DDT#Environmental impact

DDT is similar in structure to the insecticide methoxychlor and the acaricide dicofol. It is highly hydrophobic and nearly insoluble in water but has good solubility in most organic solvents, fats and oils. DDT does not occur naturally and is synthesised by consecutive Friedel–Crafts reactions between chloral ({{chem|CCl|3|CHO}}) and two equivalents of chlorobenzene ({{chem|C|6|H|5|Cl}}), in the presence of an acidic catalyst. DDT has been marketed under trade names including Anofex, Cezarex, Chlorophenothane, Dicophane, Dinocide, Gesarol, Guesapon, Guesarol, Gyron, Ixodex, Neocid, Neocidol and Zerdane; INN is clofenotane.

Commercial DDT is a mixture of several closely related compounds. Due to the nature of the chemical reaction used to synthesize DDT, several combinations of ortho and para arene substitution patterns are formed. The major component (77%) is the desired p,p{{'}} isomer. The o,p{{'}} isomeric impurity is also present in significant amounts (15%). Dichlorodiphenyldichloroethylene (DDE) and dichlorodiphenyldichloroethane (DDD) make up the balance of impurities in commercial samples. DDE and DDD are also the major metabolites and environmental breakdown products. DDT, DDE and DDD are sometimes referred to collectively as DDX.{{cite journal |pmid=22020740 |journal=J. Environ. Monit. |date=December 2011 |volume=13 |issue=12 |pages=3358–3364 |doi=10.1039/c1em10479a |title=Sources of organochlorine pesticides in air in an urban Mediterranean environment: volatilisation from soil |first1=G. |last1=Lammel |s2cid=22071869 |display-authors=et al }}

File:P,p'-dichlorodiphenyltrichloroethane.svg|p,p{{'}}-DDT
(desired compound)

File:O,p'-dichlorodiphenyltrichloroethane.svg|o,p{{'}}-DDT
(isomeric impurity)

File:P,p'-dichlorodiphenyldichloroethene.svg|p,p{{'}}-DDE
(impurity)

File:P,p'-dichlorodiphenyldichloroethane.svg|p,p{{'}}-DDD
(impurity)

DDT has been formulated in multiple forms, including solutions in xylene or petroleum distillates, emulsifiable concentrates, water-wettable powders, granules, aerosols, smoke candles and charges for vaporizers and lotions.{{EHC-ref | id = 83 | name = DDT and Its Derivatives: Environmental Aspects | isbn = 9241542837 |date=1989 }}

From 1950 to 1980, DDT was extensively used in agriculture{{snd}}more than 40,000 tonnes each year worldwide{{cite journal | vauthors = Geisz HN, Dickhut RM, Cochran MA, Fraser WR, Ducklow HW | title = Melting glaciers: a probable source of DDT to the Antarctic marine ecosystem | journal = Environmental Science & Technology | volume = 42 | issue = 11 | pages = 3958–3962 | date = June 2008 | pmid = 18589951 | doi = 10.1021/es702919n | bibcode = 2008EnST...42.3958G | url = https://scholarworks.wm.edu/cgi/viewcontent.cgi?article=1984&context=vimsarticles | access-date = August 26, 2020 | archive-date = August 29, 2022 | archive-url = https://web.archive.org/web/20220829055157/https://scholarworks.wm.edu/cgi/viewcontent.cgi?article=1984&context=vimsarticles | url-status = live }}{{snd}}and it has been estimated that a total of 1.8 million tonnes have been produced globally since the 1940s.[https://wwwn.cdc.gov/TSP/ToxProfiles/ToxProfiles.aspx?id=81&tid=20 Toxicological Profile: for DDT, DDE, and DDE] {{Webarchive|url=https://web.archive.org/web/20211125124535/https://wwwn.cdc.gov/TSP/ToxProfiles/ToxProfiles.aspx?id=81&tid=20 |date=November 25, 2021 }}. Agency for Toxic Substances and Disease Registry, September 2002. In the United States, it was manufactured by some 15 companies, including Monsanto, Ciba,{{cite news|url=http://www.al.com/news/mobileregister/index.ssf?/base/news/1215162908145190.xml&coll=3|title=McIntosh residents file suit against Ciba|last=David|first=David|name-list-style=vanc|date=July 4, 2008|access-date=July 7, 2008|archive-url=https://web.archive.org/web/20090808020048/http://www.al.com/news/mobileregister/index.ssf?%2Fbase%2Fnews%2F1215162908145190.xml&coll=3|archive-date=August 8, 2009|url-status=dead|df=mdy-all}} Montrose Chemical Company, Pennwalt,[http://www.deq.state.or.us/lq/ECSI/ecsidetail.asp?seqnbr=398 Environmental Cleanup Site Information Database for Arkema (former Pennwalt) facility] {{Webarchive|url=https://web.archive.org/web/20110723023510/http://www.deq.state.or.us/lq/ECSI/ecsidetail.asp?seqnbr=398 |date=July 23, 2011 }}, Oregon DEQ, April 2009. and Velsicol Chemical Corporation.{{cite news |url=http://www.themorningsun.com/stories/012708/loc_tests.shtml| title=Tests shed light on how pCBSA got into St. Louis water |last=Horvath |first=Rosemary | name-list-style = vanc |date=January 27, 2008 |newspaper=Morning Sun |location=Michigan, United States |publisher=Journal Register Company |access-date=May 16, 2008 |archive-url=https://web.archive.org/web/20080705170443/http://www.themorningsun.com/stories/012708/loc_tests.shtml |archive-date=July 5, 2008 }} Production peaked in 1963 at 82,000 tonnes per year. More than 600,000 tonnes (1.35 billion pounds) were applied in the US before the 1972 ban. Usage peaked in 1959 at about 36,000 tonnes.[https://archive.epa.gov/epa/aboutepa/ddt-regulatory-history-brief-survey-1975.html "DDT Regulatory History: A Brief Survey (to 1975)"] {{Webarchive|url=https://web.archive.org/web/20161220162916/https://archive.epa.gov/epa/aboutepa/ddt-regulatory-history-brief-survey-1975.html |date=December 20, 2016 }}, U.S. EPA, July 1975.

