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Fire Scene Evidence Collection Guide

Ignitable Liquid Residue & Fire Debris

Pool (Liquid)

Detailed Procedure:

Most ignitable liquids float when in contact with water, as can happen in a fire scene when water is used for suppression, and can be collected off the surface of the water. Look for possible ignitable liquid pools:

  • Within an area of ignitable liquid indicators, such as a suspected pour pattern

  • In an area where ignitable liquid may collect, such as the lowest point on the floor or at the base of a wall

  • Edge of a burn pattern or suspected pour pattern

  • In containers that may have served as ignitable liquid containers that transported accelerant to the scene

  • Near soaked debris

To collect a liquid in a pool:

  1. Select a productive sampling area.

  2. Photograph the pool in place.

  3. Wear new, unused, clean latex or nitrile gloves and eye protection.

  4. Choose either the eyedropper method or absorption method. Gather appropriate equipment.

  5. To collect liquid using eyedropper method:

    1. Use a new, sterile eyedropper or disposable pipette to collect 2 milliliters (approximately 1/2 teaspoon) of the liquid into a glass vial, preferably with a Teflon-lined cap. If a Teflon-lined cap is not available, place aluminum foil over the open vial top and screw the hard plastic cap down. Place the vial into a small metal can, cushioned with vermiculite. Never place a liquid sample directly into a metal can.

    2. Using the same procedure, collect samples of both the ignitable liquid and water layers, if present.

  6. To collect liquid using the absorption method:

    1. Open a new, unused, sterile cotton gauze pad suitable for skimming suspected ignitable liquid residue off the liquid's surface. Skim the surface of the liquid to absorb it.

    2. Place the gauze in a quart or gallon metal can.

    3. Collect samples of both the ignitable liquid and water layers, if present.

    4. Place a comparison sample of unused sterile gauze in a separate quart or gallon metal can.

  7. Seal the container(s) with evidence tape. Initial and date the tape.

  8. Label each container with identifying information, including case number, date, exhibit number, a brief description including recovery location, and your name.

  9. 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 potential ignitable liquids:

Liquids can be tested using gas chromatography mass spectrometry. This test can determine if an ignitable liquid is present and the classification of the ignitable liquid.


interFIRE. "Evidence Sampling for Ignitable Liquids Testing." Online Training Module, 2013:

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