Everyone knows that cancer rates are sky-high along the Mississippi River between Baton Rouge and New Orleans. How could it be otherwise? Louisiana is one of the three states with the most "industrial toxic emissions." Chemical refineries line the banks of the river that, loaded with the effluent of the farms and factories of the Midwest in addition to whatever it picks up in Louisiana, is the source of New Orleans's drinking water. No wonder the area's called "cancer alley."
The only problem is that what "everyone knows" just isn't true. A recent article in the Journal of the Louisiana Medical Society compares the incidence (occurrence of new cases) of cancers in five regions of southern Louisiana to national incidence rates. Two of those regions -- the river parishes and the New Orleans area, sources of more than 80 percent of the state's toxic emissions -- make up cancer alley
The article makes a total of 186 comparisons between cancer incidence rates in the alley and national rates. In 90 percent of the comparisons, incidence in the alley is comparable to national incidence. In 7 percent of the comparisons, incidence is lower in the alley than in the rest of the United States. Incidence is higher in only 3 percent of the comparisons.
Even the five comparisons that show elevated cancer incidence in the alley don't point to environmental causes. Smoking is the likely culprit for high lung cancer rates in white men and women in New Orleans and in white men in the river parishes (lung cancer is not elevated among blacks). Larynx cancer, which is elevated in white men in New Orleans, "is diagnosed more frequently among those who both smoke and drink," and many visitors to New Orleans remark on the prevalence of such conduct. The higher rate for total cancers in white men in New Orleans is a product of the high incidence of lung and larynx cancers.
In short, there is no cancer alley. Digestive and urinary tract cancers are not elevated despite claims by the Environmental Defense Fund and Greenpeace that drinking water from the Mississippi River causes those cancers. Reproductive system cancers are not elevated despite the recent hoopla about manufactured chemicals being "environmental estrogens" or "endocrine disrupters" and causing those cancers. In fact, breast, uterine and ovarian cancers occur at average rates in black women and at below average rates in white women in the alley. The incidence of prostate cancer is lower than the national average for black males in both New Orleans and the river parishes and for white males in New Orleans.
A central tenet of what is called "environmental equity" is that poor people and minorities suffer most from environmental exposure to hazardous substances. Incomes throughout Louisiana are below national levels, but the article concludes that "cancer incidence in South Louisiana is generally comparable to or lower than" national rates. No cancer occurs at higher than the national average rate in blacks who live in the alley.
Although the incidence of cancer is lower in southern Louisiana, mortality rates from cancers in black males and females and in white males (but not white females) are higher there than in the rest of the United States. The article asks, "Is cancer a more virulent disease in South Louisiana than nationally? Is the health care system-including both screening and treatment-not accessible enough?" Those questions are very different from ones about carcinogenic rivers. Answering them should improve public health. Blathering on about a "cancer alley" won't.
The cancer alley paper that appeared in the Journal of the Louisiana Medical Association had also been submitted to the Journal of the National Cancer Institute, Cancer and Cancer Causes and Control, all of which have larger circulations. All decided not to publish it, at least in part because it reported on cancer in only one state. Evidently, the national publicity about the cancer alley was insufficient to convince the journal editors that the paper would interest a wide audience.
The "cancer alley" is an environmental myth. A myth doesn't lie down and die. Unless the public learns that science has demolished a myth, the myth lives on as something "everyone knows." More people would have learned about the science, had a more prestigious journal published the paper. None did. The myth lives on; the facts remain obscure.
Michael Gough is director of science and risk studies at the Cato Institute.
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