China ceased production in 2007,{{cite web |url=http://chm.pops.int/Programmes/DDT/Meetings/DDTEG32010/tabid/1108/mctl/ViewDetails/EventModID/1421/EventID/116/xmid/4037/language/en-US/Default.aspx |title=Report of the Third Expert Group Meeting on DDT |publisher=UNEP/POPS/DDT-EG.3/3, Stockholm Convention on Persistent Organic Pollutants |date=November 12, 2010 |access-date=January 26, 2011 |archive-date=December 21, 2010 |archive-url=https://web.archive.org/web/20101221115754/http://chm.pops.int/Programmes/DDT/Meetings/DDTEG32010/tabid/1108/mctl/ViewDetails/EventModID/1421/EventID/116/xmid/4037/language/en-US/Default.aspx |url-status=live }} leaving India the only country still manufacturing DDT; it is the largest consumer.{{cite web|url=http://www.pops.int/documents/ddt/Global%20status%20of%20DDT%20SSC%2020Oct08.pdf|title=Global status of DDT and its alternatives for use in vector control to prevent disease|last=van den Berg|first=Henk|name-list-style=vanc|date=October 23, 2008|publisher=Stockholm Convention on Persistent Organic Pollutants/United Nations Environment Programme|access-date=November 22, 2008|archive-url=https://web.archive.org/web/20101217022138/http://www.pops.int/documents/ddt/Global%20status%20of%20DDT%20SSC%2020Oct08.pdf|archive-date=December 17, 2010|url-status=dead|df=mdy-all}} In 2009, 3,314 tonnes were produced for malaria control and visceral leishmaniasis. In recent years, in addition to India, just seven other countries, all in Africa, are still using DDT.{{Cite web |date=September 13, 2017 |title=Alternatives to DDT |url=http://www.unep.org/topics/chemicals-and-pollution-action/pollution-and-health/persistent-organic-pollutants-pops-0 |access-date=2024-06-10 |website=UNEP - UN Environment Programme |language=en}}

In insects, DDT opens voltage-sensitive sodium ion channels in neurons, causing them to fire spontaneously, which leads to spasms and eventual death.{{Cite journal|last=Dong|first=Ke|date=2007-01-06|title=Insect sodium channels and insecticide resistance|journal=Invertebrate Neuroscience |volume=7|issue=1|pages=17–30|doi=10.1007/s10158-006-0036-9|issn=1354-2516|pmc=3052376|pmid=17206406}} Insects with certain mutations in their sodium channel gene are resistant to DDT and similar insecticides. DDT resistance is also conferred by up-regulation of genes expressing cytochrome P450 in some insect species,{{cite journal | vauthors = Denholm I, Devine GJ, Williamson MS | title = Insecticide resistance on the move | journal = Science | volume = 297 | issue = 5590 | pages = 2222–2223 | date = September 2002 | pmid = 12351778 | doi = 10.1126/science.1077266 | s2cid = 83741532}} as greater quantities of some enzymes of this group accelerate the toxin's metabolism into inactive metabolites. Genomic studies in the model genetic organism Drosophila melanogaster revealed that high level DDT resistance is polygenic, involving multiple resistance mechanisms.{{cite journal | vauthors = Pedra JH, McIntyre LM, Scharf ME, Pittendrigh BR | title = Genome-wide transcription profile of field- and laboratory-selected dichlorodiphenyltrichloroethane (DDT)-resistant Drosophila | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 101 | issue = 18 | pages = 7034–7039 | date = May 2004 | pmid = 15118106 | pmc = 406461 | doi = 10.1073/pnas.0400580101 | bibcode = 2004PNAS..101.7034P | doi-access = free }} In the absence of genetic adaptation, Roberts and Andre 1994 find behavioral avoidance nonetheless provides insects with some protection against DDT.{{cite journal | title=Genetic erosion impedes adaptive responses to stressful environments | last1=Bijlsma | first1=R. | last2=Loeschcke | first2=Volker | journal=Evolutionary Applications | publisher=Blackwell | issn=1752-4571 | date=7 November 2011 | volume=5 | issue=2 | pages=117–129 | doi=10.1111/j.1752-4571.2011.00214.x | pmid=25568035 | pmc=3353342 | s2cid=18877551}} The M918T mutation event produces dramatic kdr for pyrethroids but Usherwood et al. 2005 find it is entirely ineffective against DDT.{{cite journal | last=Scott | first=Jeffrey G. | title=Life and Death at the Voltage-Sensitive Sodium Channel: Evolution in Response to Insecticide Use | journal=Annual Review of Entomology | publisher=Annual Reviews | volume=64 | issue=1 | date=2019-01-07 | issn=0066-4170 | doi=10.1146/annurev-ento-011118-112420 | pages=243–257| pmid=30629893 | s2cid=58667542 }} Scott 2019 believes this test in Drosophila oocytes holds for oocytes in general.

File:DDT Powder.jpg

File:DDTDichlordiphényltrichloréthane7.JPG Néocide (powder box, 50 g) containing 10% DDT, made in France.]]

{{external media | width =175px | float = right | headerimage= 175px | audio1 = [https://www.sciencehistory.org/distillations/podcast/ddt-the-britney-spears-of-chemicals "Episode 207: DDT"], Science History Institute}}

