Overhaul is the stage at which fire suppression and fire investigation interface. Controlled by the fire suppression forces, overhaul has a huge impact on the ability of any fire investigator to determine the true and accurate origin and cause of a fire.

Overhaul involves discovering and extinguishing hidden fires or hot spots that may cause rekindles, which can result in the total destruction of the remainder of a structure. By concurrently conducting at least the initial origin and cause investigation with the final overhaul, determining the fire’s origin and cause can be accomplished effectively.

Rekindles expose firefighters to greater dangers because of building instability and unsafe conditions, so rekindle prevention is important. Determining the cause of the fire is equally as important. If the origin and cause are not determined, how will the community know that the situation can be prevented from recurring? If the fire was preventable, what must we as an organization do to prevent similar fires? If the fire was intentionally set (i.e., of incendiary origin), how do we prove it and bring the perpetrator to justice? The answer: through timely and technically proficient fire investigations following nationally recognized guidelines using forensically correct procedures in conjunction with overhaul.


Ensuring the effectiveness of overhaul practices does not mean that firefighters should receive no direction other than to “make sure the fire is completely out before returning to the station as quickly as possible.” The directions given must ensure complete fire extinguishment and allow fire investigators to identify the point of origin and cause. This includes the ability to properly document the progress of the fire and collect credible evidence of its cause and impact.

Past practices must be reevaluated with the total picture in mind. In years past, some narrowly focused fire organizations adopted practices that prevented rekindles but also eliminated any possibility of locating the origin or determining the cause of a fire. Fire personnel simply cut out a section of an exterior wall below a window and washed the scene out the windows or doors using straight streams. This created a postfire scene that was cleaner than it was before the fire. One department posted on a big banner in its apparatus bay, “When in doubt, throw it out.” Some incident commanders are more concerned about completing the job quickly and with the least amount of effort than they are with ensuring that the most effective fire investigation possible is completed.

Where extensive overhaul is required, the firefighters performing the overhaul tasks face increased risks (e.g., falls, inhalation of toxic combustion products, strains, and sprains) while working in the damaged structure. Some organizations simply compromise the quality of their efforts to reduce the quantity of the work they are required to do at a fire. Although few things are more embarrassing for an IC than to have the building firefighters had just worked hours to save burn down because of a rekindle, having several fires occur that might have been prevented by effective fire investigation would ultimately be worse.

Unfortunately for some communities, some traditionalist dinosaurs among the ranks of fire service “leaders” continue to profess the methods of the past unfettered by the current technology and improvements that others have proven effective. Enjoy the war stories of past methods as history lessons and little more. Recognize that the major changes in thought, technology, and procedures now determine the current standards of practice. Overhaul, the interface between fire suppression and fire investigation, is the place to start.


Fire service personnel must understand the big picture of a fire loss today. If all a department does is put out the fire and go home, it has omitted several critical emergency service tasks. Even if a fire’s cause was accidental, firefighters have a responsibility to the fire victim to do everything possible to minimize property losses and help the victim get through such a traumatic event. Often, the fire itself is just the beginning of the nightmare.

After the fire is extinguished, the question of whether the victim was insured for his loss arises. If insured, most people breathe a sigh of relief and go on to the next task, believing the victim will be made whole by his insurance company, that every need will be taken care of, and the victim will suffer no permanent financial losses. However, it is not until you become the victim or actually put yourself in the victim’s place that you understand how devastating and permanent a fire loss often becomes.

Insurance companies simply don’t begin writing checks to the victim as soon as the fire is out and they are notified of the loss. The insurance company will compare the loss to the terms of the victim’s insurance contract. Often, the result of the origin and cause investigation helps determine whether the insurance claim applies under the contract. If the investigation results point to the insured or show that the fire was incendiary, the process is entirely different than if fire is determined to be an accident.

Proof of loss is another major obstacle facing a fire victim. The insurance company will pay for the loss according to the terms of the insurance contract and certainly won’t pay for items that were not part of the fire loss. The victim must present a proof of loss, a detailed and itemized list of the items lost because of the fire.

