微量物证在北京大兴“11·18”重大火灾事故调查中的应用

Role of Trace Evidence in Investigating Beijing Daxing“2017·11·18”Confl agration

近年来,具有重大社会影响的火灾、爆炸、矿难等生产安全责任事故时有发生。由于伤亡人数众多,此类事件极易引起社会关注,如何科学、高效地还原事件经过,考验着每一名刑事技术人员。2017年11月18日,北京市大兴区西红门镇发生重大火灾。刑事技术人员通过细致勘查发现冷库间内电气线路故障,准确提取冷库间墙面保温材料,使用气相色谱/质谱联用仪进行比对检验,迅速确定起火原因。墙面保温材料中释放出的五甲基二乙烯三胺与空气混合,在密闭空间内达到爆炸极限,遇包埋在聚氨酯保温材料内的电气线路短路发生爆炸。装修材料中挥发性有机物的爆炸比较罕见,总结刑事技术人员在微量物证现场勘查及检验鉴定中的工作经验,可以为以后类似案事件的处置提供重要参考。

At times,significant events of social impact occur with the liable production-safety accidents,e.g.,fire,explosion and mine disaster.Usually,such events could attract high-profile social attention due to the large number of casualties.Consequently,it is crucial to timely adopt proper and efficient disposal into the events and relevant matters.On November 18,2017,a heavy fire disaster happened in Daxing district of Beijing.By careful investigation,the criminal technicians found that one short-circuit incident took place inside a cold storage depot so that they collected the heatresistant materials from the wall there and examined with gas chromatography mass spectrometry.Through contrast experiment,it was revealed that one explosion was resulted from the heat-resistant material releasing its-comprising pentamethyldiethylenetriamine(PMDETA)to the concentration among 1.1%-5.7%(V),the explosion threshold of the substance when it blended with air and fitly ignited with the short circuit occurring inside the polyurethane heat-resistant materials.Such an explosion was,albeit rare,set off with the volatile organic compound from decoration materials.References are hoped to provide for criminal technicians to tackle with similar cases through the here summarization of trace evidence scene investigation and inspection.