Fire Debris

Petroleum products and other ignitable liquids are the most common types of materials used in arson cases. Because alcohol, gasoline, stove oil, paint thinners, solvents, and other similar fluids frequently do not burn completely, residues of such fluids can be recovered from fire scenes and identified. The packaging and preservation of samples from the time of collection to the time of analysis is critical. Fire debris evidence, therefore, must be submitted to the laboratory in a timely manner.

All fire debris evidence must be submitted in vapor-tight containers such as glass “mason” jars with screw-on lids or lined metal cans with friction fit lids. Unlined metal cans are not acceptable containers. Paper and/or plastic bags are not vapor-tight containers and will not be accepted by the laboratory. The evidence containers must be properly closed to provide a vapor-tight seal and not filled over three-quarters full. Debris around the rim can keep the container from sealing properly. The outside of the metal cans must be kept clean and dry to reduce corrosion of the can. Any broken lid seal (jar or can) or corrosion on the metal container may allow ignitable liquid vapors to escape.

The lab will not accept raw ignitable liquids in excess of 25 mL. Samples of suspected raw ignitable liquids must be submitted to the laboratory in a sealed bottle with  a TFE-lined cap.  The cap of the bottle should then be sealed with evidence tape.  “Mason” jars and metal cans are not suitable containers for raw liquid samples.

A tamper evident seal must be placed on each lid. All containers must be labeled with victim’s names, investigator’s name, date and time of collection, specific source and type of sample (e.g. “Burned carpet from northeast corner of master bedroom”), and any odors noted at the fire scene by either human or canine detection. In addition, a DOFS Submission Form, including a description of the fire scene, is required.