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How Fire Investigators Determine Fire Causes

3 Min Read

Analyzing and ascertaining how fires originate is central to the role of fire investigators.1

What goes into deducing fire causes — and how can you hone the essential skills for success as a fire investigator? Let’s take a look.

The Fire Investigation Process

Whether at home or in the wild, fires can begin for a variety of reasons, including:

  • Improper storage and handling of hazardous materials (e.g. chemicals or fuel)
  • Electrical hazards (e.g. faulty wiring) 
  • Inflammatory climate conditions (e.g. hot, dry weather)
  • Human activity, both accidental and intentional (e.g. arson)

Fire investigators try to determine how fires begin by applying the scientific method. Through observation and measurement, they can formulate a hypothesis, test it and form a conclusion about the fire’s origin and cause.

Since there is limited time to collect witness accounts and details upon arriving at an emergency scene, fire investigators must follow a process. This may include:

  • Evaluating the scene
  • Documenting the scene by taking notes and photographs
  • Collecting and processing evidence
  • Interviewing witnesses2 (a good investigator listens well and lets witnesses tell their story without being swayed by opinion)3

In some cases, on-site evidence gives a clear indication of how the fire began. For example, pinpointing the location of electrical arcing may help reveal the fire’s point of origin.4 In other cases, fire investigators need to be creative in hunting for clues. A witness may know the cause of the fires, for instance, but be reluctant to share that information for fear of being blamed.

Developing a Timeline

The next step is to sift through what has been learned, including witness statements, fire department response records, fire forensics and documentation. Then, the fire investigator tries to figure out what happened (and when) by creating a timeline.3

Fire investigators must be careful not to manipulate the timeline to fit a particular theory. If there are holes in the logic, it is their job to keep digging for the missing information. They must be methodical, using the facts they have gathered to come to a conclusion about the origin and cause of the fire.3

A Range of Skills Required

Qualified fire investigators possess a broad set of leadership, managerial and professional skills. In addition to the ability to investigate the fire scene effectively, they must understand the legal issues and the psychological effects of emergencies.5

The right education can prepare you for a career as a fire investigator. The online Bachelor of Science in Fire Science (BS-FS degree) at Anna Maria College was one of the first in the country to be awarded Fire and Emergency Services Higher Education (FESHE) recognition. It also includes a fifth-year option to pursue a Master of Public Administration with a Fire and Emergency Services specialization.

For more information about Anna Maria’s online Bachelor of Science in Fire Science contact us today 877-265-3201 or request information.


  1. Kerber, S. (2011) Analysis of changing residential fire dynamics and its implications on firefighter operational times. Fire Technology, 48, 865-891.
  2. National Institute of Justice: Arriving at the fire and/or arson scene: completing the investigation:
  3. Technical Advisory Service for Attorneys: Interviewing and Timeline Skills Your Fire Investigation Expert Needs:
  4. Hazelwood, T. (2012) The effectiveness of arc mapping to determine fire origin area:
  5. Fire Science Online: How to become a fire marshal:

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