Sometime in 1951, an elderly woman by the name of Mary Reeser sat down on an overstuffed chair, and mysteriously burst into flames. All that was left was one slippered foot, a pile of ashes, and a burnt chair and adjacent end table. Strangely enough, the rest of the room was unmolested.

A familiar story, maybe?

The Spontaneous Human Combustion Phenomenon

Spontaneous human combustion (SHC) is defined as the process of a human body bursting into flames without outside interference, as a result of incredible heat supposedly generated by an internal chemical reaction. If this phenomenon is not already in itself strange, its mysterious nature is enhanced by the fact that it is only the victim that seems to combust; nearby furnishings are usually untouched, or the damage is contained within a very small radius.

The History of Spontaneous Human Combustion

There have been many stories written in the course of literary history concerning the mysterious - and even horrifying - combustion of corpses. There are those who assert that the first documentation of this phenomena appeared in the Bible¹; however, their accuracy may be disputed as these accounts are much too old and based on second-hand knowledge to be considered reliable evidence.

As far back as medieval literature there have been numerous stories concerning the spontaneous combustion of corpses, including the combustion of a knight named Polonus Vorstius² sometime during the reign of Queen Bona Sforza in Milan, but it was not until the 17th Century that a story was written about a German man who'd drunk far too much brandy for his own good and burst into flames. However, the first reliable documentation of SHC dates back to 1763 when Frenchman Jonas Dupont compiled a casebook of SHC cases in a book called De Incendiis Corporis Humani Spontaneis, having been compelled by the Nicole Millet case, which involved a man who was acquitted of the murder of his wife when the court ruled that the unfortunate woman's death had been due to spontaneous combustion.

Nicole Millet was the wife of the landlord of the Lion d'Or in Rheims, who was supposedly found burnt to death in an unburnt chair in February, 1725 (on Whit Monday). Her husband was accused of her murder and arrested; however, a young surgeon named Nicholas le Cat managed to convince the court that her death was caused by SHC. The court ultimately ruled her death as 'by a visitation of God.' However, the investigative author Joe Nickell stated in his book, Secrets of the Supernatural, that Millet's body was not actually found in the chair, but that a portion of her head, several vertebrae and portions of her lower extremities were found on the kitchen floor, the surrounding ground of which had also been burnt. Three accounts were cited: Theodric and John Becks's Elements of Medical Jurisprudence (1835), George Henry Lewes's Spontaneous Combustion from Blackwoods Edinburgh Magazine No. 89 (April 1861) and Thomas Stevenson's Principals and Practice of Medical Jurisprudence (1883). Strangely, there was no mention of Nicholas le Cat.

Many hacks continued in this vein in the 1800s, dramatising these mysterious deaths in 'penny dreadfuls', the 19th Century equivalent of comic books. Of course these were mass works of gruesome fiction intended to deliciously terrify the reader; however, two well-known writers incorporated the SHC phenomenon into their works, which caused the audience to sit up. The first of these was the novel Jacob Faithful by Captain Marryat, in which the main character's mother is reduced to 'a sort of unctuous pitchey cinder' – the details of which Marryat had apparently nicked from an article in an 1832 edition of the Times of London.

The other author was – surprise surprise – Charles Dickens, who in 1852 used SHC as a device to eliminate the character Krook in his novel Bleak House. Because Krook was a heavy alcoholic, and the belief of the time was that SHC was attributed to excessive drinking, Bleak House caused quite a stir in the literary world. The philosopher and critic George Henry Lewes debunked Dickens's novel as impossible and being mired (propagating, even!) in uneducated superstition. Dickens countered this unflattering review in the preface of the novel's second edition, stating that the story was not written without prior research, that he knew of about 30 cases. He reckoned that Krook's death was modelled after the death of the Countess Cornelia de Bandi Cesenate³. Interestingly, the only other case that was cited in detail was the Nicole Millet account.

