EXAMPLE 7 Cancer clusters

Between 1996 and 2013, 37 children in Clyde, Ohio, a town of 6000 halfway between Toledo and Cleveland, were diagnosed with cancer. Four of the children had died. With many of the diagnoses coming between 2002 and 2006, state health authorities declared it a cancer cluster, saying the number and type of diagnoses exceed what would be expected statistically for so small a population over that time. In the fall of 2012, the EPA found high levels of toxic, possibly cancer-causing chemical compounds in soil samples from Whirlpool Park, formerly a residential area owned by home appliance manufacturer Whirlpool Corp from the 1950s until 2008. Locals told news reporters that “black sludge” had been dumped in the area during that time. However, as recently as 2009, state agencies had conducted tests in the area and found that levels of contamination were not high enough to endanger the lives of nearby residents.

Between 1997 and 2004, 16 children were diagnosed with cancer and three died in Fallon, Nevada, a farming community of 8300 some 60 miles southeast of Reno. This is an unusual number of cases for such a small town. Residents were concerned that perhaps high levels of naturally occurring arsenic in Fallon’s water supply, a pipeline carrying jet fuel to the local Navy base, local pesticide spraying, high tungsten levels, or an underground nuclear test conducted 30 miles away about 40 years ago might be responsible. However, scientists were unable to link any of these to the cancers. Residents were disappointed by the scientists’ findings.

In 1984, residents of a neighborhood in Randolph, Massachusetts, counted 67 cancer cases in their 250 residences. This cluster of cancer cases seemed unusual, and the residents expressed concern that runoff from a nearby chemical plant was contaminating their water supply and causing cancer.

In 1979, two of the eight town wells serving Woburn, Massachusetts, were found to be contaminated with organic chemicals. Alarmed citizens began counting cancer cases. Between 1964 and 1983, 20 cases of childhood leukemia were reported in Woburn. This is an unusual number of cases of this rather rare disease. The residents believed that the well water had caused the leukemia and proceeded to sue two companies held responsible for the contamination.