The Origin and Cause Report: Why an NFIRS Report Just Won’t Do…

By Wayne Delancey, Deputy State Fire Marshal

So, you have finished your on-scene investigation and collected photos, diagrams, and fire debris evidence. You have confirmed the facts and interviewed witnesses. What’s next?

It is now the time to place all this information into a concise, professional document, the Origin and Cause (O&C) report. The purpose of this report is not only to accurately report the facts of the incident but also, in the case of an Incendiary fire, to report your findings to a Jury in a court setting. 

What about the NIFRS report? 

The National Fire Incident Reporting System (NFIRS) is a voluntary reporting system that uniformly reports on a fire department’s activity, from fire to emergency medical calls to severe weather and natural disasters. This system is the database or clearing house used by the United States Fire Administration to report the fire problem in the United States. What it is not is a comprehensive report of a fire investigation. While some parts of the NFIRS report apply to the origin and cause reports, such as dispatch times, units, and personnel on the scene, it is not a substitute for the O&C report.

Writing the O&C Report

The Origin and Cause report should be written concisely, professionally, and readable. You must remember the audience you are writing to will be either Insurance Professionals (Private Origin and Cause Investigators), Government Investigators (ATF, SBI, FBI), and last but surely not the least, a jury of one’s peers in an open Court of Law. In addition, your report could be the basis for an opinion testimony in either criminal or civil proceedings. Because so much will hinge on your report’s accuracy, the inaccuracy risks could not be any higher.

Format of the O&C Report

A properly written and technically reviewed O&C report must meet certain criteria, including the National Fire Protection Association (NFPA) Guide for Fire and Explosion Investigations document 921.

This Guide and been considered and accepted by many in the industry and courts as the “standard of care” and should be utilized as the go-to document for writing the O&C report1. An additional document that must (read SHALL) be utilized is the NFPA Standard 10332. Standard for Professional Qualifications for Fire Investigators. This being a standard means that it is a Shall document when preparing your document. It clearly states that written reports should “reflect the investigative findings and contain the facts and data the investigator relied upon in rendering an opinion and contain the reasoning of the investigator by which each opinion was reached.”

In addition to the previously referenced standards, another standard should be utilized, which is the American Society for Testing and Materials (ASTM) International Standard Practice for Reporting Opinions of Scientific or Technical Experts (E620-18)3  is very specific in says that “all pertinent observations, calculation, and testing results shall be reported accurately” it further states that “the observations, test results, interpretations, or conclusions, shall be reported and shall include all information necessary for an opinion to be issued by a qualified individual.”

We have many guiding documents, so now, what do we put in the report?


These are the basics of information: Address, Type of incident, case number, and lead investigator.


This is an overview of the fire investigation event; it should list the date and time the call was received and who responded to conduct the Origin and Cause investigation. It should also list the Cause determination as to whether it was an Accidental, Incendiary, Natural, or Undetermined Fire Cause.


The narrative should be, just as it says, a narrative of the investigation that includes the summary and expands to include other investigators who assisted, also the lead investigator who is authoring the O&C report. It should also include the physical location of the fire loss, GIS coordinates, and the direction the structure faces (N, E, S, W). Other factors that should be considered would be any adverse conditions that may have affected the examination, such as alterations to the fire scene, including those caused by the fire, fire suppression activity, or any other condition that would compromise the ability to form a hypothesis as to the origin and causation of the fire.

Witness Statements

These should include the owner, renter, lessee, and other persons interested in the property. In addition, it is paramount that you obtain statements from fire personnel, including the 1st units on scene and those directly involved in the suppression of the fire, to ascertain if there were any issues with extinguishment and if the structure was secured at the time of the fire or if the fire department had to breach or force entry.

It is necessary to conduct a neighborhood canvas that may uncover witnesses or surveillance cameras that may not have been known at the initial time of the fire.

Building Construction

Basic building construction should be listed, including the square footage and type of construction such as wood frame, masonry, etc. You should also list the different construction types of wall and floor coverings, exterior coverings, and roof composition. The structure layout to include rooms and descriptions should also be listed.

 The electrical service should be listed to include the phrase, how and where it entered the structure (overhead service lateral or underground) and how the service was routed to the distribution panel, and the grounding and bonding means. Branch circuits, wiring types, receptacles, switches, and breakers should also be listed in this report. 

Fire and Intrusion alarms, as well as any video surveillance, should be surveyed and examined as to whether or not they may have captured any relevant information that may support a hypothesis as to the origin and cause of the fire.

Any mechanical systems such as HVAC, plumbing, and ventilation should also be reported in this report area.

