Pollution
Humain
Environnement
Economique

At about 2:45 a.m., following a power failure, a hydraulic hose fire broke out in a steel mill. The molten steel overflowed onto the fixed part of the ingot moulds. It flowed onto the sealed cobalt-60 sources intended to regulate the flow of steel through the ingot moulds. Finding themselves in complete darkness due to the power outage, the 50 employees evacuated the site and gathered at the first aid station. Firefighters were able to extinguish the fire using powder type extinguishers. Seventy people were laid off for 3 days. The furnaces were shut down while a specific protocol was developed to remove the molten steel.

The fire started as a result of an overvoltage caused by a lightning strike on the power substation at the casting hall. In addition, the generator set tripped and thus was unable to provide back-up power after the outage. At the time of the incident, 10 t of molten steel was present in the casting distributor. A system of sliding gates, located in the distributor, normally closes the openings through which the steel flows. However, the hydraulic cylinders, although with positive safety system, did not work. The 10 t of molten steel then poured into the ingot moulds without any way to control the filling process. The ductile part of the steel could not be removed by the mechanical traction system located under the ingot mould due to the power outage. A plug was created in the ingot mould. The steel, continuing to flow by gravity, overflowed onto the ingot moulds. The subsequent release of heat melted the hydraulic hoses supplying the cylinders on the ingot moulds and caused a fire.