Prevention of toxic environmental illness in the twenty-first century.

Previous introductions of new technologies have frequently resulted in unanticipated occupational and environmental illness. Prevention of such illness in the twenty-first century requires stringent application of two fundamental principles of public health: evaluation of new technologies before their introduction, and surveillance of exposed persons after the introduction of new technologies. Failure to establish these basic preventive mechanisms in advance will inevitably result in the development of new toxic diseases in the twenty-first century.