Wick effect

The wick effect is the name given to the partial destruction of a human body by fire, when the clothing of the victim soaks up melted human fat and acts like the wick of a candle. The wick effect is a phenomenon that is found to occur under certain conditions, and has been thoroughly observed. It is one commonly offered explanation for the alleged phenomenon of spontaneous human combustion (SHC).

The wick effect theory essentially says that a person is kept aflame through his/her own fats after being ignited, accidentally or otherwise. The clothed human body acts like an "inside-out" candle, with the fuel source (human fat) inside and the wick (the clothing of the victim) outside. Hence there is a continuous supply of fuel in the form of melting fat seeping into the victim's clothing. Fat contains a large amount of energy due to the presence of long hydrocarbon chains.

An investigation of a 1963 case in Leeds included an experiment with a wick effect. A small portion of human fat was wrapped in cloth to simulate clothing. A Bunsen burner flame was then applied to the 'candle'. Due to the high water content of human fat the flame had to be held on the 'candle' for over a minute before it would catch fire:

"One end of the candle was ignited by a Bunsen flame, the fat catching fire after about a minute. Although the Bunsen was removed at this point, combustion of the fat proceeded slowly along the length of the roll, with a smoky yellow flame and much production of soot, the entire roll being consumed after about one hour."

This gives some indication of the slow speed with which the wick effect will proceed.

In February 1991, in woodland near Medford, Oregon, USA, two hikers came across the burning body of a female adult, lying face down in fallen leaves. They alerted the officials and a local deputy sheriff soon arrived. The victim was described as "well nourished". She had been stabbed several times in the upper regions of the chest and back. Both arms were spread outwards from the torso. The lower legs and surface of the neck showed signs of fire damage. The soft tissues of the right arm, torso and upper legs were consumed. The majority of bones of these parts retained their integrity, although friability was increased. Between mid-chest and knees the fleshy parts of the body were mostly destroyed. Crime scene personnel reported that the pelvis and spine were "not recoverable", having been reduced to a grey powder. Her killer had soaked the clothes and corpse in nearly a pint of barbecue starter fluid and set her on fire. In the well-oxygenated outdoor environment, this combination of circumstances—an immobile and clothed body with a high fat-to-muscle ratio, accelerant (lighter fluid), and artificial ignition—made it prime for the wick effect to occur. The murderer was arrested and made a full confession. He claimed to have set the body alight some thirteen hours before it was discovered.

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Wikipedia