Rethinking DDT

June 30, 1972 is a date that lives in junk science infamy. That’s when the U.S. Environmental Protection Agency banned the insecticide DDT. The ban survives 30 years later, even as it has helped kill millions of people, mostly children.

Widespread DDT use began in the U.S. in 1945 to control mosquitoes and cotton, soybean and peanut pests. DDT’s efficacy and low-cost were - and remain - unsurpassed.

Rachel Carson inflamed the public against DDT with her book "Silent Spring." She claimed DDT harmed bird reproduction and caused cancer. But Carson misrepresented the then-existing science on bird reproduction and was dead wrong about DDT causing cancer.

Carson wrote "Dr. [James] DeWitt's now classic experiments [show] that exposure to DDT, even when doing no observable harm to the birds, may seriously affect reproduction. Quail into whose diet DDT was introduced throughout the breeding season survived and even produced normal numbers of fertile eggs. But few of the eggs hatched."

DeWitt's 1956 article in the Journal of Agriculture and Food Chemistry actually yielded a very different conclusion.

DeWitt reported no significant difference in egg hatching between birds fed DDT and birds not fed DDT. Carson omitted mentioning DeWitt's report that DDT-fed pheasants hatched about 50 percent more eggs than "control" pheasants.

Carson predicted a cancer epidemic that could hit "practically 100 percent" of the human population. This prediction never materialized, no doubt because it was based on a 1961 epidemic of liver cancer in middle-aged rainbow trout - an outbreak later attributed to aflatoxin, a toxic by-product of certain fungi.

Activists blamed DDT for the disappearance of great birds such as the bald eagle and peregrine falcon. Supposedly, the insecticide harmed bird reproduction by thinning egg shells.

But the bald eagle and peregrine falcon were hunted to near extinction decades before DDT was first used in the U.S.

Many human and environmental stressors can contribute to thin egg shells. Laboratory experiments purporting to link DDT with egg shell thinning involved massive doses of the chemical, far in excess of what occurred in the wild.

Moreover, bald eagle and falcon populations were already rebounding during the peak years of DDT use - thanks to laws limiting their hunting.

Still, anti-DDT activism led to hearings before an EPA administrative law judge during 1971-72.

After seven months and 9,000 pages of testimony, the judge concluded "DDT is not a carcinogenic hazard to man... DDT is not a mutagenic or teratogenic hazard to man... The use of DDT under the regulations involved here do not have a deleterious effect on freshwater fish, estuarine organisms, wild birds or other wildlife."

Despite the exculpatory ruling, then-EPA administrator William Ruckelshaus banned DDT anyway.

Ruckelshaus never attended the hearings, didn’t read the transcript and refused to release the materials used to make his decision. He even rebuffed a U.S. Department of Agriculture effort to obtain those materials through the Freedom of Information Act, claiming they were just "internal memos."

This wasn’t surprising given Ruckleshaus’ bias.

Ruckleshaus belonged to the Environmental Defense Fund, an activist group formed by the National Audubon Society to lobby for its agenda without endangering the Society’s tax-exempt status. That agenda included lobbying against DDT.

After the ban, Ruckelshaus solicited donations for EDF on personal stationery that read, "EDF's scientists blew the whistle on DDT by showing it to be a cancer hazard, and three years later, when the dust had cleared, EDF had won."

Another telling part of the DDT saga was unveiled during a lawsuit by scientists claiming the National Audubon Society and the New York Times defamed them as "paid liars" about DDT. Depositions revealed EDF and National Audubon Society leaders plotted to "silence" and discredit scientists who defended DDT.

DDT use has virtually disappeared. Many countries blindly followed the U.S. ban or succumbed to activist pressure. Activists recently succeeded in pushing a virtual world-wide ban in the form of a United Nations’ treaty signed by the Bush administration, but not yet ratified by the Senate. The Persistent Organic Pollutants (POPs) treaty would permit DDT use only through expensive bureaucratic processes designed to dissuade rather than encourage use.

The activists have done nothing, however, about malaria-causing mosquitoes.

U.S. Government malaria experts wrote recently in the journal Emerging and Infectious Diseases, "Today, DDT is still needed for malaria control. If the pressure to abandon this effective insecticide continues,... millions of additional malaria cases worldwide [will result].... We are now facing the unprecedented event of eliminating, without meaningful debate, the most cost-effective chemical we have for the prevention of malaria. The health of hundreds of millions of persons in malaria-endemic countries should be given greater consideration before proceeding further with the present course of action."

Rachel Carson has been canonized by environmental activists. Ruckleshaus has had a successful business career and advised presidential candidate George W. Bush. The EDF and National Audubon Society raise millions of dollars annually.

They built their "success" on junk science and the bodies of third world children. They are what’s infamous, not DDT.

Steven Milloy is the publisher of, an adjunct scholar at the Cato Institute and the author of Junk Science Judo: Self-defense Against Health Scares and Scams (Cato Institute, 2001).

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