LAUSR

Abstract Ignitable liquids are present in some shoes due to adhesives used during the manufacturing process, but the prevalence of ignitable liquids has not yet been determined. Eighty-six pairs of new/lightly used athletic shoes were analyzed using gas chromatography-mass spectrometry for the presence of inherent ignitable liquids. Individual shoes were heated at 40 °C and 65 °C to determine if a lower temperature would avoid the release of potential ignitable liquids trapped in the adhesive. The shoes in a pair were heated separately to determine if right and left shoes could viably serve as comparisons for one another. Only five of the 172 individual shoes extracted at 65 °C contained an identifiable petroleum-based ignitable liquid, and another 11 shoes contained a single ignitable liquid compound that was deemed likely to be reported due to abundance. Left and right shoes from the same pair had largely similar patterns, though some differences were occasionally observed, which suggests that caution should be taken when comparing shoes in the same pair. Differences were apparent between different models of shoes from the same manufacturer, so examiners should not use different models of shoes for comparison purposes. Very few replicate pairs of the same manufacturer and model of shoe were included in this study, so caution should be used when attempting to use another pair of the same model for comparison.