Sonne's Old Fashioned Cod Liver Oil uses Norwegian cod liver oil derived from fish caught in open waters in the North Atlantic Ocean ? away from sites of industrial pollution. In order to ensure that Sonne's Old Fashioned Cod Liver Oil is safe for consumption, sonne's routinely uses an independent laboratory to test for heavy metals and environmental contaminants (such as organochlorides). Sonne's purposely leaves their Cod Liver Oil unrefined, so it retains the natural balance of vitamins and fatty acids. Sonne's is NOT interested in refining out its natural "fishy" taste and smell at the expense of the natural nutritional content and balance.