The coal ash deposits have heavy concentrations of hexavalent chromium, a carcinogen.
One study found it to be 30 times more potent a carcinogen.
Further, estrogen or carcinogen exposure over a lifetime leads to the development of cancer.
carcinogen car·cin·o·gen (kär-sĭn'ə-jən, kär'sə-nə-jěn')
n.
A cancer-causing substance or agent.