Every year, some 1.6 million people are diagnosed with cancer, and every year, epidemiologists look at places where there appear to be clusters of people with cancer. In only two cases – one in Woburn, Mass., and another in Toms River, N.J. – were cancer clusters linked to environmental conditions. But the reality of cancer clusters is that they may have nothing to do with the environment or anything else. They might just be nothing more than statistical aberrations. But those aberrations tend to drive public awareness in strange directions.