Burns, Fire and Arson Deaths and Injuries

Pointers and common errors

Patrick E. Besant-Matthews, M.D.

Fire and heat cause many deaths, and a far greater number of injuries. In fact, burns are incredibly common, and frequently lethal. Large thermal burns are some of the worst injuries one can receive. Children are particularly likely to receive thermal injuries because they are active, and "get into things" before they're old enough to know what poses a threat. Serious damage to the skin is equivalent to putting a large hole in our outer protective covering. When we do this, things in the outside world, particularly agents of infection, have an opportunity to get inside our bodies, and make things still worse.

There are several common types of burns, including:

  • Thermal - Flame, from direct contact with fire
  • Radiation, from close exposure to heat
  • Scalds, from hot liquids or steam
  • Contact, from touching hot objects
  • Chemical, from contact with corrosive chemicals
  • Ultraviolet, from overexposure to solar radiation or sun lamps
  • Electrical, from contact with live conductors

This review will concentrate mainly on burns due to heat from outside the body. Such thermal injury only occurs when the amount of heat delivered to the skin exceeds the amount that can be removed by the body. Obviously then, the rate of delivery is often more important than the total amount. We know from experience that boiling water delivers heat to our skin much faster than an electric blanket. In scalds, burns due to hot liquids, the heat inherent to the fluid itself (the specific heat) is a major factor. Water, which is so common, happens to have a high specific heat. Although water does not usually exceed about 212°F (100°C) at sea level, other liquids, such as oils and molten metals, can reach far higher temperatures at normal atmospheric pressures.

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The duration of exposure or contact with the skin is also a major factor, so we start to see how clothing may affect the outcome if it holds hot liquids in contact with the skin, when otherwise they would have run off. Likewise melted metal may solidify as it starts to cool, and because it remains in one place, continues to deliver heat to a given area of skin. There are many variables.

Unfortunately, in this day and age, it is not safe to assume that all thermal injuries are accidental. In fact they must be evaluated with many other possibilities in mind, including arson, insurance fraud, drug abuse, child abuse, domestic violence, elder abuse, and even suicide, or attempted homicide.

The situation is somewhat reminiscent of a story about two pathologists, taking a look at the body of an attractive young woman laid out for examination in their autopsy room. The younger comments upon the abrasions and bruises on the neck, whereas the old-hand, who is nearing retirement, calls for a sexual assault kit.

In other words, there may be a great deal more to a fire, and associated thermal injuries, than first meets the eye.

To get a feel for the problem, let's consider the figures for unintentional residential structure fires in the United States during 1999, and break them down:

Per year Per day One every Trend
Residential fires 337,300 924 1 minute 33 seconds Down
Residential fire injuries 14,550 40 36 minutes 7 seconds Down
Residential fire deaths 2,390 6.5 3 hours 40 minutes Down

Cooking equipment accounted for 29% of the fires, 28% of the injuries, and 13% of the deaths. Heating and cooling accounted for 13% of the fires, 9% of the injuries and 13% of the deaths. Electric wires and fixtures accounted for 12% of the fires, 7% of the injuries and 6% of the deaths.

As we might expect, the items first ignited were upholstered furniture, followed by mattresses and bedding. Smoking materials were still responsible for roughly 23% of the deaths.

Fire-related injuries and deaths also have enormous indirect costs, such as lost productivity, and medical care.

The losses due to accidental fires, arson fires, and fraudulent claims are widely perceived, but the numbers are bigger than many expect. Here are a few estimates from The National Fire Protection Association (NFPA), also for 1999:

  • There were 72,000 deliberately set or suspicious structural fires.
  • The estimated property loss was $1.28 billion.
  • There were 370 civilian deaths due to arson.

To make matters worse, it was reported that the arrest rate for arson cases in 2001 was only 16% nationwide.

It's amazing how many insurance companies employ:

  1. Attorneys, to write policies and contracts
  2. Actuaries and statisticians, to calculate the odds
  3. Physicians, to tell them which diseases are bad
  4. Investigators, to look into what happened

and yet these companies continue to payout on the basis of poorly conducted autopsies, poorly worded autopsy reports, and seldom consult anyone who has experience in the medical aspects of death investigation.

Costly litigation is associated with both property and human losses, and further compounds the problem.

Fire not only injures survivors, but it often makes the bodies of victims hard to identify. Evaluation of a burned body is often quite difficult, and there are many potential mistakes and sources of error for the uninformed.

Arson means to start a fire, or cause an explosion, with the purpose of:

  1. Destroying a building or occupied structure of another
  2. Destroying or damaging any property, personally owned or belonging to another, in order to collect insurance or reward for such loss.
  3. The willful or malicious burning, or attempt to burn, with or without intent to defraud, a dwelling, house, public building, motor vehicle, aircraft, personal property, of another.
  4. (US Department of Justice 1980)

Arson clauses in property insurance void coverage if the fire is set by the insured, just as suicide clauses commonly void coverage for suicide within two years of taking out life insurance (see below).

In 1997, a total of 81,753 cases of arson were reported (an average of 224 a day, or one every 6 minutes 26 seconds), but some people estimate and believe that roughly six times as many cases go undetected or unreported.

There are several common categories or types of arson (deliberate fire setting):

  • Concealment of another crime
  • Fraud / profit
  • Thrill seeking / vandalism
  • Hate / spite / revenge
  • Social protest / terrorism
  • Hero / vanity
  • Juvenile fire setter
  • Pyromania (persistent compulsion to set fires)

Unless arson is obvious (e.g. trails of paper throughout parts of a building, gasoline cans, and more than one origin, with other evidence of crime) it is necessary to show that fire was not due to something else.

Make a point of looking up the proper meaning of the basic fire terms in a book on fire and arson. They have very specific meanings for those who work in the field. We need to communicate accurately with fire fighters and fire investigators, and they have their words and specialized terms, just as we have ours.

When you start learning you will soon find that misinformation is being perpetuated, just as it is in other fields. Examples include:

1) Years ago, people were taught that if a fire spread beyond the room of origin within 20 minutes then it must have been aided by an accelerant. It may have been true then, but it's not true today because of the changes in available fuel. Many modern furnishings yield far more heat than the leather, cotton and wool of days gone by.

Flashover (everything in a given room or compartment burning) always existed, but now it's often closer to 5 minutes from the first open flame, and 2-4 minutes from the time a smoke alarm first sounds. Several years ago a survey found that people expect 10-15 minutes evacuation time, when in reality it's usually far less. A house fire can double in size every 30 seconds or so.

2) Spalling of concrete does not necessarily mean that an accelerant was poured onto a floor. Spalling occurs even when fire has other origins, because there's a relationship to the shock of sudden cooling by water. Furthermore, recent research indicates that some high strength concretes may flake off (focally "explode") in areas subjected to heat, because their greater density and relative impermeability makes it harder for steam to escape.

3) In the past people claimed to be able to relate time and/or temperature to the depth of charring of wood. However, in some modern structures, wood might have been treated with fire retardant which significantly reduces the rate of penetration, so a little caution goes a long way. Engineered lumber is also increasingly common (for example, gluelam beams, laminated strand lumber (LSL), laminated veneer lumber (LVL), oriented strand board (OS8), parallel strand lumber (PSL), I-beams, open-web joists, finger jointed studs, and other manufactured lumber products.)

If like me, you're seeking the most basic of facts to serve as a starting point for observations, remember that when soft woods are exposed to heat, charring occurs and the surface layer then acts as an insulator. The best guide I can cite is that, if soft wood, such as is used in glue- laminated beams, is exposed to a fire, it will be damaged/penetrated at about 1/40th inch per minute. Of course it's uneven, being deeper at corners that on the sides, but at least it's some sort of guide.

We also need to review or learn what fire is. The three essentials are fuel, oxygen and heat.

Hydrocarbon fuel + oxygen -7 carbon dioxide + water + energy as heat and light. An initial input of heat, perhaps from a match, converts some of the fuel into a form (gas or smoke) that can mix with oxygen in the air and start to burn. The heat produces more gas and smoke, so the process keeps going. The region that contains enough heat to maintain the process, constitutes and defines what we see and know of as flame. Although gas and smoke contain many chemical compounds, the underlying reaction is:

Hydrocarbon fuel + oxygen ➔ cardon dioxide + water + energy as heat and light.

The Medical Examiner or Coroner

There is marked regional variability in the quality of death investigation in the United States, from about the best in the world, to some of the worst.

Don't judge a local death investigation system by its name. It may be a Coroner, Medical Examiner, Sheriff-Coroner, Medical Investigator, or Justice of the Peace system. Instead, judge a system by the personnel, its performance, the level of support, and the overall set-up. Is it politically or scientifically oriented and directed? An interested lay coroner often does a better job than some physician who ran for political office and doesn't care much about anything except looking important.

Do not assume that the pathologists you work with have received proper training in medicolegal matters. Too often they haven't. There are various specialties within medicine, just as there are in law and engineering. Knowing about hospital pathology (tumors and the chemistry lab) does not fully prepare them for medicolegal work without additional training, any more than being a physician qualifies me to do brain surgery without additional training. I have no idea why this simple concept is so frequently overlooked.

At present, there are many problems facing the specialty of forensic pathology (including declining budgets, low pay, employment by state and local government, shortage of trained people, and AIDS, etc.) so the situation is not likely to improve any time soon. However there are encouraging signs, suggesting that local awareness and standards may be on the way up.

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Cause, Manner and Mechanism of Death

When someone dies, the Medical Examiner or Coroner has to determine two very distinct things:

  1. The CAUSE of death.
  2. The MANNER of death.

It is essential to know and understand the definitions of cause and manner if one is involved in any kind of death investigation.

CAUSE of death is:

  • The injury, disease or combination of the two, responsible for initiating the sequence of disturbances, brief or prolonged, that produced the fatal termination.

If death occurs within seconds or minutes, say after a few thousand gallons of gasoline caught fire, just about everyone will understand that heat and burns are the cause of death. However, if death should be delayed, when for instance someone is burned by lighter fluid, subsequently develops an infection and dies a few weeks later of septic shock or organ failure, it is not unusual for people to lose sight of the initiating or proximate cause (the burns) and somehow see and regard the death as due to infection. In other words, they fail to see that the burns were the initiating event, and that without them the infection, and eventually the death, would not have occurred.

If they fail to see this obvious interconnection, the death will be seen as natural, the case may not be reported to the Medical Examiner or Coroner as it should be, and a death certificate may be improperly issued, listing kidney failure, due to low blood pressure, due to septic infection, as the sequence leading to death, but never taking the thought process back to the burns that initiated the sequence of events ending in death.

MANNER of death is:

  • The fashion or circumstances in which the cause of death arose.

In the United States we have five options (Natural, Accident, Homicide, Suicide, Undetermined), Anyone of the five can apply in a fire-related situation.

Proper determination of the manner of death is extremely important when it comes to insurance settlements. For instance:

  • Homicide - The insurer pays the face value of a policy.
  • Accident - The insurer may pay double the face value (if there is double a indemnity policy).
  • Suicide - No payment at all if there is a "suicide clause" and death occurs in less than two years after the insurance was purchased.

After a fire, a person may be found dead or may die shortly thereafter, but the manner of death could be anyone of the five. As a whole, the manner of death will usually turn out to be:

  • Accident — The majority
  • Homicide — Quite a few
  • Suicide — Not many
  • Natural — Significant numbers
  • Undetermined — Occasionally

Following are five simplified scenarios to make the idea clear:

  • A person who is smoking in bed has a "heart attack" and drops a cigarette. Eventually, after some smoldering, it sets fire to the bed. Autopsy shows no smoke inhalation, and there is no carbon monoxide in the blood. Clearly the person was dead by the time the smoldering began, and long before any flames appeared. This death is associated with a fire, but not the result of it.
  • A man decides to set his business premises on fire in order to file an insurance claim. Business has not been good and he's been losing money for months. He sprinkles gasoline around the premises but decides he doesn't have quite enough, and goes back outside for another can. Meanwhile vapors are permeating the building. He comes back in, empties the remaining can and then flicks his lighter and "woomph"! His body and two metal cans are found soon after an overhaul of the scene begins.
  • Gasoline is thrown onto a drunken man, who is sleeping on an old sofa under a bridge overpass, followed by a match.
  • A man shouts "I want to die, I want to die", douses himself with gasoline, and lights himself with a match in front of three witnesses. The flames are suppressed but despite treatment he dies several hours later.
  • Two intoxicated people are in a pool hall drinking and arguing. A scented candle is knocked over during a scuffle and ignites paper on the floor around the base of a dry Christmas tree. The matter is never resolved because both die of their burns within a few hours, each making accusations and blaming the other to the last.

The above are simple examples. There are far more difficult cases, but most of the time manner of death is fairly straightforward, if the scene and the death are properly/thoroughly investigated.

Note that even more manners of death are used in other countries. For instance "misadventure" and "open verdict" in the UK (which are variants of accident and undetermined).

So when we're confronted by a fire-related death, we have to decide if death was due to, a direct outcome, of the fire, or if death took place in a fire-related situation.

Mechanism of death is useful to know about, but it's far less important than cause and manner.

MECHANISM of death is:

  • The physiologic derangement or biochemical disturbance, incompatible with life, which is initiated by the cause of death.

For instance, the heart or lungs may stop, or as so many say, they arrest.

Clearly, if the mechanism is initiated by the cause, it must be different from the cause. There are two easy clues to recognizing mechanisms, which are that (a) when you look at them you can't tell what initiated them, and (b) all of us will have them about the time that we die! For instance, I am certain that my heart will arrest sooner or later, but what interests me is what will cause it to do so!

