UC Davis

Understanding the prevalence of Organic Gunshot Residue (OGSR) particles in a non-shooting environment can provide useful information in forensic investigations. Previous studies have shown that certain OGSR compounds are widely used in various occupational sources. This research investigated the prevalence of OGSR in various non-shooting occupational sources. Samples were collected from the hands of 90 volunteers using polyester swabs and deionized water. A total of 119 qualified samples were analyzed for the presence of 2,6 dinitrotoluene (2, 6- DNT), trinitroglycerin (TNG), and ethyl centralite (EC) using Gas Chromatography-Mass Spectrometry (GC-MS). This research determined that of those 119 samples: 100 samples contained 2, 6- DNT, 25 samples contained EC at a threshold concentration of 0.5 ug/mL or above, and no sample contained TNG at a threshold concentration of 25 ug/mL or above. According to previous studies, the presence of TNG and EC as a pair is considered characteristic of OGSR; therefore, these findings were not characteristic of OGSR. Furthermore, these results strengthen the likelihood that certain OGSR compounds, if found in pairs, are indicative of a discharge of a firearm. The use of this knowledge in conjunction with the traditional analysis of GSR can reduce the risk of false negative results. With the aid of future studies to incorporate known shooter samples to assess the threshold levels of these compounds in real life scenarios, OGSR analysis can ultimately strengthen the probative results of forensic GSR analysis in the criminal justice system.