Autopsy & forensics
Types of injuries
Environmental deaths
Authors: Lindsey Harle, M.D., Terrill L. Tops, M.D.
Last author update: 1 July 2013
Last staff update: 18 November 2021
Copyright: 2012-2023, PathologyOutlines.com, Inc.
PubMed search: fire [TI] autopsy, electric injuries [TI], hypothermia [TI] OR hyperthermia [TI] forensic "last 5 years"[dp]
Cite this page: Harle L, Tops T. Environmental deaths. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/forensicsenvironmentaldeaths.html. Accessed March 24th, 2023.
Fire deaths
Definition / general
Types of burns
Mechanism of death
Postmortem changes in charred / burned bodies
Classification of fire deaths
- Classification of burns:
- 1st degree: limited to superficial epithelium; erythematous with pain, edema, skin peeling; does not scar
- 2nd degree: involves full thickness epidermis and superficial dermis; skin appendages are spared; blistering, painful; usually do not scar
- 3rd degree: involves all skin layers, including full thickness dermis and skin appendages; no pain due to nerve injury; appears white; severe scarring
- 4th degree: complete destruction of skin, subcutaneous tissue and possibly bone
- Documenting thermal injury:
- Extent of injury recorded as percentage of body surface area; use rule of 9s in adults (eMedicine: Burn Percentage in Adults - Rule of Nines [Accessed 18 November 2021], MDCalc: Parkland Formula for Burns [Accessed 18 November 2021])
- Age adjusted body surface area chart for children; use rule of 9s for infants and young children (Minnesota Department of Health: Wallace Rule of Nines and Palmer Method [Accessed 18 November 2021])
- Factors affecting burns:
- Heat intensity, duration of exposure, presence / absence of clothing
Types of burns
- Flame: occurs when skin is in direct contact with flame
- Flash burn is due to sudden explosion of gas or particulate matter; produces uniform burn over all exposed skin
- Contact: occurs when skin is in direct contact with a hot object (e.g. iron)
- May show pattern injury reflective of the hot object
- Radiant: occurs when skin is exposed to heat waves; produces blistering and erythema
- Scalding: occurs when skin contacts hot liquid
- Immersion burn: occurs commonly when child is placed in tub of hot water
- May indicate child abuse; as child flexes to avoid water, areas of skin are spared around knees and inguinal region
- Splash or spill burn: cased by splashing of hot liquid; usually accidental in nature
- Burn pattern should correspond to the scene description, with more severe burns near the initial point of contact (e.g. child’s hand or head when a pot of liquid is pulled off the stove)
- Steam burn: can cause severe laryngeal edema when inhaled
- Microwave: occurs when skin is exposed to electromagnetic waves; usually accidental
- Tissue with higher water content shows more severe injury (e.g. muscle burns more rapidly than fat)
- Chemical: occurs when strong acids or alkali contact skin; can also be caused by phosphorus or phenol
- Burns develop more slowly than those created by thermal injury
- Alkali agents tend to cause more severe injury; are usually full thickness and appear pale and leathery
- Acid burns usually are partial thickness and appear erythematous and erosive
Mechanism of death
- Immediate mechanism of death due to thermal injury
- Neurogenic shock secondary to severe pain
- Hypovolemic shock and acute renal failure due to loss of fluid from skin
- Toxic gas inhalation - CO (most common), cyanide, acrolein, nitrogen dioxide, hydrochloric acid
- Often see soot in nose / mouth
- May produce edema, mucosal necrosis of upper airway or bronchospasm
- CO levels usually 30% - 60% in fire deaths
- Delayed mechanism of death due to thermal injury
- Delayed hypovolemic shock with renal failure
- ARDS
- Infection (pneumonia, sepsis, cutaneous)
- Pulmonary embolus due to immobilization
Postmortem changes in charred / burned bodies
- Pugilistic attitude: flexion of the upper extremities as the body cools
- Does not reflect ante or perimortem body position
- Skin / muscle splits: occur parallel to muscle fibers; can extend into body cavities
- Should not be confused with antemortem trauma
- Loss of fingers / toes / extremities: due to charring or loss at the scene
- Heat epidural: blood boiling out venous sinuses produces postmortem epidural blood pooling
- Weight and length measurements are unreliable