Mechanisms of death include: cardiac arrest, respiratory arrest, cardiorespiratory arrest, and so forth. Everyone's heart comes to a stop sooner or later, but saying that it did so doesn't tell us why (the cause of death), which is what we all want to know. There's lots of reasons for the heart or lungs to stop, all the way from being crushed by a truck, to being shot in the head, or developing cancer.

Lots of people, including many physicians, fail to distinguish mechanism from cause. You will become aware of this when a person dies after 90% of his total body surface area was burned. The autopsy is just under way when someone calls from the hospital to ask why the victim died. If you reply that he died of his burns, they will again ask why he died, making it clear that they are thinking about the immediate cause or a mechanism, to explain some observation during the last few hours or days of his life. It usually makes little difference if the lungs or kidneys failed at the last, so long as failure of either was initiated by burns. Thermal burns represent the cause, the initiating event, without which death would not have occurred.

Simple observation at the scene of a fire can, on occasion, be far more important than the autopsy. Usually you will go through a 3-step diagnostic process just as with living persons.

  • History + Physical examination ± Tests = Diagnosis & Treatment
  • Scene and circumstances (as much as is known) + Autopsy ± Toxicology (CO, Alcohol, Drugs, poisons) = Cause & Manner & Case disposition

A few simple numbers (United States) to get started:

  • There are about 2,400 deaths per year from "house fires" and of these about 80% die of "smoke inhalation".
  • Something like 2/3rds of fire deaths occur in homes, and another 1/5th or so in transportation. Other categories are quite small, and amount to only 2/15th of the total.
  • Fire is the 4th leading cause of accidental death.
  • Fire is the 2nd leading cause of death in the home.

It's impossible to list all the ways in which fires and and/or burns arise. However it's important to think in terms of general injury and event patterns, so following are a few guides according to age and behavior:

Small children:
  • Play with matches and lighters
  • Touch hot oven doors
  • Climb on stoves and pull on pot handles
  • Fall against open heaters
  • Play with wall outlets
Older Children:
  • Throw gasoline on open fires
  • Ignite sleeves on cook top (not adult stature)
  • Refill hot or still-running lawn mowers
  • Use fire inside a tent
  • Toast marshmallows
  • Fall asleep while smoking
  • Set their clothing on fire with matches or on a stove
  • Use wet oven gloves (the touch hot utensils and water turns to steam)
  • Leave spoons and other things in pots while cooking
  • Throw wet foods into hot fat, producing steam that splashes hot oil
  • Remove the lids of boiling pots carelessly
  • Use unsuitable containers in microwave ovens; forget that a cool container may be hot inside
  • Carry, and spill, hot cooking utensils between cook top and sink (bad kitchen design)
  • Cause fires with candles by failing to use proper holders, letting hot wax drip, not extinguishing them before going to sleep, putting them near draperies, and using them improperly during power outages, etc.
The elderly:
  • Drop and spill hot liquids
  • Get too close " 3 feet) to space heaters
  • Forget foods on the cook top

These lists could be greatly expanded, but what is likely to happen depends upon age.

If there has been a fire in a building, particularly in a residence, it's a good idea to proceed on the basis that there might be human remains in the debris, until it becomes clear that there aren't. If remains are found, the first step is to decide if they are animal or human.

If the remains are found to be human then the BASIC QUESTIONS are:

  1. Who is/are the deceased person(s)? Who in fact died?
  2. Were they alive or dead at the time the fire started, and while it was burning?
  3. If they were alive, why did they fail to escape?
  4. Was death due to the fire, or only associated with it?
  5. Are all the findings and injuries due to the fire?
  6. Was the fire intended to cause or conceal a crime?
  7. What was the manner of death?

Lesser, but relatively important, questions arise from time to time. For instance, federal and state laws provide for collection of taxes after death, but less obvious issues are seldom considered. For instance, if a veteran and his wife should die in a fire, is she still eligible for VA burial benefits? Perhaps so, but it won't be long before someone's wants to know who died first?

Double and triple indemnity insurance is important to family members. These policies pay the face value for natural death, but double or triple the amount for accidental death. Some won't pay for suicide at any time, while others won't pay within a specified period (e.g. 2 years) after taking out the policy.

Fires are often set to conceal homicide, suicide, or obscure identity, and to try to cover up other criminal activities such as theft or searching for drugs and valuables. Never assume (ASS-U-ME) that all fire related deaths are accidental, because many are not.

What should you note during the autopsy on a fire or burn victim? The simple answer is that you should try to note everything you would normally note during an autopsy examination, less those items that have been obscured or altered by fire. Then make additional notes on how the fire affected the body.

For instance, if time of death should be an issue, and if the body was heated for a while to an unknown degree in a fire, you obviously cannot rely on body temperature! Likewise you can't answer questions about temperature after a body has been cooled. Don't laugh, I've seen and photographed a body packed in a bag of ice, accompanied by a note stating the local temperature that day, and asking questions about the time of death!

I will assume that there are no "complications" such as hazardous chemicals or nuclear radiation to disturb or delay our routine. I will therefore proceed on the basis that we have a dead body, that was found after a fire was suppressed, or a burned living person to examine.

Common Errors and Misinterpretations include, but are not limited to:

The body is severely charred and reduced in overall size and weight, so it's not worth performing an autopsy.

This is a classic mistake.

"There is no body so badly burned, or decomposed, that it does not deserve an autopsy". (Charles P. Larson, M.D., Tacoma, WA. - deceased.)

A steak may be charred on the outside, but the inner parts, especially if the meat is thick, may still be edible after we have cut the overcooked outer portions away. Likewise in the case of bodies, the outside can be blackened and parts of the limbs completely destroyed, while the inner parts remain comparatively well preserved, frequently allowing us ample opportunity to:

  • Draw blood, urine and bile.
  • Make identification.
  • Decide if the person was alive or dead at the time of the fire
  • Determine the cause and manner of death.

Teeth are relatively hard to destroy and are particularly valuable in making identification, provided we have an idea who the dead person(s) might be, and can make contact with any dentist who provided treatment during life. This is because there are 32 adult teeth, each of which have five surfaces (biting, inside, outside, back and front). Thus, the mathematical odds of any two people having the same combination of absent teeth, and restorations of various kinds, involving the 160 different tooth surfaces is extremely small. Even the shape of the roots can establish identity.

Note that the examination should be as complete as it can be in the circumstances. Obviously you cannot examine a forearm and hand if the limb is missing below elbow level, but never make the serious mistake of doing a "partial autopsy". Partial means other than total or whole, and thus incomplete. For example, failing to open the head, to look for brain damage.

Heat causes shrinkage, in effect a contraction, of muscles.

This is like steak shrinking as it is cooked. There are several variations and possibilities for error:

  1. If a body is heated on one side, in just the right way, it will bend towards the side exposed to the heat because the muscle (and skin) contract on the heated side.
  2. Generalized heating often leads to the so-called pugilistic or boxing-like position. This results from the fact that our bending (flexor) muscles are usually stronger and bigger then our straightening (extensor) muscles, so the stronger muscles "win" when both groups are heated.
  3. Limb muscles can contract, giving rise to changes of position. Bodies may tilt, tip or even fall from the edge of a bed or a chair as heating causes muscles to pull on, and move, various joints.
  4. When the above (a, b and c) are combined, they may lead to faulty estimates of position and what a person might have been doing at the time of a crash (holding the steering wheel or operating aircraft controls?), whereas in fact you usually can't tell if that part has been heated.
  5. When muscles congeal and/or tighten, the body parts go stiff. This can be mistaken by the untrained for rigor mortis (the stiffness resulting from build up of acidity and allied chemical changes in unheated muscle). Unlike normal rigor, any stiffness due to heat has no value in estimating the time of death, nor does it pass away after a while like rigor mortis, any more than meat returns to the consistency it had prior to cooking.
  6. On occasion, the contraction of muscles can be forceful enough to cause breaks in long bones.
  7. Combine some skin tightening, some muscular contraction and some body bending with unthinking/careless measurement of body length, and you can easily come up 1 to 3 inches short of the actual living stature. This has potential for misidentification and further confusion.
  8. Note that fires have occurred in funeral homes, and embalmed bodies have converted from their usual position, on the preparation table or in a casket, to an altered, contracted, semi- crouching, boxer-like position.

Heat causes shrinkage of skin.

The combination of heating, drying and loss of water often causes skin to shrink.

This leads to several possible errors:

  1. Underestimation of age as wrinkles disappear, facial skin tightens, features flatten, and areas such as the breasts and abdominal skin firm up.
  2. Tightening and weakening of skin of the abdomen, combined with heated/expanded intestinal gas, often causes a splitting near the midline of the abdomen, whereupon small intestine bulges out, leading to the impression that the abdomen was cut or stabbed prior to the fire. A good clue is that the intestine is often visibly less burned, and appears better preserved, than the adjacent abdominal wall tissues. This is an indication that the protrusion occurred later in the sequence of events, as the skin tightened, and then the intestinal gases expanded as heat made its way inwards.
  3. Skin may be heated on one side of a body part and split near the heated area, or on the other side. For instance if a mattress smolders and then bursts into flame, and if one arm of the victim is hanging part way over the edge of the bed, the skin of the arm may split in a ragged fashion that may be misinterpreted as some form of blunt or sharp injury, such as a bludgeoning or a machete attack. A clue is that the splits are somewhat ragged at their edges because they are actually tears due to tension.
  4. If the skin of the neck and face become sufficiently taut, the tongue may stick out. It isn't that the tongue has swollen, rather the face and skin under the jaw has become too small, causing the tongue to protrude.

A reverse variant of facial change is the marked swelling of the face that may occur in a person who lives for a while after a significant burn. This can interfere with recognition and identification of the victim.

Shrinkage of bone.

Bone shrinks if it is heated in just the right way. Like most things, bone expands slightly to begin with but then, as the heat takes effect on the various components, it shrinks. Significant shrinkage has been reported, but the percentages vary. It can be more in some bones than others, and it's only recently that I've heard of a worthwhile paper on the subject. A small amount of shrinkage is reasonable in house fires. In the meanwhile, so long as you're aware that calculations of size or stature may be in error unless some allowance is made for shrinkage when heat is applied, all will be well.

Note that shrinkage in length results in an even greater reduction in area, because of simple cross sectional mathematics. (An imaginary square of bone which originally measured 1 x 1 inch, might only shrink 3% each way after heating, Thus is will measure 0.97 x 0.97, which is only 0.941 of its original area). This can lead to errors when counting the fine bone structures per unit area, (osteones), unless the two dimensional size (area) change is factored in.

  • Bone can crack and split when exposed to heat. As a guide, if bone is wet when it's heated it tends to look a bit like cracks in dried clay or mud, and to have a mosaic-like angular appearance, rather like the appearance of embers or charred wood, whereas, when heated in the dry state, there is greater tendency to longitudinal, somewhat linear cracking.
  • If the scalp is burned away, pieces of bone may flake off the outer surface of the skull, giving rise to a suspicion of head injury. (Don't mistake the joins, or sutures, between the bones of the skull for fractures, so have a good look at the normal joins between the bones next time you see an autopsy on a traffic fatality). Real fractures of the skull generally go all the way through, and look more like the slightly zigzag or curving fractures you see in glass windows.
  • Long bones can shorten when heated, leading to incorrect estimates of standing height.
  • Occasionally, heated muscles contract so forcefully that they will break long bones. Be sure to note the presence or absence of fresh hemorrhage next to such a fracture, if you can tell. If a clot (hematoma) is present next to a fracture, consider having it tested for the presence or absence of carbon monoxide. For instance it's possible that if a person fell and broke a thigh bone while attempting to escape from a fire, that the blood which leaked out of the fracture might have a lower amount of carbon monoxide in it, then the rest of blood which remained in the vessels and picked up more of the gas as the person lay on the floor, but still breathing, in the fire environment.

Heating of body fluids.

  1. In the head, bloody fluids may be forced out of the space between the inner and outer layers of the skull and cause separation of the tough fibrous lining of the skull (the dura) from the inner surface of the bone itself. This may be mistaken for bleeding due to a head injury that was present during life, shortly before death.
  2. As a guide to separating the two:
    • Bleeding due to skull fractures tends to be at the sides of the head near the fractures and those parts of the skull near the upper ears
    • The bleeding due to heating is usually more diffuse, higher up on the head and less well demarcated. This phenomenon has been seen in bodies already in funeral home, dead of other causes, but later heated by a fire in a funeral establishment.
  3. Occasionally, in cases of extremely severe burning, steam and fluid pressure can combine to push fluids and minute tissue fragments around within the circulation. This is only visible under a microscope, and tends to be associated with severe trauma.

Skin blistering, peeling and slipping

This commonly occurs following:

  • Exposure to steam heat, and even hot air.
  • Prolonged immersion in water.

In the absence of heat, skin blistering and slippage may also be seen in association with:

  1. Death following coma
  2. Death due to carbon monoxide poisoninq
  3. Decomposition
  4. Exposure of skin to unburned gasoline, and other chemicals
  5. Prolonged immersion.

Thus there is potential for misinterpretation. Blisters are not always due to heat or to steam.

Shrinkage and discoloration of internal tissues.

Sometimes, enough heat passes inwards through the body wall to, in effect, begin to cook portions of the tissues immediately beneath. For instance, if the chest wall is well heated, but not sufficiently to burn it through, more than enough heat can reach the front of the heart to cause a change of color (often a slightly variegated yellowish pallor) and some focal shrinkage.

There have been cases in which these simple changes have been mistaken, by the unaware and untrained, for shortage of blood supply to the heart muscle (heart attack, myocardial infarction) and for abnormally small (coronary) vessels on the surface of the heart. In fact the color and shrinkage were due to the ingress of heat.

