During the middle of the twentieth century, a cancer diagnosis was the expected fate of one in every four Americans—a ratio Carson found so shocking that it inspired the title of one of her chapters. Today, more than 40 percent of us (38.3 percent of women and 48.2 percent of men) will contract the disease sometime within our lifespans. Cancer is now the second leading cause of death overall, and, among adult Americans younger than 85, it is the number-one killer—beating out stroke and heart disease.

More than one-fourth of all cancer deaths are from lung cancer. Because the fatality rate is so high, lung cancer incidence and lung cancer mortality are very nearly the same statistic, and, in the United States, both closely mirror historical patterns of cigarette consumption. […] Overall, 85-90 percent of the deaths from lung cancer can be attributed to cigarette smoking or exposure to passive smoke from other smokers.

This statistic also means, of course, that 10-15 percent of all lung cancer deaths have nothing to do with smoking. This is not a trivial number: between sixteen thousand and twenty-four thousand people died in 2008 from lung cancer for which smoking or passive smoking was not the cause. If lung cancers among nonsmokers were broken out and presented as a separate statistic, lung cancer not attributable to smoking would still appear on the list of the ten most common cancers in terms of death. Thus, although smoking dominates the lung cancer picture, additional mysteries need sleuthing here.

Steingraber, Sandra. Living Downstream: An Ecologist’s Personal Investigation of Cancer and the Environment (pp. 47-48). Da Capo Press. Kindle Edition.