The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) assesses the levels and effects of exposure-ionizing radiation. UNSCEAR's scientific findings underpin radiation risk evaluation and international protection standards. This is the second of two volumes of scientific annexes that provide the supporting scientific assessment for UNSCEAR's 2008 Report to the General Assembly. It contains three scientific annexes. ""Radiation exposures in accidents"" aims to provide a sound basis for conclusions regarding the number of significant radiation accidents that have occurred, the corresponding levels of radiation exposures and numbers of deaths and injuries, and the general trends for various practices. ""Health effects due to radiation from Chernobyl accident"" provides updated estimates of exposures of workers and the general population, and an authoritative review of the early and late health effects observed that are attributable to radiation exposure.