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Criminalistics Laboratory - Fire/Explosives Section

Fire Scene

The Arson Section examines fire debris for the presence of accelerants. Explosives and explosive residues are examined for chemical makeup. All fire and explosive materials are submitted to the laboratory by the fire service and law enforcement officials.



fire scene   fire scene 2


Analysis of Fire Debris: 

The most common technique the laboratory uses for ignitable liquid analysis is called "passive headspace concentration". This method extracts trapped ignitable liquid residues that are still possibly present in the fire debris. After being extracted from the evidence sample, the trapped ignitable liquid molecules are put into a liquid solution of carbon disulfide. The solution is then injected into a gas chromatograph/mass spectrometer. This instrument creates an electronic representation of the organic chemicals in the sample mixture. The instrument produces a "total ion chromatogram" which can then be further subdivided into specific ion fragment profiles and mass spectra to determine the presence or absence of characteristics specific to ignitable liquids.


Ignitable Liquid Findings 2004-2022
Ignitable Liquids Percentage
Light Petroleum Distillates 3%
Medium Petroleum Distillates 7%
Heavy Petroleum Distillates 4%
Miscellaneous 4%
Gasoline 24%
Mixtures 3%
No Ignitable Liquids 49%
Comparison Samples 2%
Improperly Packaged 4%
Total 100%












Explosive devices, powders or residues are analyzed for chemical composition. The most common types of explosives analyzed by the DCI Crime Laboratory include black powders and substitutes, smokeless powders and pyrotechnic compositions.  All explosive devices should be rendered safe prior to submission to the laboratory.

images of examples of explosive detonators and blasting caps


For more information see the following web sites: