Around 11:30 pm, a strong smell of hydrocarbons was indicated by residents living near a petroleum depot located along the banks of the Seine River immediately after the pipeline delivery of 2,640 m³ of unleaded gasoline. Arriving on-site at midnight, fire-fighters halted all rail and river traffic in the depot vicinity, yet were not allowed inside the facility since the local manager of the operating company had refused assistance from external responders. When the Prefecture cabinet director showed up at the scene around 3 am, fire-fighters were ultimately authorised to intervene and observed the overflow of a gasoline tank. The associated retention basin, which had received several m³ of the gasoline collected, was covered by a foam blanket. This operation was complicated by an insufficient flow rate and pressure on the premixing network, as well as by the removal off-line of a portion of the fire protection network following a valve rupture.
Despite the absence of any serious consequences, this accident still would have generated a major risk in the event of ignition.
The classified facilities inspectorate issued the following observations :
- The tank that overflowed was not being directly fed, but instead fed via several intermediate tanks positioned higher and filled by the pipeline beyond their “upper” and “very high” limits, with these levels being balanced thanks to gravity ;
- For this purpose, the upper and very high level alarms were bypassed, thus depriving the site of a line of defence, given that the signal retransmission necessary for the pipeline operating company to halt delivery upon alarm signal detection was no longer available ;
- Subsequent to a modification in the internal electrical network at the depot from a few months prior, the operator was unable to restart the facility’s fire pumps from the backup power supply (electric generating set) ;
- The fire water network had not been entirely functional: due to a leak on a network tap, the operator had blocked a portion of the premixing network, thus creating the difficulties encountered by fire-fighters during the night ;
- On-site safety organisation was clearly flawed, leading the operator to ignore the deficiencies inherent in his own depot.
A prefectural order imposed a number of emergency measures : shutting off pipeline supply to the depot while waiting for service to restart, reading tank level probes, and producing an accident report. The operator received an official injunction to restore the fire water network to full capacity within 24 hours.
Feedback had not been taken into account by the site operator, who had already undergone at least 6 incidents involving depots over the previous 8 years.