A fire broke out at 8.35 am on a 3 to 4 m-high cooling tower in a plant producing industrial gases; the site was on triennial shutdown for maintenance at the time of the incident. Fire that created a great deal of smoke started 48 hours after work to replace plastic packing (used for water/air exchanges).
The alarm was raised; around 100 people carrying out miscellaneous maintenance work were evacuated with the exception of the in-house emergency response team made up of 10 employees. The company activated its internal emergency plan at 8.45 am while informing the harbour master’s office and the gendarmerie (French military police). The fire was brought under control at 8.50 am before the arrival of external firefighters 5 min later. The internal emergency plan was lifted at 9.35 am. No one was injured, but the flames had damaged over half of the 10 units constituting the affected tower block. The fire extinguishing water collected in an associated basin was evacuated to a waste disposal facility authorised for this purpose.
A sub-contractor was working on the droplet catchers and the motor of the tower fans. His work permit did not specify naked flame work, and no hot work permit had been issued as a consequence. New droplet catchers had to be fixed by bolting; this method which is difficult to implement in the field had been abandoned by the external company in favour of weld assemblies. The operator, who had not been informed of the change in procedure had carried out no reassessment of the risks beforehand. The use of suitable weld protection resources as set out in the prevention plan had not been respected, and those actually used (temporary protective metal sheet on 3 units) proved to be insufficient.
The installations were placed back in service 3 days after the incident. The operator modified several procedures related to officer training and interventions: improvement of safety induction training and accreditation of prior learning, coordination and sequencing of tasks, approval of operating procedures (with or without sub-contracting), and obligatory request for written risk analysis for any changes to the procedure.
