From wonder chemical to environmental pariah -- and back again

Barbara Hollingsworth | 27 Apr 2010
The Washington Examiner
DDT went from wonder chemical to environmental pariah right after the publication of Rachel Carson's "Secret Spring" in 1962, so defending it must be like accepting a job as Charles Manson's PR guy.

But Donald Roberts and Richard Tren do more than merely defend the banned and much maligned insecticide. In their new book, "The Excellent Powder," they boldly call the widespread withdrawal of DDT a "public health disaster" and urge its reintroduction until a similarly effective substance to battle malaria is found.

Malaria kills about 1 million people annually, according to the World Health Organization. Because most of these deaths are preventable, Roberts and Tren insist that anti-DDT groups like Greenpeace, the Environmental Defense Fund and the Sierra Club be held responsible for them.

Roberts, a professor of tropical medicine at the Uniformed Services University in Bethesda, and Tren, an economist who heads the nonprofit Africa Fighting Malaria lobbying group, say that opposition to DDT is based on an "almost endless list of claims, most of which have no scientific basis."

Claims such as: DDT kills on contact

While doing research in the Amazon, Roberts says he was "blown away" by the discovery that DDT does not actually kill most malaria-carrying mosquitoes, but proved to be highly effective in keeping the biting insects out of homes sprayed with it. The few mosquitoes that got in had to remain on a DDT-sprayed surface for at least 30 minutes before absorbing a fatal dose.

DDT is toxic to humans

Unlike malaria, there have been no human deaths attributable to environmental DDT exposure even though, for 30 years before it was banned, "no country had a greater use of DDT than the U.S.," Roberts said at a recent news conference. Studies purporting to prove that DDT causes breast cancer, reduced lactation and birth defects have been debunked. Even the National Academy of Sciences concluded that after 60 years of use, "there is still no clinical or epidemiological evidence of damage to man from approved uses of DDT."

DDT is toxic to wildlife

The authors thoroughly discredited Carson's implication that DDT was killing off robins, Americans' beloved harbinger of spring. "An examination of robin populations show that their numbers did not decrease during the years that DDT was used; indeed populations increased."

The rapid expansion of robin populations forced Carson and other environmentalists to backtrack and turn their focus on birds that were already endangered before DDT was widely used, such as eagles, peregrine falcons and condors. Roberts and Tren credit the Endangered Species Act, which Congress passed one year after the DDT ban, for their resurgence. "High concentrations of DDT do have some effect on eggshell fitness," Roberts conceded. "The problem is that such concentrations throughout the U.S. are inconsistent with any of the basic elements of data."

DDT builds up in tissues

DDT's chemical structure is similar to a number of natural compounds found in animals, which is "entirely contradictory to what the public has been led to believe." Most organisms metabolize and excrete DDT; whatever is left is stored in fat cells, rendering it less chemically active. DDT is toxic, the co-authors say, but hundreds of times less toxic than other insecticides now in use.

These inconvenient facts have been ignored by environmentalists, who invested millions of dollars (much of it public funds) in getting DDT outlawed by 2017, leaving millions of poor people vulnerable to malaria, a real killer. Since 90 percent of malaria victims are pregnant women and babies, they have a lot for which to answer.