Norway's food safety agency has issued a warning to people in the north of the country to reduce their consumption of seagull eggs. The agency claimed the eggs are contaminated with high levels of toxic polychlorinated biphenyls ( pcb s). The people of Troms and the Lofoten Islands eat up to 40 eggs annually. However, the country's National Food Agency has come upon evidence to show that consuming more than 10 eggs a year could be potentially hazardous. It is already a well-established fact that pcb s are harmful for human health and damage the immune and reproductive systems of mammals. pcb s were used in insulators in electrical equipment and in the manufacture of pesticides, lubricants and plastics.