Radioactive iodine isotopes may be released to air to a varying degree during 
accidents with nuclear reactors. Iodine tablets, taken before or shortly after 
such release, protect against intake of radioactive iodine isotopes, but not 
against other radionuclides. Iodine prophylaxis can be a relevant countermeasure 
in Norway and will be implemented according to recommendations from the Crisis 
Committee for Nuclear and Radiological Emergencies. The Chernobyl accident 
confirmed that the risk for radiogenic thyroid cancer is much higher for 
foetuses and children and adolescents under 18 years. An epidemiological study 
showed that intake of iodine tablets could reduce the risk for thyroid cancer by 
a factor of three. For children, the WHO has therefore recommended a 10 mGy 
avertable dose to the thyroid. The Norwegian Radiation Protection Authority 
acknowledge the WHO guidelines and advise that the first priority of all 
emergency preparedness planning for potential releases that can cause dispersion 
of radioactive iodine, should be given to the protection of pregnant and 
breast-feeding women, newborns and children under 18 years. Iodine tablets 
should be taken immediately (preferably not later than a few hours) in 
situations where inhalation of radioactive iodine may occur. It should be 
underlined that iodine prophylaxis is one of several emergency countermeasures; 
other measures are sheltering and evacuation. The latter two countermeasures 
will protect not only from intake of radioactive iodine, but also against other 
radionuclides that may be released. Based on the present risk assessment in 
Norway, iodine tablets have been distributed to the counties north of Salten. In 
addition, there is an emergency stockpile of iodine tablets in Oslo.