An explosion occurred on a Monday morning upon resuming activity in an LPG warehouse featuring a filling station. According to the facility layout, the electrical installation was located in the maintenance workshop, which also contained air compressors, at a distance of approx. 70 m from the filling building. Connections with the premises passed through an underground ditch covered by a concrete slab. The filling station was fitted with a product recovery system placed in the bottles (either following over-filling or for tap replacement), composed of a (1-m³) tank kept at low pressure by the LPG compressors, through which the product flowed via a steel pipe closed by a hose. This pipe contained a conical plug valve (older, with a suspected faulty seal). According to the operator’s analysis, on the Friday prior to the accident, the hose broke and butane held in the tank flowed out all weekend via the opening. The butane spread on the ground; given a temperature of around 0°, the gas remained in liquid phase upon reaching the ditch, where it continued flowing into the electrical utility room. On Monday morning, when the centre resumed operations, contactors were activated, leading to the explosion; the ensuing fire was quickly controlled with a powder extinguisher. Of the 15 employees in the workshop at the time of the accident, 8 were slightly injured, with 2 requiring several days of hospitalisation. Property damage was concentrated in the maintenance room: an electrical panel destroyed, the building walls bent, and the roof blown off. Subsequent to this accident, the operator proposed insulating the nozzles or ditches containing electrical ducts at both their ends, using for example plaster plugs, so as to prevent gas from spreading to the premises and becoming capable of causing ignition.

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