Néocide (powder box, 50 g) containing 10% DDT, made in France. DDT was first synthesized in 1874 by
Othmar Zeidler under the supervision of
Adolf von Baeyer. It was further described in 1929 in a dissertation by W. Bausch and in two subsequent publications in 1930. The insecticide properties of "multiple chlorinated aliphatic or fat-aromatic alcohols with at least one trichloromethane group" were described in a patent in 1934 by Wolfgang von Leuthold. DDT's insecticidal properties were not, however, discovered until 1939 by the
Swiss scientist
Paul Hermann Müller, who was awarded the 1948
Nobel Prize in Physiology and Medicine for his efforts. Due to the potency of DDT, it was not long before the US
War Production Board placed it on military supply lists in 1942 and 1943 and encouraged its production for overseas use. Enthusiasm regarding DDT became obvious through the US government's advertising campaigns of posters depicting US fighting the
Axis powers and insects and through media publications celebrating its military uses. In 1945, DDT was made available to farmers as an agricultural insecticide Despite concerns emerging in the scientific community, and lack of research, the FDA considered it safe up to 7
parts per million in food. There was a large economic incentive to push DDT into the market and sell it to farmers, governments, and individuals to control diseases and increase food production. The program eliminated the disease in "North America, Europe, the former
Soviet Union", and dramatically reduced mortality in
Sri Lanka and India. The program succeeded in eliminating malaria only in areas with "high socio-economic status, well-organized healthcare systems, and relatively less intensive or seasonal malaria transmission". DDT was less effective in tropical regions due to the continuous life cycle of mosquitoes and poor infrastructure. It was applied in
sub-Saharan Africa by various colonial states, but the 'global' WHO eradication program didn't include the region. Mortality rates in that area never declined to the same dramatic extent, and now constitute the bulk of malarial deaths worldwide, especially following the disease's resurgence as a result of resistance to drug treatments and the spread of the deadly malarial variant caused by
Plasmodium falciparum. Eradication was abandoned in 1969 and attention instead focused on controlling and treating the disease. Spraying programs (especially using DDT) were curtailed due to concerns over safety and environmental effects, as well as problems in administrative, managerial and financial implementation.
United States ban By October 1945 DDT was available for public sale in the United States, both as an agricultural pesticide and as a household insecticide. and had become an important part of the local economy. Citing research performed by
Michigan State University in 1946, Robinson, a past president of the local Conservation Club, opined that: As its production and use increased, public response was mixed. At the same time that DDT was hailed as part of the "world of tomorrow", concerns were expressed about its potential to kill harmless and beneficial insects (particularly
pollinators), birds, fish, and eventually humans. The issue of toxicity was complicated, partly because DDT's effects varied from species to species, and partly because consecutive exposures could accumulate, causing damage comparable to large doses. A number of states attempted to regulate DDT. In the 1950s the federal government began tightening regulations governing its use. In 1957
The New York Times reported an unsuccessful struggle to restrict DDT use in
Nassau County, New York, and the issue came to the attention of the popular naturalist-author
Rachel Carson when a friend,
Olga Huckins, wrote to her including an article she had written in the Boston Globe about the devastation of her local bird population after DDT spraying.
William Shawn, editor of
The New Yorker, urged her to write a piece on the subject, which developed into her 1962 book
Silent Spring. The book argued that
pesticides, including DDT, were poisoning both wildlife and the environment and were endangering human health.
Silent Spring was a best seller, and public reaction to it launched the modern
environmental movement in the United States. The year after it appeared,
President John F. Kennedy ordered his Science Advisory Committee to investigate Carson's claims. The committee's report "add[ed] up to a fairly thorough-going vindication of Rachel Carson's Silent Spring thesis", in the words of the journal
Science, and recommended a phaseout of "persistent toxic pesticides". In 1965, the US military removed DDT from the military supply system due in part to the development of resistance by body lice to DDT; it was replaced by
lindane. In the mid-1960s, DDT became a prime target of the burgeoning
environmental movement, as concern about DDT and its effects began to rise in local communities. In 1966, a fish kill in
Suffolk County, New York, was linked to a 5,000-gallon DDT dump by the county's mosquito commission, leading a group of scientists and lawyers to file a lawsuit to stop the county's further use of DDT. A year later, the group, led by
Victor Yannacone and
Charles Wurster, founded the
Environmental Defense Fund (EDF), along with scientists
Art Cooley and
Dennis Puleston, and brought a string of lawsuits against DDT and other persistent pesticides in
Michigan and
Wisconsin. Around the same time, evidence was mounting further about DDT causing catastrophic declines in wildlife reproduction, especially in birds of prey like
peregrine falcons,
bald eagles,
ospreys, and
brown pelicans, whose eggshells became so thin that they often cracked before hatching. Toxicologists like
David Peakall were measuring
DDE levels in the eggs of peregrine falcons and
California condors and finding that increased levels corresponded with thinner shells. Compounding the effect was DDT's persistence in the environment, as it was unable to dissolve in water, and ended up accumulating in animal fat and disrupting hormone metabolism across a wide range of species. In response to an EDF suit, the US District Court of Appeals in 1971 ordered the
EPA to begin the de-registration procedure for DDT. After an initial six-month review process,
William Ruckelshaus, the Agency's first
Administrator rejected an immediate suspension of DDT's registration, citing studies from the EPA's internal staff stating that DDT was not an imminent danger. Industry sought to overturn the ban, while the EDF wanted a comprehensive ban. The cases were consolidated, and in 1973 the
United States Court of Appeals for the District of Columbia Circuit ruled that the EPA had acted properly in banning DDT. DDT continued to be produced in the United States for foreign markets until 1985, when over 300 tons were exported. although in practice it continued to be used through at least 1970. This was followed by
Norway and
Sweden in 1970,
West Germany and the US in 1972, but not in the
UK until 1984. In contrast to West Germany, in the
German Democratic Republic DDT was used until 1988. Especially of relevance were large-scale applications in forestry in the years 1982–1984, with the aim to combat
bark beetle and
pine moth. As a consequence, DDT-concentrations in eastern German forest soils are still significantly higher compared to soils in the former western German states. By 1991, total bans, including for disease control, were in place in at least 26 countries; for example, Cuba in 1970, the US in the 1980s, Singapore in 1984, Chile in 1985, and the Republic of Korea in 1986. The
Stockholm Convention on Persistent Organic Pollutants, which took effect in 2004, put a global ban on several
persistent organic pollutants, and restricted DDT use to
vector control. The convention was ratified by more than 170 countries. Recognizing that total elimination in many malaria-prone countries is currently unfeasible in the absence of affordable/effective alternatives, the convention exempts public health use within
World Health Organization (WHO) guidelines from the ban. Resolution 60.18 of the
World Health Assembly commits WHO to the Stockholm Convention's aim of reducing and ultimately eliminating DDT. Malaria Foundation International states, "The outcome of the treaty is arguably better than the status quo going into the negotiations. For the first time, there is now an insecticide which is restricted to vector control only, meaning that the selection of resistant mosquitoes will be slower than before." Despite the worldwide ban, agricultural use continued in India, North Korea, and possibly elsewhere. DDT is applied to the inside walls of homes to kill or repel mosquitoes. This intervention, called
indoor residual spraying (IRS), greatly reduces environmental damage. It also reduces the incidence of DDT resistance. For comparison, treating of cotton during a typical US growing season requires the same amount of chemical to treat roughly 1,700 homes. ==Environmental impact==