Health data reporting mechanisms are necessary to provide a basis for research into possible causal links between health problems and environmental factors. Better surveillance of diseases and monitoring of environmental indicators that may be related to health, including occupational health, are needed. In addition to mortality data, which give only a crude and late warning of potential problems, cancer registers and sentinel surveys should be used and structured so as to maximize public access to relevant information without compromising personal privacy. Public registers on the health-threatening properties of substances, such as the International Register of Potentially Toxic Chemicals, are also of great importance.