Likewise a whitening and opacification of the corneal areas, in front of the iris of each eye, can lead to faulty estimates of eye color. The change is akin to cooking white of egg, which goes from clear to opaque white, when the protein is denatured by heat.

Alteration of hair color.

There is a natural tendency to use hair style and color for recognition and identification of deceased persons. Potential problems include:

  1. Hair may be partly consumed or destroyed, thereby reducing the overall quantity and length.
  2. Darkening and graying may result from the deposition of soot.
  3. Hair color may actually change as the hair is heated.

I have seen this many times but have yet to perform my own tests to confirm the temperatures at which it occur. However it's fairly clear that it doesn't take a great deal of heat, perhaps 1 to 3 times that of boiling water, or thereabouts.

Regardless of the exact temperatures, heat usually causes hair to change color to brassy or slightly reddish hue. Such alterations of color may be sufficient for misidentification, because it is relatively common to ask friends and next-of-kin to make identification at the very time when they are upset. Furthermore most relatives are not accustomed to seeing bodies of any kind, let alone victims of fire.

It is particularly bad if a person viewing the remains should decide that the body is not that of the friend or relative, when in fact it is, thereby delaying identification, and later tarnishing the image of the investigating personnel and their agency.

Change in the color of synthetic fibers.

A few synthetic fibers change color when heated. It is uncommon, but I have seen blue denim jeans turn a bright red, apparently when acrylic fibers reached about 180°C. Again there is potential for misidentification.

Heating, drying and reduction of body weight.

This results from actual physical destruction of parts of the skin, the outer (distal) parts of the limbs, and from evaporation of fluids. It is far from unusual for an adult body to be reduced to half the living weight, or less. Those who are unfamiliar with such losses may decide that the 200 pound man who is missing simply could not have been reduced to the 120 pounds of remains being examined. In fact even greater reductions in weight may occur if the conditions are right, so weight can be very misleading. Reduction in weight may also contribute to mistaken identity.

An adult body will not usually be totally destroyed by fire. Remember how hard it was to dispose of bodies in the WW2 concentration camps. Of course in a prolonged extremely hot, oil refinery or intense chemical fires, even an adult can be completely destroyed.

The bodies of children and animals are sometimes completely destroyed, but it isn't particularly common. It is estimated that about 56% of US households have dogs or cats, and about 35% have children, so it pays to look for remains that are far smaller than adults. (See #24 below). In general, of course, the harder and more thoroughly you look, the more you are likely to find.

Heating and drying (combined with muscle contraction) can lead to bending of the body, with resultant shortening and under-estimation of stature. This results, in part, from measuring a body when it isn't lying straight, but slightly bent at one or more joints. Add focal loss of tissue thickness (e.g. of the scalp), and the result, yet again, can be mistaken identity.

Effects of medical and surgical treatment.

  1. One of the major sequelae of burns is infection. In effect, our outer protective layer is damaged or burned away, so the outside world can get in. To prevent this, ointments of various colors (some of which contain silver compounds) may be smeared on the skin surface, and bring about focal discoloration, or darkening, resembling the tarnish on silverware. This is becoming less common that it was because of newer treatments, such as collagenase.
  2. The skin may tighten so much when it shrinks, and underlying tissues swell, that the circulation to various body parts would fail and breathing would be impeded if the tension were not released. It's much like putting a blood pressure cuff onto an arm or leg, inflating it and leaving it in position so the circulation is cut off. Surgeons make longitudinal cuts in the skin to release this tension. They usually make their incisions:
    • On the insides and outside of affected limbs.
    • On the sides of the chest.
    • On the backs of the hands.
    • If you see such linear longitudinal cuts, on a burn victim who was treated in hospital for a while, they will probably be the result of surgical treatment, not knife or box cutter slashes prior to the fire.
  3. Surgical removal of dead tissue (wound debridement) alters the appearance and apparent depth of the burns. You may also see removal of non-viable parts, such as fingers or toes. Both are done to promote healing (and re-sealing) of the body.
  4. Skin grafting. This is usually done in the most important areas first:
    • The face, to restore the best possible appearance.
    • The hands, to restore function and also appearance.
    • Near the armpits, elbows, wrists and knees, the very places we need to be able to bend and move if we are to remain active. Nowadays this may be done in 2 inch squares, or by expanding grafts with multiple cuts, much like expanded metal. The many small squares, or a modified diamond pattern, can be confusing if you haven't seen them before.
  5. You may see metal pins passing through bones. These were inserted to hold a limb clear of bedding and to facilitate treatment by grafting.
  6. Fluid loss is a major threat in the early stages of treatment of thermal burns. So, if death is delayed, and the victim of burns is treated energetically at the hospital, they may receive enough fluid to result in an increase in body weight. This can be enough to confuse relatives and lead to momentary doubts about identification. (As previously mentioned, the face may swell after thermal injury and give rise to further problems.)

Even the natural healing processes can look peculiar to those who haven't seen them before, or if the pathologist who's performing the autopsy is in a hurry on not inclined to explain.

Very occasionally deaths will result from the untoward consequences of treatment, especially in children who are treated at home for burns when they should have been taken to a hospital. Substances intended for use on small burns have been known to get into the system through larger ones, and can be toxic when used improperly (to excess).

Failure to take x-rays.

If the body surface is sufficiently intact to permit detailed visual examination there is relatively little need to x-ray it. However, if the body surface is even slightly difficult to examine, be sure to take a complete set of x-rays, or request that the body be run under a fluoroscope. A little soot can be wiped away, but as soon as there is significant burning it is all too easy to overlook features such as bullet wounds.

X-rays will help in several ways:

  1. To make sure there are no bullets, or other foreign objects, inside the body. If there are they may be important, or they could have been there for years. Only an autopsy will show which is the case. It may be that there are only a few nails and screws from burned wooden objects that were part of the premises.
  2. To locate items of jewelry and/or property, such as identifiable keys, money clips, or the clasps of plastic purses, mixed in with the charred clothing and debris.
  3. To show if there are any long standing bony abnormalities such as fractures.
  4. To provide films for subsequent matching with x-rays of known persons taken during life (e.g. outlines of frontal sinuses and ribs on chest films).
  5. To reveal medical devices such as dental restorations, artificial joints, cardiac pacemakers, plates, screws, wires and clips that will help to establish identity.

Note that x-rays of the teeth and jaws for identification purposes are best taken by a method as close as possible to that used during life, to minimize perspective distortion.

In small towns and rural areas, it is not uncommon to encounter a situation where the Coroner does not have, or does not contract for, proper access to x-rays. After all, the local hospital administrator isn't likely to be particularly keen on the Coroner hauling bags full of dirty, smelly, victims through his nice, clean premises! So if you are allowed in, be sure to learn the little tricks and tips that make you seem cooperative, and therefore more likely to be invited back, such as keeping the x-ray cassettes clean by putting them inside one or more plastic garbage bags before they are placed under the remains, and by doing most or all of the body hauling and lifting.

Failing this don't overlook the local veterinarian who often has a portable x-ray machine. He, or she, may well be accustomed to x-raying a variety of smelly goats and sick cows, and may get quite a kick out of helping you with a burned or decomposed body! I have found them to be an enormous help and ally on several occasions.

Alive or dead at the time of the fire?

Eyewitness reports of screams for help, and of banging on the inside of locked doors and windows may be received, but even if you do receive such reports, be sure to continue to look for:

  1. Soot in the airways. — This becomes more difficult to evaluate if the wall of the windpipe (trachea) is burned through, but even if it is, soot won't go all the way down into the lungs without active breathing.
  2. Swallowed soot. — This is more likely to be present if the person survived for a while in a sooty environment, and irritation caused the production of mucus which was swallowed, carrying soot into the stomach.
  3. Carbon monoxide in the blood. — More than about 5% carboxyhemoglobin in the blood usually means the person was alive at the time of the fire, or at least when it began. Below about 5% it could be due to cigarette smoking. There are exceptions, because there are a few chemicals (e.g. methylene chloride) that, if they're inhaled, are broken down into carbon monoxide by the body. So it is possible to have a significant amount of carbon monoxide in the blood without ever inhaling the gas.
  4. Other substances or combustion products in the blood that could/would only have been present after the fire began.
  5. Froth in the airways and mouth is a sign of airway irritation and lung injury by irritant products of combustion.

It may be possible to find soot in the airways days after injury. Suppose, for instance that an elderly man is in a nursing home when a fire breaks out in a nearby room. If he develops pneumonia and dies a few days later, finding microscopic amounts of soot in his lungs will almost certainly mean that his death was directly related to the fire, provided his lungs were not giving problems prior to the fire.

Note that red edges surrounding heated zones of skin do not necessarily mean the person was alive. This is a contentious subject, and a variety of opinions may be expressed, but put it this way. Suppose you had just died of some other cause, and then a part of your skin was heated, where would the blood go as the skin shrank, if not to the edges of the heated/contracting/ coagulating area?

Failure to use photographs (and/or videotapes) and diagrams to record the distribution of burns on the body surface.

Photographs and diagrams are desirable. Such documentation may enable an appreciation of how the injury occurred, leading to a determination of cause, and thence to the manner of death. For instance:

  • In a case of suspected child abuse, to separate a crawl into hot water from a intentional dipping by an adult. Entirely different parts of the body surface will be involved.
  • The relatively protected and unburned areas of skin associated with clothing, sometimes indicate the position of the injured person and/or the type of clothing being worn, when a flash fire occurred.
  • You may hear that if two people are burned in a fire, the individual with the greater percentage of burns was responsible for setting the fire. This is untrue because the kind of material (e.g. cotton vs. synthetic fibers) and how closely it fits the body affects the amount of burning. Close-fitting clothing often protects from burns whereas loose-fitting clothing may promote them, but it depends on the nature of the material. Some materials ignite more easily than others, so it may be advisable to take some identical clothing and set fire to it to see how long it takes. So white clothing may offer protection from radiant heat for a short period, it will not help as soon as it ignites, and/or melts, and/or adheres to the skin. Burning clothing can reach 600°F (315°C). If there were no variations between materials it would be pointless to provide race car drivers, fighter pilots and firefighters with fire resistant clothing, such as that made of Nomex.

Fire scene photography.

I won't go into detail, only make a few general points, and leave it at that. Obviously the scene of a fire should be photographed much like a crime scene. The fire may have been set, so take your photographs in a logical"walk-up" sequence, distant, medium and close-up. Take the various stages, if you are present, from suppression to overhaul. Your photographs should tell a story from the time you arrive until you depart. Don't just think of the fire by itself. If there is no service drop to the building, the fire is probably not due to an electrical fault. Is the gas turned on at the meter? What are the weather conditions? Are there any signs of forced entry, other than by the fire department?

   See also the instructional videos on "Crime Scene and Evidence Photography"

Any photographic or video record is better than none.

A thoughtful photographer, with an average camera will end up with more useful pictures than an uncaring person with an outfit costing many thousands of dollars. High-tech modern systems can calculate apertures and shutter speeds, but they cannot decide what pictures to take.

Most of the basic rules of photography apply.

Since the size of the light sensing chip in most digital cameras is smaller than a frame of 35 mm film there is likely to be a lack of angular coverage. It's much like taking a 4 x 6 inch print and cutting a strip about o/.-inch wide from each of the long sides and 1-inch from both ends with a pair of scissors. You'd still have a picture, but you wouldn't see as much of the scene as before. so, make sure that any digital camera you're thinking of buying has enough angular coverage for your applications.

Most cameras are designed for the average (meaning amateur) user in average conditions.

You are not an average user, nor in average conditions, when you take a camera into a fire scene. The subject matter is likely to be smoky, darkened, or verging on black. You will probably have to make exposure adjustments (deliberately increase the amount of light reaching the film or the chip) even if you are using automatically controlled flash lighting. Automatic settings are based on the assumption that an average amount of light will be reflected from nearby walls and ceilings, but this will not be the case if you are in a blackened room, or a space that's larger than average due to the collapse or overhaul of non weight bearing walls, or sliding partitions. You may have to select setting for a more distant range (for instance by setting the 16-32 foot range on the system, even though you may be working at 8-16 feet). It will depend on the type of equipment. If you're dOing any significant amount of fire scene photography and still using film, I suggest that you set your flash controls to manual, and run a few tests at various distances with the commonest subjects. That way, if you're in doubt, you'll have a proven exposure to use, that will ensure some good pictures.

The color of smoke is important in a fire investigation, and should be recorded when possible, sometimes at more than one stage. However, the color will appear different according to the angle from which it is illuminated by the sun. You can see the same effect on stormy days by comparing clouds that are between you and the sun, with others that are illuminated by the sun when it's behind you. You may have to take several photos of the smoke, or make significant allowance for the ambient lighting, if any useful information is to be derived from your photographs. The color of flames may also be important, but since these emit their own light, they are less subject to changes brought about by ambient lighting, but proper exposure becomes quite important.

When flash units are used close-up with non-automatic cameras, they tend to give under exposure, the very thing you don't need when the subject matter is already sooty and dark.

Bare bulb flash can be a useful tool to get better illumination of blackened interiors.

Holding the light source above the lens or off to one side (some distance away from the camera lens), can help to produce better pictures if the atmosphere is still smoky or steaming. This is because there will be less back-scatter of light from traces of smoke or from steam, into the camera lens.

If taking photographs of an unknown victim, never hold the lens closer than about 4 or 5 feet from the face. If you get too near, the cheeks will obscure the ears, because light travels in straight lines, and you will have trouble comparing your photographs to others taken from a longer distance during life.

