The dioxin debate: the EPA maintains that dioxin is one of the most carcinogenic substances known to man. But the National Academy of Sciences casts doubt on that assessment.(Environmental Protection Agency)

In summer months, hikers, bikers, and families looking for a nice place for a picnic visit the park where Times Beach, Missouri, used to be. Yet, just two decades ago, the area was deemed unfit for human habitation and the residents of Times Beach were evacuated. What went wrong?

The answer is government went wrong. Based on rumors that horses in the area had died under strange circumstances, investigators from the Environmental Protection Agency arrived in the town to conduct tests. By 1982, they had concluded that the town suffered from elevated levels of dioxin, a compound the EPA still claims is one of the most carcinogenic (cancer-causing) substances known. In what the agency still calls "a dramatic move for safety," the EPA "blocked off roads to the town ... and placed security guards to patrol the site around the clock." The residents were "evacuated" and the town razed at a cost of more than $32 million. The Times Beach dioxin affair was unprecedented and unnecessary.

Common Chemicals

The word "dioxin" actually refers to a class or family of similar compounds that are common byproducts of combustion and several industrial processes, including paper making and the manufacture of some pesticides, herbicides, defoliating agents (like agent orange), and some cleaners. Because it stems from such commonplace activities, most people experience some level of dioxin exposure, usually with little effect.

Very high doses can cause problems. The most common symptom of exposure to high levels of dioxin is the condition known as chloroacne in which the victim experiences severe eruptions of ache, usually on the head and face. The most recent high-profile example is the strange poisoning of Ukrainian politician Viktor Yushchenko (shown above). In 2004, at the time a candidate for the Ukrainian presidency, Yushchenko was exposed to a dose of dioxin 6,000 times higher than normal. In his public appearances afterward, his face was pocked and swollen. One might have expected him to develop cancer and die if dioxin were as lethal as the EPA suggests. On the contrary, Yushchenko, now president of the Ukraine, survived.

Moreover, the supposed relationship between dioxin and cancer is wildly overstated. There have been no dioxin-related deaths among former residents of Times Beach. In ...