Scene Processing

This should include the date of the examination and the basic methodology of the examination as included in NFPA 921, which recommends the Systematic approach and the scientific methods to consider the origin and all possible fire causes, the area that was examined from the least amount of damage to the least and that the examination was thoroughly documented through some digital media.

Exterior examination

A systematic fire scene examination should list how it was initiated, beginning on the structure’s exterior.  This systematic examination utilizes the scientific method as its foundation for analysis, testing, and conclusion.  It should list how the exterior examination commenced at the front of the structure and continued clockwise or counterclockwise around the perimeter of the structure.  Investigator observations should include ventilation patterns and areas where the fire vented the structure and list any fire patterns generated and any signs of forced entry. Another key issue to determine is whether the fire started on the structure’s exterior and extended to the interior.

Interior examination

The interior examination should mimic the exterior examination in a systematic fire scene examination. It should list how it was initiated, beginning on the structure’s interior, including commencing at the front of the structure and continuing the examination in either a clockwise or counterclockwise manner around the structure’s interior. In addition, the interior exam must list a room-by-room description of the interior condition that would describe how the fire progressed within the structure and how intense the fire was before extinguishment. This is key in the determination of the origin of the fire as we are examining the structure to determine the movement and intensity of the fire.


This portion of the report is where you need to list all evidence, including photographs, diagrams, and any fire debris that was taken during the examination of the structure.


This area should list the extension of the original fire to any other structures or items that may have been affected by the progression and ventilation of the fire to other areas.

Fatalities or injuries

This area should list the total number of injuries, including civilians and fire personnel. Any fire injuries that may cause death to the injured should obtain and listed. Any fire fatalities should be listed in this section as well.

Estimated value of loss

Include an estimated value of the structure and contents; this may become very important if insurance fraud is detected later in the investigation.


The weather at the time of the fire may lead to a further hypothesis, as lightning storms could be the cause of the fire. As a rule, try to list the weather from a reputable source and list at least an hour before and after the alarm time of the fire.

Fire suppression activities

This is the area to list any fire suppression devices and whether they were able to have any effect on controlling the fire in the incipient stage and, if not, why? You may also use this area to describe if normal fire suppression activity by fire personnel had any pertinent effect on the fire or did their efforts affect your ability to process the scene.


The conclusion paragraph should restate your hypothesis, summarizing the key supporting data you discussed throughout the work, and offer your final hypothesis on the Origin and Cause of the fire. You should also use this to explain all other hypotheses and how they were examined and excluded as to the origin and causation of the fire. The final sentence should include your opinion as to the fire cause determination as to whether the fire was Accidental, Incendiary, Natural, or Undetermined.

Technical Review

To ensure that the scientific method of each investigation is properly documented, fire departments should adopt a standard operating procedure that requires reports to contain all relevant data considered by the investigator, which hypotheses were considered, and the reason for eliminating each hypothesis through testing and examination of all relevant data. In addition, a technical reviewer who did not take part in the investigation should be given the task of conducting the review. It is also important that fire investigators recognize this need and understand the consequences of not producing a thorough and accurate report and not conducting a technical review.

I hope this article leads you to a greater understanding of why we simply cannot rely on an NFIRS report to be a substitute for a well-defined and well-written, Origin and Cause report. If you need any assistance with the format or sentence structure include verbiage. You may reach out to the Office of State Fire Marshal, Fire Investigations Unit, NC State Bureau of Investigations, Arson Unit, and the Bureau of Alcohol, Tobacco and Firearms CFI’s, and their Investigators would gladly assist you with writing a better and more accurate report.

Wayne DeLancey has been involved with emergency services for over 39 years. Mr. DeLancey has investigated hundreds of fires, which involved criminal arson investigations, civil litigation, large dollar losses, and those with fatalities and serious bodily injury. Mr. DeLancey holds a Bachelor of Arts degree in Organizational Leadership and an Associate in Applied Science in Fire Protection. Additionally, he is a North Carolina Certified Fire Investigator (NC-CFI), an Internationally certified fire investigator (IAAI-CFI), and a certified evidence collection technician. (IAAI-ECT), and Certified Instructor (IAAI-CI). He holds 29 certifications with the State of North Carolina, NFPA, ProBoard, and the International Code Council.


1. NFPA 921: Guide for Fire and Explosion Investigations. (2016) Quincy, MA: National Fire Protection Association.

2. NFPA 1033: Standards for Professional Qualifications for Fire Investigator. (2014) Quincy, MA: National Fire Protection Association.

3. Standard Practice for Reporting Opinions of Scientific or Technical Experts. (2011). West Conshohocken, PA: ASTM International.

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