DDT was first synthesized in 1874 by Othmar Zeidler under the supervision of Adolf von Baeyer.{{cite journal | author = Othmar Zeidler | year = 1874 | title = Verbindungen von Chloral mit Brom- und Chlorbenzol |trans-title=Compounds of chloral with bromo- and chlorobenzene | journal = Berichte der Deutschen Chemischen Gesellschaft | volume = 7 | issue = 2 | pages = 1180–1181 | url = http://babel.hathitrust.org/cgi/pt?id=uiug.30112025694776;view=1up;seq=231 | archive-url = https://archive.today/20160420035142/http://babel.hathitrust.org/cgi/pt?id=uiug.30112025694776;view=1up;seq=231 | url-status = dead | archive-date = 2016-04-20 | doi = 10.1002/cber.18740070278 }} On p. 1181, Zeidler called DDT dimonochlorphenyltrichloräthan.{{cite book |last=Augustin |first=Frank |name-list-style=vanc |title=Zur Geschichte des Insektizids Dichlordiphenyltrichloräthan (DDT) unter besonderer Berücksichtigung der Leistung des Chemikers Paul Müller (1899–1965) |url=https://books.google.com/books?id=hY5btwAACAAJ&pg=PA1 |year=1993 |publisher=Medizinische Fakultät der Universität Leipzig |location=Leipzig |pages=1–77 |access-date=August 29, 2022 |archive-date=July 31, 2020 |archive-url=https://web.archive.org/web/20200731150524/https://books.google.com/books?id=hY5btwAACAAJ&pg=PA1 |url-status=live }} It was further described in 1929 in a dissertation by W. Bausch and in two subsequent publications in 1930.{{cite journal | vauthors = Brand K, Bausch W | title = Über Verbindungen der Tetraaryl-butanreihe. 10. Mitteilung. Über die Reduktion organischer Halogenverbindungen und Über Verbindungen der Tetraaryl-butanreihe | journal = Journal für Praktische Chemie | volume = 127 | pages = 219–239 | year = 1930 | doi = 10.1002/prac.19301270114 }}{{cite journal | vauthors = Brand K, Horn O, Bausch W | title = Die elektrochemische Darstellung von 1,1,4,4-p,p′,p",p‴-Tetraphenetyl-butin-2 und von 1,1,4,4-p,p′,p",p‴-Tetra(chlorphenyl)-butin-2. 11. Mitteilung. Über die Reduktion organischer Halogenverbindungen und Verbindungen der Tetraarylbutanreihe | journal = Journal für Praktische Chemie | volume = 127 | pages = 240–247 | year = 1930 | doi = 10.1002/prac.19301270115 }} 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.Wolfgang von Leuthold, Schädlingsbekämpfung. DRP Nr 673246, April 27, 1934 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.

File:1955. Ford tri-motor spraying DDT. Western spruce budworm control project. Powder River control unit, OR. (32213742634).jpg as part of a spruce budworm control project, 1955]]

File:BosaDDTlog.jpg (Sardinia)]]

DDT is the best-known of several chlorine-containing pesticides used in the 1940s and 1950s. During this time, the use of DDT was driven by protecting American soldiers from diseases in tropical areas. Both British and American scientists hoped to use it to control spread of malaria, typhus, dysentery, and typhoid fever among overseas soldiers, especially considering that the pyrethrum was harder to access since it came mainly from Japan.{{Cite web |last=Sonnenberg |first=J. |date=2015-05-02 |title=Shoot to Kill: Control and Controversy in the History of DDT Science |url=https://www.stanford.edu/group/sjph/cgi-bin/sjphsite/shoot-to-kill-control-and-controversy-in-the-history-of-ddt-science/ |access-date=2022-04-09 |website=Stanford Journal of Public Health |language=en-US |archive-date=August 29, 2022 |archive-url=https://web.archive.org/web/20220829055112/https://web.stanford.edu/group/sjph/cgi-bin/sjphsite/shoot-to-kill-control-and-controversy-in-the-history-of-ddt-science/ |url-status=live }}{{Cite web |title=The Deadly Dust: The Unhappy History Of DDT |url=https://www.americanheritage.com/deadly-dust-unhappy-history-ddt |access-date=2022-04-09 |website=AMERICAN HERITAGE |language=en |archive-date=April 9, 2022 |archive-url=https://web.archive.org/web/20220409133455/https://www.americanheritage.com/deadly-dust-unhappy-history-ddt |url-status=live }} Due to the potency of DDT, it was not long before America's 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 American government's advertising campaigns of posters depicting Americans fighting the Axis powers and insects and through media publications celebrating its military uses. In the South Pacific, it was sprayed aerially for malaria and dengue fever control with spectacular effects. While DDT's chemical and insecticidal properties were important factors in these victories, advances in application equipment coupled with competent organization and sufficient manpower were also crucial to the success of these programs.{{cite book|first=Thomas|last=Dunlap|title=DDT: Scientists, Citizens, and Public Policy|url=https://books.google.com/books?id=PLL_AwAAQBAJ|year=2014|publisher=Princeton University Press|isbn=978-1-4008-5385-4|access-date=August 29, 2022|archive-date=October 19, 2021|archive-url=https://web.archive.org/web/20211019212022/https://books.google.com/books?id=PLL_AwAAQBAJ|url-status=live}}

In 1945, DDT was made available to farmers as an agricultural insecticide and played a role in the elimination of malaria in Europe and North America.{{cite journal | vauthors = de Zulueta J | title = The end of malaria in Europe: an eradication of the disease by control measures | journal = Parassitologia | volume = 40 | issue = 1–2 | pages = 245–246 | date = June 1998 | pmid = 9653750 }}{{cite web |url=https://www.cdc.gov/malaria/about/history/elimination_us.html |title=About Malaria – History – Elimination of Malaria in the United States (1947–1951) |website=CDC.gov |date=2019-01-28 |access-date=September 9, 2017 |archive-date=May 4, 2012 |archive-url=https://web.archive.org/web/20120504183309/http://www.cdc.gov/malaria/about/history/elimination_us.html |url-status=live }} 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.

DDT was also a way for American influence to reach abroad through DDT-spraying campaigns. In the 1944 issue of Life magazine there was a feature regarding the Italian program showing pictures of American public health officials in uniforms spraying DDT on Italian families.

In 1955, the World Health Organization commenced a program to eradicate malaria in countries with low to moderate transmission rates worldwide, relying largely on DDT for mosquito control and rapid diagnosis and treatment to reduce transmission.{{cite journal | vauthors = Mendis K, Rietveld A, Warsame M, Bosman A, Greenwood B, Wernsdorfer WH | title = From malaria control to eradication: The WHO perspective | journal = Tropical Medicine & International Health | volume = 14 | issue = 7 | pages = 802–809 | date = July 2009 | pmid = 19497083 | doi = 10.1111/j.1365-3156.2009.02287.x | s2cid = 31335358 | doi-access = free }} The program eliminated the disease in "North America, Europe, the former Soviet Union", and in "Taiwan, much of the Caribbean, the Balkans, parts of northern Africa, the northern region of Australia, and a large swath of the South Pacific"{{cite news |last=Gladwell |first=Malcolm |author-link=Malcolm Gladwell |name-list-style=vanc |title=The Mosquito Killer |newspaper=The New Yorker |date=July 2, 2001 |url=http://gladwell.com/the-mosquito-killer/ |access-date=August 20, 2014 |archive-url=https://web.archive.org/web/20160416165010/http://gladwell.com/the-mosquito-killer/ |archive-date=April 16, 2016 |url-status=dead }} and dramatically reduced mortality in Sri Lanka and India.

