The first book on how to investigate fires was Fire Investigations,1 published in 1945 by Harry Rethoret, who had previously published several pamphlets on the subject. The title might suggest a modern approach to the subject matter, but the book was focused only on arson detection and prosecution. This was common during the next three decades or so, where books on this subject were mostly written either by or for police personnel. During that era, it was called “arson investigation.” That a fire investigator ought to approach a fire scene without any preconception as to whether any incendiarism is involved wasn’t recognized. Rethoret’s book did not offer any reliable, systematic guidance on how to organize a fire investigation.
- Fire Investigation Basics
- Firefighting and Preserving the Fire Scene: Finding the Balance
- Overhaul for Successful Fire Investigation
Fire Investigation Science
Things changed greatly in 1969, when Professor Paul Kirk of the University of California—Berkeley published Fire Investigation.2 Kirk was a biochemist and a renowned forensic scientist and produced the first book to introduce science into the profession. He established that the first two things a fire investigator must do, in this order, are determine the origin of the fire and then determine the cause of the fire. After making these two determinations, Kirk said he must distinguish accidental vs. incendiary fires.
Later Developments
Progress does not always march forward. In 1980, the National Institute of Standards and Technology (NIST) published its Fire Investigation Handbook.3 In some areas (mainly the electrical sections), the book was reliable and progressive but in others it collected and republished old myths.4 Frank Brannigan was a highly respected fire service author, but he mainly contributed only his name. Nora Jason, the primary author, was a librarian, not a technical expert. Dick Bright, who was indeed a competent electrical engineer, wrote the electrical sections. For these reasons, this NIST publication did not advance the field and in some ways thwarted progress.
National Fire Protection Association (NFPA)
Kirk’s book alone did not make fire investigation into a science-based profession. During the 1970s and 1980s, fire investigator education was still largely based on teachings that often not only lacked a science basis but were later documented to be outright myths.5, 6 Thus, in 1985, the NFPA established the Committee on Fire Investigations. It was to develop a standard of care for fire investigations that would provide scientific foundations for the profession. The committee elected to do this by adopting the use of the scientific method in fire investigations, separating out myths from scientific facts, and incorporating guidance based on legitimate scientific research. This work resulted the publication of the first edition of NFPA 921, Guide for Fire and Explosive Investigations7, in 1992, with subsequent editions every three years or so.
The NFPA committee now is comprised of 32 voting members, including fire investigators; attorneys; insurance interests; and, most importantly, fire science experts. Thus, a direct mechanism exists for making sure that fire science is properly presented.
Although early books on fire investigation typically presented material as a hodgepodge of information, NFPA 921 endeavored to also present the teachings in an organized, systematic manner. NFPA 921 expanded on Kirk’s methodology for investigating fires and describes the three main steps that must be accomplished, as follows: determine the origin, determine the cause, and assign responsibility for the fire if appropriate.
The cause of the fire is defined as “the circumstances, conditions, or agencies that bring together a fuel, ignition source, and oxidizer” but of special importance is that the cause must be sought only within the area of origin of the fire. Thus, the competent and ethical fire investigator will first seek to determine the area of origin. This may often involve hard, dirty, physical work, requiring examining and moving piles of debris. If he successfully determines the origin, then the investigator can proceed to determining the fire cause. In most cases, if the fire origin cannot be determined, then the investigator must document this and cease the investigation.
In rare cases, the investigator may legitimately assign the cause or the responsibility without having identified the fire origin. He must carefully document these exceptions as to why this was appropriate in the specific fire case. If the investigator successfully determines the cause, then he might be able to assign responsibility for the fire if the cause resulted from a human or a corporate action.
“Responsibility” is usually understood to be responsibility for the cause of the fire but, in some cases, it could mean responsibility for something other than the cause—e.g., the death or injury of persons or inappropriately poor performance of a building. The above represents the highlights of what a proper fire investigation should accomplish.
The Easy, Unethical Alternative
Except for very small fires, thoroughly and competently working to determine the origin of the fire is likely to require hard work. Furthermore, since NFPA 921 section 4.1 instructs that the investigation “should be accomplished objectively, truthfully, and without expectation bias, preconception, or prejudice,” the results may not be what the investigator was hoping to find. This can be a problem in the public sector8 and in the private. In the private sector, an investigator may desire to ingratiate himself with an insurance company client by finding a target for subrogation, irrespective of whether the target is culpable.
In my career, I have seen way too many investigations in which the investigator took the easy way out by reversing the order of the steps to accomplish: determine the culpable party, determine the cause of the fire, and determine the origin of the fire. Investigation is very easy with such an attitude. Once the investigator has identified the patsy, the cause is obviously an incendiary act the patsy committed (for the public sector) or a defective product (for the private sector). The origin then becomes trivially easy to identify; this is where the cause was found. This is easy and quick and the investigator may not even need to get dirty. It is, however, unethical.
