31 people died at the time of the disaster, and 28,200 sq. km. (10,900 sq. miles) of land and 1.7 million people were exposed to radiation. Figures from the Ukraine Radiological Institute suggest that over 2,500 deaths were caused by the Chernobyl accident. Because of the absence of systematic records, it is not clearly known how many of the 200,000 people involved in the clean-up operation died in the several years following the disaster. Though 60% of the radioactive fallout landed in Belarus, a portion of it drifted over parts of the western Soviet Union, Eastern Europe, Scandinavia, UK, and the eastern United States (p. 107, Hart, 2005). It is difficult to accurately assess the damage figures, as most of the expected long-term fatalities, especially those from cancer, have not yet actually occurred, and will be difficult to attribute specifically to the accident.
The workers involved in the recovery and cleanup after the accident received high doses of radiation. In most cases, these workers were not equipped with individual dosimeters to measure the amount of radiation received, so experts can only estimate their doses. Even where dosimeters were used, dosimetric procedures varied. Some workers are thought to have been given more accurate estimated doses than others. According to Soviet estimates, between 300,000 and 600,000 people were involved in the cleanup of the 30 km evacuation zone around the reactor, but many of them entered the zone two years after the accident. In the first year after the accident, the number of cleanup workers in the zone was estimated to be 211,000, and these workers received an estimated average dose of 165 millisieverts (16.5 rem) (Hart, 2005, p. 34). The plume of radioactive debris has been said to be equal to the contamination of 400 Hiroshima bombs. This is correct, but misleading. The main effect of the bomb was the direct radiation from the gamma blast. Compared to that, the contamination was only a minor addition. Some children in the contaminated areas were exposed to high radiation doses of up to 50 grays (Gy) because of an intake of radioactive iodine-131, a relatively short-lived isotope with a half-life of 8 days, from contaminated milk produced locally (Hart, 2005, p. 35). Several studies have found that the incidence of thyroid cancer among children in Belarus, Ukraine and Russia has risen sharply. The IAEA notes "1800 documented cases of thyroid cancer in children who were between 0 and 14 years of age when the accident occurred, which is far higher than normal" (http://www.who.int), but 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.
Right after the accident, the main health concern involved radioactive iodine, with a half-life of eight days. Today, there is concern about contamination of the soil with strontium-90 and