That someone could burn to death and be reduced to ashes without being in a fire sounds incredible. Yet the bizarre phenomenon of 'spontaneous human combustion' has been well documented by police investigators and forensic pathologists around the world. The evidence suggests that it is real. But how it possibly happen?

 

One of the earliest descriptions of it comes from Howe's Chronicles of 1613:

 

Hitchell, a carpenter, had been at the house of John Dean, of Parley Court, and returning home on Saturday eve, went to bed with his wife and young child. At midnight there happened a great and sodaine lighting. Hitchell's wife was upon a sodaine very grievously burned all the one side of her, and her husband and child lay dead close by her, but perceiving that her husband still burned inwardly, she drew him to the open street, where through the vehemency of the fire she was constrained to forsake hime and he lay burning upon the earth for ye space of almost three days. There was no outward appearance of fire, but only a kind of smoke and glowing heat ascending from his body, until it was quite consumed to ashes, except only some small pieces of his bones which some of the sad beholders cast into a pit made neere the place.

 

When a person dies in a normal fire, the extremities may burn away but the torso, although possibly badly charred, remains intact. Most cases of spontaneous human combustion, by contrast, are marked by the almost complete destruction of the torso. A modern gas-fired crematorium achieves the same effect by burning up to 1,000 cubic feet of gas with 20,000 cubic feet of air at 900°C. Under ordinary circumstances, it would be impossible to reduce an entire body to ashes without temperatures of over 1,600°C for several hours. Yet, astonishingly, in every well-documented account of spontaneous human combustion, the fire damage to the surroundings of the victim was minimal.

 

John Heymer, a scene-of-crime officer with the Gwent Police in Wales, recalled the extraordinary aftermath of such an incident on January 6, 1980:

 

The house was located on top of a hill and the weather was bitterly cold. On entering the house I was struck by the pleasant warmth. There was no sign of central heating or any other form of heating. The uniformed officers who had requested my presence told me that the fire had occurred in the living room.

 

I opened the door and stepped into a cooling oven. There was a steamy sauna-like heat and the room was bathed in a garish orange radiance. The orange light emanated from a bare light bulb which was coated with a sticky orange substance as was the window. The temperature of the room had recently been extremely high. The walls were radiating heat. Condensation was running down the window. Heat had cracked one of the window panes.

 

The light bulb was bare because the plastic lamp shade had melted, oozed down the bulb and fallen to the floor. The walls, ceiling, and all surfaces were coated with a greasy black soot.

 

On one wall was an open grate which contained the dead ashes of a coal fire. The hearth was tidy. There were no signs of any coals having fallen on the floor.

 

On the floor, about a meter from the hearth, was a pile of ashes. On the perimeter of the ashes, further from the hearth, was a partially burned armchair. Emerging from the ashes were a pair of human feet clothed in socks. The feet were attached to short lengths of lower leg encased in trouser bottoms. Protruding from what was left of the trousers were calcined leg bones which merged into the ashes. The ashes were the incinerated remains of a man.

 

Of the torso and arms, nothing remained but ash. Opposite the feet was a blackened skull. Though the rug and carpet beneath the ashes were charred the damage did not extend more than a few centimeters beyond the perimeter of the ashes. Less than a meter away a settee fitted with loose covers was not even scorched. Plastic tiles which covered the floor beneath the carpet were undamaged.

 

Although extremely high temperatures had developed in the room, nothing had burnt that had not been in contact with the body while it was being consumed. Reason told me that the scene I was viewing was impossible. Everyone at the scene experienced the same sensation of incredulity, a strong urge to deny the evidence of their senses.

 

Heymer learned of a similar incident in the same part of Wales a month later, involving a woman. Some extraordinary parallels emerged between the two cases. Both victims, being elderly, had taken great care to draught-proof the rooms in which they died, blocking out every possible gap around doors and windows.This prevented oxygen entering from outside and was presumably the reason that the contents of the room hadn't caught fire. The torsos of both people were completely destroyed. Not a single organ survived, except a leather-like shrunken left lung in the case of the woman. All the bones were reduced to ash from the neck to the mid-thigh, while the blackened skulls and untouched lower portions of legs remained. Forensic tests revealed that both the man and the woman had almost certainly been alive at the start of the incineration.

 

These facts present science with what seems like a formidable challenge. One response has been the so-called "candle theory," according to which a human body – especially an obese one – has the potential to burn like a candle. Subcutaneous fat would supply a wax-like fuel while clothes substituted for a wick. Many cases of the phenomenon, as it happens, have involved overweight people.

 

Yet there are many questions that this theory doesn't seem properly to address. How does the body catch alight in the first place? And, if the person were alive at the start, why wouldn't they make some concerted effort to extinguish themselves? In the cases just described, if a lack of oxygen prevented furniture and other objects in the room from burning, how was it that the bodies themselves were so thoroughly consumed? If spontaneous human combustion is real then it seems that strongly exothermic chemical reactions can occasionally take place in our bodies of which, at present, we have a very poor understanding. Although, having said that, at least new interesting line of speculation has recently opened up.

 

For centuries, people have spoken of seeing fleeting ghosts in water-logged graveyards and will-'-the wisps flitting across marshy ground. It's long been suspected that the pale light observed in such cases is caused by the ignition of marsh gas, or methane – a chemical produced in large amounts by the kind of anerobic microorganisms that thrive in boggy places. But the stumbling block to this idea lay in explaining how the methane could be ignited. Then, in 1993, two German researchers, Dieter Glindemann and the satisfyingly named Gunter Gassmann, of the Helgoland Biological Institute in Hamburg, furnished what could be a vital clue.

 

Following earlier reports that phosphine had been detected in sewage sludge and marine sediments, Glindemann and Gassmann posited that this flammable gas might be produced in the same strongly reducing conditions in which methane is made. Sure enough, their investigations confirmed this suspicion. There seems every likelihood, therefore, that the wispy, glimmering lights sometimes seen over marshy ground are caused by methane that has been ignited by phosphine.

 

One further fascinating conjecture by the two German researchers stemmed from their observations that phosphine, along with large amounts of methane, is produced in the guts of cattle. Glindemann and Gassmann reasoned that the process of digestion in humans should generate even greater concentration of phosphine since our diet is richer than that of herbivores in sources of phosphate, including processed meats, cheese, and cola drinks. A build-up of phosphine and methane in the body could be the recipe for disaster – the ignition of a chemical cocktail that might just be the crucial process underlying spontaneous human combustion. For the moment, it remains merely a conjecture. But if confirmed it could lead in future to coal cans carrying some very unusual warnings from the Surgeon General.