Illegal levels of malachite green, a chemical that has been banned in Britain after evidence it may have links with cancer, was found in farmed salmon found in Morrisons supermarkets.
In addition to this, Scottish farmed salmon on sale in UK stores has been found to have high levels of flame retardants called PBDEs.
Two of the three main types of PBDEs will be banned this week by the EU after studies linked them to cancer, hormone disruption and impaired brain development.
Reports state that the salmon is likely to have been contaminated through the feed used in fish farms, which is a mixture of ground-up fish and oil.
Farmed salmon has been found to be far more contaminated that wild salmon and European farmed fish contained more PBDEs than those from North America or the Southern hemisphere.