In the public sector, I encountered such an example early on in my forensic career. Late one Friday in December 1995, a large apartment complex being built in a Dallas, Texas, suburb suffered a massive fire. The weather was foul, and so the responding fire department’s investigator chose not to dig out the fire scene. Conveniently, while he was sitting in the cab of his truck writing up his report, an individual approached him and informed him that he knew how the fire started. According to this person, the last workman seen on the job site was a plumber who had been sweating some pipes there. Thus, the investigator was able to complete his report without venturing into the bad weather, and he described how the fire was caused by the plumber. The plumber’s firm was sued, and its insurance carrier might have had to pay a large settlement. Fortunately, its law firm hired a much more competent private fire investigator to dig into the matter. This investigator proceeded to interview the first-in fire company and various neighborhood people; the fire department investigator had not done so. The new investigation revealed that the first-in fire company’s captain had seen independent fires burning at two locations; the plumber had worked only at one location. Further interviews revealed that a gang of teenagers had been spotted entering the construction site a little while before the fire broke out. These facts exonerated the plumber, but this was information that the public fire department investigator should have collected had he been willing to investigate the fire ethically instead of looking for a patsy first rather than finding the origins of the fire.
Unfortunately, in my experience, improper investigation is even more common in the private sector than in the public sector. An unethical investigator will look for electrical devices or heat-producing devices first before establishing the area of origin. As a result, the cause will be a device malfunction and—no big surprise—the origin will be wherever the device was found.
I have encountered a wide array of such improper efforts at fire investigations. The investigator is likely doing such a bad job because he is lazy or else wants to curry favor with an insurance company by presenting a subrogation opportunity. In some cases, it can later be established that the origin of the fire was not properly determined, but the process is likely to be costly to all parties concerned.
The problem of an inverted order of fire investigation is thus one that can be found in the private and public sectors. In the public sector, the effects can be worse, since an innocent person may be falsely accused of arson. This miscarriage of justice is a story in itself; a number of such cases have received wide publicity. I have no quick fixes to propose, but publicizing the problem can be the first useful step.
Negative Corpus
Another tool for the unethical fire investigator is negative corpus. This term means “identifying the ignition source for a fire by believing to have eliminated all ignition sources found, known, or suspected to have been present in the area of origin and for which no supporting evidence exists.” Typically, such abuse of the fire investigation process involves the investigator’s inability to find a natural or an accidental fire cause. The investigator then concludes that since no accidental cause was found, this was arson.
In contrast, an ethical fire investigator will accuse someone of arson only if some evidence is found that indicates incendiarism. The investigator has a wide latitude in looking for evidence, but he must find some credible evidence if he is to make such an accusation. Public sector officials have used negative corpus to put innocent persons in prison.9,10 NFPA 921 specifically cautions the investigator that he must not use negative corpus for a determination of fire cause, fire origin, or assigning responsibility for a fire cause. Why? “Speculative information cannot be included in the analysis” (Section 19.1); any information lacking supportive evidence is speculative. In some cases, the criminal justice system still needs to catch up with this concept of justice. Thus, for example, California does not yet prohibit this unethical stratagem. Although this is of most concern to public officials, private sector investigators also have been known to engage in such investigative abuse.
References
1. Rethoret, H, Fire Investigations, Recording and Statistical Corp. Ltd., Toronto (1945).
2. Kirk, Paul L, Fire Investigation, Wiley, New York (1969).
3. Brannigan, FL, Bright, RG, and Jason, NH, Fire Investigation Handbook (NBS Handbook 134), [U.S.] Natl. Bur. Stand., Washington DC (1980).
4. Lentini, JJ, Fire Investigation: Historical Perspective and Recent Developments, Forensic Science Review, 31, 37-44 (2019).
5. Lentini, JJ, The Mythology of Arson Investigation, pp. 301-312 in ISFI 2006—Intl. Symp. on Fire Investigation Science and Technology, Natl. Assn. of Fire Investigators, Sarasota FL (2006).
6. Hansen, M, Badly Burned: Long-Held Beliefs about Arson Science Have Been Debunked after Decades of Misuse and Scores of Wrongful Convictions, ABA J. 101:12, 36-43 (Dec. 2015).
7. Guide for Fire and Explosion Investigations (NFPA 921), National Fire Protection Assn., Quincy MA (1992, 1995, 1998, 2001, 2004, 2008, 2011, 2014, 2017, 2021).
8. Babrauskas, V, Using Modern Fire Science…to Put Undeserving Persons in Prison, The National Fire Investigator (NAFI) 7-8 (Winter 2015). Reprinted in: Flash Point (Fire Investigation Association of Alberta) 40, 9-10 (Spring 2015).
9. Davis, K, The Age of Innocents, ABA J. 100:9, 54-57 (Sep. 2014).
10. Beety, VE, and Oliva, JD, Evidence on Fire, North Carolina Law Rev. 97, 483-528 (2019).
Vyto Babrauskas, Ph.D., is known for his research contributing to the field of fire investigation. In addition to his earlier book, Ignition Handbook, he has recently published two new books, Electrical Fires and Explosions and Smoldering Fires. His firm, Fire Science and Technology Inc., is located in Cornville, Arizona.
