Pollution
Humain
Environnement
Economique

Two subcontractors were performing hot spot works on a cooling tower at a Seveso-rated plant manufacturing sodium carbonate and bicarbonate when the exchanger housing (gasket), made of plastic and PVC, ignited around 8 am. The ensuing fire spread within a few seconds to the tower’s plastic cladding and its structural wood frame, then to a lorry-mounted crane parked nearby. The workers fled, without enough time to use the extinguisher on hand. The crane operator, who barely had the time to leave his cab, sustained slight burns to both sides of his neck. The combustion of lorry oil released thick black smoke that was visible from afar. The fire-fighters extinguished the fire using 2 water hoses, with 2 more hoses being installed to protect the 6 cooling towers surrounding the one in flames. The fire was extinguished at 8:30 am. The plant operator activated the internal emergency plan and assembled a crisis response unit. The crane driver received care at the plant’s infirmary before being transported by ambulance to a nearby hospital. The extinction water remained confined in the tower’s retention basins. Property damage was estimated at hundreds of thousands of euros. One cooling tower was destroyed and another seriously damaged by the heat flux. The plant lost 30% of its cooling containers, causing 15% production losses, lasting several weeks.

The investigation revealed that fire had broken out while the subcontracted employees were cutting bolts with a blowtorch (flame cutting), in order to facilitate bolt removal by a reducing device scheduled for replacement on the cooling tower that had been idled the previous day. No hot work permit had been issued since the possibility of such works had not been raised by the subcontractor to the operator when preparing the prevention plans. Moreover, the subcontractor attested to having used a fire-retardant protective tarp on the exchanger, although the appraisal conducted was unable to confirm the presence of any such tarp.