The incidence of cancer in northern Sweden increased following the accident at the nuclear power plant in Chernobyl in 1986. This was the finding of a study from Linköping University in Sweden that asked: Was the increase in cancer caused by the radioactive fallout from Chernobyl or could it be explained by other circumstances? In two studies using different methods, Martin Tondel showed a small but statistically significant increase in the incidence of cancer in northern Sweden, where the fallout of radioactive cesium 137 was at its most intense… –JULIA WHITTY