Even though we might think we are pretty good at knowing our possessions, most people fall far short of being able to present an itemized list of all of the contents of their home or office. To demonstrate this, without looking, sit down and list all of the contents of the bookcase where you store your favorite books at home. Can you list all of the contents? Few people have such detailed recollection, and even fewer have a closeup videotape, photograph, or handwritten inventory.

Now think about what that bookshelf would look like after a fire in that room. For some, the loss of just the books alone is significant. How do you make a postfire inventory to complete the required proof of loss? It would be tough even under the best possible circumstances.

Take the same situation and add firefighters that adhere to historical, antiquated overhaul methods. To make sure that no rekindle occurs, the entire contents of the bookshelf would be knocked onto the floor using fire hoses equipped with smooth-bore nozzles. The soggy mess would then be flushed out onto the front yard through the gap cut in the wall below the nearest window.

Any chance to reconstruct the loss and make a complete inventory of the books that were damaged in the fire is now infinitely more difficult. There would be no rekindle, but even if there were, the pile of debris would be in the street and not in the building. The problem is that the victims will be traumatized again when their actual loss is many times greater than what they can remember to list on their proof of loss form.

If firefighters had done minimal overhaul to the bookshelf over sufficient time to make sure the fire in the bookshelf was out, the majority of book titles could be recreated after careful disassembly of the books at their original location. The edges of the books might be extensively damaged while the insides of the books remain readable. This requires firefighters to take time to balance the need to put the fire completely out (and stop the loss) against the need to completing the job quickly and easily.


How can modern overhaul techniques facilitate reaching the larger goals of customer service and fire prevention? First, limit overhaul to the minimum amount necessary to stop the fire’s progress (i.e., stop the loss). Don’t damage anything unnecessarily. Second, work closely with the incident’s fire investigator to coordinate and complete the process.

Call fire investigators to the scene as early as possible so they can begin their work without delay. Many aspects of the investigation can start even before the fire is brought under control, including planning the investigation, gathering resources, and coordinating activities with the IC so the investigation can proceed as a continuation of the suppression efforts. This includes interviewing witnesses, victims, and firefighters to get the best information possible about the situation before and during the fire.

Once the fire is under control, coordinated efforts to limit or prevent additional damage to the structure and preserve evidence of the origin and cause are important. This includes limiting physical access to the building and avoiding the “show-and-tell” aspects of a call so that those not on the initial fire attack crews can see the damage. Assign a small crew to watch the area in case any flare-ups occur while the scene is being documented and the investigation process is being planned. A small hoseline should be staged close enough that it can be put it into service with limited delay. Douse the remaining areas of smoldering materials with care so as not to cause further destruction or alter the scene.

Hidden fires are often more effectively found by waiting them out than by using large quantities of water. Hidden fires are sometimes encapsulated by wet debris and continue to smolder until the water drains off or the material dries out. As it dries out, the smoldering embers ignite and a rekindle occurs. Using less water but using it at just the right location is often more effective. If a hidden fire increases its rate of burning before the investigation reaches its exact location, the spotters can advise the investigators, and the smoldering spot can then be dealt with at that time. Really stubborn, deep-seated fires in latex foam mattresses and overstuffed cotton furniture that cannot be drowned should simply be selectively removed so that the fire cannot rekindle. Other furnishings must be left in place.

The air quality at the scene should be monitored so that personnel operating within the structure know whether they need respiratory protection when working inside. Electric ventilation fans may be needed to remove toxins from the atmosphere. Gas-powered fans add products of combustion, including carbon monoxide, to the scene and should be avoided.


Before it is disturbed, the entire scene should be photographed with a still or video camera, or both. Overhaul must stop at this time. Once the scene is altered, it can never be reconstructed, and the potential for the loss of key evidence of the origin and cause is significant. During this time, firefighting crews, with few exceptions, should be out of the building. Being patient during this time is difficult; it is easier to let them go outside than to leave them inside and inactive. This is a good time for the firefighters to pass through the rehab area, take a breather, get some refreshments, and have their postincident vital signs taken by on-scene paramedics.

