More often than not, cancer clusters have no scary environmental cause. There are many agents at work. People who are related tend to live near one another. Old people tend to retire in the same areas. Eating, smoking, and exercise habits tend to be similar region to region. And, after all, one in three people will develop cancer in his or her lifetime. To accept that things like residential cancer clusters are often just coincidence is deeply unsatisfying. The powerlessness, the feeling you are defenseless to the whims of chance, can be assuaged by singling out an antagonist.