However, failure to sustain the program, increasing mosquito tolerance to DDT, and increasing parasite tolerance led to a resurgence. In many areas early successes partially or completely reversed, and in some cases rates of transmission increased.{{cite journal | vauthors = Chapin G, Wasserstrom R | title = Agricultural production and malaria resurgence in Central America and India | journal = Nature | volume = 293 | issue = 5829 | pages = 181–185 | year = 1981 | pmid = 7278974 | doi = 10.1038/293181a0 | bibcode = 1981Natur.293..181C | s2cid = 4346743 | doi-access = free }} 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".{{cite journal | vauthors = Sadasivaiah S, Tozan Y, Breman JG | title = Dichlorodiphenyltrichloroethane (DDT) for indoor residual spraying in Africa: how can it be used for malaria control? | journal = The American Journal of Tropical Medicine and Hygiene | volume = 77 | issue = 6 Suppl | pages = 249–263 | date = December 2007 | pmid = 18165500 | doi = 10.4269/ajtmh.2007.77.249 | doi-access = free }}

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.{{Cite book| publisher = Palgrave Macmillan| isbn = 978-1-349-31322-8 | pages = 133–153| editor1-first = Virginia |editor1-last = Berridge| editor2-first=Martin| editor2-last=Gorsky | last = Clarke| first = Sabine| title = Environment, Health and History| chapter = Rethinking the Post-War Hegemony of DDT: Insecticides Research and the British Colonial Empire| location = London| date = 2012}} 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. Efforts shifted from spraying to the use of bednets impregnated with insecticides and other interventions.{{cite journal | vauthors = Rogan WJ, Chen A | title = Health risks and benefits of bis(4-chlorophenyl)-1,1,1-trichloroethane (DDT) | journal = Lancet | volume = 366 | issue = 9487 | pages = 763–773 | year = 2005 | pmid = 16125595 | doi = 10.1016/S0140-6736(05)67182-6 | s2cid = 3762435 | url = https://zenodo.org/record/1259797 | access-date = June 13, 2019 | archive-date = October 17, 2019 | archive-url = https://web.archive.org/web/20191017205259/https://zenodo.org/record/1259797 | url-status = live }}

By October 1945, DDT was available for public sale in the United States, used both as an agricultural pesticide and as a household insecticide. Although its use was promoted by government and the agricultural industry, US scientists such as FDA pharmacologist Herbert O. Calvery expressed concern over possible hazards associated with DDT as early as 1944.{{cite book|last1=Davis|first1=Frederick Rowe|title=Banned : a history of pesticides and the science of toxicology|date=2014|publisher=Yale University Press|location=[S.l.]|isbn=978-0300205176|page=26|url=https://books.google.com/books?id=kuIdBQAAQBAJ&pg=PA26|access-date=25 July 2017|archive-date=July 31, 2020|archive-url=https://web.archive.org/web/20200731130621/https://books.google.com/books?id=kuIdBQAAQBAJ&pg=PA26|url-status=live}} In 1947, Bradbury Robinson, a physician and nutritionist practicing in St. Louis, Michigan, warned of the dangers of using the pesticide DDT in agriculture. DDT had been researched and manufactured in St. Louis by the Michigan Chemical Corporation, later purchased by Velsicol Chemical Corporation,{{cite web|url=http://www.velsicol.com/|title=Leading Chemical Company – Manufacture, Distribution & Sales|website=Velsicol Chemical, LLC|access-date=October 23, 2017|archive-date=October 16, 2017|archive-url=https://web.archive.org/web/20171016054516/http://www.velsicol.com/|url-status=live}} and had become an important part of the local economy.{{cite web|url=http://www.stlouismi.com/1/stlouis/history_by_decades.asp|title=History by Decades|website=www.stlouismi.com|access-date=October 23, 2017|archive-date=November 18, 2006|archive-url=https://web.archive.org/web/20061118003950/http://www.stlouismi.com/1/stlouis/history_by_decades.asp|url-status=live}} Citing research performed by Michigan State UniversityAmerican Potato Journal, June 1947, volume 24, issue 6, pp. 183–187. Results of spraying and dusting potatoes in Michigan in 1946. in 1946, Robinson, a past president of the local Conservation Club,"Conservation Club, St. Louis, Has Program", Lansing State Journal (Lansing, Michigan), p. 14, March 2, 1931. opined that:

{{blockquote|perhaps the greatest danger from D.D.T. is that its extensive use in farm areas is most likely to upset the natural balances, not only killing beneficial insects in great number but by bringing about the death of fish, birds, and other forms of wild life either by their feeding on insects killed by D.D.T. or directly by ingesting the poison.{{cite report | title = A Nutritionist Ponders the D.D.T. Problem | first = Bradbury | last = Robinson | author-link = Bradbury Robinson | name-list-style = vanc | location = St. Louis, Michigan | work = Private Publication | date = 1947}}}}

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.{{cite journal |last1=Conis |first1=Elena |title=Beyond Silent Spring: An Alternate History of DDT |journal=Distillations |date=2017 |volume=2 |issue=4 |pages=16–23 |url=https://www.sciencehistory.org/distillations/magazine/beyond-silent-spring-an-alternate-history-of-ddt |access-date=20 March 2018 |archive-date=November 22, 2019 |archive-url=https://web.archive.org/web/20191122192729/https://www.sciencehistory.org/distillations/magazine/beyond-silent-spring-an-alternate-history-of-ddt |url-status=live }}{{EHC-ref | id = 009 | name=DDT and its derivatives | date = 1979 | isbn = 92-4-154069-9 }} In the 1950s the federal government began tightening regulations governing its use. These events received little attention. Women like Dorothy Colson and Mamie Ella Plyler of Claxton, Georgia, gathered evidence about DDT's effects and wrote to the Georgia Department of Public Health, the National Health Council in New York City, and other organizations.{{cite news|last1=Conis|first1=Elena|name-list-style=vanc|title=DDT Disbelievers: Health and the New Economic Poisons in Georgia after World War II|url=https://southernspaces.org/2016/ddt-disbelievers-health-and-new-economic-poisons-georgia-after-world-war-ii|access-date=25 July 2017|work=Southern Spaces|date=October 28, 2016|archive-date=August 6, 2017|archive-url=https://web.archive.org/web/20170806021326/https://southernspaces.org/2016/ddt-disbelievers-health-and-new-economic-poisons-georgia-after-world-war-ii|url-status=live}}

