Wildfire Origin and Cause Investigation - Part 2

In Part 2 of “Wildfire Origin and Cause Investigation,” we will continue to discuss the main points for the local fire investigator to focus on when conducting a wildfire investigation. Hopefully, last month’s article was an eyeopener for some local...

Power lines: These types of fires usually result from hardware, insulator or conductor failure. The indicators of this type will be downed power lines, signs of arcing, blown fuses, or dead birds in the area of origin. Remember that it is critical that the investigator ensures that the power has been secured prior to entering the area of origin.

Cutting and welding operations: Cutting and welding operation fires can result from agricultural, industrial and residential operations. Indicators of this type of fire are welding rods, slag, and metal fragments.

Firearms: Many types of ammunition can cause a fire. Some types of ammunition are tracer rounds, steel core and incendiary. Remember, if the investigator uncovers any unexploded ordnance do not attempt to move it. This is a job for specially trained explosive ordinance disposal (EOD) personnel.

Spontaneous combustion: Certain types of fuels will spontaneously ignite from internal heating caused by biological and chemical processes. This type of fire may occur on hot, humid days in materials such as sawdust, hay, wood chips, and manure.

Flares: Flares will burn at a temperature of about 3,600 degrees and are used for industrial, military or commercial applications. Indicators of a flare fire will include flare debris such as caps, strikers and slag. Grayish slag will remain at the point of origin.

Fireworks: Fireworks are classified as handheld, ground based or aerial. These types of fires may occur during the holiday period. The fireworks can provide ignition through flaming debris and sparks. At the area of origin there may be remains of the fireworks or packing material.


For the local fire investigator, the wildland fire is a difficult task to complete. The conditions may be in an environment that you are unfamiliar with. Remember, when conducting the examination, always search the area systematically and look for items that do not belong in the area. Learn to concentrate on a small area and filter out the background. Take your time during the examination and do not prejudge the cause. Keep an open mind and support the facts. It was the intention of these articles to give the reader a basic over view of wildland fire investigations.


  • NFPA 921, Guide for Fire and Explosion Investigations, 2008 ed. Quincy, MA: National Fire Protection Association, 2008. Print.
  • Wildfire Origin & Cause Determination Handbook, 2005 ed. National Wildfire Coordinating Group, 2005. Print.

ROBERT DISBROW JR. IAAI-CFI is a 22-year veteran of the fire service. Rob is a career firefighter/investigator with the City Of Bayonne, NJ, Fire Department and also conducts origin and cause investigations for a forensic engineering firm based in New Jersey. He is a life member of the Laurelton Fire Co. # 1 and a fire commissioner for the Howell Township Fire District # 1. Rob holds an associate degree in fire science and is a IAAI-CFI certified fire investigator and NAFI -CFEI certified fire and explosion investigator. He is also certified as a fire inspector, hazardous material specialist, fire instructor and juvenile firesetter intervention specialist and has been investigating fires for the past 15 years. View all of Rob's articles hereHe can be reached via e-mail at: disbrow282@hotmail.com.