Cancer incidence and trihalomethane concentrations in a public drinking water system.

Four thousand two hundred fifty-five cases of esophageal, stomach, colon, rectal, bladder, and pancreatic cancer reported from Erie County, NY between 1973 and 1976 were analyzed in terms of their relationship to type of water source, level of trihalomethane (THM) and various social and economic parameters. Among white males, a significant positive correlation existed between pancreatic cancer incidence rates and THM level. No other significant correlations were observed. This research lends little or no support to the hypothesis that THM levels which meet present standards are related to the incidence of human cancer.