502LESSONS FROM CHERNOBYLcesium (cesium-134 and cesium-137) , which has long half-life. Iodine-131 was detected in various produce including food, drink, and beef cattle immediately after the accident. Panic was caused not only through the reality of the accident but also by the widespread of groundless rumors through media and the Internet. As a countermeasure, the Japanese government specified values of radioiodine and cesium contained in food and drink as the provisional standard. They regulated shipping produce with higher content of radioiodine and cesium in order to prevent people from ingesting contaminated foods and drinks. We must remember the tough decision taken by the people working in the primary sector of industry in Fukushima Prefecture. Without this sacrifice, the chance of internal exposure to contaminated food could not be decreased. This countermeasure was taken based on the experiences of internal exposure in Chernobyl described above. Careful health evaluation is still required from now on , however, we assume the impact on people's health that we will see in the future will be far different from those in Chernobyl even though the accident was categorized in the same level seven. In 2006, 20 years after the Chernobyl accident, the World Health Organization (WHO) evaluated impacts on health of people in Chernobyl dealing with International Atomic Energy Agency (IAEA). The materials the group of experts examined were mainly internationally-reviewed manuscripts. They also used publications in countries around Chernobyl (The Republic of Belarus, Russian Federation and Ukraine). Those experts primarily evaluated two health-related issues3). One of the issues was health impacts which were directly related to radiation exposure, and the other was diseases that were not thought to be directly related to radiation exposure, however, the relation with the accident could be in doubt. After the evaluation, they submitted a report to the relevant governments. The results showed the drastic increase of thyroid-gland cancer among children who had been younger than 15 years at the time of the accident. According to the report, nearly 5,000 operations of thyroid-gland cancer have been implemented for children in this age group in Russian regions around Chernobyl, Ukraine, and The Republic of Belarus by 2002 (the number of operations increased to 6,000 by 2006). The age predilection is about to move to 25 or older to middle aged. As described above, the increase in thyroid cancer in infants attributed to excess internal exposure to thyroid gland via ingestion of radioiodine immediately after the accident. lt is possible to assume that the chronic iodine deficiency at that time further increased the number of sufferers4). Additionally, the occurrence frequency of thyroid cancer in infants and the dose of internal exposure to the thyroid gland had positive correlation4). lt was very fortunate that 99% of patients had good prognosis and survived after the operations. Radioiodine therapy after the total extirpation of the thyroid gland against lung metastasis showed significant effects and metastasis treatment had a high cure rate6). However, the problems of long prognosis, recurrence, and other complications still remain and further tracing and appropriate treatment are essential. On the other hand, no increase in leukemia has been seen among citizens including infants and adults though that was primarily concerned from the experiences of atomic-bomb survivors in Hiroshima and Nagasaki. This is probably because people in Hiroshima and Nagasaki suffered mainly from external exposure while it was internal exposure to radioiodine immediately after the accident in Chernobyl. Despite the fact that enormous efforts were expended to analyze genetic abnormality of radiation-induced thyroid cancer, the analyses have not been able to distinguish between induction by radiation and spontaneity at the molecular level7). Apart from thyroid cancer, increase in solid IMPACTS ON HEALTH OF PEOPLE IN CHERNOBYL