The Castlereagh Regional Waste Disposal Depot (CRWDD) has been the focus of community concerns regarding the impact of hazardous waste disposal on their health and that of their local environment. As part of a phased epidemiological approach to investigate the levels of illness in people living in the vicinity of the CRWDD, routinely collected data were used to determine the rates of cancer and mortality in the area around the site and whether these rates were higher than expected when compared with New South Wales (NSW). The area investigated was based on eight census collection districts around the boundary of the CRWDD. Cancer incidence and mortality in the study area were calculated and compared to NSW using the indirect method of age and sex standardisation. Over an 18-year period, brain cancer in males (six cases) was the only cancer where the incidence in the study area was significantly higher than expected (SIR 380, 95% CL 139.4, 826.6). When this data were examined over smaller (arbitrary) time periods, there was an apparent cluster of brain cancer in males (three cases) between 1989 and 1991 (SIR 905, 95% CL 187,2646). There was a significant concentration of cases of cancers of the breast in females and cancers of the uterus over the smaller time periods. Although continued surveillance of these cancers is recommended, there are several basic limitations associated with small area data analysis that prevent a clear interpretation of these results. This limits our ability categorically to resolve the concerns of those living in the vicinity of the CRWDD.