Linked from
The 15 pages that link to Thermal runaway, each with the reason it gives.
DetonationRelated: Runaway heat release can trigger initiation or intensify a reaction zone.
BatteryRelated: In some batteries, it can trigger fire or propagate from cell to cell.
PyrophoricityRelated: It can intensify pyrophoric oxidation after ignition begins.
Helium flashRelated: Degenerate helium burning amplifies small temperature rises into rapid fusion.