In an optical fibre laying site, a toothed trenching machine severed and ripped out a natural gas distribution pipeline (diameter 125 mm, pressure 4 bar). The employees switched off the engine of their vehicle. The gas department was informed and arrived onsite at 3.26 pm. It closed a valve upstream after spending 50 min trying to cut off the pipeline’s gas supply. Repair operations started at 6.30 pm and the gas supply was restored as of 9.00 pm to some customers.

The inspection authorities for classified facilities arrived onsite and the operator had submitted the formal Start of Works Notification and a yellow warning fence was found buried 0.6 to 1 m deep in the debris on the pipeline.

Further to this accident, the report of the inspection authorities for classified facilities stated that it was not easy to read the maps provided with the formal Start of Works Notification (DICT). The map provided by the technical team of the gas departments in two parts specifies that the pipeline crosses the RN5 at the Y junction of the road. The two parts of each of the maps were accurate but the assembly scales were not properly adapted. The bifurcations of the successive roads led to an error in precisely locating the position of the pipeline.

The accident had significant social consequences: road traffic was stopped and 320 residences deprived of gas.