Compared with an explosion in an open space, an explosion in a confined space results in a higher incidence of primary blast injury a greater mortality and a greater injury severity (measured as the Injury Severity Score, ISS). In a study of 297 victims of 4 terrorist bombings in Israel (Leibovici and others, 1996) 204 casualties from open air bombings were compared with 93 casualties from bus bombings. The following differences were noted: Difference in blast types resulting in injuries
Bus bombOpen air bombSignificance Mortality49%7.8%p Primary blast injury77.5%34.2%p=0.00003 Median ISS184p