At 5:25 pm, the bowl of a centrifuge broke inside a corn starch mill at a food processing plant located in an industrial zone and harbour facility. No victims were reported, but several tens of kilograms of debris (some of which were sprayed over a 25-m radius) sliced through 2 reinforced concrete columns, perforating a steam pipe pressurised at 16 bar. Process fluid pipes were also cut, in damaging the electrical cables, along with a centrifuge, rotary filter, the laboratory, a conference room whose double partition was ripped through by a piece of debris, and lastly the control room window.

Technicians shut down the unit and cut the “steam network”, which in turn caused a cessation of all site activities, then isolated the pipe and notified rescue services. Fire-fighters and gendarmes arrived on the scene at 5:45 pm, joined 15 min later by a local official. Responders provided assistance to an employee in a state of shock. Since the building could potentially collapse, a safety perimeter was marked off around 3 stories, and 4 supports were introduced. The electrical control room was consigned. Informed during the evening, the classified facilities inspectorate combined a labour inspection with a site visit on the next day. The Prefecture was also informed of the accident.

Losses were estimated at €1.5 million. Workshop operations were suspended, resulting in a production loss of 750 tonnes/day (75% of the site’s total output). Clients’ supplies were interrupted. No redundancies however were scheduled.

The investigations conducted supported the hypothesis of an unanticipated fatigue in the metal (ferralium alloy) used to make the bowl. No anomaly had been identified during a control by bleeding carried out on the bowl on 2nd February; the bowl in inventory had been placed back into service 12 days prior to this incident. According to some sources, ferralium is well-known for its rupture risks when heat treatment is imperfectly controlled at the end of manufacturing. Metal crystallization can display anomalies that are solely detectable by a sampling of specimens, thus leading to bowl destruction. Several similar centrifuges, all built in 1993, were installed on the site around the same time and under identical conditions; a common failure mode was thus feared. With the approval of its supplier, the operator decided to systematically replace the bowls made of ferralium with those made of type AL1112377-02 forge duplex stainless steel, which is simpler to control (with potential cracks slower to spread and more easily detected by bleeding) and which up until then had not been involved in any accidents, as opposed to ferralium bowls (already responsible for at least 3 recordings of broken bowls). All machines underwent an in-depth vibratory control before service restart. Meetings were organised in order to inform the entire workforce.