The autopsy evaluation of “straightforward” fire deaths
The autopsy evaluation of “straightforward” fire deaths
Roger W. Byard 0
0 Discipline of Anatomy and Pathology, School of Medicine, The University of Adelaide , Frome Road, Level 3 Medical School North Building, Adelaide, SA 5005 , Australia
1 Roger W. Byard
Deaths caused by fires are not uncommon in forensic practice
but can be amongst the most difficult to investigate. Not only
is important scene evidence often destroyed in the
conflagration, but so may be all, or part, of the body under investigation.
Fire deaths arise from a wide variety of events that range from
isolated single domestic accidents initiated by a candle
burning curtains to mass disasters involving dozens of victims in
nightclub fires, or from arson for insurance purposes to
culturally determined homicides in the form of dowry murders
]. Autopsy evaluations have to be adapted for each of
these situations and may be complicated by issues with
identification, determination of the cause and manner of death, and
interpretation of the potential significance of heat-related
artefacts such as bone fractures and heat epidural hematomas .
Any approach to a fire death that assumes that all will be
straightforward should be quickly abandoned, as each case
must be examined with an open mind and an awareness of
the numerous pitfalls that may be encountered.
Deaths in fires may occur from a variety of mechanisms. In
house fires where there may be low intensity burning of
household effects and furnishings for some time away from
victims, there may be minimal damage to bodies, with deaths
occurring from inhalation of the products of combustion. This
usually involves carbon monoxide (>50–60% saturation), but
may also include cyanide if plastics have been burnt. Testing
for the latter may therefore provide useful information in such
Bodies may show characteristic cherry-pink discoloration
typical of carbon monoxide exposure, and the upper airways
should be carefully examined for evidence of smoke
inhalation. This may take the form of soot soiling of the nares and
oropharynx with soot-stained mucus lining the trachea and
main bronchi [
]. Unfortunately in cases where there has been
extensive burning and charring, the integrity of the airways
may have been compromised and soot may be present within
air passages purely from external contamination and not from
inhalation. This may be exacerbated if there has been
extensive destruction of the building with collapse of internal walls
and ceilings causing further damage to the remains.
In cases where there has been more intense burning, bodies
may range from having the characteristically pugilistic
postures of the deeply charred, to forming mere piles of
carbonized bones and ashes. This is clearly a problem in cases of
multiple deaths, for example after bush (brush) fires, where
there may be comingling of remains [
]. Teeth are often
essential for identification, particularly if skin, soft tissues and
fluids have all been destroyed, and so steps should be taken at
the scene to use glues and fixatives to reinforce and protect
dental material prior to transport [
A major issue in fire deaths lies in determining whether a
decedent was dead before a fire started. This may have an
entirely innocent explanation if, for example, an elderly
individual has collapsed from a lethal cardiac dysrhythmia and
knocked a heater over during the terminal fall. Alternatively,
setting fire to a dwelling where a body has been dumped is a
well-recognized method of attempting to disguise a homicide.
It should also be appreciated that levels of carbon monoxide
that are not normally regarded as lethal (25%) may still have
fatal consequences in those with significant underlying
cardiovascular disease [
]. In other cases where there has been
very rapid burning with fast consumption of environmental
oxygen, for example with accelerants or a bush fire [
“flash fire” effect may also cause death from oxygen
deprivation with minimal levels of carbon monoxide being present.
The lack of carbon monoxide in the peripheral blood in
circumstances such as this should not therefore be taken as
evidence that death had occurred before the fire began [
At autopsy, skin slippage may have occurred which could
interfere with fingerprint identification [
]. Careful layer
dissection and examination of remaining tissues and organs
should be undertaken to look for evidence of injuries or
lesions that do not seem to fit with the observed scene. This is of
course sometimes complicated by putrefactive changes that
have occurred due to heating of the body by the fire, and the
prolonged time that it may have taken to locate the remains
and to safely remove them [
]. In addition to soot staining,
the upper airways may show burns to the tongue, pharynx,
glottis, larynx and tracheobronchial tree if there has been
inhalation of hot air. This may also induce prominent pulmonary
Intense heat also results in fracturing of bones and in
socalled epidural heat hematomas, where a collection of heated
blood accumulates between the dura and skull not related to
antemortem fractures [
]. It is differentiated from an
antemortem collection by having a similar carboxyhemoglobin level
to the peripheral blood [
]. An additional artefact that is
created by intense temperature is splitting, when heated skin
contracts and tears. This most often occurs over the head, extensor
surfaces and joints and may be mistaken for antemortem
wounding. Although there is no blood in these splits, the
distinction between an ante- or postmortem effect may not
always be easy [
]. The separation of antemortem injuries
from postmortem heat artefacts is a particular problem in high
speed vehicle crashes where there has been subsequent
incineration; i.e. determining whether death was due to significant
blunt force impact or incineration may not be possible.
The nature of fire deaths also varies depending on age, with
the very young and old being particularly vulnerable. Both
age groups may have limited understanding of the dangers
of fire, and also reduced cognitive ability to plan an escape.
It is, for example, well recognized that young children will try
to hide from a fire rather than leaving the area. Car fires are a
good example of this, where children playing with lighters
may set a car on fire and hide in the back seat rather than
exiting through the doors [
While most fire deaths are accidental, suicides and
homicides by fire do occur, although self-immolation is a rare form
of suicide in Western, compared to other, countries [
example, the highest incidence of suicidal self-burning in local
South Australian data (6% of cases) occurred in adolescence,
most likely reflecting lack of access to other more usual
methods favored by adults [
]. Homicide by burning is also
rare in Western countries, with most cases involving
individuals who have died when buildings have been set on fire. In
some situations accelerants such as kerosene may be poured
on victims and ignited, as in dowry murders in India where
there are often attempts to make the deaths appear accidental
due to kitchen fires [
]. Disguising homicides by burning the
body and its surroundings has already been referred to.
In its simplest form, a fire death may occur when a socially
isolated individual drops a cigarette while intoxicated and
accidentally sets fire to his or her bed. Unfortunately even this
does not escape from added complexities, with occasional
cases being attributed to “spontaneous human combustion”.
This urban myth refers to an alleged situation where a victim
has purportedly burst into flames and then been incinerated
]. Despite recent use of the term in Western medicolegal
circles the most likely scenario is of an obese alcoholic
wrapped in blankets or coverings who has dropped a cigarette
and then smolders away due to a type of “wick” effect. Thus,
while there is no doubt that combustion has occurred, it is far
from spontaneous [
In summary, the safest approach to assessing a fire death is
to assume that there is seldom going to be anything
resembling a straightforward case. Once that point has been
appreciated, then the case can be processed in an orderly and
meticulous fashion with appropriate attention being duly paid to
all aspects of the history, scene, autopsy and ancillary
evaluations. In this way clear documentation of findings can be
ensured with maintenance of an appropriate chain of custody.
This is really the only “straightforward” way to handle these
potentially highly complex cases.
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