This monograph is an amalgamation of two draft documents "Principles for the Assessment of Risk from Exposure to Chemicals" and "General Principles and Methods for Chemical Safety (Human Health Protection)". Both documents were planned to cover different aspects of chemical safety and risk assessment; one dealing with the basic science for general readers, and the other providing more practical approaches to risk assessment of chemicals for risk assessors. This Environmental Health Criteria monograph is aimed at furnishing a practical overview of chemical safety and at providing the framework of risk assessment for regulatory and research scientists, as well as risk managers.