Researchers continue to argue about the total number of deaths that will ultimately be attributable to Chernobyl. The debate hinges on a number of unknown factors, including the total amount of radiation released and the likelihood of a given level of exposure ultimately causing a fatal cancer or other illness. One of the most widely quoted death tolls was twelve hundred, offered by Leonid Ilyin, vice president of the Soviet Academy of Medical Science, in 1990. This figure has since been challenged by new research that suggests the ultimate death toll is more likely to be upwards of fifteen thousand people. So far, there have been approximately two thousand cases of thyroid cancer among children who were up to fourteen years old in 1986, with perhaps five times as many cases expected in the future. This rate is much higher than normal. An estimated...