What happened at the fish food processing plant in Halsa, Norway?

In August 1975 an industrial explosion occurred at a fish food processing plant in Halsa on the west coast of Norway. The plant was located in a 30 metre tall building that also contained large storage and a mixing silo.

What caused the fish food processing plant explosion/fire?

The system had inherent design flaws causing metal bolts to fall into the mill. Upon investigation by an engineer when opening the mill, chute sparks were seen as a result of the grinding of the metal objects, which ignited the dust cloud.

What can the industry learn from the fish food processing plant explosion/fire?

Investigation into the incident confirmed that the risk of explosion was not fully understood by the process facility.

The dust generated in this case was at lower concentrations than perhaps other food process plants, such as grain. However, it can be mixed to produce a stoichiometric mixture in the air. The circumstances gave rise to the three key ingredients needed for generating a serious dust explosion:

• Large empty enclosures apart from explosive dust clouds
• Large quantities of dust throughout the entire building
• An ignition source
  
   

Other key factors included:

• Poor housekeeping
• No dust extraction
• Poor conveyor and screw design