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fire & explosion · forensic engineering

Vehicle fire investigation.

Whether a fire started before, during, or after a collision changes who is liable entirely. That sequence is read from what the vehicle itself recorded.

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Vehicle fires apply the same origin-and-cause discipline used in structure fires to a much denser, more compact system, where the engine bay, wiring harness, fuel system, and — increasingly — a high-voltage battery pack are all stacked within a few feet of each other. The question that dominates automotive cases is sequencing: did the fire cause the collision, did the collision cause the fire, or did the fire start independently sometime after impact. That determination reallocates liability entirely, between the driver, the manufacturer, an aftermarket installer, or no one at all, and it is answered by combining physical burn-pattern evidence with electronic data the vehicle recorded about itself in the moments leading up to and during the event.

mechanisms

How vehicle fires ignite.

Vehicle fire mechanisms cluster around a handful of systems packed close together — identifying which one applies also usually identifies who is responsible.

Fluid-on-hot-surface ignition

Fuel, oil, or transmission fluid leaking onto the exhaust manifold or turbocharger housing and auto-igniting on contact with a surface hot enough to ignite it.

Electrical harness chafe & short circuit

Wiring insulation abrading against the frame or a moving component, often at a point near an aftermarket accessory or wiring modification.

High-voltage battery thermal runaway

Collision-induced cell damage, or a manufacturing or battery-management defect, propagating cell-to-cell through an EV or hybrid pack.

Fuel system breach

A collision-related failure of the tank, lines, or fittings inconsistent with the crashworthiness performance expected under FMVSS 301.

Catalytic converter ignition of external material

Dry vegetation or debris contacting an underbody hot surface, a well-documented ignition source for vehicle-sparked wildland fires.

Pre- versus post-collision sequencing

Establishing whether the fire began before impact, during it, or afterward — a determination that reallocates liability among the parties entirely.

methodology

What the evidence shows — and what we examine.

Vehicle fire work pairs component-level teardown with the vehicle's own electronic data, since modern vehicles record far more about their final moments than the physical wreckage alone.

NFPA 921-consistent vehicle protocolOrigin-and-cause methodology adapted to automotive systems and the compressed layout of an engine bay and undercarriage.
Component-level examinationFuel and oil lines, the wiring harness, and the battery pack removed and examined individually under controlled conditions.
Burn pattern & undercarriage mappingCorrelating char and melt patterns to isolate origin between the engine bay, cabin, and undercarriage.
EV/HV battery forensicsCell-level teardown, BMS data recovery, and thermal-propagation analysis to determine whether runaway began internally or was collision-induced.
Crash data & sequencing analysisEvent data recorder (EDR) extraction and collision reconstruction to sequence impact timing against fire onset.
Recall & TSB reviewCross-referencing manufacturer recalls, technical service bulletins, and aftermarket part history against the failure observed.
what's at stake

One vehicle, several parties who could be responsible.

A vehicle fire typically forces a liability question among several possible parties:

fatality & injury litigation product liability against OEM or parts supplier total-loss insurance dispute tow-yard & storage reignition liability wildfire ignition liability arson-for-profit fraud investigation

Do not release the vehicle to salvage.

A burned vehicle, and especially a burned EV or hybrid, needs to be held and examined before disposal. High-voltage packs can retain stranded energy and reignite days later — storage facilities need to be told what they are holding before they release or scrap it.

common questions

Vehicle fires — the questions we hear.

How do you determine whether a fire started before or after a collision?

Burn pattern location relative to the impact damage is the first indicator — a fire that started before impact typically shows heat and soot damage that pre-dates and is independent of the crush pattern, while a fire ignited by the collision follows it. Event data recorder information, showing pre-impact vehicle behavior such as braking, speed changes, or an existing fault code, is often decisive corroboration alongside the physical evidence.

Why do EV fires sometimes reignite days after being extinguished, and what does that mean for evidence handling?

A damaged lithium-ion pack can retain stranded electrical energy in cells that were not fully involved in the initial event, and heat can continue propagating slowly, cell to cell, well after visible flames are out. That is why damaged EV and hybrid battery packs need monitored storage, often with continuous thermal monitoring or submersion protocols, rather than routine tow-yard handling — and why evidence preservation plans for these vehicles need to account for reignition risk from the outset, not as an afterthought.

Can a vehicle fire be linked to a manufacturer recall or defect?

Yes, when the physical failure mode matches a known issue. Comparing the recovered components — a wiring harness routing, a specific fuel line fitting, a battery cell design — against active recalls, technical service bulletins, and prior complaint data can establish whether the vehicle shared the defect condition that triggered the recall, which is frequently the strongest evidence in a product liability claim against an OEM or supplier.

What evidence survives when the vehicle is a total burn?

More than it appears. Metal components, wiring conduit, the battery pack housing and cell modules, and mechanical hardware generally survive even a fully involved fire, and metallurgical and burn-pattern examination of what remains can still establish an origin area. Electronic modules, including the EDR, are often protected enough by their housings to be readable even after significant fire damage, which is why recovery and preservation matter more than the vehicle's outward condition suggests.

How is a vehicle-caused wildland fire traced back to the vehicle?

Physical evidence at the fire's point of origin — particles of metal, catalytic converter material, or paint transfer consistent with vehicle undercarriage components — is compared against the suspect vehicle, often alongside tire tracks, witness accounts, and any available traffic or dashcam footage placing the vehicle at that location and time. This overlaps directly with wildland fire origin work, since the ignition-point analysis on the ground is the same discipline regardless of what turns out to have caused it.

insights

Analysis on vehicle fire.

Technical briefings from our work in this area.

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I can help scope a vehicle fire — likely origin, what to preserve, and which expert fits. What happened?