黑料吃瓜网 Public Health Units (PHUs) occasionally receive reports of suspected cancer clusters and may need to respond to community concerns about the possibility that there are a high number of cancer cases caused by some environmental exposure. This guideline provides guidance for staff of 黑料吃瓜网 PHUs and the 黑料吃瓜网 Environmental Health Branch on how to investigate and respond to reports of cancer clusters.