Carry several rulers with you for use as scales of size. These should be free of all advertising and ideally you should have two or three, especially one gray and one black. If you put a dark ruler next to a dark object you will be able to adjust the overall exposure for a reasonable result. But put a white ruler next to a black subject and the white ruler will "burn out", meaning become seriously overexposed.

Black body bags are far better than white ones for fire victims. There is simply too great a brightness range, between white plastic and black charred subjects, for the average film or camera to encompass. If you increase the exposure for two black or dark objects, neither will be excessively overexposed, whereas a white object in the same field would probably "burn out" (become seriously overexposed).

When making videos, follow the basic rules of motion picture photography:

  • Pan slowly.
  • Use a monopod or tripod whenever you can.
  • Don't keep zooming in and out.
  • Watch the auto focus because it may not do very well with low contrast smoky-black subjects.
  • Arrive at a deliberate policy decision about the use of sound. Later, perhaps in court, you do not need sound that includes all sorts of unwanted or embarrassing asides and spontaneous comments, such as "Geeze Fred, look at that crispy cat!" Think carefully, and then make a positive decision to turn the sound off (perhaps by putting a knockout plug in the external microphone jack), or make everyone aware that the sound is on and being used to document what you are doing. e.g. "The date is 12-17-01 and the time is 11 :17 a.m. This tape is being recorded inside the premises at 219 West Main Street. This video begins in the kitchen, starting with the East wall, commencing at the sink, and proceeding clockwise through South, back to the starting point." In short, have a policy and follow it.

It's hard to do your own photography and keep your hands and equipment clean when working in the sooty mess that follows a fire. It helps to have an assistant, and it makes the investigation more efficient.

Don't let anyone try to qualify you as an expert in photography, unless you really are. It's usually better to qualify as a regular user and practitioner. Know what equipment and film or digital camera you used, plus how you set it, and simply stick with and attest to the fairness and accuracy of the photographs you took, or saw being taken.

Have you considered a question about chain of custody of your photographs during processing? Do you know which lab processes your photographs, or who does the work?

With digital photography, have you instituted a policy of burning your images to a CD-ROM as quickly as possible, then making all subsequent images by duplicating the original which remains completely unaltered? This can eliminate many criticisms and possible allegations. For instance, if you have one of the portable $200 devices that takes images from a solid-state card and burns them onto CD-ROMs at the scene, when you don't have computer, it's hard to allege that you altered or did something to the images. Make two CDs, so that one becomes part of the permanent record, and the other becomes the working copy for making prints. Be sure to mark your CDs with a solvent-free (CD-safe) pen, because some "write on anything" marking pens contain solvents that can damage CDs.

Ulcers of the stomach and duodenum.

Curling's ulcers, involving the stomach and duodenum, are a form of bodily over-reaction to the insult of severe burns. Medical science is better at preventing these ulcerations than it was years ago, but it is not long (perhaps 15 years) since significant perforation or bleeding would occur from the stomach and/or duodenum in about 10% of burn cases (1/2 stomach, 1/3 duodenum, 1/6 from stomach and duodenum combined).

In practical terms this means that a person may be severely burned, survive for while and then develop significant bleeding from the intestinal tract, or even perforate an ulcer of the upper tract into the abdominal cavity. Severe blood loss or serious infection of the abdominal cavity (peritonitis) may follow, and lead on to death.

Such events may perplex law enforcement officers and the District Attorney, because the doctors at the hospital may be talking about ulcers and infections when everyone else is ready to charge someone with throwing gasoline. The problem is that the medical staff failed to trace the unbroken downhill sequence back to the initiating event, which was the thermal burns that gave rise to the ulcers.

Not really understanding what "degree of burning" means.

Severity of a burn is a product of time, temperature, and cause, all combined. So, how do physicians grade or report the severity of a burn? Without going into needless details, you are likely to encounter the following methods:

a) By depth.


1st degree (superficial partial thickness), involves epidermis
  • red or pink skin (blanches with pressure)
  • minimal swelling
  • over sensitive
  • tingling
  • need pain relief and skin care
  • Causes: a severe sunburn, transient contact with hot liquids
2nd degree (partial thickness), involves epidermis and dermis
  • red or mottled
  • blisters and broken skin surface
  • considerable swelling
  • wet surface
  • painful
  • sensitive to cold air
  • can heal spontaneously in 2-3 weeks (few need grafting)
  • Causes: Hot water (scalds), short duration "flash" flame burns
3rd degree (full thickness), involves epidermis, dermis to subcutaneous fat
  • pale, white or charred appearance, leathery
  • dry surface
  • fat may be exposed
  • painless, insensitive to pinprick (nerve endings are destroyed)
  • edema
  • general symptoms - shock, blood in urine, blood breakdown
  • needs grafting to heal
  • Causes: Fire, hot objects, electrical burns, chemical burns
Most systems stop at 3rd degree, but a few continue on to higher numbers:
  • 4th degree, deep into muscle tendon or even bone, tissue loss, very severe sometimes even to
  • 5th and 6th degree, according to the amount and nature of tissue destruction.

b) By the proportion, percentage, of the total body surface, which is involved.

Confusion can result from use of the term degree when it indicates the approximate extent of burning, in terms of the total body surface area (TBSA) or body surface area (BSA) that is involved:


  • A small burn involves 1 - 15%
  • A moderate burn involves 15 - 49%
  • A large burn involves 50 - 69%
  • A massive burn involves 70% and up.

Years ago very large burns were regarded as inevitably fatal, and very little could be done apart from making the patient/victim comfortable. Today, all burns are treated, and an amazing number that were inevitably fatal not many years ago are now survivable. Note however that inhalation (airway and lung) injury doubles the risk of death in burn cases, because of pneumonia and organ failure complications.

Note that large burns, involving 60% of the total body surface area are declining in number, also that small burns involving 10% or less of the body surface area are increasing.

So how does one estimate the percentage of the body surface area which is involved? There are several guides:

The "rule of nines", which applies only to normal adults:

  • 9% for the head
  • 9% for the right arm
  • 9% for the left arm
  • 18% (2 x 9%) for the right leg
  • 18% (2 x 9%) for the left leg
  • 18% (2 x 9%) for the back and front of the trunk
  • 1 % for the genitalia

Different figures must be used below the age of 15, because of different body proportions. Lund and Browder charts take into account the change in relative size of the various body parts as a child develops.

The "rule of palms".

The palm of a person's hand is roughly 1 % of the total body surface area. This is convenient for estimating the extent of small burned areas. It is not accurate for estimating large areas. Also, it does not seem to apply equally to all racial groups and may lead to over-estimation of burn area. It's a useful guide in the right circumstances.

c) The percentage of full or partial thickness of burn, is used by surgeons for purely practical reasons:

  • Partial thickness burns. These can heal from the remaining skin structures that survived at the base of the burned area, such as hair follicles, and from the edges, so they don't usually don't need grafting.
  • Full thickness burns - can only heal from their edges, because of damage to all the layers of the skin, and they usually require grafting (because they are too big to heal quickly from the edges).

d) Burn index.

Burn index was devised at the Brook Army Medical Center burn unit. The index combines depth and area to better indicate severity, and the statistical outlook for injured patients.

  • 1.0 point for each 1 % of 3rd degree
  • 0.5 point for each 1 % of 2nd degree

[About 15-20 years ago 45 points meant a 50% probability of death in young adults, but this may no longer be true because treatment has improved so much in the last decade or two.]

Note: That the odds of survival vary considerably with age as well as in proportion to the amount of the body surface involved. Young adults, age 20-25, are the most likely to survive burns. Chances are worse for the very young and for the very old because of their lesser ability to tolerate injury.

e) Computer-based scanning techniques are relatively recent, and seem to be the most accurate.

Rapidity of death.

Death from fire and burns need not be immediate, and is often delayed. If and when it's delayed, we will encounter the old problem of people losing sight of the initiating cause. Generally the process breaks down into three categories:

Rapidity of death Immediate causes
Rapid Heat, hypoxia, CO, toxic products of fire in general, free radicals
First day Fluid and electrolyte problems
Delayed Infections and organ failures/shutdowns

Is it safe to delay the autopsy examination of a burned body for a day or so?

Probably, if the death was rapid and if the body will be refrigerated. More history will be valuable and this should help guide the autopsy. The body was probably in reasonably good shape prior to the fire, then the surface parts were heat sterilized and partially cooked.

Probably not, if death was delayed and the problems are mainly medical and infectious. The body is likely to deteriorate fairly rapidly because of bacterial infection, so within reason, the sooner you look at the body the better, before things change. If possible, try not to delay more than several hours.

Failure to save samples for accelerants.

Strive for:

  1. A suitable sample.
  2. A new metal paint can. Check with your lab staff if there is any sort of plastic lining to make sure it will not interfere with their chemical tests. Note that fire debris is often corrosive and may cause holes in cans to develop quite rapidly.
  3. Take at least one control sample.
  4. Tell the lab what you suspect, and what you want them to look for.

Problems include:

  1. Pyrolysis or breakdown products are hard to separate from true accelerants. Good labs try to make a genuine distinction, but the "bad" ones do not.
  2. The wording "hydrocarbons detected" does not mean that something was used to light the fire. It can be a by-product of the fire. Wording like this is sometimes deliberately used for monetary gain. Wood is a hydrocarbon!
  3. Taking specimens for analysis from totally charred areas, which can no longer contain very much. The best specimens are likely to be found at the edges of burned areas. It has been shown that water soaks into carpet backing by way of the center of tufts of fiber. Other common fluids, including accelerants perhaps, may behave in the same way.
  4. Bad, poor or questionable labs which are not absolutely honest, supported by vested interests and/or which survive by reporting "detection". Be suspicious of labs with very high success rates. A good lab may find good evidence of accelerants in about 40% of cases submitted. If you find positive results at about double this rate, check for reciprocal involvement with insurance companies, also question their methods, techniques and the way they make their interpretations. Naturally the success rate will depend upon the quality of the specimens submitted. Unscrupulous use of some phrase such as "hydrocarbons detected", has finally resulted in a move towards better guidelines and standards for test procedures and reporting of results.
  5. Looking for the wrong thing. About 3/4 of arson cases involve the use of gasoline. However, the other 1/4 involve things such as medium range petroleum distillates e.g. naptha, paint thinners, diesel fuel, heating oils, and kerosene.
  6. You will be unable to detect anything that is completely consumed, such as newspaper, and probably those substances that are quite volatile, and/or water soluble.

Failure to examine remnants of clothing and things stuck to or immediately surrounding the body.

Remnants of clothing, even if most of the clothing has been burned away, can be helpful in establishing identity. For instance the material from the tail of a shirt may be recognized by family members, as being similar to the known clothing of the deceased. Look for remains of clothing between the body and whatever it was lying upon or against.

Burn patterns are generally in accordance with the nature and distribution of clothing over the body surface, for instance less burning under a thick belt and waistband, but there are occasional exceptions with unusual fuels and whenever thinner clothing acts like a wick.

Clothing also helps with the preliminary sorting of bodies, for instance by gender and age.

Analysis of clothing remnants occasionally reveals traces of accelerants. If accelerants are suspected, put the article(s) of clothing in a new clean metal paint can to prevent evaporation. This is the main exception to the general rule that clothing should be dried before it's packed for storage. Packing damp or wet (non-burned) clothing in plastic bags, will cause it to mildew and/or rot. Items, other than those put into a can for accelerant analysis, should be air dried, and then packed in paper bags.

If in doubt, make a point of looking through the ash, or so-called "muck and ash" that is relatively close to the body. It may well contain keys, billfolds, purses, pocket knives, jewelry and all sorts of helpful things. Experienced fire investigators often sort through everything within 4-6 feet of a body.

If you find a lot of blood next to the body, be very suspicious. Its presence strongly suggests the presence of injuries prior to the fire. Bodies that are affected by heat tend to seal themselves off, just as a steak may be seared to retain natural juices.

I recall a case in which identification was considered hopeless, however I told the investigators to send all the charred fragments and clumps within a foot or two of the body. Within five minutes of starting the examination I found a melted vinyl purse, in which were the victim's check book, drivers license and other such items, most of which were quite well preserved and easy to read.

Discharge of weapons and cartridges in fires.

Handgun and rifle cartridges can "cook off' when exposed to heat both inside a weapon, or prior to loading. Bullets coming from cartridges lying around in a box, or loose, develop very low velocities. Even a military rifle cartridge supported at one end is unlikely to give a bullet more than about 150 - 200 fUsec. Cartridge cases and primers may fly around, but pose little hazard unless you happen to get one in the eye. If you suspect that a bullet may not have come from a gun, but simply cooked off in the heat, check for the absence of land and groove impressions on the sides of the bullet, and the absence of firing pin impressions on the cartridge cases. Only a bullet that came down a barrel will have land and groove impressions.

The exact temperature at which the various components will cook off is not entirely clear. A recent study indicated that common .22 rim fire cartridges will go off at about 330-403°F (151-192°C). To date I haven't found many credible references to the ignition temperature of ammunition, figures for which must vary somewhat according to how and where the heat was applied.

Various figures are quoted for ignition of cartridge components, e.g.

  1. Primer mixtures 280°F (138°C), 400°F (204°C)
  2. Smokeless powder 350°F (177°C), 374°F (190°C), 400°F (204°C)
  3. Black powder, 572°F (300°C)

The very similarity of these figures suggests they may have been mixed up, or that primers and powder were tested together, in primed cartridge cases.

