Fire Scene Evidence Collection Guide
Ignitable Liquid Residue & Fire Debris
Fire Debris
Detailed Procedure:
Fire debris is typically collected so it can be analyzed for the presence of ignitable liquids.
To collect fire debris for ignitable liquid residue testing:
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Select a productive sampling area. Productive sampling areas contain some or all of the following characteristics:
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Absorbent material
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Within an area of ignitable liquid indicators, such as a suspected pour pattern
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In an area where ignitable liquid may collect, such as the lowest point on the floor or at the base of a wall
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The edge of a burn pattern or suspected pour pattern
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Raw, unsealed or torn edges, ends, nail holes, cracks, knot holes, or other similar areas
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Photograph the fire debris in place.
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Wear new, unused, clean latex or nitrile gloves.
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To collect the debris, use a new, unused or properly cleaned tool, such as a trowel or shovel, to lift the debris into the collection can. Collect an entire cross-section if the liquid appears to have penetrated deeply. Because the debris may contain ignitable liquid residue, it must be collected in an airtight container. If not confined in an airtight container, the ignitable liquid vapors may evaporate. Therefore, place the debris inside a new, unused, metal paint can of sufficient size. Leave 1/3 headspace in the can for vapors.
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Clean the lip of the can using a properly cleaned screwdriver or other suitable tool.
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Tightly close the can by gently tapping it with a rubber mallet to seal it. Do not dent the can because it may compromise the seal.
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Seal the container with evidence tape. Initial and date the tape.
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Label the container with identifying information, including case number, date, exhibit number, a brief description including recovery location, and your name.
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Store the item(s) in a secure location, such as a locked evidence van or your vehicle, until you are able to transport it to the laboratory.
Laboratory examination of fire debris for ignitable liquids:
Fire debris can be tested for ignitable liquids using gas chromatography mass spectrometry. This test can determine the classification of the ignitable liquid.
Source:
Crime Scene and Evidence Collection Handbook. Bureau of Alcohol, Tobacco, Firearms and Explosives, 2005.
interFIRE. "Evidence Sampling for Ignitable Liquids Testing." Online Training Module, 2013: