The actual study Kerry was garbling, by the National Research Council, estimated that for the five percent of the U.S. population whose water contained arsenic, which occurs naturally, there was a 1-in-100 lifetime chance of cancer, not a certainty. Far more certain is the fact that 25 percent of men and women develop cancer regardless of their arsenic intake.
A joint study by the Brookings Institute and the American Enterprise Institute estimated that putting the strict arsenic standard into effect might save ten lives per year, but with money that would save more lives if spent elsewhere, about $190 million annually. Indeed, there would even be a net gain to public safety if keeping the money would help citizens buy a new car or gas range.