Fire Origin & Cause

Possible fire-cause hypotheses should be developed from the available data and tested against the evidence rather than selected from a single fire pattern or observation. Investigators may consider electrical equipment, appliances, heating equipment, open flames, fuel or gas sources, spontaneous heating, human activity, and other possibilities supported by the evidence. The inability to disprove a hypothesis does not establish that it is true, and eliminating alternative explanations does not by itself prove a remaining cause. If no hypothesis is adequately supported, or if two or more reasonable hypotheses cannot be rejected, the cause may remain undetermined.

A vehicle fire investigation may involve electrical wiring, batteries or high-voltage battery systems, fuel systems, engine-compartment components, exhaust and other hot surfaces, aftermarket equipment, maintenance and repair history, photographs, vehicle data when available, and the distribution of fire effects. An expert can evaluate these materials together with fire patterns and other evidence to determine the area of origin and test proposed electrical, fuel-related, hot-surface, friction-related, battery-related, or external ignition scenarios.

A fire origin-and-cause investigation begins without presuming a particular ignition explanation. The expert develops and tests hypotheses using the physical, documentary, and other available evidence and may conclude that the evidence does not support a specific cause. An arson expert witness addresses the narrower question of deliberate fire-setting when intentional ignition is alleged or suspected. These areas can overlap, but a technical finding concerning intentional ignition does not by itself establish all of the legal elements or identify who is responsible for an act of arson.