Campaigns like the WWF’s are common in many countries. “Pollutants Contaminate Blood of Federal Politicians” read the headline of a 2007 press release from Canada’s Environmental Defence announcing that testing had found dozens of “harmful pollutants” in the blood and urine of several leading Canadian politicians. Enormous media coverage followed, most of it focused heavily on the scary nature of the chemicals and giving little mention, if any, to the quantities involved. It was another success for a campaign Environmental Defence calls “Toxic Nation,” whose slogan is “Pollution. It’s In You.” There is extensive information on the “Toxic Nation” Web site about the abundance of synthetic chemicals in our bodies, but there’s almost no mention that the presence in the body of tiny quantities of “dangerous” chemicals may not actually be dangerous. Only in a glossary of technical terms, under the definition of toxic, does the Web site let slip that while chemicals may cause harm “the quantities and exposures necessary to cause these effects can vary widely.”
Such sins of omission are common. “Many pesticides that have been shown to cause cancer in laboratory animals are still being used,” says the Web site of Natural Resources Defense Council, a leading American organization. There is, of course, no concern expressed at the one-half of natural chemicals that have also been shown to cause cancer in laboratory animals. Similarly, the Environmental Working Group (EWG), a Washington, D.C., organization, says on its Web site that “there is growing consensus in the scientific community that small doses of pesticides and chemicals can adversely affect people, especially during vulnerable periods of fetal development and childhood when exposures can have long-lasting effects.” It’s true that scientists agree these chemicals can do harm, and there is no definition of “small doses” in this statement, so in a very narrow sense this statement isn’t wrong. But EWG has widely publicized—always with a tone of alarm— the fact that traces of these chemicals exist in our bodies, and so it is making it easy for people to conclude that there is “a growing consensus in the scientific community” that the tiny amounts of these chemicals in our bodies “can adversely affect people.” And that’s false.
There’s also an essay on the Web site of the Worldwatch Institute that warns readers that “the 450 million kilograms of pesticides that U.S. farmers use every year have now contaminated almost all of the nation’s streams and rivers, and the fish living in them, with chemicals that cause cancer and birth defects.” Left unmentioned is the fact that the level of contamination in most places is believed by most scientists to be far too low to actually cause these harms to humans, which would explain why the United States is not experiencing massive increases in cancers and birth defects despite this massive contamination.
But then, the existence of an “epidemic of cancer” is often taken by environmentalists to be such an obvious fact that its existence hardly needs to be demonstrated. In a 2005 newspaper column, Canada’s David Suzuki—a biologist and renowned environmentalist—blamed chemical contamination for the “epidemic of cancer afflicting us.” His proof consisted of a story about catching a flounder that had cancerous tumors and the fact that “this year, for the first time, cancer has surpassed heart disease as our number-one killer.” But it is not true, as Suzuki seems to assume, that cancer’s rise to leading killer means cancer is killing more people. It is possible that heart disease is killing fewer people. And that turns out to be the correct explanation. Statistics Canada reported that the death rates of both cardiovascular disease and cancer are falling, but “much more so for cardiovascular disease.”
The Cancer Prevention Coalition (CPC), an activist group headed by Sam Epstein, made a more determined effort in a 2007 press release. “The incidence of cancer has escalated to epidemic proportions, striking most American families,” the release says. “Cancer now impacts about 1.3 million Americans annually and kills 550,000; 44 percent of men and 39 percent of women develop cancer in their lifetimes. While smoking-related cancers have decreased in men, there have been major increases in non-smoking cancers in adults as well as childhood cancers.” Elsewhere, the CPC puts it a little more colorfully: “Cancer strikes nearly one in every two men and more than one in every three women.”
What’s left out here is the simple fact that cancer is primarily a disease of aging, a fact that has a profound effect on cancer statistics. The rate of cancer deaths in Florida, for example, is almost three times higher than in Alaska, which looks extremely important until you factor in Florida’s much older population. “When the cancer death rates for Florida and Alaska are age-adjusted,” notes a report from the American Cancer Society, “they are almost identical.”
Lifetime risk figures—like “one in every two men” or Rachel Carson’s famous “one in every four”—ignore the role of aging and don’t take into account our steadily lengthening life spans. To see how deceptive that is, consider that if every person lived to one hundred, the lifetime risk of cancer would likely rise to almost 100 percent. Would we say, in shocked tones, that “cancer will strike nearly every person”? Probably not. I suspect we’d consider it cause for celebration. Conversely, if some new plague ensured that we all died at thirty-five, the lifetime risk of getting cancer would fall spectacularly, but no one would be dancing in the streets.
In the 1990s, as worries about breast cancer rose, activists often said that “one in eight” American women would get breast cancer in their lifetimes. That was true, in a sense. But what wasn’t mentioned was that to face that full one-in-eight risk, a woman has to live to be ninety-five. The numbers look very different at younger ages: The chance of getting breast cancer by age seventy is 1 in 14 (or 7 percent); by age fifty, it is 1 in 50 (2 percent); by age forty, 1 in 217 (0.4 percent); by age thirty, 1 in 2,525 (0.03 percent). “To emphasize only the highest risk is a tactic meant to scare rather than inform,” Russell Harris, a cancer researcher at the University of North Carolina, told U.S. News & World Report.
Aging shouldn’t affect data on childhood cancers, however, and those who claim chemical contamination is a serious threat say childhood cancers are soaring. They are up “25 percent in the last 30 years,” journalist Wendy Mesley said in her CBC documentary. That statistic is true, to a degree, but it is also a classic example of how badly presented information about risk can mislead.
Mesley is right that the rate of cancer among Canadian children is roughly 25 percent higher now than it was thirty years ago. But what she didn’t say is that the increase occurred between 1970 and 1985 and then stopped. “The overall incidence of childhood cancer has remained relatively stable since 1985,” says the 2004 Progress Report on Cancer Control from the Public Health Agency of Canada.