When the last hose line is picked up, it is tempting to think the danger is over. For fire investigators, the work is just beginning, and many of the hazards remain. The 2018 Utah Chapter IAAI conference addressed this directly in a session titled "The fire is out, my scene has to be safe?" The answer, of course, is no. A burned structure can collapse, utilities may still be energized, the air and surfaces are contaminated with combustion products, and the investigator is often working alone for hours. This article outlines the hazards to look for and the practical controls that help investigators go home healthy.
Safety Is a Professional Requirement
Scene safety is not optional. NFPA 1033 includes a job performance requirement to complete a site safety assessment, and NFPA 921 contains extensive guidance on investigator safety, which the 2024 edition expanded to address health and wellness. The IAAI also publishes Fire Investigator Health and Safety Best Practices. Treat safety as the first step of every investigation, and document your assessment just as you document the scene.
Structural Hazards
Fire weakens structural members and connections. Before entry, walk the exterior and look for:
- Leaning or cracked walls, sagging roofs and failed trusses.
- Burned-through floors, stairs and landings, including floors that look intact but are weakened below.
- Heavy objects above you, such as HVAC units, water heaters or stored materials, that may fall.
- Masonry chimneys and parapets that may have lost support.
If the building is unsafe, consider shoring, removing hazards with heavy equipment under documentation, or examining from a safe vantage point. No investigation is worth an injury.
Utilities and Energy Sources
Electricity
Never assume a building is de-energized. Verify with the utility or a qualified electrician that power has been disconnected at the service, and remember that solar panels, generators and battery storage systems may still produce power. Our article on investigating electrical fires discusses electrical safety during examinations.
Natural gas and propane
Confirm that gas service has been shut off and that damaged piping, appliances and tanks are not leaking. Use a combustible gas detector where appropriate.
Stored energy
Pressurized cylinders, lithium-ion batteries, vehicles, springs and hydraulic components can release energy unexpectedly. Damaged batteries can reignite hours or days after a fire.
Atmospheric and Contamination Hazards
Post-fire atmospheres may contain carbon monoxide, hydrogen cyanide and other toxic gases, particularly in enclosed areas or while debris is being disturbed. Soot and ash contain combustion products, some of which are associated with cancer risk, and older buildings may release asbestos and lead during debris removal. Investigators are exposed by inhalation, by skin contact and by ingestion when contaminated hands touch food or the face.
Controls include air monitoring before and during work, ventilation, respiratory protection selected for the hazards present, and avoiding work in enclosed spaces while materials are still off-gassing.
Personal Protective Equipment
PPE should match the hazards identified in your assessment. A typical baseline includes:
- Head protection suitable for overhead hazards.
- Eye protection.
- Appropriate respiratory protection, used under a respiratory protection program.
- Protective gloves, with disposable gloves for evidence handling.
- Protective coveralls or clothing that can be removed and laundered or disposed of after the scene.
- Puncture-resistant, protective footwear.
- Hearing protection when heavy equipment or power tools are used.
Decontamination and Clean Practices
Limiting exposure continues after you leave the scene:
- Perform gross decontamination of boots and gear before leaving the scene.
- Remove and bag contaminated clothing and PPE before entering your vehicle, and keep it out of the passenger compartment.
- Wash hands and face before eating, drinking or using your phone.
- Shower as soon as possible and launder clothing separately.
- Clean tools, cameras and equipment, and keep your vehicle's cab clean.
Other Hazards Investigators Face
- Sharp objects and holes hidden in debris.
- Hazardous materials such as pool chemicals, pesticides, fuels, and in some cases illicit drug lab chemicals.
- Biological hazards, including decomposed food, animal remains and, in fatal fires, human remains.
- Weather, heat, cold and fatigue during long scene examinations.
- People and animals, including upset occupants, curious onlookers and frightened pets.
Work Practices That Reduce Risk
- Do not work alone. If you must, tell someone where you are and check in at set times.
- Coordinate with the incident commander before entry while suppression resources are still on scene.
- Establish scene control and a safe entry route, and restrict access to people who need to be there.
- Reassess continually. Conditions change as debris is removed, weather shifts or structural members dry and shrink.
- Plan breaks, hydration and rehab, especially during summer scenes.
Special Situations
Vehicle fires
Vehicle scenes add traffic hazards, fuel and fluid leaks, airbag and seatbelt pretensioner components, pressurized struts and, in electric and hybrid vehicles, high-voltage batteries that can reignite. Position yourself away from traffic and treat high-voltage components as energized. See vehicle fire investigation basics.
Wildland scenes
Smoldering fuels, snags, uneven terrain, heat and changing weather are constant concerns. Coordinate with fire personnel on scene and know your escape routes.
Commercial and industrial buildings
Large buildings may involve heavy structural loads, stored hazardous materials, process equipment and confined spaces. Obtain building information, safety data sheets and knowledgeable escorts before entry.
Mental Health and Wellness
Investigators, especially those who handle fatal fires, are exposed to traumatic scenes repeatedly. Recognizing stress, using peer support and employee assistance programs, and debriefing after difficult cases are part of a sustainable career. The IAAI has made mental health and wellness one of its initiatives. See also our article on fatal fire investigations.
A Simple Pre-Entry Checklist
- Is the fire fully extinguished and overhaul complete?
- Have electricity, gas and other energy sources been verified as controlled?
- Is the structure stable enough to enter, and where are the unsafe areas?
- Has the atmosphere been evaluated?
- Do I have the right PPE and decontamination supplies?
- Does someone know where I am and when I expect to finish?
Learn More
Safety is best learned through practice and shared experience. Check the Training page for conference sessions, read about the Utah IAAI annual conference, and explore our other investigator resources, including evidence collection and fire scene photography.