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.{{Cite web |last=Knox |first=Robert |date=2012 |title=Duxbury celebrates Rachel Carson's 'Silent Spring' |url=https://www.bostonglobe.com/metro/regionals/south/2012/05/23/duxbury-celebrates-local-nature-lover-voice-rachel-carson-silent-spring/uhxGAO38m3kHbDMlYQfPqO/story.html |access-date=2023-12-16 |website=BostonGlobe.com |language=en-US}}{{Cite web |last=Johnson |first=Jenn |date=2018-02-22 |title=Her Heart's Home {{!}} Timeless New England |url=https://newengland.com/yankee/magazine/her-hearts-home-timeless-new-england/ |access-date=2023-12-16 |website=New England |language=en}} 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,{{cite journal | vauthors = Greenberg DS | title = Pesticides: White House Advisory Body Issues Report Recommending Steps to Reduce Hazard to Public | journal = Science | volume = 140 | issue = 3569 | pages = 878–879 | date = May 1963 | pmid = 17810673 | doi = 10.1126/science.140.3569.878 | bibcode = 1963Sci...140..878G }} and recommended a phaseout of "persistent toxic pesticides".{{cite book |last=Michaels |first=David | name-list-style = vanc | title = Doubt is Their Product: How Industry's Assault on Science Threatens Your Health|publisher=Oxford University Press|location=New York|year=2008|isbn=978-0-19-530067-3|title-link=Doubt is Their Product }} In 1965, the U.S. 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.{{Cite web|title=Technical Guide No. 6 – Delousing Procedures for the Control of Louse-borne Disease During Contingency Operations |publisher=United States Department of Defense Armed Forces Pest Management Board Information Services Division|date= November 2011|url= https://perma.cc/HY4A-ENXM }}

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.{{r|n=CARTERLJ19671222|r={{cite journal | author-last=Carter |author-first=Luther J. | journal=Science | title=Environmental Pollution: Scientists Go to Court | volume=158 | issue=3808 | pages=1552–1556 | publisher=American Association for the Advancement of Science | date=22 December 1967 | url=https://www.science.org/doi/10.1126/science.158.3808.1552 | doi=10.1126/science.158.3808.1552 |pmid=6060359 |bibcode=1967Sci...158.1552C | access-date=26 October 2024}}}} 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.{{r|n=PRIMACKJR_VONHIPPELF1974|r={{cite book | author-last1=Primack |author-first1=J. R. | author-last2=Von Hippel |author-first2=Frank | date= 1974 | title=Advice and Dissent: Scientists in the Political Arena | chapter=The Battle Over Persistent Pesticides: From Rachel Carson to the Environmental Defense Fund | publisher=Basic Books | pages=128–142 | chapter-url=https://sgs.princeton.edu/sites/default/files/2019-10/Advice-and-Dissent-Chapter10.pdf | isbn=978-0-465-00090-6}}}}{{cite magazine|title=Sue the Bastards |url=http://www.time.com/time/magazine/article/0,9171,910111-2,00.html |magazine=Time |date=October 18, 1971 |archive-url=https://web.archive.org/web/20120119181231/http://www.time.com/time/magazine/article/0,9171,910111-2,00.html |archive-date=January 19, 2012 |url-status=dead |df=mdy }}

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.{{r|n=HENKINH_MERTAM_STAPLESJM1971|r={{cite book | author-last1=Henkin |author-first1=Harmon | author-last2=Merta |author-first2=Martin | author-last3=Staples |author-first3=James M. | date=1971 | title=The Environment, the Establishment, and the Law | publisher=Houghton Mifflin | isbn=978-0-395-11070-6}}}} 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.{{cite journal|first1=David B.|last1=Peakall|first2=lloyd F.|last2=Kiff | name-list-style = vanc |title=Eggshell thinning and dde residue levels among peregrine falcons falco peregrinus: a global perspective|publisher=Wiley Online Library|date=April 1979|doi= 10.1111/j.1474-919X.1979.tb04962.x|volume=121|issue = 2|journal=Ibis|pages=200–204}} 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.{{r|n=DUNLAPTR1978|r={{cite journal | author-last=Dunlap |author-first=Thomas R. | journal=Wisconsin Magazine of History | title=DDT on Trial: The Wisconsin Hearing, 1968-1969 | volume=62 | issue=1 | pages=3–24 | date= 1978 | url=https://content.wisconsinhistory.org/digital/collection/wmh/id/33630 | issn=1943-7366 | access-date=11 December 2024}}}}

In response to an EDF suit, the U.S. 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. However, these findings were criticized, as they were performed mostly by economic entomologists inherited from the United States Department of Agriculture, who many environmentalists felt were biased towards agribusiness and understated concerns about human health and wildlife. The decision thus created controversy.

The EPA held seven months of hearings in 1971–1972, with scientists giving evidence for and against DDT. In the summer of 1972, Ruckelshaus announced the cancellation of most uses of DDT{{snd}} exempting public health uses under some conditions. Again, this caused controversy. Immediately after the announcement, both the EDF and the DDT manufacturers filed suit against EPA. Many in the agricultural community were concerned that food production would be severely impacted, while proponents of pesticides warned of increased breakouts of insect-borne diseases and questioned the accuracy of giving animals high amounts of pesticides for cancer potential.Susan Wayland and Penelope Fenner-Crisp. [http://www.epaalumni.org/hcp/pesticides.pdf "Reducing Pesticide Risks: A Half Century of Progress"]. {{Webarchive|url=https://web.archive.org/web/20190412070256/https://www.epaalumni.org/hcp/pesticides.pdf |archive-url=https://web.archive.org/web/20161022222635/http://www.epaalumni.org/hcp/pesticides.pdf |archive-date=2016-10-22 |url-status=live |date=April 12, 2019 }}. EPA Alumni Association. March 2016. 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. During the late 1970s, the EPA also began banning organochlorines, pesticides that were chemically similar to DDT. These included aldrin, dieldrin, chlordane, heptachlor, toxaphene, and mirex.

