Haypiles and compost piles may self-ignite because of heatproduced by bacterial fermentation.Linseed oil in a partially confined space can oxidizeleading to a build-up of heat and thus ignition.COAL can ignite spontaneously when exposed to OXYGEN whichcauses it to react and heat up when there is insufficient VENTILATION forcooling.Pyrite oxidation is often the cause of coal spontaneousignition in old Mine tailings.Pistachio nuts are highly flammable when STORED in largequantities, and are prone to self-heating and spontaneous combustion.Large MANURE piles can spontaneously combust duringconditions of extreme heat.Cotton and linen. When these materials come into contactwith polyunsaturated vegetable oils (linseed, massage oils), bacteria slowlydecompose the materials, producing heat. If these materials are stored in a wayso the heat cannot escape, the heat build-up increases the rate ofdecomposition and thus the rate of heat build-up increases. Once ignitiontemperature is reached, combustion occurs.