Shortly before midnight, a violent deflagration in a five-storey building destroyed the entire stairwell of a building that collapsed forming a 900 m³ heap of gravel and dust. The red alert was sounded. Significant human and material resources were deployed to clean up the wreckage and attend to the victims. Eleven dead bodies and 3 injured people including one seriously injured child were extracted from the debris. A legal enquiry and expertises were carried out to determine the precise cause and circumstances of the accident.
According to the gas department in question, a first expertise report claimed that the rupture of a 100 mm grey cast iron pipeline at 3.5 m from the building that was commissioned since 1955 led to the explosion. This report also stated that equipment was cased during operations carried out in the mid eighties upon the request of the members of the co-ownership. Two different materials used to lay the piping may have weakened it over the years causing it to rupture. The resistance of the pipeline to withstand external stress was weakened by the grey cast iron widely used from 1940 to 1970 (comprising 1/3rd of the network according to the operator). The use of grey cast iron in new pipes has been discarded for over 20 years and has been mainly replaced by polyethylene since 1980. As part of the nation programme on modernising its gas supply networks, the gas department had moreover planned to gradually replace all existing grey cast iron pipes over several years.
However, given that the gas department was aware of the fragile and dangerous nature of grey cast iron and it failed to further its objective of replacing all pipelines despite sufficient financial resources, the French Criminal Court sentenced the gas department to pay e fine of 204,500 euros for involuntary manslaughter and injury on 23 March 2006. The ruling was upheld on the 21 December 2006 by the Dijon Court of Appeal that based its verdict on the facts taken into account for the initial ruling (non-renewal of the pipeline, insufficient odour of gas, mistake in the map.)
