What item in the area of origin is examined to indicate the fire cause?

• A. Residue
• B. Debris
• C. Soot
• D. Ash

Answer: (B)

In fire investigations, the area of origin is where the fire started, so the evidence found there is key for identifying the cause. The item most helpful to indicate the fire’s cause is debris—the remains of materials present at the origin. Debris can include partially burned items, contents, containers, wiring, and other fragments that may retain traces of an ignition source or accelerants. Analyzing this debris, sometimes with lab tests for ignitable liquids, can reveal how the fire began and what started it. Soot and ash are burn byproducts that show what burned and the intensity, but they don’t directly point to the ignition mechanism. Residue can be vague and less specific about the starting cause.