Types of Spontaneous Human Combustion

Spontaneous Human Combustion cases may be divided into two categories: fatal and non-fatal, the former category being more common.

Fatal SHC

Most of these so-called SHC cases are fatal. The victim is usually found reduced to a pile of ashes except for the odd limb or portion of the head/body. Only objects associated with the body are burnt; the fire apparently does not spread to the surroundings. A greasy soot deposit is found on the walls and ceiling, usually stopping within four feet from the floor; and only objects above this line are damaged by the heat. Most of the time the victim is alone, and nobody realises that something has gone wrong until they stumble upon the victim's charred corpse or ashes; however, in a small fraction of fatal SHC cases, there are testimonies by witnesses that they had indeed seen the victim go up in flames, and that there were no possible sources of ignition; the flames had mysteriously broken out on the victim's skin. These cases, however, are poorly documented, and there is little to substantiate the claims of these witnesses.

Occasionally, 'selective burning' takes place, whereby objects associated with the victim that should have by rights combusted as well (eg, the victim's clothing) mysteriously remain undamaged. Again, poor documentation makes these cases hard to investigate.

Non-fatal SHC

A small percentage of SHC cases involve a victim who survives the mysterious phenomenon. They most commonly involve the sudden eruption of mysterious flames or smoke on the victim's skin when there is supposedly no identifiable external source of fire. A small proportion of these fall into the category of 'mysterious burns' - the victim develops unexplained burn marks on their skin (which commonly begin with small discomforts that grow into large painful burn marks), for which there is no known external cause.

Theories on SHC

Initially, it was believed that Spontaneous Human Combustion was caused by a 'visitation from God' (no doubt Moses's burning bush had something to do with this); however, out of the ashes of the Dark Ages, scientific reasoning arose and with it, the search for a scientific answer to this phenomenon.

Alcohol Consumption

In the 1700s and 1800s it was believed that SHC was caused by excessive drinking, the rationale being that a body saturated with such combustible fluids would be prone to combustion at the slightest spark. It was based on this hypothesis that Dickens wrote the novel Bleak House, which elicited an uproar and annoyed Lewes. However, investigation yielded evidence that many of these SHC victims were not alcoholic to begin with; physicians argued that the said victims would have succumbed to alcohol poisoning or liver cirrhosis long before they became fire-fuel.

The reason is this: the concentration of alcohol in a body would never be high enough for ignition to occur. Dilute alcohol will neither burn nor spontaneously explode in an anaerobic condition – there is no chance of the person combusting unless he has been liberally doused with alcohol and is standing too close to the hearth. In fact, the chemist Justus von Liebig demonstrated in 1850 that tissue soaked with diluted alcohol would not burn to ashes, even when an external flame was applied. Furthermore, the fact that grossly burned corpses still maintain largely preserved internal organs, serves to fortify the argument that the immolation could not possibly have started from within the body.

Bacteria

As it is common knowledge among farmers that haystacks sometimes burst into flames for no apparent reason, there were some who attempted to explain the SHC phenomenon by the same logic. It is now known that conditions for growth are optimal for bacteria growing in the middle of a haystack, to the extent that they occasionally reproduce at such incredible rates that their collective body heat causes the dry straw to catch fire. For a while it was speculated that similar processes in the human body might cause it to ignite; however, it has been shown that such conditions are not achievable in the human body⁴. In the event that there was an uncontrolled burst of microbial growth, the human being would succumb to massive infection even before the body became hot enough to combust.

Electricity

When the late Professor Robin Beach of the Brooklyn Polytechnic Institute theorised that people, under certain conditions, could build up enough static charge to accidentally ignite combustible material, little did he know how horrendously misconstrued his hypothesis would become in connection with SHC. The authors of Strange Stories, Amazing Facts devoted almost an entire chapter discussing Professor Beach's theories; and while neither the professor nor the authors correlated this natural build-up of static charges with SHC⁵, many people took this to imply that static electricity was at least one of the contributing factors of human combustion. Others, who had apparently not been wearing their glasses while reading these research papers, further speculated that the electrical fields within the human body might be capable of short-circuiting, causing a chain reaction that produced incredible internal heat.

