What differentiates hazardous material (hazmat) shipments from the transport of other materials is the risk associated with an accidental release of the material. The paper concerns the problem of routing and scheduling hazmat in urban and suburban road networks. This problem involves conflicting objectives among interested parties: the shipping company, the client, the vehicle driver, the environment agency of the area, the population. In presence of conflicting interests, the use of a decision support system (DSS) is recommended. The paper outlines an ongoing work to develop a DSS based on a Geographical Information System (GIS) for hazmat transport in the city of Milan. We use a probabilistic risk assessment model, which takes into account, as route selection parameters, the probability of accidents and the consequences of an accident for each road segment. The model considers population, vulnerable facilities (schools, hospitals, …), territorial infrastructures (e.g. railways, electric lines), natural elements (water bodies, green areas, …), critical areas (e.g. areas which may be a target for a terrorist attack). An hazmat multi-objective route planner has been developed in Python language using ESRI ArcGIS to perform spatial analyses and to optimize the procedure. The planner, which is in a prototype phase, has been tested on Niguarda, an area of the city of Milan characterized by the presence of an important hospital.