Pollution
Humain
Environnement
Economique

Around 9 am, after unloading a convoy of 26 railcars (5 of which were carrying monomer vinyl acetate, 11 had acetic acid and the other 10 were rolling empty but not yet degassed of methanol) inside a chemical plant in the direction of the marshalling yard, 5 of the cars derailed. Two of these cars were transporting 80,000 litres each of monomer vinyl acetate (MVA, a non-toxic yet highly flammable product) overturned below the 5-m high embankment, causing two manholes to open and their contents to spill into the soil.

The gendarmerie set up a 500-m safety perimeter and evacuated 16 local residents; rail traffic and road traffic on the D817 highway were halted; the passenger rail station was also evacuated. Over 70 fire-fighters were called to the scene and laid a 1,000-m² foam blanket under the cars; they were only able to close one of the two manholes, then installed both a buffer storage to recover the MVA still flowing and a dam to prevent pollution from reaching the AULOUZE River. At 4:45 pm, the safety perimeter was scaled back to 100 m and rail traffic resumed; train speed however was reduced until the intervention was over. Up to the morning of 15 November, the derailed cars were emptied, inerted and placed upright using two 200 t and 90 t cranes. During these operations, the emergency response team set up powder nozzles around the tanks receiving these transferred products and regularly replaced the foam blanket. The chemical site which sent the convoy emptied the cars on 15 November and the polluted soil on 17 November. The responders patrolled the zone and measured the explosibility potential until the morning of 16 November: the 16 evacuated residents were allowed to return home. The classified facilities inspectorate and an elected official made a site visit.

A fire-fighter who sustained an injury to his right thumb and received foam projections in the eye, was transported to the hospital. Since MVA is 90% biodegradable within 14 days, aquatic pollution could be avoided and soil pollution limited. Rail traffic was stopped for 7 hrs, 45 min and the highway was closed for 5 hrs, 10 min.

The accident occurred on a turn known to be dangerous, hence the train’s reduced speed. According to the rail network operator, this derailment was caused by a technical flaw of the system; embankment sliding due to heavy rains over the previous 2 weeks was cited.