An authoritative report from the United Nations (IAEA, 2005) indicates that: “It is impossible to assess reliably, with any precision, numbers of fatal cancers caused by radiation exposure due to Chernobyl accident. Further, radiation-induced cancers are at present indistinguishable from those due to other causes.” However the IAEA International Expert Group “predicts that among the 600 000 persons receiving more significant exposures (liquidators working in 1986-1987, evacuees and residents in the most “contaminated” areas), the possible increase in cancer mortality due to this radiation exposure could be up to a few per cent.