Pollution
Humain
Environnement
Economique

On a Sunday at around 4:00 p.m., a fire broke out on 120 m³ of hazardous waste at a steel mill. The waste had been set aside in the mill’s storage area for waste containing high amounts of metal. The waste, which consisted of highly flammable grinding sludge containing oil and metal) was stored in three bunkers a storage area divided into five bunkers separated by concrete walls. The fire was noticed by employees, who alerted the on-call manager and the firefighters. The firefighters put the fire out by spraying with water and foam compound. The stored waste was moved to the nearby bunkers and the sludge was divided amongst all five bunkers. The next day, after noticing that the temperature of the sludge rose to 80 °C, the firefighters again sprayed it to cool it down. The firewater was collected and treated on the site. There was a concern that deposits in the smoke may have polluted the ground on and off the site. At the request of the inspection authorities for classified facilities, the operator tested the soil, plants, and crops.

The fire, which started on the surface of one of the heaps, was most likely caused by auto-ignition of the oil following a rise in its temperature and the presence of an ignition source such as a cigarette butt or sun magnification on a plastic bag or directly on the sludge. The heaps of materials were exposed due south and the area was experiencing a heat wave. Puddles of a few litres of oil, which had drained from the waste and accumulated due to the faulty drip collection system, were also found in front of the piles. In addition, the excessive amount of sludge in the bunkers allowed the fire to spread over the divider walls. The drip collection systems were also inadequate and allowed the burning oil to flow from one bunker to the next. The storage area did not have a fire hose cabinet.

The operator plans to either install a fire detection system or increase the frequency of monitoring rounds (currently every two hours) for the waste. The operator plans to store foam compound on the site. The fire had been identified as a scenario in the site’s safety report. The modelled scenario was verified, in particular the hypothesis of short 1 m flames and small heat fluxes.