There is agreement in the risk perception literature that community concerns about the environmental risks posed by locally unwanted land uses are linked to a wide range of psycho-sociological factors, such as the involuntary nature of the risk and the trustworthiness of the regulatory authority. This paper argues that land-use planning officers need to have an understanding of these wider factors in order to award public anxieties an appropriate weight. It tests this contention by examining planning officers' understandings of public concern about the environmental risks posed by waste-to-energy incinerators. Recommendations are made as to how public concern can be accurately and transparently assessed in terms of a full range of psycho-sociological factors.