The Deadly Dust: The Unhappy History Of DDT

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Credit for the fact that public, governmental, and scientific attention was focused on the threat of DDT and other chemicals in the environment must certainly go to Rachel Carson’s Silent Spring . Researching it meticulously (her argument was sustained by no fewer than fifty pages of closely printed source notes), she wrote the book in longhand, slowly, most of it in her home in Silver Spring, Maryland, and much of it at night, over a period of nearly four years, beginning in 1958. She well knew that her warning of the threat to the environment from the indiscriminate use of ever more and stronger pesticides would provoke attacks upon her motives, professional competence, and “scientific objectivity"; and so she was not surprised by the storm of controversy her book aroused even before its formal publication date in 1962. But with scientific colleagues, with the general public, and with many governmental policy makers, Silent Spring was enormously persuasive.

One of Rachel Carson’s central points was that man, like every living thing, is a creature of his environment, and, consequently, any chemical fatal to his environment must ultimately be fatal to him (a concept commonly understood today but new to many a decade ago). She also challenged the constantly reiterated assertion that DDT and its close chemical affiliates are not directly toxic to human beings.

True, most Americans now probably have 10 to 12 p.p.m. DDT in their body fats, which is 3 to 5 p.p.m. more than the F.D.A.-set tolerance level for human food; and we seem unharmed by it. But what of the effects that may not show up for two or three decades or generations? Is DDT damaging chromosome structure? Is it, through subtle attacks on the central nervous system, slowly impairing mental processes? Is it a carcinogen (cancer-inducing agent)? Rachel Carson cited disturbing evidence that the answer to such questions might be affirmative.

Today DDT is increasingly suspected of direct injury to man. Evidence of the carcinogenic effects of DDT have multiplied since 1962. Indeed, in the very year following publication of Silent Spring , Dr. William C. H. Hueper of the National Cancer Institute reported DDT to be “cancer producing according to presently available evidence” and incriminated DDT in the “production of benign and malignant tumors of the liver, cancers of the lung, and leukemias.”

Two years after her best seller was published—in mid-April, 1964—Rachel Carson, aged fifty-six, died of cancer. (Dr. Paul Müller died in October of the following year, at the age of sixty-six.) But before she died she had the satisfaction of knowing that her work was influencing public policy.

In 1963, in direct response to the public concern aroused by Silent Spring , President Kennedy’s Science Advisory Committee recommended a reduction of DDT use with a view to its total elimination as quickly as possible, along with other “hard” pesticides. Soon thereafter Secretary of the Interior Stewart Udall issued an order banning the use of DDT on Interior-controlled lands “when other chemicals can do the job.” Wisconsin, Michigan, California, Massachusetts, and other states began to move toward state prohibitions of DDT. Finally, in November of 1969, acting on the recommendation of a special study commission on pesticides, Robert H. Finch, Secretary of Health, Education, and Welfare, announced that the federal government would “phase out” all but “essential uses” of DDT within two years. Many Americans assumed that this phasing out means the end of DDT. But not so.

Even though, belatedly, the search has been intensified for safe alternatives to persistent pesticides, the worldwide demand for DDT increases as underdeveloped countries face the immediate desperate problems of feeding and protecting the health of exploding populations. The U.N.'s World Health Organization and the Food and Agricultural Organization have strongly opposed any prohibition or even reduction of DDT’s use, arguing that it is the cheapest effective pesticide (it costs about fifteen cents a pound as compared with a dollar or more for other chemicals), that poor countries cannot afford substitutes, and that without the kind of crop protection and disease control provided by DDT, millions must surely and quickly die. In India, for instance, U.N. consultants are now working with the government to double within a year the percentage of cropland sprayed by hard pesticides, chiefly DDT. Even in America the government has moved so slowly to implement its “phase out” policy that citizen conservation groups, led by the crusading Environmental Defense Fund, have taken action to stop the manufacture and use of DDT through legal suits against government agencies and the major manufacturer.

And so the use of DDT continues, even as its disastrous effects on living things are being established beyond any doubt. The need for some system of broadly assessing the likely consequences of technological innovations before they are unleashed seems all too apparent. In the case of DDT, however, we can only hope to live with our mistakes.