Some uses of DDT continued under the public health exemption. For example, in June 1979, the California Department of Health Services was permitted to use DDT to suppress flea vectors of bubonic plague.{{cite web |url=http://www.aei.org/outlook/27063 |publisher=AEI |title=The Rise, Fall, Rise, and Imminent Fall of DDT |archive-url=https://web.archive.org/web/20110102120306/http://www.aei.org/outlook/27063 |archive-date=January 2, 2011 |url-status=dead |df=mdy }} DDT continued to be produced in the United States for foreign markets until 1985, when over 300 tons were exported.

In the 1970s and 1980s, agricultural use was banned in most developed countries, beginning with Hungary in 1968{{cite book | editor1-first=Nicholas P. | editor1-last=Cheremisinoff | editor2-first=Paul E. | editor2-last=Rosenfeld | title=Handbook of Pollution Prevention and Cleaner Production: Best Practices in the Agrochemical Industry | chapter=6 DDT and Related Compounds | publisher=William Andrew | year=2011 | isbn=978-1-4377-7825-0 | pages=247–259}}{{cite journal | last1=Nagy | first1=B. | last2=Vajna | first2=L. | title=The Increasing Possibilities of the Application of Integrated Control in Plant Protection in Hungary | journal=EPPO Bulletin | publisher=European and Mediterranean Plant Protection Organization (Wiley) | volume=2 | issue=6 | year=1972 | issn=0250-8052 | doi=10.1111/j.1365-2338.1972.tb02138.x | pages=95–96 | s2cid=84111430}}{{cite web |url=http://www.fvm.hu/main.php?folderID=1564&articleID=6169&ctag=articlelist&iid=1&part=2 |title=Selected passages from the history of the Hungarian plant protection administration on the 50th anniversary of establishing the county plant protection stations |url-status=dead |archive-url=https://web.archive.org/web/20090110025539/http://www.fvm.hu/main.php?folderID=1564&articleID=6169&ctag=articlelist&iid=1&part=2 |archive-date=January 10, 2009 |df=mdy-all }} {{ndash}} although in practice it continued to be used through at least 1970.{{cite book | title=Environmental Health Criteria 9 - DDT and its Derivatives | date=1979 | location=Geneva | isbn=92-4-154069-9 | hdl=10665/39562 | oclc=67616765 | pages=194}} {{OCLC|1039198025}}. {{OCLC|504327918}}. {{ISBN|978-92-4-154069-8}}. {{OCLC|1158652149}}. {{OCLC|882544146}}. {{OCLC|5364752}}. This was followed by Norway and Sweden in 1970, West Germany and the United States in 1972, but not in the United Kingdom 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.{{Cite journal |last1=Aichner |first1=Bernhard |last2=Bussian |first2=Bernd |last3=Lehnik-Habrink |first3=Petra |last4=Hein |first4=Sebastian |date=2013 |title=Levels and Spatial Distribution of Persistent Organic Pollutants in the Environment: A Case Study of German Forest Soils |url=https://www.researchgate.net/publication/256836176 |journal=Environmental Science & Technology |language=en |volume=47 |issue=22 |pages=12703–12714 |doi=10.1021/es4019833|pmid=24050388 |bibcode=2013EnST...4712703A }}

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.{{Cite web|url=http://www.pic.int/Portals/5/DGDs/DGD_DDT_EN.pdf|title=DDT, Decision Guidance Document, Joint FAO/UNEP Programme for the operation of Prior Informed Consent, UNEP/FAO, Rome, Italy, 1991.|access-date=August 24, 2014|archive-date=April 13, 2020|archive-url=https://web.archive.org/web/20200413043928/http://www.pic.int/Portals/5/DGDs/DGD_DDT_EN.pdf|url-status=live}}

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.{{Cite web|url=http://chm.pops.int/Portals/0/Repository/convention_text/UNEP-POPS-COP-CONVTEXT-FULL.English.PDF|title=Stockholm Convention on Persistent Organic Pollutants.|access-date=August 24, 2014|archive-date=June 5, 2015|archive-url=https://web.archive.org/web/20150605092808/http://chm.pops.int/Portals/0/Repository/convention_text/UNEP-POPS-COP-CONVTEXT-FULL.English.PDF|url-status=live}} Resolution 60.18 of the World Health Assembly commits WHO to the Stockholm Convention's aim of reducing and ultimately eliminating DDT.{{Cite web|url=http://www.who.int/ipcs/capacity_building/ddt_statement/en/|archive-url=https://web.archive.org/web/20090404040645/http://www.who.int/ipcs/capacity_building/ddt_statement/en/|url-status=dead|archive-date=April 4, 2009|title=WHO | Strengthening malaria control while reducing reliance on DDT|website=WHO}} 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."{{cite web|url=http://www.malaria.org/DDTpage.html |title=MFI second page |publisher=Malaria Foundation International |access-date=March 15, 2006 |archive-url=https://web.archive.org/web/20101026080133/http://www.malaria.org/DDTpage.html |archive-date=October 26, 2010 |url-status=live |df=mdy }}

Despite the worldwide ban, agricultural use continued in India,{{cite news |title=Concern over excessive DDT use in Jiribam fields |agency=The Imphal Free Press |date=May 5, 2008 |url=http://www.kanglaonline.com/index.php?template=headline&newsid=42015&typeid=1 |access-date=May 5, 2008 |archive-url= https://web.archive.org/web/20081206120016/http://www.kanglaonline.com/index.php?template=headline&newsid=42015&typeid=1 |archive-date=December 6, 2008}} North Korea, and possibly elsewhere. As of 2013, an estimated 3,000 to 4,000 tons of DDT were produced for disease vector control, including 2,786 tons in India.{{cite web |url=http://chm.pops.int/Implementation/DDT/DDTMeetings/DDTEG62016/tabid/5348/Default.aspx |title=Report of the Sixth Expert Group Meeting on DDT |publisher=UNEP/POPS/DDT-EG.6, Stockholm Convention on Persistent Organic Pollutants |date=November 8, 2016 |access-date=March 4, 2018 |archive-date=March 5, 2018 |archive-url=https://web.archive.org/web/20180305063542/http://chm.pops.int/Implementation/DDT/DDTMeetings/DDTEG62016/tabid/5348/Default.aspx |url-status=live }} 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.{{cite web|url=http://www.malaria.org/DDTcosts.html |title=Is DDT still effective and needed in malaria control? |publisher=Malaria Foundation International |access-date=March 15, 2006 |archive-url=https://web.archive.org/web/20110721175925/http://www.malaria.org/DDTcosts.html |archive-date=July 21, 2011 |url-status=live |df=mdy }} For comparison, treating {{convert|40|ha|acre}} of cotton during a typical U.S. growing season requires the same amount of chemical to treat roughly 1,700 homes.{{cite journal | vauthors = Roberts DR, Laughlin LL, Hsheih P, Legters LJ | title = DDT, global strategies, and a malaria control crisis in South America | journal = Emerging Infectious Diseases | volume = 3 | issue = 3 | pages = 295–302 | date = July–September 1997 | pmid = 9284373 | pmc = 2627649 | doi = 10.3201/eid0303.970305 }}

File:DDT to DDD and DDE.svg

DDT is a persistent organic pollutant that is readily adsorbed to soils and sediments, which can act both as sinks and as long-term sources of exposure affecting organisms. Depending on environmental conditions, its soil half-life can range from 22 days to 30 years. Routes of loss and degradation include runoff, volatilization, photolysis and aerobic and anaerobic biodegradation. Due to hydrophobic properties, in aquatic ecosystems DDT and its metabolites are absorbed by aquatic organisms and adsorbed on suspended particles, leaving little DDT dissolved in the water (however, its half-life in aquatic environments is listed by the National Pesticide Information Center as 150 years{{cite web|title=DDT (Technical Fact Sheet)|url=http://npic.orst.edu/factsheets/archive/ddttech.pdf|access-date=1 August 2018|archive-date=February 19, 2018|archive-url=https://web.archive.org/web/20180219141527/http://npic.orst.edu/factsheets/archive/ddttech.pdf|url-status=live}}). Its breakdown products and metabolites, DDE and DDD, are also persistent and have similar chemical and physical properties. DDT and its breakdown products are transported from warmer areas to the Arctic by the phenomenon of global distillation, where they then accumulate in the region's food web.{{cite journal|title=The Grasshopper Effect and Tracking Hazardous Air Pollutants |journal=The Science and the Environment Bulletin |publisher=Environment Canada |issue=May/June 1998 |url=http://www.ec.gc.ca/science/sandemay/PrintVersion/print2_e.html |url-status=dead |archive-url=https://web.archive.org/web/20040928235911/http://www.ec.gc.ca/science/sandemay/printversion/print2_e.html |archive-date=September 28, 2004 }}

Medical researchers in 1974 found a measurable and significant difference in the presence of DDT in human milk between mothers who lived in New Brunswick and mothers who lived in Nova Scotia, "possibly because of the wider use of insecticide sprays in the past".{{Cite journal |last1=Musial |first1=C. J. |last2=Hutzinger |first2=O. |last3=Zitko |first3=V. |last4=Crocker |first4=J. |date=1974 |title=Presence of PCB, DDE and DDT in human milk in the provinces of New Brunswick and Nova Scotia, Canada |url=https://doi.org/10.1007/BF01709117 |journal=Bulletin of Environmental Contamination and Toxicology |language=en |volume=12 |issue=3 |pages=258–267 |doi=10.1007/BF01709117 |pmid=4215516 |bibcode=1974BuECT..12..258M |issn=1432-0800}}

Because of its lipophilic properties, DDT can bioaccumulate, especially in predatory birds.{{cite book | title = Introduction to Ecotoxicology | publisher = Blackwell Science | year = 1999 | isbn = 978-0-632-03852-7 | page = 68 | url = https://books.google.com/books?id=X-ik73-vnXAC&pg=PA68 | first1 = Des W. | last1 = Connell | first2 = Paul | last2 = Lam | first3 = Bruce | last3 = Richardson | first4 = Rudolf | last4 = Wu | name-list-style = vanc | access-date = August 29, 2022 | archive-date = March 19, 2015 | archive-url = https://web.archive.org/web/20150319000333/http://books.google.com/books?id=X-ik73-vnXAC&pg=PA68 | url-status = live }} DDT is toxic to a wide range of living organisms, including marine animals such as crayfish, daphnids, sea shrimp and many species of fish. DDT, DDE and DDD magnify through the food chain, with apex predators such as raptor birds concentrating more chemicals than other animals in the same environment. They are stored mainly in body fat. DDT and DDE are resistant to metabolism; in humans, their half-lives are 6 and up to 10 years, respectively. In the United States, these chemicals were detected in almost all human blood samples tested by the Centers for Disease Control in 2005, though their levels have sharply declined since most uses were banned.{{cite journal | vauthors = Eskenazi B, Chevrier J, Rosas LG, Anderson HA, Bornman MS, Bouwman H, Chen A, Cohn BA, de Jager C, Henshel DS, Leipzig F, Leipzig JS, Lorenz EC, Snedeker SM, Stapleton D | title = The Pine River statement: human health consequences of DDT use | journal = Environmental Health Perspectives | volume = 117 | issue = 9 | pages = 1359–1367 | date = September 2009 | pmid = 19750098 | pmc = 2737010 | doi = 10.1289/ehp.11748 | bibcode = 2009EnvHP.117.1359E }} Estimated dietary intake has declined, although FDA food tests commonly detect it.USDA, Pesticide Data Program Annual Summary Calendar YearPesticide Data Program Annual Summary Calendar Year 2005, November 2006.