More recently, I came across the following figures on the Internet. I can't vouch for their accuracy, but they "feel" about right:

  Black powder Gunpowder (double base) Nitroglycerine
Ignition temperature,
necessary to ignite
"Explosion" temperature,
at a constant volume
Approximate burning rate,
at 1 atmosphere
1/14 inch per sec
1.8 mm per sec
1/360 inch per sec
0.07 mm per sec
1/170 inch per sec
0.15 mm per sec

For the techies, the melting point of ingot iron and carbon steels is in the range of about 2,600- 2,800°F (1,430-1 ,540°C) so you will see why there's heat erosion (also called throat erosion) due to the heat and pressure that occurs in the first part of some rifle barrels.

I don't have any better figures than these at the moment. The point is Simply that ignition temperatures are relatively low, say very roughly 1 1/2 to 3 times that of boiling water. This fits well with the tendency, in years past, of overheated machine guns to keep firing in battle after the trigger was released.

Not understanding the conditions in a fire, the so-called fire environment.

Great advances in understanding have been made in recent years because of high-tech sampling and analysis, combined with computer simulations. Interest grew, and research really got going, after the air crashes in Denver in 1961 and Salt Lake City in 1965.

It's not just a matter of heat and carbon monoxide.

There is considerable correlation between the conditions of the fire and what is produced because the physical conditions determine to a large extent how the chemical substances break down and recombine. For instance it requires 1, 128°F (609°C) to convert carbon monoxide to carbon dioxide. Many such details are now known to those who study the chemistry and dynamics of fire. That's not my field, but it's interesting, and I'd like to know more.

There are all manner of nasty substances, including free radicals, running around in the fire atmosphere. If the post-fire atmosphere makes your eyes water, you don't need to breath it into your lungs, so keep your respirator or breathing apparatus on and continue breathing clean air for a while longer after most of the fire is put out. Some of these highly reactive chemicals may be related to the increased incidence of heart attacks in firemen, and some may even cause cancer. If you look at some of the studies, there is a higher incidence of bladder cancer, which suggests that cancer causing chemicals are getting into the body, and being excreted in the urine. We don't have all the necessary information as yet, so err on the safe side and when in doubt breath clean air, even if it does feel hot and confining.

Failure to correlate the circumstances with the injuries. We tend to see different types of injuries according to the circumstances.

For instance it takes hot steam to get heat far down into the airways. The circumstances and conditions of a fire can tell you a lot about the likely mechanisms of injury, and what to expect at an autopsy.

It takes a lot to destroy an adult body:

a) Cremation is the process of reducing human remains to bone and tooth fragments by the use of heat and evaporation. In the United States, using a gas-fired furnace, the process of cremation usually takes about 2 - 3 hours at a temperature of 1,500 - 1 ,900°F (815 - 1,040°C), including cool down time, or alternatively, more than 1 hour at 2,600°F (1 ,425°C). After this, the cremains (cremated remains), consisting of ash and bone fragments, usually weigh about 4-8 lb, according to the size of the adult body.

In short, it takes a great deal of external heat to reduce a human adult to a few pounds of ash. For a while I couldn't find any reliable figures, but in recent months I've had better luck, largely because of the Internet. My latest, and seemingly most credible, figures are the energy equivalent of:

  • About 40-60 liters of fuel oil, let's say 50 liters, for an average size body, at 9,320 StulL.
  • About 40-60 liters of Kerosene, again let's say 50 liters, for an average body, at 8,988 StulL.
  • About 20 cubic meters of gas (type and heat content unspecified, but probably natural gas)
  • About 660 pounds, or 300 kg, of wood, exemplified by traditional Indian outdoor funeral pyres.
  • About 2-4 cubic meters of wood (e.g. burning at the steak for witchcraft in medieval times).

If these figures are anywhere close to correct, and making allowance for heat loss outdoors, we can think in roughly equivalent (enclosed furnace/container) terms of:

  • About 135 kwh, meaning a 1,000 watt electric heater for 135 hours.
  • About 117,500 kilocalories.
  • About the energy released by 0.1175 tons (115-120 pounds) of TNT.

I'm still looking for figures, but it stands to reason that bodies cannot burn completely away unless they're exposed to things like the prolonged and intense heat of chemical, industrial, and refinery fires.

If this isn't convincing, there is a move to reduce the amount of energy devoted to, and the pollution derived from, the present cremation process. It has been proposed that bodies be treated sequentially with liquid nitrogen and then steam, culminating in an hygienic powder, amounting to about a quarter of the live body weight, which would break down rapidly, and could therefore be buried quite superficially.

(b) Ordinary house fires seldom result in complete destruction of adult bodies, or even most children. They are not hot enough, or sufficiently prolonged.

(c) Small children and small animals can, and occasionally seem to completely consumed, but not often. It is possible, and more likely that they wi" not be found following a house fire if they were young and/or small, and the search was not thorough enough. What and how much people find is roughly proportional to the amount of time and effort they devoted to sorting through debris and sifting the ashes. It's often hands and knees work, followed by a lot of sieving/screening and sorting. Only that kind of effort will reveal remnants of teeth.

(d) Large chemical fires can burn intensely for far longer periods than house fires, and may be far hotter, so they may eventually destroy large adult bodies. Bodies will burn up any time there's enough heat and oxygen for a sufficient period of time.

Failure to understand the basics of Carbon monoxide toxicity and the "numbers" derived from the analysis of blood:

  1. There is no exact fatal concentration of CO, because it depends on a variety of factors including age end overall health. If you don't have a medical background, simply compare knocking out a small percentage of the oxygen carrying capacity of the blood of:
    • An Olympic champion long distance runner (not even a headache).
    • An elder lady with severe anemia, emphysema, and coronary artery disease (probably death).
  2. There are mathematical guides to the amount in the blood, with respect to amount, duration of exposure and the volume of air that is breathed.
  3. Variation of the rate of increase in the saturation, according to the level of activity. We breath deeply and rapidly with exertion, but less deeply and more slowly at rest.
  4. Not understanding the normal rate of loss from the blood, namely the tendency to return to
    • normal after exposure. Removal of carbon monoxide is speeded about three times by the
    • administration of 100% oxygen. So if a person is exposed to carbon monoxide, gets a low to
    • moderate concentration in the blood, and is then treated or revived with 100% oxygen, it isn't long before a lot less is present than was the case before treatment, so people sometimes come to the wrong conclusions.
  5. Not correlating autopsy findings with results from animals, and others exposed at about the same time and place. (See item #29 below).
  6. Overlooking preceding tell tale signs and symptoms such as recurring headaches, and/or unexplained flu-like symptoms, especially at the start of the heating season.
  7. Inappropriate, 50-called "crazy" acts arising out of hypoxia and exertion. (e.g. looking for a check book when the house is ablaze, and the front door is open. It's much like hypoxia at altitude in an aircraft.)
  8. Ignoring increased susceptibility to CO due to pre-existing natural disease, especially of the lungs and blood vessels.
  9. Possible interpretations of the CO% saturation include:
    • High - and clearly representing the immediate cause of death
    • Moderate and rising - but death supervened before the CO could get really high
    • Quite low - present in the blood, but not due to the fire (e.g. to smoking instead)
    • Absent - even though death was due to the fire, as in intense flash fires.
  10. Detection and measuring of CO in an atmosphere is relatively easy and inexpensive. Companies such as Mine Safety Equipment offer relatively inexpensive CO detectors. A local engineer, or a private fire investigator, may have a detector, and the local fire department probably does. CO saturation of the blood can usually be measured on that which remains in a body even if it is quite badly charred.
  11. Look at the color of the tissues in the tissue bag or jar, after they've been in formalin for a while. They tend to look pinker than usual, and stay pink longer.
  12. Be aware of the difference between old time heating gas, that was made from coal and contained a large amount of CO, whereas today most communities use natural gas that contains virtually none. The CO in old time gas would kill rapidly, but present day heating (natural) gas mainly displaces oxygen.
  13. Rapid escape from the fire atmosphere is the key to survival, and to retrospective interpretation of amounts of CO in the blood. Likewise a fire may produce a lot of CO, but if the victim is outdoors and upwind, then the amount that's breathed in may be small.

Ignoring the color of smoke and flames.

These vary widely and can mean a lot to fire experts, so remember to ask, and if you are there at the time of the fire, take good photographs. (See the section on photography).

Misinterpretation of changes brought about by the fire, and fighting the fire.

  • Injuries may be due to parts of the building falling onto the body.
  • Clothes can be torn by water from high pressure hoses.

Note that some chemical foams and extinguishing agents may interfere with certain chemical tests. If in doubt check with a forensic toxicologist.

From an investigative perspective, it makes little sense to displace all the evidence with a jet or intense stream of water, throw it out of the building, and then wonder why one's having difficulty working out what happened, and/or what caused the fire. It's yet another way to destroy evidence. It's usually the result of shortage of time and personnel.

Failing to do the usual, and appropriate, tests for drugs and alcohol.

Toxicology forms an integral part of the fire investigation. In fact it's more important than in many other types of cases, because of carbon monoxide and the other by-products of fire.

The fire environment contains many different chemicals that are formed by the action of heat on materials (pyrolysis). Some are relatively easy to detect while others are not. They include free radicals which are parts of molecules, looking for something to attach to, which are particularly irritant and damaging to the lungs. A large proportion of persons dying in house fires, die from smoke inhalation and carbon monoxide polsoninq, and are heated or burned later, as the fire progresses.

Just because a body looks bad on the outside doesn't mean that you should alter your routine of testing for carbon monoxide, alcohol, and drugs (both abusive and medicinal).

We can't measure the carbon dioxide (dioxide, not monoxide) in a body in a meaningful way after death, but this gas is clearly a factor in some fire cases.

You should request carbon monoxide saturation, and blood alcohol concentration tests as an absolute minimum, and add routine drug screening in the case of anyone who might be an abuser, or who may have been taking drugs for medical reasons.

Carbon monoxide will be reviewed separately because it's so important in fire-related cases.


Draw blood, urine, vitreous, and bile if possible, so you'll be able to compare the alcohol concentration in three or four separate specimens. The idea is to use the various specimens to cross-check and verify each other.

Importance of correct sampling techniques.

(e.g. A car crashes and burns. The body of the sole occupant/driver is severely damaged by the subsequent fire. One of the locals sticks a needle through the chest wall, and wonders why the blood contains 2% of alcohol (not 0.2%) when the result comes back two weeks later! Question - where was the tip of the needle when the so-called blood was drawn? Perhaps the stomach that contained recently ingested beer ruptured into the left chest at the time of the impact? Such an approach to the procurement of important specimens is idiotic. They should have been drawn from a major blood vessel instead, or failing this through a small incision).

Remember the basic principles of forensic toxicology, especially the importance of sending sufficient material to the laboratory to allow proper testing.

As a guide send not less than the following minimum amounts of fluids and tissue:

  1. Blood: 30 ml, 1 fluid ounce, of blood and make sure to specify where in the body it was obtained.
  2. Urine: 30 ml, 1 fluid ounce
  3. Bile: all available
  4. Vitreous: all available
  5. It is essential to be aware that it is possible, and commonplace, to save samples of solid organs, for instance: about 100 grams, 3 ounces, of brain and liver or 50 grams, 1.5 ounces, of kidney.

Having obtained the materials from the body, send the following information to the laboratory with the specimens, even if the lab personnel don't ask for it, or show any interest in receiving it.

  1. Case numbers.
  2. Full names of the deceased.
  3. Age.
  4. Race.
  5. Sex.
  6. Occupation. If retired, specify what the deceased formerly did.
  7. Circumstances of death/injury/discovery: e.g. Found on bathroom floor of tavern that caught fire just after closing time.
  8. Likely manner of death. Specify: Natural, accident, homicide, suicide, undetermined?
  9. Embalming: Specify: yes or no; and if yes the route (by arteries or by trocar).
  10. General condition of the body and/or the degree of decomposition.
  11. Drug abuse status: Specify: Yes, probably, possibly, probably not, unknown.
  12. Known prescription medications: Specify: None, or list the known prescriptions.
  13. Autopsy findings/suspected conditions/ cause of death: e.g. Smoke inhalation and thermal burns.
  14. Particular drugs or substances suspected, if any: e.g. Carbon monoxide and alcohol.
  15. Make sure your name and phone number are clearly shown, so that the lab personnel know how to contact you in case they need more information.

With a suitable form, all this information can be conveyed with a few words, circles and check marks.

It's also important to know a little about the test methods used within the laboratory itself. If you're dealing with a first class forensic laboratory, that's fine, but in rural areas, the Coroner may use the lab in a local hospital. The problem is that hospitals often test for alcohol by a method, called alcohol dehydrogenase, which only detects the kind of alcohol you and I would consume (grain alcohol, ethyl alcohol, ethanol).

However, serious/dedicated/dyed-in-the-wool/career alcoholics may drink:

  1. Methanol, wood alcohol
  2. Ethanol, ethyl alcohol, grain alcohol, drinking alcohol
  3. Isopropyl alcohol, rubbing alcohol, isopropanol
  4. Antifreeze
  5. Listerine
  6. Distilled boot polish, or anything else they can get their hands on, in the absence of booze!

So, you could have a case in which a hospital lab, that doesn't use a method capable of detecting all the common alcohols, report the result of the blood alcohol as negative, yet the victim may have been intoxicated with, say, rubbing alcohol. The method they employ simply doesn't detect it.

So, it's highly desirable to use a lab that has a gas chromatograph to pick up all the common alcohols, plus acetone (from starvation, diabetic acidosis or from metabolizing rubbing alcohol), and even a few of the common volatiles, (from glue, paint thinner, and solvent sniffing).

