In accordance with international treaties and EU law, Norway has a program that controls the levels of medication, illegal substances and contaminants in animals that are used for food production. NIFES (the National Institute of Nutrition and Seafood Research) is responsible for analyzing and reporting on the state of Norwegian farmed fish on behalf of the Norwegian Food Safety Authority.
In 2014, NIFES analyzed the levels of dioxin and dioxin-like PCBs, heavy metals, pesticides and brominated flame retardants in farmed fish. None of the samples were above the target threshold. In 2015, around 2,500 samples of farmed fish, representing around 12,000 fish, were analyzed (see report below).
The main pollutants in wild and farmed fish are PCBs, dioxins and mercury, and salmon absorb these substances through fish feed. The levels found in farmed salmon have decreased thanks to an increased use of plant (vegetable) ingredients in feedstock. Today, farmed salmon contains less pollutants than fatty wild fish.
The Norwegian Scientific Committee for Food Safety evaluated the benefits of consuming the nutrients found in fish against the risk of eating fish. They concluded that the benefits clearly outweigh the negligible risk posed by the current levels of pollutants and other known contaminants in fish. The levels of PCBs, dioxins and mercury in farmed and wild fish are not harmful, not even to those who eat fish regularly.