New Report Focuses on Fire Debris Analysis

A new technical report, Interpretation of Ignitable Liquid Residues in Fire Debris Analysis: Effects of Competitive Adsorption, Development of an Expert System and Assessment of the False Positive/Incorrect Assignment Rate (pdf, 153 pages), was recently released by NIJ through the National Criminal Justice Reference Service.


J. Graham Rankin, Ph.D., Nicholas Petraco


This study had three major goals. The first was to investigate the effect of competitive adsorption of substrates typically found in fire debris on classification by ASTM E1618 methodology. Findings confirmed prior studies that charred yellow pine can affect the distribution and relative abundance of ignitable liquid components, especially the normal hydrocarbons present in petroleum distillates.

The second goal was to develop and validate an expert system for assisting forensic analysts in classifying ignitable liquid residues in fire debris. The authors note that a series of challenge samples created by spiking commercial ignitable liquids onto charred substrates proved that the developed system needs more testing and refinement before adoption for actual case work.

Finally, the authors sought to provide statistical evaluation of error rates for experienced fire debris analysts in reviewing “case files” of gas chromatograph-mass spectrometry data for identifying and classifying ignitable liquid residues in simulated fire debris. The statistical evaluation of experienced fire debris analysts’ error rates in identifying the presence of and classifying ignitable liquid residues showed no false positives or misclassification; however, because the sample size was small, the authors caution that further testing is required.

You can download the 153-page PDF here.

Source: OJP

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