The Deadly Dust: The Unhappy History Of DDT

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Everyone knows a little about the rise and fall of DDT—how it was once hailed as a great boon to mankind; how useful it was in field and garden, house and yard; and how at last to our dismay it was unmasked as a killer, the chemical Al Capone, a threat to our environment and possibly our very existence. Everyone knows that the federal and state governments are acting to end the DDT menace, saving us, if narrowly, from disaster. We can breathe easy again. . . . Or can we?

The history of DDT is well worth pondering, for its fatal implications extend to the whole of our civilization. The central character of the story is, of course, the chemical compound itself. But there are also two human protagonists—a chemist in Switzerland and a marine biologist in the United States—and our story begins in 1936, a year of crucial career decision for each of them.

The chemist, Dr. Paul Herman Mûller, was thirty-seven years old that year, an employee of the great dye-manufacturing firm of J. R. Geigy, S.A., of Basel. As a remarkably skillful and creative laboratory technologist, he had developed a number of synthetic tanning substances; by 1936 he had turned his attention to pesticide research.

Also in 1936 a short, slender, solemn-faced woman, twenty-nine years old and single, was teaching in the zoology department of the University of Maryland. In her student years she had majored in English composition as well as biology, followed by postgraduate work at the Marine Biological Laboratory in Woods Hole, Massachusetts. Now her desire to write moved her to accept a position in the U.S. Bureau of Fisheries (soon to be the Fish and Wildlife Service) offered her that year. When the school year ended, her name was listed on the U.S. civil service rolls: "(Miss) Rachel Carson, aquatic biologist. …”

Meanwhile, Dr. Müller’s pesticide research was leading to quick results. Within a few years he had invented two new insecticides, trade-named Gesarol and Neocid; their specific toxic ingredient, however, remained mysterious to him. In 1939, in search of this specific, he synthesized a chlorinated hydrocarbon whose unabbreviated chemical name is dichlorodiphenyltrichloroethane. Müller soon dubbed it DDT. He also soon learned that he was not the first man to make it. Back in 1874 a German student named Othmar Zeidler, working toward a doctor’s degree, had synthesized it as an exercise in pure chemistry. But Zeidler had no notion how, if at all, the new compound could be used.

Not until Müller took some of it home with him one day and tried it out on houseflies did anyone realize that DDT kills insects. It was, indeed, the toxic ingredient of the two earlier insecticides Müller had compounded. And he soon found ways to make it even more potent.

By that time World War II had begun, and during its opening months Müller, having already proved DDT’s effectiveness in controlling Colorado potato beetles on crops, found it equally effective in destroying lice on war refugees.

With each test, his and his firm’s excitement grew. They became convinced that he had discovered the most powerful synthetic insecticide then known—fatal on contact in extremely minute quantities to an incredibly wide range of insects, yet apparently wholly nontoxic to man. Geigy quickly patented the formula (1940) as a general insecticide, and the manufacture of DDT began.

The patent descriptions were sent to Geigy’s branches in Britain and the United States and, through them, made known in early 194210 British and American entomologists, who read the patents with mingled hope and skepticism. Of immediate concern to them, because of the millions of Allied army and navy personnel spread around the world, was DDT’s possible use for control of malaria (carried by anopheles mosquitoes), epidemic typhus (carried by body lice), and dysentery and typhoid fever (both carried by houseflies). With growing desperation they had been searching for a substitute for pyrethrum, a contact insecticide extracted from a flower and, before the war, imported chiefly from Japan. War with Japan cut off the major source of supply just as the demand for pyrethrum soared. Allied doctors and sanitation engineers began to have nightmares about losing the war to germs that could kill more people than all the bombs and bullets imagined in prcatomic years.

Urgently needed was the kind of synthetic contact insecticide—easy and safe to handle, capable of being economically mass-produced—which DDT seemed to be. British and American scientists were quick, therefore, to begin testing. Geigy’s claims, which had at first seemed wildly excessive, were soon verified. With the War Production Board encouraging its manufacture, DDT production was approaching its wartime maximum of three million pounds a month by the time it was placed on Army supply lists in May, 1943, and on Navy lists in January, 1944. All DDT was allocated to the armed services save a few hundred thousand pounds for further experiments. Among these were field tests in which DDT in powder form was successfully used, in 1943, to arrest small typhus epidemics in Mexico, Algeria, and Egypt.