Research into risk perception has been typically focused on the study of social conflicts motivated by potentially dangerous technologies and events. However, in this article an attempt is made to understand why, in certain cases, the population exposed to an obvious risk are not actively mobilised and do not protest against it. Based on a case study in the petrochemical area of Tarragona, the population’s perception and practices in connection with risk are analysed by using data from a series of focus groups (8) and a questionnaire survey (N= 400). The results allow us to disregard unawareness of risk as a reason, and to assess the importance of the perceived benefits from exposure to risk, as well as to understand the fundamental role of trust and dependency that are embedded in a social and institutional context characterised by a marked asymmetry in power relations.