Explosive Diets

Might SHC be caused by a poor diet and explosive combination of chemicals in the digestive tract? At least Jenny Randles, who wrote Strange & Unexplained Mysteries of the 20th Century, thinks so. She points out that the majority of SHC occurs in European and American societies, and that the marked lack of cases of spontaneous combustion in animals and people of non-European descent is attributed to the difference in diet. (Apparently European people eat plenty of foods that can readily ignite their bodies). While it may account for flatulence, people in the Western world should not take this explanation too seriously. After all, when was the last time you saw somebody combust because they'd just eaten a steak?

Other Theories

Among other hypotheses that believers of SHC have come up with to explain this phenomena, is the pyrotron theory, which involves a supposed subatomic particle that can ignite a combustible source; the theory that these victims had built up considerable amounts of methane in their gastrointestinal tract, which had been subsequently ignited by enzymatic processes; maser (microwave amplification by stimulated emission of radiation) induction, geomagnetism, and even kundalini (a form of yoga/mystic body heating). Perhaps the most preposterous suggestion is that stress can cause a person to burst into flames (perpetuated by Larry Arnold), or that hydrogen and oxygen remain as gasses in human cells and are thus highly ignitable – in which case the reader would do well not to inhale.

Occam's Razor Says...

Of two equivalent theories or explanations, all other things being equal, the simpler one is to be preferred. Rather than seek far-fetched answers to explain why Spontaneous Human Combustion occurs, why not look for perfectly commonplace ones?

Bear in mind that cremations are traditionally carried out at an incredible 920°C (1,700°F), which is why these funeral ovens are constructed with bricks – so that the whole funeral parlour doesn't go up in smoke along with the body. A minimum temperature of about 250°C (480°F) alone is required to burn a body. A raging bacterial infection, no matter how severe, would cause at most a high fever of 43°C or so (that's about how hot your hot water supply at home is) – hardly high enough to do more than turn the victim's brain to mush, let alone set him on fire. Therefore, if a person combusts, there must be an external factor.

The clue to the SHC mystery is this: there is always a period of a few hours between the time a victim is last seen alive, and the time he or she is found immolated. The question is: what happens during those few hours?

Source of Fire

The opinion that a man can burn of himself is not founded on a knowledge of the circumstances of the death, but on the reverse of knowledge - on complete ignorance of all the causes or conditions which preceded the accident and caused it.
- Justus von Liebig (1855)

Consider this. Despite witnesses' claims that there was no identifiable source of ignition, the victims were almost always found close to a fire source. Despite retellings of the legend, Nicole Millet was actually found only 'a foot and a half' away from the kitchen hearth (and not on a chair), where she usually went to warm herself when she couldn't sleep; furthermore, according to historical documentation, she was an alcoholic who 'got intoxicated every day'. Countess Cornelia di Bandi was found on the floor of her bedroom, thoroughly immolated; an oil lamp was mysteriously found on the ground, drained of oil. On a table were two candlesticks which retained their wicks, but whose tallows were gone, with a suspicious moisture gathered around the feet of the candlesticks. 60-year-old Grace Pett, the wife of a fishmonger in Ipswich, ignited on 9 April, 1744; her daughter found her lying on her right side across the hearth, burned 'like a log of wood consumed by fire', her torso 'like an heap of charcoal covered with white ashes'. Madame De Boiseon, an octogenarian, was found by her waiting-maid seated in a chair by the fire - burning.

