BCA Logo

Bureau of Criminal Apprehension

A Division of the Minnesota Department of Public Safety

Fire Debris Introduction

Fire debris analysis is the examination of materials from a fire to determine the presence or absence of an ignitable liquid.  If an ignitable liquid is present, the scientist will categorize the ignitable liquid and give suggestions as to possible sources.

Most materials analyzed for ignitable liquids are done using a three-step process: extraction of volatile compounds from the submitted material, separation, and detection of those volatile compounds, and data analysis to identify those compounds and their possible source.

Fire Debris Analysis: 

The term “arson analysis” is an archaic term no longer used by most fire debris analysts.  It implies that the evidence has been submitted with the assumption that a crime has taken place, when in fact, the scientist does not make the determination as to the presence, or absence of an ignitable liquid until all data has been gathered.  In addition, the field investigator determines whether a fire was arson. 

Ignitable Liquid: 

The term ignitable liquid covers two terms that may be more familiar to the general public: flammable liquid and combustible liquid. A flammable liquid is a liquid which has a flash point below 37.8°C (100°F), while a combustible liquid has a flash point between 37.8°C (100°F) and 93.3°C (200°F).

The term “accelerant” is not used by the laboratory.  Whether or not a liquid has been used as an accelerant in a fire is a determination made by the investigator, not the scientist in the laboratory.  


Charred NewspaperCommon Fire Debris Evidence

While most materials to be tested for ignitable liquids consist of debris from a fire, other items that can be tested include clothing from a victim or suspect, suspected liquids, soil or vegetation from around building exteriors, or empty containers that may have been used to carry an ignitable liquid to the scene.






See Evidence Submission for Fire Debris Evidence Collection Tips