The use of space is being intensified near and above transport routes of hazardous materials. In The Netherlands, some buildings are even realized above infrastructure with transport of hazardous materials like LPG. An accident with an LPG-tank may result in a BLEVE, causing injuries and large structural damage to the spanning building and the vicinity. Fortunately, such disasters are scarce up to now. However, one should be aware of that such accidents may occur and escalation from accident to disaster should be prevented. On one hand, this paper presents the modelling and the analysis of the explosion effects and the dynamic response of the structural elements. On the other, an analysis of structural measures to control the consequences for the spanning building when the explosion occurs in the underpass is given: two mitigating measures to minimize the effects of a gas explosion or a BLEVE are analyzed, i.e. a steel tube for packing the infrastructure in which the LPG is transported or a buffer zone by adding two extra stories to the building, in which the first two lower floors are designed to be severely damaged under explosive loading forming a buffer zone between the infrastructure and the building above. Subsequently, the cost-effectiveness of these safety measures is determined.