The main elements of an integrated emergency management system are: prevention preparedness response releif Prevention Public authority and corporate policies related to hazardous installations should have, as primary objectives, the prevention of accidents involving hazardous substances and limitating any adverse health consequences should an accident occur. Public authorities should set general safety objectives and establish a clear an coherent control framework with respect to accidents involving hazardous substances. In this regard, they should seek to protect the health of workers and the public through the development and implementation of appropiate laws, regulations, standards, codes and guidance. Management of a hazardous installation (see Annex 2 of module Bl-2/B "Technological risks and effects") has the primary responsibility for designing, constructing and operating the hazardous installation in a safe manner and for developing the means to do so. It should therefore put into place the systems, procedures and structures needed to help ensure the prevention of accidents and, should an accident occur, to ensure timely and adequate response to limit adverse health consequences or other damage. Employees and their representatives should be involved in the development and implementation of such systems, procedures and structures. Public authorities, including health authorities, in different countries should co-operate and exchange information which could help prevent accidents or human exposure to chemicals. Health/medical professionals should be involved in decision-making relating to the prevention of chemical accidents.