Classification of fire deaths
- Death due to an intentionally set fire is generally a homicide
- Suicidal if the individual sets him / herself on fire
- Look for accelerants or volatiles on clothing from the decedent
- Many fires are accidental
- Antemortem versus postmortem burn
- Postmortem burns may appear yellow and dry; microscopic evaluation should reveal no inflammatory reaction
- Some postmortem burns can be impossible to distinguish from antemortem burns
Electrical injuries
Definition / general
Ohm's law
Voltage deaths (alternating current / AC)
Voltage deaths (direct current / DC)
Scene findings
Gross findings
Histological findings
- 2 types of current cause death in U.S. and Europe: direct (rare, e.g. car battery or lightning) and alternating (most common, e.g., household items or downed power lines)
Ohm's law
- V = IR or I = V/R
- I = Current is measured in amperes
- V= Volt is a unit charge of potential energy; the difference between a point of a circuit (e.g., a live wire) relative to a reference point (e.g., ground)
- R= Resistance (ohms) of the flow of electrical energy through an organic or inorganic substance (conductor)
- If a human is in contact with a live current, then the amount of energy (volts) transmitted into the person (conductor) is inversely related to the resistance at that point of contact
- For example: decedents with moist skin are at higher risk for electrocutions than those with dry, callous skin because the latter group is more resistance to current than the former
Voltage deaths (alternating current / AC)
- Generally, low voltage is arbitrarily considered to be < 1000 volts
- Most U.S. households have wall outlets in the 110 to 120 volt range while the home's circuit breaker consists of twice as much voltage (e.g., 220 to 240 volt range)
- Industrial work environments in the U.S. may have outlets in the high 400 volt range
- Gross findings: low voltage electrocutions may leave little, if any injuries on the body
- Death: primarily due to cardiac arrhythmia (ventricular fibrillation)
- Generally, high voltage is arbitrarily considered to be > 1000 volts
- Power lines can range from 10,000 to over 100,000 volts
- High voltage arcs can emanate from power source and make contact with the victim who may be several feet away
- Gross findings: obvious charring on the body is common in high voltage deaths
- Death: organ damage related to thermal energy released into the body
Voltage deaths (direct current / DC)
- Lightning is a naturally high voltage form of direct current
- Once lightning strikes a body, the lightning blast could throw the victim several feet away from the site of initial impact
- Fern-like skin lesions may develop on the body because the thermoelectric energy causes discoloration of the cutaneous blood vessels
Scene findings
- At low voltage death scenes (e.g., at family dwellings), it is important to:
- Disconnect the power source to the suspected household item that may have led to the decedent's death (e.g., hair blow dryer) or remove any unusual foreign objects in contact with electrical socket (e.g., fork or knife)
- Collect any suspicious household items located near the body to be inspected systematically for faulty wiring or poor workmanship by a certified electrician
- Any electrical manufacturing defect(s) found in the product may ultimately result in a nationwide recall of that product
Gross findings
- Full inspection of the decedent's clothing (e.g., shoes, hat, gloves, pants) may offer clues regarding the location of skin lesions
- At autopsy, especially for low voltage deaths, a careful full body (e.g., scalp, underarms, webs of the fingers / toes) inspection to find subtle skin injury
- If inspection is negative, repeat the full body inspection again to avoid missing any injuries
- If inspection is negative for the second time, have another forensic pathologist carefully look over the body for lesions
- If negative for the third time and suspicion of an electrical death is high, briefly state in the autopsy report that there were no electrical injuries identified times 3 inspection attempts
- In high voltage deaths, at autopsy, finding skin lesions are more obvious (e.g., arc / charred marks)
Histological findings
- Thermoelectric damage in high or low voltage may lead to the display of:
- Nuclear streaming or palisading of the epidermis
- Steam blisters that are present in the epidermis or dermis