More recent cases? The 'cinder woman', Mary Reeser was last seen by her physician son sitting in a big chair, wearing flammable nightclothes and smoking a cigarette when she should have been in bed, having taken two 'Seconal' sleeping pills (and intending to ingest another two); she was found roasted, along with the chair and an adjacent table and lamp. Dr John Irving Bentley was found consumed by fire in 1966, in the bathroom of his home; only his lower leg was recognisable. One might be tempted to call the case 'unexplainable', until you throw in the fact that the 90-year-old man was a pipe-smoker, and had the tendency to drop matches and hot ashes upon his robes (whose burn-marks affirmed Bentley's sloppy smoking habits). Even more suspicious are the broken remains of a water pitcher found in the commode.

So many more cases may be referred to; however, these only serve to highlight that, despite witness testimonies, it is clearly documented in official reports that there was always a source of ignition close to the victim, and this explains how the victims had caught fire in the first place. Many of these aftermath scenes suggest that the victim had been trying to light the hearth, a candle or some other source of fire, or had been smoking in bed when they unwittingly set fire to themselves.

Fuelling the Fire

One popular argument in favour of the spontaneous combustion explanation is that (1) human bodies, being largely composed of water, aren't readily combustible (and there isn't much else to burn other than methane gas and fatty tissues), and (2) crematoria traditionally carry out cremations of human remains at over 1,700°F for three hours; therefore a victim who perished due to SHC would burn at much higher temperatures because the immolation takes less time than traditional cremation; surely such incredible temperatures are not achievable under ordinary circumstances?

The answer to this argument is this: yes, the body is actually quite readily combustible, and no, shorter periods of burning do not mean higher temperatures. The high water content in the human body does not quench fire; it boils off before fire consumes the body, and thus does not impede the burning process. In fact, this fortifies the argument that the victims could not possibly have spontaneously combust – there is no way that fluid-saturated tissue could possibly self-ignite. Furthermore, the authors of Medicolegal Investigation of Death (1980) asserted that a body can be reduced to ashes in a mere hour and a half at temperatures of 1,600 - 1,800°F (although in most cases it isn't as thorough as funeral parlour cremations), although the longer a body has to burn, the lower the temperature requirement. Similarly, according to Douglal Drysdale:

In a crematorium you need high temperatures - around 1,300°C, or even higher - to reduce the body to ash in a relatively short period of time. But it's a misconception to think you need those temperatures within a living room to reduce a body to ash in this way. You can produce local, high temperatures, by means of the wick effect and a combination of smouldering and flaming to reduce even bones to ash. At relatively low temperatures of 500°C – and if given enough time – the bone will transform into something approaching a powder in composition.

In addition, the German forensic scientist Burkhard Madea, has determined that corpses of children can be completely destroyed at temperatures of 500°C in two hours, and that it only takes an hour for a fire of 800 - 1,000°C to reduce corpses of adults to less than 1kg of crumbly substance. NF Richards reported from his observations of adult corpses cremated at about 680°C that it took only ten minutes to heavily char the arms, 14 minutes for the legs, and 15 minutes for fire to reveal the skull and bones of the upper arm. In fact, it has been determined that these burning bodies will attain temperatures of up to 500 - 600°C – made possible by the fat content in the human body. And in the wonderful spirit of experimentation, Dr John de Haan of the California Criminalistics Institute wrapped an entire pig carcass in cotton and set it ablaze⁶, with gasoline used as an accelerant to mimic a blaze ignited by a cigarette. Liquefied fat from the carcass leeched into the cotton, causing the pig to simmer in pork heaven for hours; within five hours, the bones were steadily being destroyed.

The slow consumption of a body by fire at lower temperature may be explained by the 'candle effect', a term coined by DJ Gee in 1965. Think of the body as a candle, and the clothing as a wick. The wick provides the initial fuel for combustion; when the body ignites, fat from the body provides further fuel for the fire to continue burning. Indeed, many a plump corpse has caused damage to a cremation oven when it burned too fiercely. Liquefied fat seeping into the armchairs or carpet in contact with the victim would cause the fire to attack the said objects. In a room that is poorly ventilated, oxygen is quickly exhausted by the fire; henceforth the body smoulders, producing a heavy smoke thick with grease from the burning body fat and soot from clothing and body tissues, which would drift upwards and coat the walls and ceiling, starting at a point several feet above the floor. This is because the smoke would tend to dissipate and escape at lower levels before it can coat any given surface.

