After nearly 40 years of hysteria, I'm still waiting for scientific evidence that any percentage of cancers are related to the environment. 

Boston University's Dr. Richard Clapp once again has sounded the alarm about cancers caused by the environment. Cancer is an "urgent environmental health issue" and 2 percent of cancer deaths are related to the environment, Clapp wrote in the Canadian Medical Association Journal (Oct. 17). Rather than debating estimates or placing them in perspective, Clapp urges "it is in everyone's interest to take [environmental carcinogens] seriously and seek opportunities to prevent further exposure." 

Pardon me for continuing the debate. 

Rachel Carson was the first to sound the alarm about cancer and the environment. Carson predicted a cancer epidemic that could hit "practically 100 percent" of the human population. This prediction hasn't materialized, no doubt in large part because it was based on an unexplained 1961 epidemic of liver cancer in middle-aged rainbow trout. 

Clapp is much more modest, but no less scientifically bankrupt than Carson in his assessment of cancer and the environment. 

In support of his allegations, Clapp writes, "In the U.S., much of the concern has focused on toxic chemicals and radiation, both ionizing and nonionizing, and their relation to clusters of cancer in communities... Citizens'... organizations have focused on some dramatic examples, such as Times Beach Missouri, and Love Canal, New York... In Europe, widespread concern followed the chemical plant explosion in Seveso, Italy and the nuclear plant disaster in Chernobyl, Ukraine... However, numerous, less publicized examples have occurred in communities throughout North America..." 

Certainly if notoriety constituted scientific evidence, Clapp's case might be more persuasive. Here's what the published science on these issues report: 

Cancer clusters: The Centers for Disease Control and Prevention investigated and reported on 108 so-called "cancer clusters" between 1961 and 1990. CDC could not link any of the clusters with environmental causes. Because cancer clusters are usually unexplainable except that they occur by chance, state public health departments view cluster investigations as wild goose chases. Many have procedures in place to avoid tying up already scarce resources with pointless investigations. 

Times Beach: A 1984 government study of the soil at Times Beach reported the soil was contaminated with dioxin — labeled by the Environmental Protection Agency as the most potent manmade cancer-causing substance. The federal government proceeded to evacuate the town's residents permanently. No study ever reported health problems among Times Beach residents, although there was a suicide by a man distraught over having to leave his home. A senior CDC official later admitted in congressional testimony, "Though [dioxin] is extremely toxic to guinea pigs, it may be without consequence even in very high exposure to humans... it looks as though the evacuation [of Times Beach] was unnecessary." 

Love Canal: Thirty-five residents of Love Canal were evacuated by New York state in 1978 after a discovery that homes were built over a former chemical dump and the chemicals began seeping to the surface. But a subsequent scientific study reported no increase in chromosomal aberrations, a potential indicator of cancer risk, among Love Canal residents. Another study reported, "Data from the New York Cancer Registry show no evidence for higher cancer rates associated with residence near the Love Canal toxic waste burial site in comparison with the entire state outside of New York City." No study reports an increased cancer rate among Love Canal residents. 

Seveso: A 1976 explosion of a chemical plant in Seveso exposed the surrounding population to very high levels of dioxin — by reputation, the most potent manmade cancer-causing substance. According to the most recent review of cancer mortality among Seveso residents, researchers reported " no increase for all-cancer mortality or major specific sites." 

Chernobyl: In the aftermath of the accident at the Chernobyl nuclear power plant, a nuclear power critic estimated 1 million cancer cases, half of them fatal, would occur. A less hysterical estimate at the time was 5,000 to 10,000 Chernobyl-linked cancer deaths. Reality has been quite different, though. The United Nations' International Atomic Energy Agency recently reported that about 1,800 children developed treatable thyroid cancer and that "with this exception, there is no scientific evidence of increases in overall cancer incidence or mortality or in nonmalignant disorders that could be related to radiation exposure." 

There simply is no meat to Clapp's claims. Even the American Cancer Society — not an organization known to shy away from alleging cancer risks — dismisses as "unproven" alleged cancer risks from pesticides, nonionizing radiation (e.g., from electric power lines and cell phones), toxic wastes and nuclear power plants. 

So how does Clapp get away with blaming the environment for causing what amounts to about 24,000 cancers in the U.S. this year? The same way the Canadian Medical Association Journal let him get away with claiming he had no conflict of interest in authoring the article. 

Though the media depicts Clapp as an epidemiologist from Boston University, this description hardly does him justice. Clapp is a long-time environmental activist masquerading as a scientist. 

He recently participated in a report titled America's Choice: Children's Health or Corporate Profit; The American People's Dioxin Report. The report was published by the Center for Health, Environment and Justice, a dioxin activist group started by a former resident of Love Canal. 

Along with a veritable "Who's Who" of anti-chemical activists, Clapp is listed as an "environmental health research" contact by Environmental Media Services. EMS is an affiliate of the notorious Fenton Communications — the activist public relations firm behind numerous health scares including alar in apples, silicone breast implants, and so-called "endocrine disrupters." 

The Canadian Medical Association Journal is not nearly as well-known and well-read as prestigious journals such as the New England Journal of Medicine and the Journal of the American Medical Association. If it hopes to develop a reputation as a solid medical journal, it will surely need to avoid this kind of Clapp-trap. 

— Steven Milloy is a biostatistician, lawyer, adjunct scholar at the Cato Institute and publisher of Junkscience.com.