After the shock, comes the time for the investigation and explanations.
A luminous "flash" phenomenon was observed just before the series of three explosions which hit the Manuco site (Eurenco Group) in Bergerac (Dordogne) on Wednesday during a "piping assembly site", injuring eight people, the group's management said on Monday.
"The observed phenomenon is a kind of flash of light which then triggered a first explosion, followed by a fire and two other explosions", summed up the CEO of Eurenco Thierry Francou.
Last Wednesday, on this site classified Seveso "high threshold" producing nitrocellulose (an explosive substance), the incident left eight injured, including one seriously.
All are now "out of danger" and five have already been released from hospital, the company said on Friday.
In a new update on its internal investigation on Monday, management specifies that "three projects were underway in the nitrocellulose refining area" at the time of the accident.
“The first concerned pipe assembly work on a tank, the second routine maintenance of refiners and the third concerned maintenance on electrical installations,” Eurenco detailed in a press release.
A fire at the origin of the other two explosions
According to "the first testimonies", "a flash would have occurred in the area of the piping assembly site where an operation to reconnect a new pipe to the existing installations was being carried out".
"The causes of this reaction remain to be clarified" but this operation would have triggered "a first explosion in the northern part of the building then resulting in a fire and two other explosions", explained Eurenco.
On Friday, the group indicated that a maintenance operation "would be the cause of the accident", while arguing that "the high temperatures and especially the very low humidity", had "also been able to play a role" .
At the time of the accident, the site was shut down to carry out these operations.
Read alsoExplosions in Bergerac: how do emergency services manage accidents on Seveso sites?
The internal investigation "calls on internal and external experts but also on the employee representative elected to the CSSCT (specific commission created within the social and economic committee, which deals with questions of health, safety and working conditions) of Manuco,” said management.
Two other procedures are carried out in parallel.
One, judicial, was opened by the Bergerac public prosecutor's office while an administrative investigation is also being conducted by the Bureau of Investigation and Analysis of Accidental Risks, created in December 2020 after the Lubrizol accident in Rouen.