At this point, the operational activities within the structure should be transferred from the suppression section chief to the lead investigator. The investigator should identify and request the personnel and equipment necessary to ensure that the fire is completely extinguished and all hidden fires are out during the completion of the on-scene investigation. This includes spotters, whose job is specifically to watch for hot spots and report them to the investigator. The transfer should include transmitting pertinent information that may assist with the investigation, such as anything suspicious, statements made by witnesses or victims, and the observations of various firefighters.

Understand that the point of origin is often found in the area of the most extensive damage and that the same area may contain remaining smoldering fires and critical pieces of evidence relating to the origin and cause. The cause of the fire (i.e., the heat source, the first fuel, and the mechanism that brought them together) is normally found at or very near the point of origin. Thus, it is critical for the firefighting crews to do their best to protect these areas from destruction, since the evidence of the cause of the fire may be fragile and easily destroyed. For a successful fire investigation, evidence must be left in place and protected.

The fire investigation proceeds from the areas of least damage toward the areas of greatest damage. If the scene can be left undisturbed during this process, the investigator will be able to get a clear view of the fire scene. Any remaining or suspicious locations that could contain hidden or smoldering fires can be eliminated more easily; the contents of the scene can be fully documented; and evidence can be identified, photographed, and collected at this time. The entire process can be done systematically and thoroughly. Although this takes a little longer than the old “wash it out onto the lawn” method, it is actually less work for the firefighting crews and reduces some risks of injury to firefighters from lifting or falling.

This coordinated approach provides better customer service to the fire victims, considering their need to compile a complete inventory of their lost property. It is a tragedy that only compounds the crime when overhaul destroys vital evidence of arson. Moreover, some departments have been found liable for unnecessary damage and even spoliation of evidence in court cases.

Today, proper fire investigation involves the reconstruction of the fuel load-what was in the room, what it was made of, and where it was located. If the entire live fuel load is dumped outside, this critical reconstruction is vastly more complicated, time-consuming, and prone to error. The burn patterns on individual furnishings reveal direction of flame spread and are just as important as and sometimes even more important than patterns on walls and floors. The days of clearing out all the remains of furnishings to bare walls and floors to reveal patterns on floors are over. With the advent of all-synthetic carpets and pads that can melt, shrink, and burn, “unusual” patterns are all too common and have nothing to do with the origin and cause of the fire.

As the fire investigation proceeds, so does the process of final overhaul. The process is completed systematically and effectively. Some resources may need to remain on the scene longer than they might have if they were using old methods, but in the scope of things, the improvements in results far outweigh the costs.

There is more to good overhaul practices than simply making sure the fire is out. We must take a more global view of our purpose, serving our community as it relates to overhaul practices. We must overhaul a fire in such a way that it limits the amount of additional property damage. We must detoxify the atmosphere quickly and effectively because we now understand that some of the most hazardous atmospheres occur after the fire has been controlled and a few remaining hot spots are producing smoke and toxic gases. We must conduct overhaul tasks at the proper time and in the proper manner to protect the evidence of the origin and cause of the fire.

MARK WALLACE is chief of the Golden (CO) Fire Department. He taught fire investigation throughout the United States and also in Canada, Australia, and New Zealand for more than 20 years and has taught fire investigation courses for the National Fire Academy. He is a past president of the Colorado State Fire Chiefs Association. Wallace is also the author of Fire Department Strategic Planning: Creating Future Excellence (Fire Engineering, 1998) as well as numerous articles and papers for Fire Engineering and other periodicals. He is the sole proprietor of Fire Eagle Ltd., a consulting firm.

DR. JOHN DeHAAN is a criminalist who has been involved with fire and explosion investigation for more than 30 years. He is the author of Kirk’s Fire Investigation and numerous articles and papers on fires and explosions in police, fire, and forensic journals. A member of the National Fire Protection Association, he served on the NFPA 921 Technical Committee between 1991 and 1999. Dehaan is a member of the Institution of Fire Engineers and a fellow of the American Board of Criminalistics (Fire Debris) and holds a diploma in fire investigation from the Forensic Science Society (U.K.). He is president of Fire-X Forensics, Inc., a consulting firm.

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