Another limitation of hospital laboratories is that they are seldom set-up to analyze clotted blood. Blood from living patients is usually fluid so they haven't set up the methods and procedures applicable to clotted blood. Any lab that is doing work for a major trauma center, or occasional Coroner's work, should be prepared to look for alcohols and carbon monoxide in clotted blood.

So, if you have regular contact with a particular hospital lab, take the time to find out what their methods are, and what, in fact, they are capable of detecting.

Failure to examine any animals found dead at the scene.

It pays to examine the bodies of any animals which are found dead at the scene of a suspected carbon monoxide or fire death. Most elected officials:

  1. Never think of it.
  2. Consider it ridiculous even if they do think of it.
  3. Have never done it before.
  4. Don't believe that anyone in their right mind would bother.

I mention this particularly with respect to carbon monoxide, but if a person is dead of smoke inhalation, an animal exposed to the same atmosphere should be dead also. In years past, well before the days of gas detectors, miners used to take caged birds (canaries) down the mines with them for safety. If the birds collapsed it was time for the humans to leave. If a human is found in a fire and foul play is suspected, be sure to examine the dead animals too.

In reality it is quite common to autopsy animals found dead with humans. You can run carbon monoxide tests just as easily on the blood of dogs, cats and most other pet animals and birds, as you can in humans.

In a few places you could run into a situation where it is the responsibility of animal control to deal with and dispose of dead animals. In such cases they may not be aware of the evidence that may be lost by failing to examine them. You may even have to seek an injunction through the district attorney.

Thermal burns in children

No review of this kind would be complete without mention of child abuse and burned children. Not only is child abuse a thing of concern, but many abusive injuries take the form of thermal burns (usually with a hot fluid, or sometimes a hot object, as opposed to flame burns), so they must be included in a review such as this.

There are also many accidental injuries. Each year about 35,000 - 40,000 children are treated for hot water burns. It is said that about 70% of such accidental burns result from scalding with hot fluids, as when a child is in the bath, or pulls on a saucepan handle. One Shriners Burns Institute study showed that about 85% were less than 3 years of age, and the other 15% aged 4-15 years.

The following brief notes should further understanding:

a) About 10% of child abuse is perpetrated by burning.

b) About 10% of children admitted to bum units have injuries that are not accidental.

c) Many people don't know how to distinguish a scald from a flame burn, or even that it is possible.

d) If you study burns in children under the age of 10 years, you are likely find numbers that are similar to:

  • Non-abuse:
    • Age = just over 3 years
    • Mean total surface area = 12%
    • Sex = 73% male, 27% female (roughly 3 males to 1 female)
    • Mortality = 2 - 3%
  • Abuse:
    • Age = just over 1 Yz years
    • Mean total surface area = 14.5%
    • Sex = 52% male, 48% female (roughly 1 male to 1 female)
    • Mortality = 4 - 5%

Note that burn area is not very different in the two groups but that the age is distinct. Eventually you will come to realize that a child under the age of 1 year is unlikely to be burned accidentally, unless it is involved in a house fire or something. But the same age of child, causing aggravation by screaming and/or giving problems with diapers, is quite likely to be abused. In effect, a very young child isn't yet smart enough to keep itself out of trouble with angry, short tempered or intoxicated adults.

e) Analysis of the mechanism of injury reveals figures like:

  • Abuse:
    • Scalds = 85% (Tap water = 73%; other liquid = 10%),
    • Flame = 8%
  • Non abuse:
    • Scalds = 52% (Tap water = 10%; other liquid = 42%),
    • Flame = 32%

Normally, above the age of 4, there is little or no thermal abuse, because by then, children have wised up, take care not to offend, and stay well clear way of adults who might harm them. However there is are exceptions with special groups, such as the mentally retarded.

The accidentally injured child is at greatest risk just after becoming relatively mobile and getting into things before learning, often the hard way, how to stay out of harm's way.

Abuse is more likely to arise from tap water, whereas accidental injury comes from other hot liquids, such as grease, coffee, tea or soup, and from pans on a stove - much as one would anticipate. To over-simplify, the average abusive adult doesn't usually make coffee to pour on a child. Tale a good look at the overall picture and things may stand out.

f) The distribution of burns is important, particularly the depth and severity within an individual burn.

Think of it this way, (and let's suppose you are evaluating a burn involving the hand and lower half of the forearm of a child of an age such that it might have been abuse, or accidental) and that you are trying to decide which it probably was.

If the child approached a pail of hot water standing on the floor, and immersed his hand, about the time the hot liquid hit the lower forearm the child would already have "decided" that the water was far too hot and that the hand had to come out. So the fingers would go in first and then the water level would move up the fingers, across the palm, over the wrist and then up to the mid forearm. At this moment the motion reversed and the water level went back down towards the fingers. This means that the fingers were immersed for a significantly longer period than the wrist, and the skin near the uppermost part of the forearm for the shortest time. Thus if the child did the moving, the burn should be deeper and more severe, at the fingers and far more superficial, less severe, at the mid forearm.

If however it was a case of abuse, the child might have been grabbed by the left upper arm and the upper right forearm. The perpetrator then forced the right hand and lower forearm into the water and held it there with the child thrashing and screaming but unable to withdraw. The extremity might have been immersed for as much as 10 seconds. There will be little difference in the depth and severity of the burn throughout its length because the fingers were immersed for 10 seconds and the lower forearm for over 9 seconds, which isn't much difference. Thus, there isn't the progressive change, or gradation of depth, seen in the rapid in-and-out situation.

Of course there are exceptions, such as when hot viscous liquids do not drain off immediately (oil or napalm) or if the accident victim cannot get out of hot fluid fast enough for some other reason, such as lack of a handhold. The circumstances, as revealed by the investigation, wi" be the key most of the time.

Note that if a child really did appear to sustain an accidental burn in a bath tub, it may be a good idea to measure the slope or inclination of the bottom of the tub. This helps with body positioning and subsequent scene reconstruction. Also note how much turning force is required to turn the taps or push the levers. A child can't turn a tap that an adult finds hard to move. If a faucet is loose and/or worn, it's very different. Lever style handles are different again.

You must use common sense. Unless there was great difference in depth or severity, you would find it hard to distinguish between the burns on the palmar surface of the hand and fingers of a child who:

  • Put his hand flat on the metal door of an oven during the cleaning cycle and
  • A child whose hand was held flat against the same hot oven surface.

So it's very important to ask the treating physician for detailed information concerning, the distribution and depth of the burns, and to chart the distribution and depth very carefully. That rings us back to photography and drawing the injuries on outline diagrams of the body.

g) Who causes thermal abuse?

  • The numbers you'll probably find if you research the subject, will be something like (in decreasing order): mother> boy friend> father> and then an assortment of other relatives, step parents and baby sitters.
  • Mothers are frequently the abusers because of their prolonged contact and exposure to the child; and boy friends inflict abuse because a child may get in the way and/or interfere with a relationship they are trying to establish with the child's mother.

h) Flame type burns may be harder to evaluate than hot liquids because of their lesser size. For instance was it a hot piece of metal, or a hot utensil?

i) X-rays are important in cases of suspected child abuse. It's not quite the same as in adults but it is equally helpful. Just as it is desirable to find an unexpected bullet in a badly burned adult found dead in house fire, so it's helpful to find a variety of unsuspected healing fractures in the skeleton of an abused, and subsequently burned, child.

j) Common sense safety measures include: not leaving a child alone in the bath, testing the water properly before putting a child in, facing the child away from the taps and fixtures, thinking about installing anti-scald devices, making sure the water heater isn't set excessively hot, not establishing the kitchen as a recreational area, and keeping hot things out of reach.

Don't proclaim child abuse too soon. Unfortunately people tend to over react and over diagnose abuse; and to make matters worse, some of the child welfare agencies are inadequately regulated. Much injustice is done. Strange things can and do happen, but histories are often overtly absurd! (Three month old babies, who are barely mobile, seldom conveniently and suddenly fallinto buckets of hot water that just happen to be standing by their bedsides!)

Don't say too much, too soon, to the wrong persons. Be suspicious by all means, but keep an open mind. Observe everything, and document carefully and thoroughly, particularly the distribution of burns in the body position alleged at the time of injury.

Be on a constant look out for one or more of the following warning signs of abuse:

  • A history that is incompatible with the injuries observed.
  • Repeatedly changing and contradictory histories. Be sure to ask how the burns occurred early in the sequence of events, because caretakers who are not telling the truth tend to give one version to the triage nurse, another to the physician in the emergency department, another to the treating physician, and another on the floor after admission.
  • Circumscribed buttock/genital injuries.
  • Deep immersion burns of the hands and feet, which are not tapering with respect to severity and depth.
  • Multiple or repetitive burns.
  • Pre-existing fractures and soft tissue trauma.

Before moving on, it is appropriate to mention some practical safety measures to help prevent accidental scalds in children:

  • Test water with a thermometer or a more sensitive area of the adult body such as an elbow.
  • Remember that children have thinner skin than adults and are more susceptible to burns.
  • Never bathe a child under running water.
  • Keep young children away from stoves while you prepare food, by a means such as a playpen or by putting them in high chairs.
  • Don't drink very hot liquids or handle hot things while holding a child.
  • Make hot items as inaccessible as possible by putting pan handles to the back and by cooking on the back burners of a cook top or stove.
  • Test the temperature of microwaved foods and liquids before serving them to a child. The outside of a container may not feel hot, when the food inside does.
  • Check the thermostat setting on the water heater, and if it's too high turn it down, but don't turn it too low. In recent years there has been a push by well-meaning but uninformed individuals, to lower water heater and furnace settings in the belief that it will largely eliminate scalding by hot water. While it may reduce it, it doesn't prevent it, and it introduces another problem, which is that the water may not get hot enough to kill harmful bacteria in water pipes. This isn't the place to discuss it in detail, but the logical steps are:
    • Install a water heater that is energy efficient. Sufficient insulation prevents wastage of heat.
    • Set the water heater high enough to kill off Legionellae and other microorganisms, and wash things (dishes and laundry) properly. (As a guide it takes 151°F to kill Legionella in 2 minutes).
    • Buy a tub and shower valve that is pressure balanced, and has separate controls for flow and temperature, as well as an adjustable upper temperature limit/stop. These are available for about $121 in home stores. Pressure-balanced means that if bath or shower water is running when someone flushes a toilet or the laundry machine draws off some cold, the pressure of cold water may drop enough to burn a child. Pressure balanced valves balance the hot and the cold, regardless of ordinary pressure fluctuations.
    • If a burn is sustained, immediately immerse the part in cold water to minimize damage, apply a clean dry cloth dressing, and seek medical attention.
    • Finally, and most regrettably, in some jurisdictions it is wise for adult caregivers and/or parents of young children to document the scene of any injury, by means of a videotape or still camera, and then make a copy to give to a friend, to help protect themselves against ill-founded accusations of child abuse.

For detailed information on maintenance and repair of water heaters, see "The Water Heater Workbook", by Larry and Suzanne Weingarten, 1992. Elemental Enterprises, P. O. Box 928, Monterey, CA 93942. (408) 394-7077.154 pages, soft cover @ $20.

Misunderstanding the time necessary to result in a burn.

In the middle of a star at many millions of degrees, a body would turn to ash and vapor in some minute part of a second. On the other hand we could, in theory, remain in water at our normal skin temperature until we became waterlogged, but we'd never, ever, burn. Between these two hypothetical extremes, damage occurs more rapidly as temperatures increase. Heat transfer is generally in proportion to temperature difference.

High quality books describing the treatment for burns, often quite figures such as:

  • Below about 113°F (45°C) little cellular damage occurs.
  • At about 117°F (47.2°C) there will be some cellular damage but recovery's likely.
  • At about 126°F (52.2°C) there will be irreversible damage to cell proteins.
  • At about 140°F (60°C) death of cells is inevitable.
  • Such figures are a useful guide.

Burning occurs more rapidly than many believe to be possible, especially at higher temperatures. A few studies have been done, but research is obviously limited by the lack of enthusiastic volunteers! Nevertheless, the studies that have been done, give us a pretty good idea of the speed at which burning occurs from hot metal or water.

I am unable to verify the following figures from personal experience, but I have every reason to believe they constitute a reasonable guide for use in our work. However I deliberately used the word guide, because I have never seen a logical discussion of factors such as skin thickness, part of the body, racial ancestry, skin pigmentation, vascularity, arterial and venous flow rates, age, and physics of heat transfer together. (It's much like the studies of bullet velocity necessary to penetrate human skin that don't mention the shape, size or weight of the bullets, not the age, gender and parts of the skin that was tested.)

If you wish to go into detail, note that the older articles may use slightly different terminology especially when it comes to the depth of a burn. Therefore studies separated by a period of years may not be exactly comparable, and it's particularly likely that studies done by pathologists may not employ the same definitions of the depth/extent of burns as those used by surgeons.

As an approximate guide, the time needed for a deep burn, in an adult is:

  1. 5 minutes at 122°F
  2. 1 minute at 127°F
  3. 30 seconds at 130°F
  4. 5 seconds at 140°F
  5. 2 seconds at 150°F
  6. 1 second at 158°F

Children burn more rapidly, so the approximate time needed for a child to get a full thickness burn from hot water is:

  1. 10 seconds at 130°F
  2. 4 seconds at 135°F
  3. 1 second at 140°F
  4. 0.5 second at 149°F

At the bottom of page 98 of the January 1998 issue of Popular Mechanics magazine I found a chart of times that was said to be used by the US Consumer Product Safety Commission:

1st degree burn 2nd or 3rd degree burn Water temperature
35 min 45 min 116°F
1 min 5 min 122°F
5 sec 25 sec 131°F
2 sec 5 sec 140°F
1 sec 2 sec 149°F
1 sec Instantaneous 154°F

This table doesn't indicate if it is applicable to children or adults, and "instantaneous" is not scientific, but it's worthy of inclusion because (a) the figures are similar to the others, and also because (b) people often regard such government-sponsored tables as totally credible, and may refer to them blindly, without any thought.

