Ignition occurring when an internal exothermic chemical or biological reaction generates enough heat to cause the material to combust. Substances that have been known to self-heat to temperatures sufficient for spontaneous combustion include linseed oil rags, hay, and powder-free latex gloves.

For more information on this term, see the interFIRE VR Resource File article: “Spontaneous Ignition, Part II: Investigation” by John D. DeHaan