'Spontaneous' Combustion: Can Bodies Burn From the Inside Out?

Can bodies burn from the inside out? When human beings are discovered burned to a crisp alone in their otherwise unscathed homes amidst no evidence of mayhem -- no telltale blowtorches, cigarettes or Butane -- rumors swirl: of mysteries and miracles in which bodies inexplicably burst into flames. It might be an urban legend, sheer magic or divine wrath (hey, it happens in Leviticus), but it is one of the most hotly debated (and hot) causes of death.

The official name of this phenomenon -- at least, among those who believe it is a phenomenon -- is spontaneous human combustion. Super-supernaturalists -- Syfy viewers, say, and exorcists -- call it SHC for short. Theories abound. Is the perspiration of heavy smokers and drinkers some kind of natural lighter fluid? Can creosote collect in their lungs, igniting in the mere proximity of extreme heat? According to scientific studies and the kind of people who thought The Blair Witch Project was real, possible culprits include high alcohol blood content, ball lightning, gamma rays, the metabolic molecule acetyl-CoA (aka acetone) and God.

"Autopsy results are pending, but experts say it could be a case of spontaneous human combustion,"  TV station KSLA reported last week after 65-year-old Danny Vanzandt was found incinerated on the kitchen floor of his otherwise undamaged Oklahoma home where the alcoholic chainsmoker lived alone.

Other news agencies chimed in: "Sheriff Rules Out Homicide, But Not Spontaneous Combustion," blared Arkansas TV channel KFSM. "Police are investigating whether an Oklahoma man died from spontaneously bursting into flames," echoed Virginia TV channel WTVR. "Possible spontaneous human combustion victim is identified," announced the Tulsa World. "Danny Vanzandt May Have Died from Spontaneous Human Combustion," declared the Huffington Post.

Such stories surface periodically. Full disclosure: I want to believe them. I want to believe that the spirits of the dead are watching us, and that crows sometimes try to talk to me. I want certain things to defy explanation. Science usually comes along and says "tough nails" to that.

In December 2010, 76-year-old diabetic Michael Faherty was found burned to death in his Galway, Ireland home. Although the charred corpse lay alongside a fireplace, its head near an open fire, a coroner officially ruled Faherty's death a case of SHC: Score one for the super-supernaturalists.

The idea of SHC triggers some of our trip-wiriest fears: dying painfully. Dying alone. Dying. The body as its own worst enemy, slaying itself not with the premeditated surrender of suicide but sneaking up unnoticed on itself when no can hear you scream and flash! Surprise. The body as volcano, light show, torch, burning itself out. Saving your loved ones the cost of cremation.

"Nadab and Abihu, the sons of Aaron, took either of them his censer, and put fire therein, and put incense thereon, and offered strange fire before the Lord, which he commanded them not. And there went out fire from the Lord, and devoured them, and they died before the Lord," reads Leviticus 10:1-2. "And when the people complained, it displeased the Lord ... and the fire of the Lord burnt among them, and consumed them," Numbers 11:1 helpfully explains.

John DeHaan doesn't buy the damnation bit. The veteran fire researcher, who has taught forensic science at UC Davis, authored fire-investigation textbooks and spent 40-plus years aiding fire-related criminal investigations, says that the way human bodies are built -- with flammable fat sandwiched between very moist, thus flame-resistant, muscle and skin -- pretty much prevents their burning from the inside out.

Human bodies do not burn easily even from the outside, even when doused with gasoline, as many murderers have realized to their chagrin.

"There's absolutely no mechanism I've ever seen demonstrated that will cause a body to catch fire from within and burn by itself," says DeHaan. Through his work with the San Luis Obispo Fire Investigation Strike Team and his own company, Fire-Ex Forensics, DeHaan has examined hundreds of charred corpses, and for educational purposes, torched many himself.

"When the first reference everybody drops about a subject is Charles Dickens, you have to wonder about its veracity," DeHaan says. In Dickens' novel Bleak House, an alcoholic junk dealer spontaneously combusts, his remains resembling “the cinder of a small charred and broken log of wood sprinkled with white ashes." This scene is cited frequently as classic literature's most prominent case of SHC.

"What many people don't know about Dickens is that he was an ardent prohibitionist," DeHaan says. "He devoted a tremendous amount of energy to campaigning against the evils of alcohol. He created Krook as an example of the bad things that can happen to an alcoholic."

As do most scientists, DeHaan credits alleged SHC to the "wick effect," by which an external ignition source -- say, clothes or hair ignited by a cigarette -- acts as a wick that splits the skin, penetrating the dermal layers to expose highly flammable subcutaneous body fat, which burns madly, shooting out flames that split more skin, exposing more fat, which burns madly.

"Candlewax burns fine," DeHaan says, "but only as long as you give it a wick."

According to his experiments, subcutaneous body fat has a heating value of 32 kilojoules per gram. So does ethanol, compared to candlewax's 44 kilojoules per gram, gasoline's 46 and muscle tissue's puny five. Human skin has an even lower heating value than muscle, virtually sealing the body in a watery sheath.

In one case he helped investigate, a California woman was last seen alive at 9:30am. By 2:30pm, smoke was wafting from under her front door. Her still-burning corpse lay inside, much of its upper half burned away, as was the carpet beneath it.

"There was no other fire damage. But leading from the kitchen to the front door, almost too small to see, was a tiny trail of melted plastic and cloth," DeHaan says. "One of the electric elements of her stove was still on. She had placed foil on a burner to create an improvised hotplate" on which she had tried to cook a plastic-wrapped meal.

"This lady was an alcoholic. The postmortem showed a .31 blood-alcohol level. Because of her inebriated state, she lost track of how hot her improvised hotplate was. It set fire to the plastic. Instead of throwing this into the sink, she picked it up and made for the exit. If you run while holding a flaming object, the air current moves that flame toward your body. The loose top she was wearing caught fire. She looked down, saw the flames and inhaled. Phoom!"

DeHaan says that in virtually all alleged SHC cases, "The so-called mystery is that the external ignition source is almost certain to be in another room where you might not think to look for it. People who are found burned through their bathroom floors probably set themselves on fire in the kitchen or living room and made for the bathroom, because that's where the water is." In the hotplate case, "if not for the little trail of burned plastic, you could never have traced it."

Inhaling flames causes instant death, the corpse then consumed via the wick effect. Don't look down at your burning shirt, keep your mouth shut, "and the flames divide up around the chin to the back of the scalp" rather than entering the respiratory system. Hellish, but potentially survivable, DeHaan says.

The main cause of alleged SHC? Burning shirts.

"Cotton and cotton-polyester blends are the most flammable fabrics, needing just one tiny flame to ignite them. Looking down at your burning shirt is simply not survivable. But honestly: If your shirt caught fire, what's the first thing you'd probably do?"