A brochure printed by the Chicago Faucet Company in 1995, included the words, "As water temperature decreases, so does the chance of a third degree burn. Then followed a bar graph, the basis and origin of which was not specified:

  1. 0.5 second 150°F
  2. 1 second 140°F
  3. 10 seconds 130°F
  4. 1 minute 125°F
  5. 4.5 minutes 120°F

Regardless of the exact numbers, or the methods by which they were obtained (hot solid objects vs. hot water), if bath water reaches about 140-150oF, a person cannot pull a child out fast enough to prevent a burn, even if they immediately become aware that the water's too hot.

Conversely if the water temperature is kept below 120°F (49°C) a child is fairly safe. If people live in an apartment, and cannot install a modern tub/shower valve, there are alternatives, such as:

  • Bathtub spout, faucet, and shower head sensors that halt the flow of water if the outflow temperature reaches 114°F. (ScaldSafe™, by Resources Conservation, P. O. Box 71, Greenwich, CT. (800) 243-2862, (203) 964-0600, Fax (203) 324-9352.)
  • Chicago Faucet Company has a product called ReAct™, that automatically turns water off if the temperature exceeds 118°F, and their TempShield™ bath/shower valve, has a stop at 112°F.

So prevention sounds easy, but as with most things water temperature is a compromise. If the temperature is too low there may be bacterial contamination, and/or the water may not be hot enough (130°F) to deal with dust mites in bedding, kill off bacteria in towels and clothing, or allow adequate cleansing of dishes (135-140°F) by dishwashers that don't have booster heaters to get the water to about 180°F to sterilize them.

A question you may, sooner or later, be asked is "what is a comfortable shower temperature"? I suggest you borrow an accurate thermometer (e.g. one from a laboratory), take a shower and set the water temperature so that it feels just right. Then measure the temperature immediately after the water leaves the shower head, and then a little lower down where the water hits your body. There will be a slight difference. Then, to "ice the cake", reduce the temperature slightly to a point at which you'd prefer it a shade warmer, andthen increase it to a point at which you'd prefer it a shade cooler. That will give you three reliable figures that suit you individually, and will help you to answer the question, assuming of course that you're not a devotee of exceptionally cold or hot showers.

Personally, I find that water for a comfortable shower leaves the head at about 104°F (40°C) and hits me when it's about 1°F cooler.

I strongly advocate shower controls that:

  1. Are pressure balanced, meaning that if the pressure of the cold water drop, for instance when someone else flushes a toilet or the laundry machine draws cold water, a valve keeps the shower temperature steady.
  2. Have separate controls for temperature and rate of flow, and
  3. Have an adjustable stop for the upper limit of temperature.

There are several good ones, by major manufacturers. I bought one in August 2002 for only $121.23 including sales tax. They effectively eliminate scalding, and hold temperature so well that they're a pleasure to use. Since the flow can be adjusted without changing the temperature they also save water, if only because you can vary the flow for various tasks such as showering and rinsing your hair. Personally I like to run a shower at about 1-1% US gallons per minute, not like a fire hose, as some seem to do.

The key point is that the relationship between water temperature and the time taken to burn is non-linear, and as temperatures rise, the time required to produce a burn shortens dramatically, in a way that many, perhaps the majority, do not understand.

Thus, there are variations on the theme of time, including:

  1. An attendant in a nursing home momentarily puts her hand (an elbow might be more sensitive) into some bath water to check the temperature. It seems safe, so she proceeds to help an old person into the tub. Immediately thereafter the phone rings. The water might have been safe for a minute or two, or until the old person complained, but not cool enough to allow for five to ten minutes of immersion. By the time the attendant returns the old person has sustained a burn. Look back at the listings of time and temperature. If questioned the attendant may say something such as, "the water wasn't that hot", and he or she may well be telling the truth. For a moment or two it wasn't, for a young healthy person with a good circulation, but when an elderly person with poor circulation and atrophic skin was immersed for many minutes without moving, the situation was different. What is safe for the hand of a healthy young adult for several seconds is not necessarily safe on old body wall skin for ten minutes. Indeed, old people with senile atrophic skin and impaired circulation tend to burn faster, more like children than the young healthy adults in whom much of the time-taken-to-burn research has been done.
  2. Investigation of scalds in nursing homes is a frequent problem. Although there may be health department regulations pertaining to the maximum temperature of water in public facilities, they only apply to the normal usage of water. Furthermore old folks may have diminished sensation, and/or may have had strokes or Alzheimer's disease, and can't tell you, or the nursing assistant, what occurred, even if they're still alive and "conscious".
  3. A person starts to take a shower. The water is a little hot, but fine for someone who is moving around. Then the victim sustains a heart attack or has a seizure and is exposed to the hot water for a much longer time, and an extensive second degree burn, or worse, results before they are found, semi-conscious or dead.
  4. Failure to determine how hot the bath water was, or what the conditions were, at or near the time of injury. This results from several factors:
    • The water was hot and caused a burn, but by the time the victim is found it has long since run nearly cold, and nobody thought about the temperature being higher when the flow first began.
    • If a mishap occurs in a rental property, or if a law suit seems likely, the owner or manager may fix the thermostat, alter the thermostat setting, or replace defective valves, and then say that the conditions were that way all along.
    • Even if nothing was deliberately altered, by the time a case gets to court, months or years after injury, thermostats will inevitably have been readjusted, defective faucets and old water heaters will have worn out and been replaced, and the original situation changed beyond a point from which the situation might reasonably be reconstructed.
    • The burns may not, in the heat of the moment, be all that obvious, or even if they are obvious, seem all that relevant, so important observations are not made. Be sure to measure the water temperature as soon as you can after an incident, long before something can be changed, particularly if circumstances other than accident are suspected. It may be worthwhile allowing time for the water heater to recover before taking another temperature reading. Photograph and/or record the setting of the thermostat on the water heater, and make a note of the condition of the water and shower controls. Are they loose or quite tight? Don't overlook a slightly less obvious defect, such as when one temperature of water comes out the spout into the bath, but when you flip over to the spray head the back pressure results in a shift within the valves, an~ a mu~h colder delivery issues from the shower head (because of back-pressure from a water saving device). Try all the likely combinations before it's too late.

At the time the water temperature is being measured it is sound practice to measure the maximum flow rate of hot water, to see if a tub could really have filled as fast described if the phone rang, or a child really could or did turn the hot water "full-on" accidentally.

So here's a short check list for "child in hot water" problems, not in order of importance:

  • When a shower flows the water is hotter near the outlet than when it reaches the tub (bend down and see) so measure both the spout and tub temperatures.
  • Greatest possible depth of filling.
  • Rate of filling (depth against time, because the average tub with curved sides will not fill at a linear rate). Be sure to include figures for the approximate depth of the water in question.
  • Slope of the bottom of the tub (usually not very significant, and a few degrees at most)
  • Is there a plug or not, or a mechanical drain control.
  • Type of bath or sink (china, metal, acrylic/plastic, fiberglass, etc.).
  • Time taken to drain a full and half-depth filling.
  • Maximum temperature in other places (e.g. the kitchen sink can be 10-20°F hotter than a bath tub, depending on their distance, and where the pipes run, on the way from the water heater.
  • If it's a pier and beam foundation is there a chance that water can get under the house after heavy rains and lower the maximum water temperature because the supply pipe is partly submerged in damp soil, and/or accumulated rainwater? The maximum temperature may be quite different if there's water under the house.
  • What kind of control valve or taps are present? Some mixing valves for showers and tubs are pressure balanced, so that if the hot or cold water pressure suddenly changes, a valve moves to compensate and keeps the output temperature almost constant.
  • Are the taps "stiff' to an adult, or loose and capable of being turned with a finger, or by a child?
  • What is the water heater setting or thermostat dial position? Make a note or take a clear picture.
  • Are there any other deep sinks or tubs (e.g. in the laundry space) in which the burn could have occurred?

From this, in an immersion burn case, it's obvious that it would be a good idea to estimate the level of the high water mark at the time of an autopsy. If the burn is roughly 12 inches "deep" and the sink is only 7 inches deep then the burn probably didn't occur in the sink, as might be claimed.

Consider videotaping any such investigations, or take a full set of photographs as you proceed.

Documentation of shower temperature and flow rates is much the same. There's a lot of stupidity in the literature about being scalded by shower water. There is some sense to it of course, but so much of it is overdone. We all know that some people like cold showers, and some like them hot. One manufacturer's catalog states that the comfort range is between 90°F and 100°F, which raises the question of what is the normal temperature for a shower? If you investigate hot water problems you should know what's right for you. Hence my previous comments.

In short, the only fixtures that make sense to me are the modern pressure-balanced valves that have separate dials for flow and temperature, or second best, entirely separate hot and cold controls that can be adjusted long before wetting the skin.

Some would say that single control valves are acceptably safe, by in my experience this is not so. This is because some of the older ones were designed to supply water to unrestricted heads. However, if one of the flow-limiting heads is substituted to save water, the valves are exposed to a back pressure for which there were never designed. After years of experience in hundreds of hotels I found that many of the combined "joystick" (flow and temperature combined) regulators are unpredictable, and take a lot of getting used to. I've had a number of unpleasant experiences with them in (quite good) hotels.

One way it can happen is this. You step into a tub, and see an older valve with a single control, which may be a bit loose. You turn the water on, but let it run into the tub until the temperature is nearly right, then pull up or down on the diverter. A blast of far hotter water comes out of the shower head, because the valve is suddenly exposed to back pressure from the flow restricted head instead of a free flowing spout.

So much for fluids. Now let's think about solid surfaces.

You may wonder why even more figures are potentially useful, so I'll outline an example. In November 2003, a friend contacted me about a case involving a young adult male who had committed suicide by hanging after being arrested and put in a cell. The circumstances leading up to the arrest don't matter much in an educational context, but it was soon claimed that he was not observed with sufficient frequency to prevent his self-induced death. At autopsy some burns were poorly described, and no photos were taken, but he hanged himself in such a way that his body came to rest against a metal radiator. He was seen alive at one time, then found hanging about 25-30 minutes later. Therefore, people wanted to know if he hanged himself just after the time when was last seen alive or not long before he was found hanging. It was claimed that the temperature of the jail radiators had been limited to 115°F, to prevent the prisoners from burning themselves and each other, but roughly two years had elapsed since the death, so taking temperature measurements at such a late date didn't seem worth the effort. If they were hot people would claim they had changed, and if they were too cool to cause such burns it wouldn't have helped. The question then became what sorts of surface finishes and temperatures would have been "safe" for the skin. This led to the thought of safety standards for domestic appliances, and in due course I found some figures on the Web site of the Royal Society from Prevention of Accidents in the UK. Here are some excerpts from an 8-page article.

EN 563: 1994 Safety of machinery - Temperature of touchable surfaces - Ergonomics data to establish temperature limit values for hot surfaces.

Likely contact time
1 sec
4 sec
10 sec
10 min
8 hr
Uncoated metal 65°C — 149.0°F 58°C — 136.4°F 55°C — 131.0°F 48°C — 118.4°F 43°C — 109.4°F
Painted metal 83°C — 181.4°F 64°C — 147.2°F 55°C — 131.0°F 48°C — 118.4°F 43°C — 109.4°F
Enameled metals 74°C — 162.5°F 60°C — 140.0°F 56°C — 132.8°F 48°C — 118.4°F 43°C — 109.4°F
Ceramics, glass, stone 80°C — 176.0°F 70°C — 158.0°F 66°C — 150.8°F 48°C — 118.4°F 43°C — 109.4°F
Plastics 85°C — 185.0°F 74°C — 165.2°F 70°C — 158.0°F 48°C — 118.4°F 43°C — 109.4°F
Wood 110°C — 230.0°F 93°C — 199.4°F 89°C — 192.2°F 48°C — 118.4°F 43°C — 109.4°F

The likely contact times were seemingly chosen as being representative of daily activities:

1 sec Accidental contact with oven doors and the sides of toasters
4 sec Parts held for short periods, such as knobs and switches
10 sec Parts continuously held in normal use, such as handles
10 mins Prolonged use, such as handles
8 hours Continuous use, such as handles

The next table indicates upper burn threshold limit values for various surfaces for an unintentional contact period of 1 second.

1 sec
Uncoated metal 70°C — 158.0°F
Heavily coated metal 95°C — 203.0°F
Ceramics, qlass, stone 86°C — 186.8°F
Plastics 94°C — 201.2°F
Wood 140°C — 284.0°F

So, as you will see, assuming that the radiator in question was metal and painted, these values served as a guide to the combination of time and temperature it would have taken to burn the skin of a young adult person. If the radiator was indeed at 115°F (46.1°C) a burn would make sense if his skin was in contact with the radiator for more than 10 minutes (let's say closer to 15 minutes for our purposes here). This estimate would move the time at which he hung himself closer to the time when he was last seen alive.

You can find the whole article, and references to the safety standards, under the heading "Temperatures of touchable surfaces" at: www.rospa.com/CMS/index.asp

So, it's nice to have a collection of numbers to serve as a guide, when trying to reconstruct the circumstances surrounding a death or an injury. However they are only guides, and one must apply a liberal amount of common sense, because touching a hot toaster or a handle with the thicker skin of a manual worker's hands is not the same as the less keratinized skin of the trunk. Those who's hearts have partially or completely ceased to pump blood, do not have the normal circulation to carry heat away from the affected portions of skin, are likely to burn a bit faster that would someone with a good circulation. Children and the elderly burn sooner that young healthy adults, frequently male, on whom much of the research has been done. In short, we should expect variations from person to person, and situation to situation.

