Proponents of krill oil supplements believe they are superior because they have a lower level of toxic contamination. Pollution is evident in the every ocean, even the Antarctic. And there's air pollution everywhere. It's highly unlikely to find any marine source that is completely free of contamination and this includes krill. On the other hand, omega -3 fatty acid supplements undergo a rigorous decontamination process. Krill oil does not. For that reason, claiming krill oil is free of toxic contamination is a bit of a stretch.