If the cause of a fire cannot be determined with at least 50% certainty, then of which type cause is it?

• A. Natural
• B. Undetermined
• C. Accidental
• D. Suspicious

Answer: (B)

The idea is that fire cause classification relies on showing a probable cause with enough confidence. If investigators cannot identify a cause that has at least a 50% likelihood based on the available evidence, the fire is labeled undetermined. This reflects uncertainty and keeps the findings open to revision if new evidence emerges.

Natural, accidental, and suspicious require identifiable evidence pointing toward those categories—for example a natural heat source or weather event, an evident human action or mechanical failure, or signs of deliberate ignition. Without sufficient evidence for any of those, the responsible designation is undetermined.