With the type and amount of a substance leak or spill, as well as the meteorological conditions as the main variables, the accident consequence simulations are performed similar to the transportation accident case to support emergency response measures or related training exercises.

The main case study for process plant accidents, coordinated by SYRECO, will be Ponte S.Pietro near Bergamo, Northern Italy. This area covers about 40 km2, distributed over 8 communities with about 30,000 inhabitants. 10% of the area is under industrial land use. A number of Seveso-class chemical process plants and so-called Level 2 installations with a total of more than 3,000 employees operate in this area. The main hazardous substances include Acrylate, Acrylonitrile, Butadyene, Styrol, Methyl Alcohol and Alifatic Alcohols, Formic Aldehyde, Ethylene Oxide, Phenol, Toluene, Amine, Flammable Solvents, Pesticides, Cyanides, LPG, etc, distributed over about 500 storage tanks from 5 to 1,500 tons of capacity and a total quantity of around 10,000 tons of toxic and flammable substances.

In addition to their storage and use in the process industries, these dangerous substances are transported by road, mainly trough the A4 Milan-Venice highway and other roads of provincial interest. The average daily traffic involves 16,000 vehicles. About 10% of these are trucks carrying hazardous substances: more than 10% of these transport toxics, another 45% flammable substances with a flash point below 65 degree Centigrade.

SYRECO has performed extensive safety audits and analyses in this area, including process plants, storage locations, and the transportation of hazardous substances, and compiled large amounts of recent safety related data and the necessary environmental background information. This will form the basis of the simulation exercises, which will cover main possible major accident scenarios as foreseen in the recent amendments (COM(94) 4) to the Seveso Directive (82/501/EEC, 87/216/EEC).

Rail transport in Alpine Valleys (Switzerland)

The case study will address the the release of a hazardous substance to the atmosphere or into a water body (surface or possibly groundwater) from a transportation accident. The vehicle involved (truck or railway car) uses an emergency information system to broadcast its position (GPS derived, through GSM) and freight data (substance, amount) to a control center running the HITERM} main system. From this information the control center with (access to) the appropriate HPC resources initiates further data collection (for example, from the nearest meteorological station(s) or an appropriate hazardous chemicals data base), loads the local GIS data, and initiates the simulation of the accident consequences to guide emergency response measures.

The consequence simulation involves complex dispersion modeling (atmosphere, soils, water bodies), parallel (Monte Carlo) error and sensitivity analysis, and the graphical visualization of the accident consequences (for example, population exposure in space and over time in the form of interactively animated topical maps), as well as providing integrative instructions and decision support for field personnel or in a training situation. Using a discrete multi-criteria DSS approach to suggest optimal strategies to the operators, the interactive interface allows people on site to introduce their observations, constraints, and objectives. This information can be accessed remotely (again through GSM phone links or dedicated channels) through TCP/IP Internet protocols and IP/ISDN with simple, mobile and hand-held terminal equipment (PC, laptop running http clients).

The case study, under the primary responsibility of ASIT, will address transportation risks (roads and railways) in the Canton of Uri, part of the Gotthard alpine transit corridor linking France and Germany with Italy. This will provide a model for several similar North-South alpine corridors of strategic economic and environmental importance. Detailed geographical, environmental and transportation systems data, as well as existing traffic telematics systems (using GPS and GSM) are already in place.

The study will involve the evaluation of the HITERM system under the special conditions of the alpine region (narrow valleys, long tunnels, high traffic densities), and involve crew training on the basis of a simulated major accident with dangerous goods on the N2 (E35) highway or the Gotthard railway. A number of Swiss authorities, including the National Alarm Head Office, Chemical Accidents Intervention Forces of the Canton Uri, Swiss Federal Railways and the Swiss Federal Highway Office, as well as the Association of Chemical Industries have expressed their interest in the project and are expected to collaborate actively.

Road transport of hazardous goods: the Lisbon-Aveiras route (Portugal)

The impact assessment for road accidents involving hazardous goods involves a number of real-time communication elements: the identification of the truck and the determination of its location, based on GPS/GSM in an on-board unit installed in the truck, operated by the driver or automatically in the case of an accident. The assessment must also considers dynamically updated environmental criteria to accurately predict accident consequences, based on time-variable local conditions such as temperature, precipitation, wind speed and direction, surface water flow, in addition to traffic related information. Short-time patterns of population distribution (day-night cycles) could also be considered for impact assessment. The models used (spill/evaporation, fire, explosion, atmospheric dispersion, and infiltration/soil contamination) are all run as stochastic models in a Monte Carlo framework.

Given a dynamically generated alarm from a vehicle in transit, the possible impacts of the accident are determined through simulation of accident scenarios based on the hazardous substances involved, their amount, and the degree of damage to the vehicle, i.e., the nature of the accident.

Given the requirements of a large fleet of hundreds of vehicles, and the inherent complexity of the risk calculations (e.g., involving heavy gas dispersion modeling, fire and explosion models) the need for HPCN should be obvious. An additional complexity can arise through the inclusion of on-line sensitivity analysis, where the robustness of the solutions is tested against increasing levels of data and parameter uncertainty.

The vehicle fleet (tanker trucks with hazardous cargo) of PETROGAL and its Portuguese distribution (road) network, and in particular the highway between Lisbon (airport) and the fuel depot and loading station in Aveiras north of Lisbon, will be used as an example. The Petrogal fleet includes: