The U.S. Environmental Protection Agency banned the use of the pesticide DDT in order to protect human health and the environment.
On June 14, 1972, the chief administrator of the U.S. Environmental Protection Agency (EPA), William D. Ruckelshaus, announced that the pesticide use of the chemical known as DDT would be prohibited in the United States, except in cases of emergency, effective December 31, 1972. The ban ended nearly three decades of domestic use of the chemical, which had become controversial in the late 1950’s and 1960’s because of its potential to harm human health and the environment.
DDT is an abbreviation for the chemical name dichloro-diphenyl-trichloroethane. It was accidentally discovered by German chemist Othmar Ziedler in 1874, although it was not until the 1930’s, when the Swiss chemical firm J. R. Geigy began searching for an economical pesticide to control potato beetles, that its insecticidal properties were discovered. The project was directed by Paul Hermann Müller, who won the 1948 Nobel Prize in Physiology or Medicine for applying DDT to public health crises. In 1942, Geigy representatives brought samples of a 5 percent solution of DDT to the U.S. Department of Agriculture (USDA) in the form of a pesticide spray and powder, trade name “Gesarol.”
While domestic use of DDT did not begin until near the end of World War II, the U.S. military used the material to control disease-carrying insects such as typhoid-carrying lice in Italy and malaria-carrying mosquitoes in the South Pacific. By the end of the war, when production exceeded War Production Board requirements, the surplus was released for domestic civilian use. While DDT gained its early popularity in the realm of public health, its domestic use in the control of disease had dropped dramatically by 1972 with the advent of safer alternatives and, unfortunately, developing insect resistance to the poison. From 1946 to 1956, however, the U.S. Public Health Service
The most important economic use of the substance was as an agricultural insecticide to control pests such as the boll weevil and the cabbage worm. For example, through 1972, the cotton industry applied pesticides to well over two-thirds of its acreage, accounting for 80 percent of all domestic DDT use. The USDA used DDT to control tree-destroying insects such as the gypsy moth, which was responsible for the destruction and defoliation of hundreds of thousands of acres of U.S. forests. Between 1945 and 1972, the USDA applied pesticides, mostly DDT, to an estimated 30 million acres of woodlands. Despite its obvious economic and public health benefits, concerns regarding DDT’s health hazards had surfaced as early as the mid-1940’s. These concerns escalated in the wake the growing environmental movement of the 1960’s. Most evidence pointed to the fact that DDT posed a more significant threat to wildlife than to human health. Concerns over chronic effects increased with the 1962 publication of Silent Spring
The earliest medical tests conducted during the war showed that humans suffered few if any immediate adverse effects from DDT exposure and ingestion of low doses, although sufficiently high amounts could kill. Deaths from DDT poisoning fell into two categories: accidental ingestion of relatively high quantities and suicide. According to the Food and Drug Administration
The U.S. Committee on Medical Research, however, concluded a 1948 DDT study with the findings that DDT accumulated in the body and was stored in fatty tissues. In addition, DDT was regularly excreted in mother’s milk and, therefore, could be passed on to nursing infants. The study showed that in the short term, this accumulation was a factor in minor kidney and liver damage, but since the study was conducted over a short period of time, it could not conclude whether this accumulation resulted in any long-term ailments or caused cancer. Tests of DDT’s potency as a carcinogen conducted by the FDA and the National Cancer Institute remained inconclusive regarding cancer in humans, although liver cancer did occur in laboratory rats exposed to low levels of DDT over long periods of time.
The ambiguity of studies of chronic health effects and cancer in humans were the main ingredients in Carson’s Silent Spring. The book begins with the cautionary tale of an ecology destroyed by indiscriminate chemical usage. The work polarized anti- and pro-DDT coalitions, moving health and environmental disputes from the scientific literature into courtrooms and legislatures. DDT had most assuredly saved hundreds of thousands of human lives from disease and starvation, but it was becoming clear that careless application of the material was harming the environment. While fears over cancer and uncertainty over other chronic effects caused some public alarm, fears of widespread environmental damage were the major cause of DDT’s eventual demise.
Scientists and laypersons alike began to notice the ecological effects of widespread DDT use as early as the late 1940’s. One of the earliest signs was the high proportion of robins and other birds killed in areas where the chemical was used to control tree disease. Fish deaths were widely reported in New York’s gypsy moth eradication campaigns. From the late 1940’s into the early 1960’s—corresponding to the highest use of DDT—the average thickness of some bird species’ eggshells, most notably the bald eagle, peregrine falcon, and California brown pelican, decreased. This resulted in higher than normal mortality rates among offspring and posed the very real danger of extinction. When this information was combined with Carson’s argument that DDT residues had spread as far as the polar regions, where no DDT spraying had occurred, citizen environmental groups, including the Environmental Defense Fund, pushed for legislation that would greatly curtail or ban DDT use.
