On a Sunday evening at around 9:30 p.m., a fire broke out in an outdoor storage area of a hazardous waste treatment centre. An infrared alarm was triggered and alerted the shift crew. The employees attempted to put out the fire with fire hoses but were hindered by the explosion of numerous aerosols. The fire brigade offered assistance by deploying foam via several hoses. The analysis of the black smoke released showed no signs of toxicity. The intervention ended at around 10:30 p.m.
The fire had consumed 11,200 kg of waste: 2,000 kg of special household waste (SHW, also known as hazardous household waste, HHW) from waste collection centres, 4,000 kg of various packaging materials (pallets, crates and plastic containers, etc.) and 5,000 kg of rubber hoses. The 120 m³ of extinguishing water was recovered in a retention basin.
Causal analysis
The fire started from a stock of 60-litre plastic crates containing special household waste from waste collection centres. These crates had been delivered just before the weekend and had not yet been sorted.
The operator suspected that an exothermic reaction caused by mixing of incompatible SHW may have been the cause of the fire.
Feedback and measures taken
The accident highlights the importance of storing unsorted SHW in an area equipped with infrared detection equipment. The fact that the area used to store waste pending was isolated from buildings helped prevent the fire from spreading. However, even though this didn’t happen on the day of the accident, the site’s hazard study did not anticipate that the projection of aerosol cans caught in the fire could have resulted in a domino effect on a nearby building.
An ‘internal contingency plan’ exercise, based on the fire scenario that occurred on the day of the accident, had taken place just a few months earlier. This allowed the employees and emergency services to react accordingly.
Following the accident, the operator took the following measures:
- limitation of the stock of unsorted SHW and its isolation from other types of waste on standby (aerosol cans and hydraulic hoses are not to be stored in the same area, the presence of which complicated internal intervention by generating projectiles and heavy smoke);
- aerosols are now stored in a dedicated and isolated area, in a wire enclosure;
- addition of recording capability to the video surveillance system;
- inclusion of the scenario involving a fire of the SHW pending sorting in the hazard study.
