Monday, August 31, 1998 Published at 06:45 GMT 07:45 UK
New light on human torch mystery
Scientists say a human body can burn for hours
Scientists believe they have found the secret behind stories of people suddenly bursting into flames.
BBC 1's QED - which brought together the world's top fire experts - looked at cases of spontaneous human combustion from around the world.
Using a dead pig wrapped in cloth, they simulated a human body being burned over a long period and the charred effect was the same as in so-called spontaneous human combustion.
The QED team spoke to Paul Haggarty who as a young fire officer was called to investigate a fatal fire in Pennsylvania. The victim was an elderly widow and what he saw still haunts him.
Mr Haggarty said: "There is no way you could explain it. None of the firemen had seen anything like it."
The most recent recorded case in the UK happened in 1992 in northern England.
Again, the woman's legs were left untouched, while the rest of her body was burned to a cinder.
Home Office pathologist Mike Green, who examined the body, does not believe in spontaneous human combustion.
But he said: "The first time you see it you rock back on your heels and your ask yourself 'How is it that the body has been totally consumed and nothing else has been damaged?'
"It beggars belief."
But forensic scientists are now convinced that the cause of such incidents is the so-called wick effect, started by a source as simple as a cigarette.
This means that in certain rare circumstances a human being can burn like a candle.
But the fact that human bones were completely destroyed remained a mystery, until now.
Even in human crematoria where temperatures are 700-1000 centigrade, the bones are not destroyed.
Dr John de Haan of the California Criminalistic Institute used a dead pig in a gruesome experiment to show that small flames can consume a human being with the help of burning body fat.
The pig was wrapped in a blanket and a small amount of petrol was poured on it.
After five hours of continuous burning the bones were being destroyed.
Dr De Haan said: "The sort of damage here is exactly the same as that from supposed spontaneous human combustion."
The wick effect means that a person could burn slowly without attracting attention from passers-by.
It also explains why only part of the body, the part which is rich in fat, burns while the rest stays intact.