Spontaneous Combustion - Affected Materials

Affected Materials

• Haystacks and compost piles may self-ignite because of heat produced by bacterial fermentation.
• Linseed oil in a partially confined space (such as a pile of oil-soaked rags left out in an uncovered container) can oxidize leading to a build-up of heat and thus ignition.
• Coal can ignite spontaneously when exposed to oxygen which causes it to react and heat up when there is insufficient ventilation for cooling.
• Pyrite oxidation is often the cause of coal spontaneous ignition in old Mine tailings.
• Pistachio nuts are highly flammable when stored in large quantities, and are prone to self-heating and spontaneous combustion.
• Large cow manure piles can spontaneously combust during conditions of extreme heat.
• Cotton and linen. When these materials come into contact with polyunsaturated vegetable oils (linseed, massage oils), bacteria slowly decompose the materials, producing heat. If these materials are stored in a way so the heat cannot escape, the heat build-up increases the rate of decomposition and thus the rate of heat build-up increases. Once ignition temperature is reached, combustion occurs with oxidizers present (oxygen).

In addition large areas of woodland, shrubland and grasslands during periods of dry hot weather are known to be capable of spontaneously combusting – though the mechanisms causing this are poorly understood. This has been proven to occur via the lifecycle of a variety of plants which require the area to be burned prior to germination.

People have also been reported as spontaneously combusting. This phenomenon is not considered true spontaneous combustion, as it is largely attributed to the wick effect, whereby an external source of fire ignites nearby flammable materials and human fat or other sources.