Historical analysis of accidents in the transportation of natural gas

The purpose of the present analysis is to determine the main features of accidents occurring in the transportation and distribution of natural gas (in a gaseous state). A survey of 185 accidents taken mainly from the database MHIDAS has been performed. Of these, 131 (70.8%) occurred in transport systems, 32 (17.3%) in process plants, 13 (7.0%) in storage plants and nine (4.9%) in domestic/commercial activities. The 131 accidents occurring in gas pipes were selected for further analysis. The data show that the most frequent accident was explosion (86 cases, 65.6%) followed by loss of containment (63 entries, 48.1%) and fire (56 entries, 42.7%). The cause of the accident was identified for 90 cases (68.7%). Of these, the most frequent causes were mechanical failure (39 entries, 43.3%), impact failure (37 entries, 41.1%) and human error (32 entries, 35.6%); of the specific causes, impact failures due to excavating machinery were especially numerous (21 cases, 23.2% of known causes). The consequences of the accidents, in terms of both human and economic losses, are assessed. Finally, some conclusions are given about the risks involved in natural gas transportation.