Chemical burns.

These are mentioned mainly for sake of completeness.

  • Chemical agents usually do not usually "burn" in the sense that heat is involved although considerable heat may be produced when a chemical first contacts water.
  • Chemical burns mainly result from the adverse effects of chemicals on the skin.
  • It is estimated that thousands of chemicals can produce injury of the skin.
  • Hazardous chemical families include: oxidizing agents, reducing agents, corrosives, poisons, desiccants, and vessicants.
  • Tissue damage and destruction result from: anoxia, coagulation and denaturation of proteins, cellular dehydration and polsonlnq,
  • The amount of damage depends upon quantity, concentration, and contact time.
  • It is difficult to assess the depth and severity of chemical burns until about 3 days have passed.
  • In general, alkalis are worse and more common than acids, because acids tend to coagulate and cut off blood supply, whereas alkalis tend to liquefy tissue and cause deeper injury
  • Chemical burns tend to be work-related.
  • More males are "burned" by chemicals than females, and younger men more than older men.
  • Chemicals are often absorbed into the body and may adversely affect organs other than skin.
  • So-called chemical burns account for about 4 -5% of admissions to burn units.
  • In laboratory or industrial settings, chemicals may be hot, in which case chemical and thermal effects are combined.

Radiation burns

  1. Infra red
    • If the skin is exposed to the heat radiating from red-hot objects such as molten metal and hot ingots of metal, then burns can result. They are relatively uncommon but they are possible. In short, the skin has to be near enough to a sufficiently hot entity. Steel workers wear "silvery" reflective clothing for this very reason.
  2. Ultraviolet burns.
    • We all know about, and have probably experienced sunburn, which was mentioned as a common cause of 1st degree burns. We also know the common spectral colors which extend from red to violet. Just beyond the last of the visible violet lies the ultraviolet, which is divided into three bands. The closest to violet is UV-A which is the least energetic. The next is UV-8 which is more energetic. A large part of this is blocked by the ozone layer in the upper atmosphere but enough gets through to put sunbathers at risk. Some fear that reduction of the ozone layer will let more of this band through and cause more skin damage, and ultimately cancer. The third band called UV-C is farthest from the visible and by far the most energetic and potentially dangerous however it is completely blocked by the ozone layers and doesn't pose a hazard. A suntan is the skin's attempt to protect itself from harmful rays by stepping up the production of melanin in the surface layers of the skin.
    • It's important to protect the skin of youngsters because the majority of exposure to UV occurs during childhood and adolescence. As a rule of thumb, some estimate that about % of our total lifetime exposure occurs in the first Y.. of our lives.
    • Occasionally a child is brought in with a sunburn, and it may be severe enough that lack of care (by parents or caregivers) is thought to be responsible. Adults may also be severely sunburned. You should therefore be aware that there are at least 30 relatively common drugs that increase the susceptibility to sunburn. They include antibiotics, antihistamines, cardiovascular drugs, diuretics, pain relievers, and oral contraceptives. Children are less likely to be on them than adults, but it is possible, so be sure to obtain a good history.

Remember also that there are burns due to exposure to nuclear explosions, and other caused by accidents involving radioactive materials. Neither of these are day-to-day problems, but the possibility should not be forgotten.

Smoke detectors.

No discussion of fire-related deaths would be complete without brief mention of smoke detectors. Smoke detectors were first marketed in 1969. Today an estimated 93% of US homes are equipped with them, but many are not in proper working order because of failure to check and maintain them, and/or to replace their batteries.


  • The most common type.
  • Respond faster to flaming fires.
  • Air molecules are ionized by alpha particles from Americium 241 (T% = 458 years)
  • Smoke particles attach to these ions and reduce current flow.
  • Reduced current flow triggers the alarm.


  • The second most common type.
  • Respond faster to smoldering fires.
  • Light from a diode is either scattered by smoke particles onto a cell at the side of the light path, or the amount of light reaching a photocell opposite the source is reduced.
  • A change in the amount of light falling on the receptor triggers the alarm.

Combined ionization and photoelectric:

  • This third type combines both principles to ensure good performance with smoldering or flaming combustion.

Why do people still die when detectors are present? Too often because the detectors are inoperative, and all too often for some stupid reason such as dead batteries. For example, surveys have reported that smoke detector batteries are missing or dead in more than 90% of deaths due to fires in homes equipped with detectors. An estimated 23% of persons don't check their batteries often enough, and as many as 8% think they are dead, but do nothing about it. For this reason, many experts advise the use of mains (115v) powered detectors, or making detectors part of an alarm system which incorporates back-up power, or establishing a routine such as checking batteries when the clocks are moved back an hour in October. The thinking is that heating will be used more in winter than in summer.

Spontaneous human combustion.

Occasionally a human body is found burned in unusual circumstances. Usually the body is found indoors in a relatively small room or equally confined space. The trunk may be largely burned away while parts of the limbs and head remain intact. The upper part of the interior of the room is often coated with greasy residues and soot, plastic items such as televisions may have partly melted, and metal objects may be warm or even hot to the touch.

Until a better understanding of fire dynamics and combustion processes were developed, some people felt that the body had somehow caught fire spontaneously, and advanced a number of scientifically and technically unfounded theories to explain these peculiar observations. Even today outrageous theories are being advanced, and much is made of such cases, often for profit. There is no reason to believe that a body can self-ignite, because most body parts require more heat to burn them than they can generate by burning. If this were not so, bodies could be cremated by lighting them with an acetylene torch, and there would be no need for crematoria, funeral pyres, and the like. Furthermore, if bodies did burn fairly well, it would have been a public spectacle at some time in the past, much like public executions. Burning people at the stake in the middle ages required chains to keep them in place, also large piles of wood to kill them and partly destroy their bodies.

Investigation of "unusual" burned-body situations (spontaneous combustion) usually reveals that most of the following conditions are present:

  1. An ignition source was or is present near the body, such as a stove, heater or open flame. Alternatively a criminal may have tried to destroy a body using a flammable liquid. Old and/or senile and/or intoxicated people may fall, become unconscious, or for some other reason fail to put the heat source (often a Cigarette or match) out. Regardless, something was capable of producing a flame hot enough to initiate the melting of body fat. If it isn't found then it probably means it was destroyed or burned up in the fire.
  2. The body was clothed, or has bedding or something else, such as a towel, over it, or a carpet beneath it, capable of acting as a wick when body fat melts.
  3. Indoors, an enclosed environment may permit the oxygen concentration to fall to 16% or below, which prevents prolonged flaming combustion, but does still permit prolonged slow burning. However, flickering flames 12 to 18 inches high have been observed and photographed outdoors, which proves that oxygen restriction is not the primary cause of slow burning. It is more often the gradual rendering of fat.
  4. If burning occurs indoors the cooler surfaces of a room are often covered by condensed moisture and sooty residue from the smoke formed as the body fat burns.
  5. Indoors, heat rises into the upper parts of a room, sufficient at times to melt some objects (plastics) and heat things up, but burning human fat does not produce heat quickly enough to ignite a whole room.
  6. Research (based on flame height, loss of body weight, and the heat of combustion of subcutaneous fat) has shown that a flickering flame supported by burning fat generates a fire of about 40-50kw, whereas a fire in a trash can generates closer to 150kw. Research using dead pigs has shown that the bodies of lean pigs self-extinguish, whereas those of fat pigs can sustain combustion. If the equivalent of clothing is put on a suitable dead pig, and ignited with a liter of gasoline, the gasoline burns intensely for a short time before it subsides. The "clothing" generates some heat also, but soon smolders and then serves as a wick, so as subcutaneous fat melts and flows onto the carbonaceous char, fluid fat can support a flickering flame with a plume about 12 to 18 inches high, corresponding to a fire of about 30-40 kw. Burning will continue for 4-5 hours, consuming fat and tissue at a rate of 1-4 grams per second, or about 3% - 14 kg (70/.. - 31 Ib) per hour, sufficient to account for the loss of about two thirds of the weight of a body in a period of 5 or 6 hours. Heat release in the range of 20 - 130 kw is possible. The localized flames, at about 800°C (about 1 ,4700F) cause intense local damage in a relatively confined area over time. When the bulk of the fat has been used up, and only parts such as the equivalent of the lower legs and forearms remain, the flames self-extinguish, thus leaving parts of the extremities. In one experiment a 170 Ib pig lost 70% of its body weight in 6% hours, equivalent to a steady fire of 70 kw.
  7. Bones may be reduced to a fragile ash, because of the fat in the marrow spaces. Outdoors, the region immediately beneath and next to the burned body parts are scorched and/or burned, also burned leaves and grass under a body may serve as a wick.

Helpful figures include:

  1. 1 kw = 0.94845 BTU/sec = 239.00574 calories/sec
  2. 1 BTU/sec = 1.05435 kw

Thus, very occasionally a body is ignited by a nearby source of heat in a fashion such that a flame is started, fat melts, clothing, bedding, or something else such as carpet serves as a wick, and those parts of the body where there is ample fat slowly burn, much like a candle, sometimes but not necessarily in conditions of slightly reduced oxygen, slowly destroying the body, partly ashing the bones and eventually self-extinguishing when most of the fat has been consumed, leaving parts of one of more limbs and/or the head intact. Any alcohol the individual may have consumed has nothing to do with it, because the concentration <1/2% in water) is far too low to be relevant.

Hence the appearance of localized severe damage to a body, in largely undamaged, albeit greasy, moist and smoky surroundings. If a few cases remain unexplained it's probably because the source of ignition, such as a cigarette, was itself burned away.

In short, there may be human combustion, but it's not spontaneous!

Further reading:

    Combustion of animal fat and its implications for the consumption of human bodies in fires, by J. D. DeHaan, S.J. Campbell, and S. Nurbakhash. Science and Justice, 1999; 39(1): 27-38.

    A case of Not-So-Spontaneous Human Combustion, by J. D. DeHaan, The Fire Place, IAAI, Fire & Arson Investigator, June 1997. (Reprinted in The Fire Place, Sept-Nov 1998, pp 18-24.)


The reality is that a surprising number of people don't understand fire, the fire environment, what fires can do to a body, nor the problems created by fire for those who have to examine one or more victims.

Bodily features, including apparent injuries, may even result from the processes of fire fighting and post-fire overhaul. Even some of the chemicals used in fighting fires can cause problems for the toxicologist if they contaminate the blood and body fluids.

Investigation of fire and bums is a team effort. A good pathologist needs information from the fire investigator, every bit as much as the investigator needs information from the pathologist. There should be a free exchange of information, but all too often this doesn't take place. We should do our utmost to see that the necessary information is made available. We may even need help from other experts, such as forensic dentists or forensic anthropologists.

When fires are investigated it is possible to determine the cause about 85% of the time, but this still leaves 10 - 15% with undetermined cause. This is because fire, by its very nature, destroys the clues and/or the causes, making them unavailable to the investigator.

Finally the interpretation of fire-related deaths. Make absolutely sure to distinguish between:

  • Deaths occurring in, or simply in association with, fires
  • and
  • Deaths that are the result of, from, due to, or the consequence of fires.

Above all, don't hesitate to say "I don't know". Many times, too often in fact, it's the right answer.

Potentially Unfamiliar Medical Terms

  • Debridement — Excision of devitalized tissue from a bum or wound.
  • Dermis — In lay terms, the inner layer of skin, extending from the fat and muscle outward to the epidermis.
  • Epidermis — In simplest terms, the outermost layer of skin which is constantly renewed.
  • Eschar — The thick coagulated crust or slough which develops following a thermal bum of the skin. Its day-to-day meaning is the damaged material resulting from a full thickness skin burn.
  • Fasciotomy — Incision through fascia; used in the treatment of conditions in which swelling of tissue or tightening of the skin could compromise the inflow of blood.
  • Render (fat) — To make or cause to become of a certain nature or quality; to obtain or extract by melting.

Selected Reading and References

    The relative importance of time and surface temperature in the causation of coetaneous burns, A. Moritz and F. Henriques, American Journal of Pathology 23: 695-720, 1947

    Specific patterns of infected burn injuries, F. Lenoski and K. Hunter, Journal of Trauma 17: 842-846, 1977

About the Author

Patrick Besant-Matthews. M.D.

    Patrick Besant-Matthews, M.D. is a highly acclaimed and popular consultant and lecturer in the area of forensic medicine and criminalistics. He is the former Deputy Chief Medical Examiner for Dallas County, and Chief Medical Examiner for Seattle/Kings County.

    He has presented thousands of programs to nurses, physicians, law enforcement officials, and various scientific groups. He is also an experienced expert witness, and is highly skilled in the area of medical photography. Dr. Besant-Matthews was an integral contributor to the origination of the American Association of Forensic Nurses. His expertise in his field, his sense of humor, and his flair for drama combine to produce a highly enjoyable seminar.

Creative Commons License Burns, Fire and Arson Deaths and Injuries  Copyright: © 2004 by Patrick Besant-Matthews, M.D.. Copyright for this article is retained by the author, with publication rights granted to the Crime Scene Investigation Network. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License which permits unrestricted noncommercial use, distribution, and reproduction, provided the original work is properly cited and not changed in any way. Based on a work at https://www.crime-scene-investigator.net/burns-fire-and-arson-deaths-and-injuries.html.

Article submitted by the author. The Crime Scene Investigator Network gratefully acknowledges the author for allowing us to reproduce the article .

Article posted September 16, 2019