133–180 °C). Adiabatic tests reveal decomposition between 70.95–125.66 °C. Hazard assessments classify decomposition heat as level 3, thermal runaway potential as level 2, and severity as level 2, highlighting notable exothermic potential and explosion risks. Activation energies are determined as 97.27 kJ mol⁻¹ (nonadiabatic) and 142.54 kJ mol⁻¹ (adiabatic), with reaction mechanisms described as G(α) = (1 − α)⁻1–1 and f(α) = (1 − α)2. These findings offer essential safety data for AIBN's production, handling, and storage.