Beginning in 1962, public hearings in Wisconsin, Michigan, and Arizona ushered in the eventual banning or restriction of DDT use in twenty-seven states. By 1970, the USDA canceled nearly all uses of DDT, including those on tobacco, shade trees, and aquatic areas. By 1971, federal responsibility for pesticide use was transferred to the EPA, which announced in January its intent to ban all nonemergency DDT uses. Public hearings beginning in August and lasting until March, 1972, included testimony from public health officials, chemical manufacturers, farmers, the USDA, and the Environmental Defense Fund. Faced with growing evidence of the dangers of DDT misuse and the fact that, in most economically sensitive applications, DDT use had already been severely curtailed, EPA administrator Ruckelshaus canceled all remaining crop uses of the chemical effective December 31, 1972. From that point forward, DDT could be used only in cases judged by the EPA to be public health emergencies.
Moth pesticide containing 5 percent DDT.
Since the 1972 ban on all crop uses of DDT came at a time when farmers and pesticide manufacturers were searching for, and implementing, alternatives to the chemical, the economic impact of the ban was minimal. The greatest impact of the ban itself could be seen in the effects of curtailed DDT use on the overall ecology. Sociologically, the ban was the culmination of a series of events, beginning with the publication of Silent Spring, which raised awareness of the effect of human actions on the environment and changed the nature of environmental disputes from purely scientific debates to issues of science, economics, and politics.
The EPA released a comprehensive impact statement on the DDT ban in July, 1975. They concluded that the ban had very little effect on agriculture and public health. While the ban increased the cost of cotton farming by at least six dollars per acre, the EPA estimated that the cost passed on to consumers resulted in an overall price increase of 2.2 cents per person. The bulk of this cost went to the development and implementation of DDT alternatives, such as methyl parathion. Most important, the ban seemed to have little effect on crop yield in cotton and other agricultural sectors.
The most visible effect of the ban was the recovery of species brought to near extinction by its use, especially bird species harmed by decreases in eggshell thickness. DDT’s chemical stability in the environment had made it possible for it to accumulate in the food chain, starting with an accumulation in plankton, chemical resistant insect strains, invertebrates such as mollusks, and fish. While certain levels of DDT were lethally toxic to these organisms, some of those that survived were eventually eaten by predatory fish and birds. The accumulated DDT was then either excreted by these animals or retained in fat tissues. The retained DDT adversely affected the reproductive success of several fish and bird species, including the bald eagle, peregrine falcon, and brown pelican. The study noted that evidence of increased eggshell thickness in threatened bird species had accompanied an increase in their populations which coincided with curtailed DDT use.
Finally, the DDT controversy coincided with the rise of American environmental activism. Beginning in 1967, groups including the Environmental Defense Fund, the National Audubon Society, and the National Wildlife Federation carried the cause of the environment to courtrooms and legislatures. For these groups, DDT served as a highly visible target for their overall concern that indiscriminate use of synthetic chemicals was damaging the ecological balance. Their victory in the DDT dispute set a precedent for the continued use of the judicial and legislative branches of government to regulate human control of the environment.
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Bate, Roger, and Richard Tren. Malaria and the DDT Story. London: Institute of Economic Affairs, 2001. Argues that with the resurgence of malaria in the world’s poorest countries, anti-DDT environmentalists and donor agencies have hampered efforts by health agencies and companies trying to fight the disease. -
Beatty, Rita Gray. The DDT Myth: Triumph of the Amateurs. New York: John Day, 1973. Presents the pro-DDT perspective, arguing that its benefits in public health and agriculture far outweighed its potential risks. Journalistic, not scientific, in its presentation. -
Carson, Rachel. Silent Spring. 1962. Reprint. Boston: Mariner Books, 2002. The book that catapulted environmental concerns into the public consciousness. Lucid in presentation, but lacking in scientific data to back assertions that indiscriminate chemical use will lead to long-term environmental and human catastrophe, a “silent spring.” Argues that humans must live within the environment rather than dominating it from without. -
Dunlap, Thomas R. DDT: Scientists, Citizens, and Public Policy. Princeton, N.J.: Princeton University Press, 1981. Presents the history of DDT use in the United States from the pre-DDT history of insects, disease, and insecticides in the United States to the 1972 ban. Well balanced. Contains excellent appendixes for those interested in the more technical aspects of DDT contamination, production, and metabolism. Includes bibliography. -
Whitten, Jamie L. That We May Live. Princeton, N.J.: D. Van Nostrand, 1966. Argues that pesticides are necessary for the survival of humans on Earth and that DDT opponents distorted scientific claims to the contrary. Often lost in the attacks on the environmental movement, showing the difficulties both sides in the dispute had in dealing with inconclusive scientific data on the detriments associated with DDT. Whitten was chair of the U.S. House Appropriations Subcommittee for Agriculture during the years of DDT use and wrote this book as a response to Carson’s Silent Spring. -
World Wildlife Fund. Resolving the DDT Dilemma: Protecting Biodiversity and Human Health. Washington, D.C.: Author, 1998. Presents a brief overview of the harmful effects of DDT on humans, animals, and the environment. Includes illustrations and bibliography. -
Zimmerman, O. T., and Irvin Lavine. DDT: Killer of Killers. Dover, N.H.: Industrial Resarch Service, 1946. Small volume is one of the first comprehensive books published on the use, properties, and detriments of DDT. Obviously pro-DDT in its stance, for studies that revealed even slight human health and environmental concerns had yet to be conducted. Details some environmental dangers, but asserts that such dangers are present only when the chemical is improperly used. A fine example of the enthusiasm with which the chemical was initially received.
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