Characteristics of the Vapour Cloud Explosion Incident At the IOC Terminal in Jaipur, 29th October 2009

At approximately 6:10pm on 29^th October 2009, a leak of gasoline occurred on the Indian Oil Corporation's (IOC) Petroleum Oil Lubricants Terminal at Jaipur, India. This leak continued for some 75 minutes, when the vapour cloud ignited, resulting in a severe vapour cloud explosion (VCE) followed by major fires. The incident caused eleven fatalities, six on the IOC site and five offsite and was investigated by an Indian independent inquiry committee, whose report provides a comprehensive description of the sequence of events and fundamental causes of the incident. However, the VCE in the Jaipur incident shared a number of characteristics with the VCE at the Buncefield terminal in the UK in December 2005. Given these similarities, evidence related to the Jaipur VCE was collected by the author over a three day period at the site during February 2010, at which time much of the evidence on the site was relatively undisturbed. This evidence is compared with that observed at Buncefield and, in particular, the consistency with proposed explanation of the Buncefield VCE, most likely involving a deflagration to detonation transition, is examined. The combination of the evidence from the two incidents, supported by information from a small number of previous incidents, provides both an indication of the VCE potential for dense vapour clouds and the nature of key forensic evidence that is likely to be observed following such events.