Science Provides the Answer
Many SHC victims have been nearly completely consumed in some substantial parts of the body by the fire, especially the torso - with bones turned to a powdery ash. The claim by tabloid journalists is that even commercial crematoriums do not produce the temperatures needed for such complete combustion.

So what kind of temperatures are needed? As it turns out, the human body burns at temperatures typical of just about any other normal fuel. In fact, a burning body is regarded by fire investigators as part of the fuel load of a burning room. But a body burns at a low rate, and without a crematorium the body requires a longer period of time to burn. In SHC cases the victim typically hasn't been seen by anyone for many hours prior to the discovery of the body.

Recent studies by English researchers and renowned American fire scientist Dr. John DeHaan, author of "Kirk's Fire Investigation", have determined burn rates for burning bodies by studying fire effects on pig carcasses. Prior to the tests, Dr. DeHaan had estimated the burn rate of a human body from actual photographs of a murdered woman found burning in woods. The animal tests confirmed his estimate. They have found that a body burns at a rate of approximately 8 to 24 pounds per hour, and the rate of heat released from the burning body (as in a smoldering fire) is very low with a steady flame height in the 16 to 18 inch range.

Dr. DeHaan and the other researchers confirmed that the fat in our bodies can actually add fuel to the fire when certain conditions - such as sufficient initial burn time and wicking - are met. In instances of supposed "SHC", the human body, once it has been exposed to flames for a period of time, actually begins to behave like a candle - only with the wick (usually clothing or bedding) outside of the body instead of inside. Even bone marrow will burn under these conditions, and the bones can become powdery after only four to five hours of exposure to typical fire temperatures.

Summary:
At Fire & Accident Causation Technical Services (FACTS), we've observed a number of truly bizarre fire scenes where interesting and unexpected elements produced unique and often puzzling fires. Because important clues were noted, though, these fires were all found to have rational explanations. The difference between a bizarre fire and a "mysterious" one is simply that important facts are missing or mis-interpreted in the latter case.

Remember this the next time you see a TV show or read an article about SHC. The real experts on SHC are the fire investigators and scientists who deal professionally with fire and its effects - not writers who have researched the subject with the goal of a sensational book. Be a skeptic!

For more on SHC: http://www.csicop.org/si/show/not-so-spontaneous_human_combustion/
                                 http://www.csicop.org/si/show/case_of_shc_demystified/
                                 http://www.csicop.org/si/show/fiery_tales_that_spontaneously_destruct/