The American Spectator

Unable to find harm to human health, DDT opponents turned to bird health, alleging a decline of bald eagles and other birds of prey, which they associated with heavy DDT usage. Rachel Carson led the accusation. It has been repeated so often and so passionately that the public is still convinced of it.

The charge is that DDT thinned the shells of eggs. When nesting parent birds sat on the eggs, the shells cracked and no babies hatched. Carson charged that DDT was bringing bald eagles and robins to the “verge of extinction” — while noted ornithologist Roger Tory Peterson was reporting that the robin was the most abundant bird in North America.

Bald eagles between 1941 and 1960 migrating over Hawk Mountain, Pennsylvania, doubled during the first six years of DDT-use. Their numbers increased from 9,291 in 1946 — before much DDT was used — to 16,163 in 1963 and 19,765 in 1968.

Professor Edwards reviews how bald eagles died of non-DDT causes. In Alaska, 128,000 were shot for bounty payments between 1917 and 1956. Between 1960 and 1965, 76 bald eagles found dead were autopsied: 46 had been shot or trapped; 7 had died of impact injuries from flying into buildings or towers. Between 1965 and 1980, shootings, trappings, electrocutions, and impact injuries chiefly accounted for their deaths.

Although some birds declined before DDT, they became much more abundant during the years of greatest DDT-use. But facts have not impeded the endless repetition of Carson’s bird myth.

Scientists tested the popular shell-thinning hypothesis. U.S. Fish and Wildlife Service biologists fed birds for 112 days on a diet with 100 times as much DDT as they were getting from the environment. No thinning of egg shells was found. The DDT had no effect on the birds.

One experimenter, to demonstrate eggshell-thinning, fed quail a diet with DDT but containing only one-fifth of the normal amount of calcium. His experiment succeeded in producing thinner eggshells, but his deception was exposed.

IN 1969, THE ENVIRONMENTAL DEFENSE FUND (then, three guys with a clipboard; now “Environmental Defense”), Sierra Club, and National Audubon Society petitioned the Secretary of Agriculture to ban DDT, claiming it is carcinogenic to humans. He agreed to partially phase it out by December 31, 1970, which did not satisfy the environmentalists.

The Audubon Society and the Natural Resources Defense Council, to stop exports of DDT to third-world countries, instituted a number of lawsuits, ultimately gaining the support of the U.S. Agency for International Development (USAID) in 1977.

EPA appointed Administrative Law Judge Edmund Sweeney to evaluate DDT. In 1971-2 he conducted a seven-month hearing. EPA actually participated, testifying against DDT!

Judge Sweeney, after 80 days of testimony from 150 expert scientists, ruled that DDT “is not a carcinogenic, mutagenic, or teratogenic hazard to man” and does “not have a deleterious effect on freshwater fish, estuarine organisms, wild birds, or other wild life. There is a present need for the continued use of DDT for the essential uses defined in this case.”

The Environmental Defense Fund appealed Sweeney’s decision. The appeal should have been passed to an independent jurist, according to Ruckelshaus’s general counsel, John Quarles, but Ruckelshaus decided to rule on it himself. Not surprisingly, he upheld his own ban “on the grounds that ‘DDT poses a carcinogenic risk’ to humans.” (In 1994, he was to deny that that was the basis for the ban.) He had banned DDT though he had not attended a day of the 80-day hearing nor read a page of the transcript (as he told the Santa Ana Register, July 23, 1972).

In 1979, on April 26, Ruckelshaus wrote the American Farm Bureau Federation that his ban was imposed for political, not scientific, reasons: “Science, along with other disciplines such as economics, has a role to play, but the ultimate judgment remains political,” he wrote. But in 1994 he wrote in a letter to the Wall Street Journal, “The scientific basis for the ban was solid then and still stands. DDT is a highly persistent chemical that moves up the food chain, and it accumulates in the fatty tissue of humans.” However, according to Professor Edwards, it does no harm. Professor Edwards says that “DDT residues do not ‘build up’ in animal food-chains, because they are metabolized and excreted by fish, birds and mammals.”

In his March 24, 1994 Wall Street Journal letter, Ruckelshaus wrote that the direct ecological effect, and the basis for his decision, “was its proven impact on the thickness of egg shells of raptors, birds such as the brown pelican and the peregrine falcon. The decision was not based on any claim of human carcinogenicity.” But in 1972, he had overridden Judge Sweeney on the ground that DDT does pose a carcinogenic risk to humans.

THE BROWN PELICAN AND the peregrine falcon did suffer declines in population, but not because of DDT, according to Professor Edwards’s article, “DDT Effects on Bird Abundance and Reproduction.”