Some goods, such as copra or coal, can spontaneously heat and catch fire, when stored in bulk. Under a standard Fire policy, damage to such goods is normally excluded, unless specifically requested. However, any damage resulting to other property from such a fire is covered.

An ignition caused by the accumulation of heat generated by the slow oxidation of coal in an air supply sufficient to support oxidation but insufficient to dissipate the heat. An example of where this can occur is a storage pile. The tendency of a coal to spontaneously combust or self-heat increases with increasing amounts of sulfur and moisture.

ignition of a substance (as oily rags) resulting from an internal oxidation process