Pollution
Humain
Environnement
Economique

At around 1:15 a.m., an explosion occurred in the furnace feed hopper of a household waste incineration plant. The bottom of the hopper was destroyed (the side and rear walls were blown off). Many electrical cables installed near the hopper were ripped off. The employees secured the unit by shutting off its electricity and gas supplies and installing protection systems to catch falling materials. A technician was slightly injured in a fall during the operation.

At the time of the accident, the incineration line was being shut down in preparation for two weeks of technical maintenance that was scheduled to start the following morning. The last batch of waste had been fed into the hopper at around 11:00 p.m.

Shortly before the explosion, the operator had noticed several problems:

  • The draught fan, used to supply oxygen to the combustion chamber, had lost power several times. These cuts shut off the auxiliary gas burners used to maintain the flue gas temperature at 850 °C, as required by regulations;
  • The temperature of the water circulating in the shell surrounding the bottom of the hopper (to prevent it heating) had risen to 160 °C (its temperature is 40 °C under normal conditions).

The accident occurred during a holiday period, when only a few teams were present on site. A first, small explosion had been felt a few minutes before the main explosion. An employee went to the incinerator and saw steam leaking from near the flange of the thermostatic valve. As the jet of steam was small, intermittent, and difficult to locate, the employee left the area without taking any action. That was when the second, larger explosion occurred.

As the incineration line was under repair for an extended period, temporary alternative solutions were implemented to treat household waste.