Risk analysis of the transportations of hazardous materials in urban areas

The study of the problems associated with the transportation of dangerous goods must be considered to be as important as that connected with the risks associated with chemical plants. Accidents in the transportation system may occur in environments which are not sufficiently well controlled or protected such as areas of high population density or of natural and historical beauty. Sicily with a very high concentration of chemical plants is an area with a great risk of accidents. The peculiarity of chemical and refining industry is the presence of very large chemical plants located in the eastern side of the region (Priolo, Augusta Gela and Milazzo) accompanied by the almost total absence of small and medium enterprise operating in the chemical area. About the 90% of chemicals produced in Sicily are transported to the chemical industry located in the North of Italy. As a consequence, in this region, there are urban areas subject to an intense traffic of hazardous materials. In this paper the risk analysis of land transport of hazardous materials in the area of the straits of Messina is outlined. The area which is the object of this study is the city of Messina, which has a population of approximately 280,000 inhabitants; its geographic position confers it the role of ‘door of Sicily’ for all the connections with the Italian peninsula which go through it. Since the downtown has developed around the harbour, the road network between the highway exits and the ferry terminals cross densely populated areas and zones of intense commercial activity. Fig. 6 shows schematically the situation. There are four highway slip roads for entering the city (Boccetta, Centro, Gazzi and Tremestieri) and two ferry terminals, one operated by the National Railway Service and one operated by private companies; the principal highway sliproad, Boccetta, reaches the sea between these two terminals. The use of the other sliproads, Centro and Gazzi, is sporadic because they have a larger travelling time due to high commercial traffic. About 22,500 trucks per year of dangerous goods are directed to the Italian Peninsula; in addition approximately 800,000 other heavy lorries and 2,500,000 cars cross yearly the Straits of Messina. In addition Messina is an earthquake zone. For a careful evaluation of both individual and societal risk a detailed analysis of a census data is necessary, in order to define, among others, the hazardous materials traffic flows, the population distribution, and the meteorological conditions. An innovative procedure for risk estimation is applied to Messina. Both individual and societal risk relevant to transport of hazardous materials have been estimated. A careful analysis of the annual rail and road transport of hazardous materials coupled with a determination of the population density of the urban areas traversed has been made. Some scenarios have been identified and the analysis of the consequences was carried out using the TRAT code developed by the University of Bologna. The results obtained permits the evaluation of the global risk relevant to the transport of chemical products. An appropriate transport risk analysis makes it possible to propose a code of practice and law in order to minimise the frequency of incidents based on the diversification of the transportation system, the use of alternate routes and suitable procedures for the loading and discharging hazardous materials.