Despite the relatively clean environment on the islands of Hawaii, residents have been concerned about clusters of disease due to environmental exposures. Close to 40 inquiries related to perceived increases in health conditions have been examined during the last three years. The standardized incidence ratio approach was the preferred strategy to evaluate occurrence of disease. Three examples of cluster investigation are presented. Even though all investigations except one showed results within the expected range, cluster investigations appear to be useful in allaying fears, in particular about cancer, by providing comparative numbers and factual information on carcinogenesis.