Experience suggests that some Fire Investigators have historically interpreted the finding of an Ignitable liquid at the fire scene as meaning an "accelerant" and accordingly, an incendiary fire. Chapter 19, of the 2001 Edition of NFPA 921 cautions the Fire Investigator not to draw this conclusion until further investigation is undertaken.

Chapter 19 categorizes "Incendiary Fire Indicators" as those details found at the fire scene that may be related to an incendiary fire. "Ignitable liquids" are identified in the chapter as an incendiary fire indicator. The Chapter states that indicators are not conclusive in and of themselves, but require further investigation before the Fire Investigator can draw conclusions concerning their relationship to the fire’s cause.

When "ignitable liquids" are in the area of origin, the Fire Investigator must determine whether their presence is deliberate or inadvertent. For instance, gasoline in the living room or bedroom of a home would represent strong evidence that an accelerant was likely deployed. However, gasoline in a basement or garage may have a legitimate explanation and not signify an accelerant. Thus, the distinction between an "ignitable liquid" and a "liquid accelerant" is determined by its intention or lack of it to facilitate the fire.

The question that must be answered by the Fire Investigator is, "Did the ignitable liquid have an illicit purpose within the fire scene?" If the answer is yes it can then be safely concluded that the function of the "ignitable liquid" was unlawful and consequently an incendiary fire.

The term "accelerant" only applies after the Fire Investigator has learned, as a result of scrutiny of the empirical data, that the "ignitable liquid" was at the scene for an illicit purpose-"to accelerate the fire." When this is achieved, the evidence is so compelling that the fire’s cause can be established as incendiary. (See NFPA 921, Section 16-2.4, "Undetermined Fire Cause.")

The pivotal issue is determining what purpose, if any, the "ignitable liquid" played in the fire scenario. It is mandatory for the Fire Investigator to thoroughly investigate the issue before concluding that an "accelerant" is present and consequently an incendiary fire has occurred. Drawing this conclusion without a proper and complete investigation of the circumstances is unethical. The consequences are severe-the wrongful conviction of an innocent person or the denial of insurance coverage can result.

The analysis of fire debris using gas chromatography in concert with mass spectroscopy has been heralded of late. The Fire Investigator must use caution in interpreting findings using this procedure. The methodology detects the presence of flammable liquids in such infinitesimal quantities that their significance must be closely scrutinized.

To illustrate-a Senior Chemist employed at The Centre of Forensic Sciences, Toronto filled his vehicle at a self-serve gasoline station. In doing so great care was taken not to spill the fuel. The Chemist returned to the laboratory and subjected his clothing to analysis. The analysis detected trace quantities of gasoline, even though no spillage of the fuel had occurred.

The explanation is that gasoline vapours likely impregnated the Chemist’s clothing while he was pouring the fuel.

In interviewing the former Chemistry Section Head of the same laboratory I was advised that if an air sample was taken during rush hour on a busy Toronto street and analyzed using GC/MS/MS, traces of gasoline would likely be detected.

It is imperative that Fire Investigators remain diligent in their pursuit of the facts. Fire Investigators must be aware that "accelerants" are only present at incendiary fires but "ignitable liquids" can be present at any fire, whatever the cause.