At around 11:30 p.m., a fire broke out on a 10,000 l polythene tank at an old powder mill that was being rehabilitated. The tank contained 2500 l of alkaline water (30% sodium hydroxide) used to scrub flue gases emanating from a furnace in which soil contaminated with DDT (dichlorodiphenyltrichloroethane) is incinerated. The furnace was a temporary installation used to remediate the soil on the construction site. The flames spread to the flue-gas scrubbing tower, causing three cylinders of calibration gas (nitrogen and carbon dioxide) located inside a nearby container to explode. The shift manager tried to put the fire out with a fire extinguisher but was unable to. He alerted the guardhouse and the manager, and then left the area. The plant’s internal emergency plan was implemented and external emergency response teams were alerted. The gas and electric utilities cut off the power supplies. Firefighters put out the fire at around 5:00 a.m. Air quality measurements were taken but found no abnormal pollution levels.

The shift manager, whose hands were burnt while using the extinguisher, was taken to hospital. Only the flue-gas cleaning equipment (bag filters, activated carbon cells, stack) were damaged. The furnace was intact. The rehabilitation work was put off indefinitely. The firewater, which had flowed to an excavation ditch, was pumped out and discharged into a permanent retention pond. The soil was tested.

The operator learned that a particle measuring device that was inside the furnace stack contained a carbon‑14 source. A survey found that the casing had melted and that the source may have burnt, meaning that the individuals who helped to fight the fire may have been contaminated. A mobile radiological intervention unit was called in but did not find any values higher than background radioactivity levels.

At the time of the accident, the facility was operating normally. The shift manager reported that he noticed a ‘scrubber temperature rise’ fault on the analyser shortly before the fire. He therefore implemented the standard corrective procedure, which involves injecting cold water into the system and draining out the hot water. However, a ‘high temperature at the scrubber gas outlet’ fault then occurred. The fire broke out shortly thereafter. According to the operator, the failure could be electrical in origin. It found no link with the pollutants present on the site undergoing remediation.

The operator changed the facility’s fire suppression systems and updated its internal emergency plan. It also conducts fire drills more frequently.