(Ed. note: An earlier version of this story incorrectly reported that two workers were hurt in the incident.)
Salmon production equipment manufacturer Fiizk and Norwegian producer Osland Havbruk said two semi-closed cages have suffered "unexpected damage" at their Sognefjord production site in Western Norway.
The incident, following stormy conditions last week, injured two people, and 400 liters of diesel oil spilled from one unit. Two cranes were also damaged.
The extent of the injuries is unclear.
Safeguards are being put in place to prevent further damage to the cages and "consequential damage to the site," the companies said in a statement on Wednesday.