I wouldn't have thought a compost heap would get hot enough to smoke :-)

They do give off a lot of water vapour though (not quite steam).


--
Andy Clews University of Sussex Computing Service
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A lecturer at college last year told of a 'phone call he had received from a
friend who was working with an industrial sized compost heap. The freind had
had his compost heap catch light with the heat produced by the microbial
activity within the heap. A team were trying to put the fire out, but adding
water to the heap was in effect adding moisture and creating a situation where
the microbes were enjoying perfect conditions. This meant that they were
breaking down more compost and creating even more heat, which was fueling the
fire. The fire was eventually extinguished.

Small compost heaps rarely get to very high tempereatures and usually compost
best anaerobically, where large compost heaps compost aerobically. Straw tends
to be most likely to create a lot of heat which can cause fires, and many
farmers have straw stacks spontaneously combust. Straw from stables mixed with
horse litter often catches fire in summer if given the right (or wrong,
depending on how you look at it) conditions.

Dave.