Furthermore, the 'multiple wick effect' helps explain why clothed parts of the body are generally reduced to ashes whereas exposed limbs and other regions generally survive the inferno – because these items of clothing serve as multiple wicks, soaked in liquefied fat, and thus sustain flames for a considerable period of time. O Prokop, Germany's leading authority in forensic medicine, stated:

The liquefied [body] fat of the subcutaneous layer can soak into the clothing, causing it to act like a wick, which maintains the fire. Only this mechanism can explain the most severe combustions which are observed in persons who, for example, fall asleep whilst smoking.

In fact, it has been demonstrated that although liquefied human fats will burn at roughly 250°C (480°F), a cloth 'wick' placed in the liquefied fat will burn even when the temperature has dropped to a mere 24°C (75°F); such was the case of the immolation of a woman in 1854, beneath whose body 'was a hempen mat, so combustible, owing to the melted human fat with which it was impregnated, that when ignited it burnt like a link (ie, a pitch torch)'.

Interestingly enough, in cases where the victim wasn't reduced to a pile of ashes, their organs were usually found to be intact or minimally damaged, despite the gross destruction of the whole body. This is because the there is a steep temperature gradient between the outside of the body, which is burning fiercely, and the body cavity, where fluids in the various organs help prevent their incineration. Although, of course, given enough time and fuel, these will also be consumed by fire.

It is worth noting that higher temperatures are achievable owing to the additional objects burned along with the victim – usually adjacent furniture, or flammable rugs. Nickell and Fisher have established that in cases where damage to the body was minimal, there was little else but the victim's body to fuel the fire; where there were adjacent flammable objects present, the victim's body was considerable or severe.

Spreading Like Wildfire

'But if the body were ignited by an external source, surely the fire would have spread?' defenders of the spontaneous combustion theory cry. If the victim had been burnt to death by fire from the hearth, why didn’t the house burn down along with the victim?

The common misconception amongst SHC fans is that a normal fire, once ignited, will spread to consume everything; hence the external fire explanation must be wrong. However, a fire, no matter how devastating, is only a fire – one whose spread is limited by a variety of factors.

Those of you who took science in school will surely know that there are three factors influencing the burning of a flame: there must be (1) a source of ignition, (2) oxygen, and (3) fuel for the fire. Remove the first factor, and the fire will never burn; remove the remaining factors and a fire will cease to burn. And then of course, there is the nature of the material to consider. An object with a large surface area to mass ratio will ignite and burn more quickly than one with a lower ratio. Materials that are thermoplastic and melt when heated will retard flames. Objects that are vertically aligned will burn faster and more easily than those that are horizontal – which is why fire on a carpet will not spread as readily as on a curtain. (If you doubt this, go and light a match. You will find that the fire spreads more readily when the matchstick is held vertically, but slowly when it is held horizontally. Do not immolate yourself in the process).

Given these factors, it is easy to explain why the fire that consumed all those victims did not spread too far. The majority of these combustion cases took place in badly-ventilated rooms; therefore there was no steady input of oxygen to fan the flame and the fire had, in most of these cases, died down to a smoulder, causing greasy soot to coat the surfaces in the room. The oxygen supply in the room would have been even more quickly depleted by the number of combustible objects close to the victim – their clothing and, very often adjacent, furniture. While plastic and other heat-labile, flammable objects would have readily combusted in the fire, they are unmolested by the smoke that follows. If the walls and floors were made of concrete or brick, the fire would have been unable to spread – which is what contained the fire that immolated Mary Reeser. The fact that fires have difficulty spreading laterally accounts for why there are body parts left over in most of these combustion cases – once the victim collapsed to the ground, limbs laid parallel to the ground would have not burned readily. (Limbs that are extended, for example, on footstools are similarly spared.)

