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The City of Portland, Oregon

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Phone: 503-823-3700

Fax: 503-823-3710

55 SW Ash Street, Portland, OR 97204

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Arson Dog Facts

Firefighters solve arson fires with K-9 units, or arson dogs. These dogs are specially trained to sniff out evidence at the scene of a suspected arson crime. When there is a suspicious fire the firefighters and police must try to figure out if the fire was an accident, or started on purpose. The job of the arson dog is to help in finding that evidence which would point to crime.

An arson dog is a dog which has been trained to respond to trace amounts of flammable materials which could have been used to start a fire. Materials like gas, naphtha, butane, and kerosene, among many others, are known as “accelerants,” referring to the fact that they can be used to accelerate a fire. Arson dogs are more properly known as accelerant-detection dogs, because they search for traces of accelerants which could be used to prove that a fire was due to arson.

A wide variety of dog breeds are used as arson dogs, although Labradors are especially common. Many arson dogs come from police and guide dog training programs which they proved unsuitable for, and their training takes at least three months, and often longer. At the end of training, an arson dog has learned to signal his or her handler about the presence of traces of accelerant to receive a food reward, and he or she is also capable of navigating hazardous or challenging environments.

Schooling begins before the dog and fire detective meet.  Trainers direct the dog to a container that has two drops of 50% evaporated gas in it.  The dog gets a few chunks of food.  It quickly learns that the smell of gas and is rewarded by getting food.  Before the handlers come, people who handle the dogs learn “primary alert” and “secondary alert”!  Primary alert is when a dog finds the accelerant, he is supposed to sit.  Secondary alert is when the dog changes its attitude.  Salivation, excitement, and attempts at eye contact with the handler occur.   The dogs are able to detect tiny amounts of accelerants; amounts that machines cannot even detect.  The dogs are able to find accelerants easily, but the lab does the research.

Most arson dogs have two different responses when they identify an accelerant at the site of a suspicious fire. The “primary alert” is simply to sit down near the area of interest, alerting the handler to the fact that a sample should be taken and tested for accelerants. In a “secondary alert,” an arson dog uses any means possible to pull the handler to an area of interest, and then the dog will intently sniff the area where the accelerant is concentrated.

Dogs have famously good noses, and an arson dog is capable of detecting trace amounts of materials which would be almost impossible to find using other means; these dogs can literally find the needle in the haystack which could prove that a fire was deliberately set. They are also subjected to regular training to ensure that their senses are still sharp, with trainers testing the dogs with various decoy substances which smell similar to accelerants to test their noses.

Every arson dog comes with a handler, who commits to working with the dog for a set number of years. The handlers are typically trained law enforcement or arson investigation personnel. The dogs live with their handlers, and often establish very close, friendly relationships. Because the dogs are fed exclusively on a food reward system, they must literally work for food, learning that they get treats when they find something of interest.

It is important to remember the dog is not the final judge that decides whether a person goes to jail for starting a fire or arson.  The dog is skilled at finding the accelerant.  Today there are over 200 dog teams working in the US.

Arson dogs are used for different types of searches.  They are:

  • Fire searches: In a fire scene search, an arson dog checks out a large area in half the time it would take a person, due to their keen sense of smell and their ability to cover a lot of ground.
  • Equipment searches: In an equipment search, the dog's sense of smell - 200 times greater than a human nose - helps identify evidence from a possible arson crime scene.
  • Vehicle searches: Dogs are used in vehicle searches because an arsonist may carry the liquid into his car, where the dog can sniff them out.  Their training allows them to distinguish these accelerants from normal car fluid scents.
  • Crowd searches: In crowd searches, the dogs are used to sniff out arsonists in crowds because many arsonists like to return to the scene of their work to admire the fire.  By walking the dog through the crowd, the dog may be able to sniff out the fire-starting fluids that may be on the arsonist’s clothes.  This alone will not put someone in jail but the suspect can later be placed in a lineup and sniffed out by the dog.
  • Clothing searches: Clothing searches are done once a suspect is identified. The dog is used to search the suspect's clothing in a lineup of clothes, so he can zoom in on a spot or two on the clothes.
  • Area searches: In area searches, the dog is used to search large areas outside of the fire scene quickly, saving time.  There may be physical evidence or accelerants left behind by the arsonist.

Despite all of the help the dog gives, the dog is not perfect.  The dog is only a tool to help arson investigators locate the spots where the evidence lays.  The dog alone cannot testify – it is up to their handlers and the arson investigators to make sure the dog’s findings are used in a valuable way, to catch and prove in court that the suspected arsonist is guilty.

Overall, using dogs is a huge benefit to finding the accelerants.  They are better than humans.  Despite this, the dogs will never be as good as a skilled veteran arson investigator.