Industrial development is essential to improvement of the standard of living in all coun tries. In a given region, old and new plants, processes, and technologies have to coexist Technological penetration and substitution processes are generally taking place; they are entirely dynamic and this trend is going to stay like this. People's health and the environment can be affected, directly or indirectly, by rou tine waste discharges or by accidents. A series of recent major industrial accidents and the effect of poUution highlighted, once again, the need for better management of rou tine and accidental risks. Moreover, the existence of natural hazards complicate even more the situation in any given region. Managing the hazards of modern technological systems has become a key activity in highly industrialized countries. Decision makers are often confronted with complex issues concerning economic and social development, industrialization and associated infrastructure needs, population and land use planning. Such issues have to be ad dressed in such a way that ensures that public health wiD not be disrupted or substan tially degraded.