ABSTRACT
This chapter introduces the reader to several important definitions and concepts concerning risk. It discusses risk, risk assessment, risk management, risk communication, and safety. Exposure to low levels of ionizing radiation and chemicals is associated with a special type of risk. These risks are primarily linked to cancer and are very small and extremely difficult to measure in occupational and environmental settings. Additional human data are available from medical exposures where patients were given high doses of radiation for treatment of cancer and noncancer diseases. The Nuclear Regulatory Commission report focused on chemical carcinogens, but the framework is also applicable to ionizing radiation and other physical and biological carcinogens. In practical risk assessment, elements may be considered in parallel, and information about one element may be important in the evaluation of other elements. The chapter also presents an overview of the key concepts discussed in this book.
