<P> Soviet authorities started evacuating people from the area around Chernobyl only on the second day after the disaster (after about 36 hours). By May 1986, about a month later, all those living within a 30 km (19 mi) radius of the plant (about 116,000 people) had been relocated . This area is often referred to as the zone of alienation . However, significant radiation affected the environment over a much wider scale than this 30 km radius encloses . </P> <P> According to reports from Soviet scientists, 28,000 square kilometers (km, or 10,800 square miles, mi) were contaminated by caesium - 137 to levels greater than 185 kBq per square meter . Roughly 830,000 people lived in this area . About 10,500 km (4,000 mi) were contaminated by caesium - 137 to levels greater than 555 kBq / m . Of this total, roughly 7,000 km (2,700 mi) lie in Belarus, 2,000 km (800 mi) in the Russian Federation and 1,500 km (580 mi) in Ukraine . About 250,000 people lived in this area . These reported data were corroborated by the International Chernobyl Project . </P> <P> Some children in the contaminated areas were exposed to high radiation doses of up to 50 gray (Gy), mostly due to an intake of radioactive iodine - 131 (a relatively short - lived isotope with a half - life of 8 days) from contaminated milk produced locally . Several studies have found that the incidence of thyroid cancer among children in Belarus, Ukraine, and Russia has risen sharply since the Chernobyl disaster . The International Atomic Energy Agency (IAEA) notes "1800 documented cases of thyroid cancer in children who were between 0 and 14 years of age when the disaster occurred, which is far higher than normal", although this source fails to note the expected rate . The childhood thyroid cancers that have appeared are of a large and aggressive type but, if detected early, can be treated . Treatment entails surgery followed by iodine - 131 therapy for any metastases . To date, such treatment appears to have been successful in the vast majority of cases . </P> <P> Late in 1995, the World Health Organization (WHO) linked nearly 700 cases of thyroid cancer among children and adolescents to the Chernobyl disaster, and among these, some 10 deaths are attributed to radiation . However, the rapid increase in thyroid cancers detected suggests some of this increase may be an artifact of the screening process . Typical latency time of radiation - induced thyroid cancer is about 10 years, but the increase in childhood thyroid cancers in some regions was observed as early as 1987 . </P>

One kind of cancer that increased after chernobyl was