The incident, involving the accidental leakage of 15,000 litres of the disinfectant - which is used to clean processing water - took place at Grieg Seafood Finnmark's harvesting plant in Alta.
According to the salmon producer, the leak did not harm any people, but killed 96,000 fish - corresponding to approximately 430 tonnes – in the pens at the plant.
The company says that it does not yet have a complete overview of how the leak has affected the environment in the fjord, but it has engaged with Akvaplan Niva to conduct an independent assessment of the environmental impact.
“Chlorine is rapidly diluted and breaks down quickly in water. According to what we know today, the leak had a short-term, acute impact on organisms that were in the water around the harvesting plant when the incident occurred. The environmental assessment, which is expected to take a few days, will provide a full answer,” announced the company.
“Grieg Seafood Finnmark is working to clean up the pens. The harvesting plant's silage system and silage boats will take care of the dead fish, which is monitored continuously. It is expected that the clean-up will take a few days,” it added.
The fish were insured but Stine Torheim, manager of the harvesting plant, said: “This is very sad. Our focus is now first and foremost on cleaning up. We will get all facts about this incident on the table, to ensure that it will not happen again.”