But while it has a long history in folklore, a close look at the supposed phenomenon finds little reason to believe it’s real. The term refers to a human bursting into flames because of heat generated by an internal chemical action. Common characteristics attributed to victims are a severely burned head and torso, unscathed extremities and unaffected areas around them, and a smell akin to perfume. Most telling, the other common factor is no witnesses.
There are a tiny handful of cases that have no determined cause, so there is a razor thin chance of it being due to spontaneous human combustion. But there are better reasons to think it’s not true, and making it a default or even eventual position is unjustified.
For a few centuries, many people believed being soused to be the cause. Perhaps persons felt this was divine retribution for sinning, or maybe it was due to a poor understanding of chemistry and anatomy. But this idea is unreasonable because there would be many more instances of drunk persons catching fire if it were true. I would have gone poof sometime in my mid 20s. Besides, it takes a Blood Alcohol Content of about .5 percent to hasten death. By contrast, one would need about a 60 percent concentration to set ablaze a water-ethanol mixture.
An equally unlikely idea posits that spontaneous combustion comes from static electricity. Static discharges can cause fuel explosions, but they can’t light up humans. If they could, you’d be in danger every time you drug your feet across the carpet. A drunk slinking across a room would have been in great peril, per the old way of thinking.
Since the middle of the 20th Century, the idea of spontaneous human combustion has been championed primarily by police officers and fire inspectors when unable to determine how a fire victim died with little damage to the surrounding area. In 2011, even a reputable British coroner ascribed a case to spontaneous human combustion because he could come up with nothing else.
But this commits a logical fallacy of Affirming the Consequent. The thinking here is, “If spontaneous combustion were real, the person would be roasted while areas around him would not be. This describes the victim and his surroundings. Therefore, this is spontaneous combustion.”
However, the human body is about 60 percent water, so it’s not terribly flammable. It takes two hours of being broiled at 1600 degrees to complete cremation. Short of quaffing two gallons of pureed oil rags, followed by a chaser of tanked oxygen, spontaneous combustion ain’t happenin’.
Most alleged cases can be resolved by considering the Wick Effect. Once a body is ignited by an external source, the Wick Effect from body fat would burn hot enough in some places to destroy bones.
This was demonstrated by Dr. John de Hann, who wrapped a dead hog in a sheet, poured on some gasoline, and fired it up. This Pig in a Blanket ended up almost identical to purported spontaneous human combustion victims. It took five hours to complete, so most of the pig was thoroughly blackened, but the extremities are surrounding area were unscathed. de Hann had selected a pig since it has the same fat amount as a person, lending more credence to his theory.
In supposed spontaneous human combustion cases, the victim’s clothing acts as a wick, with body fat being the fuel source. The burning clothes are maintained by liquid fat, causing a slow, controlled, burn. This burning is intense and long enough to cause great damage without spreading the fire. This explanation would also account for the perfume aroma, since sugars and fats are being vaporized.
National Geographic highlighted the case of a woman whose clothes suddenly caught fire and burned her thigh. She had put a seashell in her pocket, a seashell that was covered in sodium from a fireworks show. Later, she stuck a wet handkerchief in the pocket. This caused a fire, probably due to sodium reacting with water, thus releasing self-igniting hydrogen.
This demonstrates the type of events that could take place and lead to supposed cases of spontaneous combustion. There are humans and there is spontaneous combustion, but it’s unlikely they are ever combined.