Anyway, there are plenty of cases where whole houses caught fire, and the occupants burned with them. Such cases are normally known to fire-fighters as 'household fires'.

Why Did These Victims Burn?

There is one last psychological hurdle to cross before a person can become convinced that human combustion is not a paranormal phenomenon. If these people had burned when their clothing had caught fire, why didn't they do anything to smother the flames? A person, even when transformed into a human torch, will have precious seconds to douse himself, to throw himself upon the ground and roll out the fire. Why is it that these victims did not take actions to save themselves? Ask yourself – how many people will act reasonably when they find themselves on fire? How often do you hear accounts of immolated persons rolling themselves on the ground to smother the flames, instead of streaking a blazing path until the fire consumes them? It may be what fire-fighters have taught us; yet when panic strikes, many will lose all sense of reason. Ironically, those who do take measures to put themselves out never seem to be numbered among the Spontaneous Human Combustion victim ranks; they are simply identified as those who had sustained first/second/third-degree burns in an unfortunate accident.

Then there is the consciousness factor. Take a look at the human combustion cases and their victims' backgrounds, and an answer emerges. Nicole Millet was intoxicated on a daily basis. Mary Reeser had been smoking in a chair after taking two sleeping pills. In fact, a full 40% of 75 people who had burned to death in closed rooms in Cologne between 1964 and 1973 and 54% of 87 Oslo fire victims had a blood alcohol level greater than one part per thousand. In an altered state, a victim – especially one who fell asleep while smoking – may not necessarily be sufficiently aware of what is happening, or his/her reaction responses may have been dampened by alcohol or medication for the victim to take actions quickly enough to avoid death by immolation. Forensic investigations on the fiery deaths of the aged have revealed that some of these people had suffered a stroke or heart attack prior to pitching headfirst into the hearth – many forensic textbooks discuss these cases in detail.

Sometimes it is not the victim's mental state but his physical one – Dr Bentley had certainly tried to put himself out when he caught fire, as his broken water jug testified, only his advanced age and agility had worked against him. Elderly people who are similarly plagued with severe arthritis or Parkinson's Disease will hardly be able to move fast enough, or to coordinate their movements sufficiently well to extinguish fire – as was in the case of the elderly woman who suffered involuntary spasms in her hands and thus was unable to save herself when her cigarette fell from her twitching hands.

Endnote

Mankind has always been fascinated by the unknown. In a world where mystery fans the flame of curiosity, there is a tendency for people to speculate on strange occurrences and phenomena, fuelled by the blazing fires of their imagination. Alas, at the end of the day the romantically fiery supposition of Spontaneous Human Combustion, like many other branches of pseudoscience, is all too easily quenched by the spring of science and reason.

References

• Benecke, M, 1998. Spontaneous Human Combustion: Thoughts of a Forensic Biologist Skeptical Inquirer Vol. 22(2)

• Dee, DJ, 1965. A case of 'spontaneous combustion' Medicine, Science and the Law 5: 37-8

• Dickens, C, 1853. Bleak House 2nd edition Bradbury & Evans, London

• Nickell, J and Fischer, JF, 1988. Secrets of the Supernatural Prometheus Books

• Nickell, J, 1996. Not-So Spontaneous Combustion Skeptical Inquirer Vol. 20(6)

• Randles, J, 1994. Strange & Unexplained Mysteries of the 20th Century Sterling Publishing Co, Inc

• Stevenson, Thomas, 1883. The Principles and Practice of Medical Jurisprudence, 3rd ed Lea, Philadelphia

• Williams, B, 1998. Cold Water on a Hot Topic The Skeptic Vol. 18(4)

Internet resources:

• Carroll, RT, Spontaneous Human Combustion (SHC). The Skeptic’s Dictionary.

• Haslam, G. 2003. Spontaneous Human Combustion.

• Fire Safety.

Related BBC Links

• Learn more about the human body with BBC Science.