Despite being banned for many years, in 2018 research showed that DDT residues are still present in European soils and Spanish rivers.{{cite journal | vauthors = Silva V, Mol HG, Zomer P, Tienstra M, Ritsema CJ, Geissen V | title = Pesticide residues in European agricultural soils – A hidden reality unfolded | journal = The Science of the Total Environment | volume = 653 | pages = 1532–1545 | date = February 2019 | pmid = 30759587 | doi = 10.1016/j.scitotenv.2018.10.441 | bibcode = 2019ScTEn.653.1532S | doi-access = free }}{{cite web |last1=Roman |first1=Dolores |last2=Lysimachou |first2=Angeliki |last3=Balaguer |first3=Rodrigo |last4=Dimastrogiovanni |first4=Giorgio |last5=García |first5=Kistiñe |last6=González |first6=Erika |name-list-style=vanc |title=Ríos hormonados: Contamination of Spanish Rivers with Pesticides |url=https://www.pan-europe.info/resources/reports/2018/02/r%C3%ADos-hormonados-contamination-spanish-rivers-pesticides |website=Pesticide Action Network Europe |access-date=26 February 2019 |archive-date=February 27, 2019 |archive-url=https://web.archive.org/web/20190227060806/https://www.pan-europe.info/resources/reports/2018/02/r%C3%ADos-hormonados-contamination-spanish-rivers-pesticides |url-status=live }}

The chemical and its breakdown products DDE and DDD caused eggshell thinning and population declines in multiple North American and European bird of prey species.{{cite journal | vauthors = Vos JG, Dybing E, Greim HA, Ladefoged O, Lambré C, Tarazona JV, Brandt I, Vethaak AD | title = Health effects of endocrine-disrupting chemicals on wildlife, with special reference to the European situation | journal = Critical Reviews in Toxicology | volume = 30 | issue = 1 | pages = 71–133 | date = January 2000 | pmid = 10680769 | doi = 10.1080/10408440091159176 | s2cid = 11908661 }}{{cite journal |doi=10.1080/23273747.2016.1173766 |title=California condors and DDT: Examining the effects of endocrine disrupting chemicals in a critically endangered species |journal=Endocrine Disruptors |volume=4 |pages=e1173766 |year=2016 |last1=Tubbs |first1=Christopher W. | name-list-style = vanc |doi-access=free }}{{cite journal |doi=10.1046/j.1474-919X.2003.00132.x |title=California Condors and DDE: A re-evaluation |journal=Ibis |volume=145 |issue=1 |pages=136–151 |year=2002 |last1=Snyder |first1=Noel F. R. |last2=Meretsky |first2=Vicky J. | name-list-style = vanc }} Both laboratory experiments and field studies confirmed this effect.{{cite news | url = https://www.epa.gov/caddis-vol1/case-ddt-revisiting-impairment | title = The Case of DDT: Revisiting the Impairment | work = US Environmental Protection Agency (EPA) | access-date = August 5, 2021 | archive-date = August 5, 2021 | archive-url = https://web.archive.org/web/20210805060600/https://www.epa.gov/caddis-vol1/case-ddt-revisiting-impairment | url-status = live }} The effect was first conclusively proven at Bellow Island in Lake Michigan during University of Michigan-funded studies on American herring gulls in the mid-1960s.{{cite web |last1=Smith |first1=Jeff |title=The Science Behind Northport's Gull Island |url=https://mynorth.com/2017/05/the-science-behind-northports-gull-island/ |website=MyNorth.com |access-date=8 September 2020 |date=9 May 2017 |archive-date=May 19, 2021 |archive-url=https://web.archive.org/web/20210519235311/https://mynorth.com/2017/05/the-science-behind-northports-gull-island/ |url-status=live }} DDE-related eggshell thinning is considered a major reason for the decline of the bald eagle, brown pelican,"Endangered and Threatened Wildlife and Plants; 12-Month Petition Finding and Proposed Rule To Remove the Brown Pelican (Pelecanus occidentalis) From the Federal List of Endangered and Threatened Wildlife; Proposed Rule", Fish and Wildlife Service, U.S. Department of the Interior, February 20, 2008. {{Federal Register|73|9407}} peregrine falcon and osprey. However, birds vary in their sensitivity to these chemicals, with birds of prey, waterfowl and song birds being more susceptible than chickens and related species. Even in 2010, California condors that feed on sea lions at Big Sur that in turn feed in the Palos Verdes Shelf area of the Montrose Chemical Superfund site exhibited continued thin-shell problems,{{cite news | last = Moir | first = John | name-list-style = vanc | url = https://www.nytimes.com/2010/11/16/science/16condors.html | title = New Hurdle for California Condors May Be DDT From Years Ago | work = The New York Times | date = November 15, 2010 | access-date = February 7, 2017 | archive-date = September 21, 2017 | archive-url = https://web.archive.org/web/20170921194609/http://www.nytimes.com/2010/11/16/science/16condors.html | url-status = live }}{{cite journal |vauthors=Kurle CM, Bakker VJ, Copeland H, Burnett J, Jones Scherbinski J, Brandt J, Finkelstein ME |title=Terrestrial Scavenging of Marine Mammals: Cross-Ecosystem Contaminant Transfer and Potential Risks to Endangered California Condors (Gymnogyps californianus) |journal=Environmental Science & Technology |volume=50 |issue=17 |pages=9114–9123 |year=2016 |pmid=27434394 |doi=10.1021/acs.est.6b01990 |bibcode=2016EnST...50.9114K |s2cid=206559840 |url=http://www.escholarship.org/uc/item/1646t91t |access-date=June 13, 2019 |archive-date=June 22, 2020 |archive-url=https://web.archive.org/web/20200622174112/https://escholarship.org/uc/item/1646t91t |url-status=live }} though DDT's role in the decline of the California condor is disputed.

The biological thinning mechanism is not entirely understood, but DDE appears to be more potent than DDT, and strong evidence indicates that p,p{{'}}-DDE inhibits calcium ATPase in the membrane of the shell gland and reduces the transport of calcium carbonate from blood into the eggshell gland. This results in a dose-dependent thickness reduction.{{cite book | vauthors = Walker CH, Sibly RM, Hopkin SP, Peakall DB | title = Principles of ecotoxicology | publisher = CRC/Taylor & Francis | location = Boca Raton, FL | isbn = 978-0-8493-3635-5 | year = 2006 | edition = 3rd | url = https://books.google.com/books?id=WxfSBQAAQBAJ&pg=PA300 | pages = 300 ff | access-date = August 29, 2022 | archive-date = July 31, 2020 | archive-url = https://web.archive.org/web/20200731135732/https://books.google.com/books?id=WxfSBQAAQBAJ&pg=PA300 | url-status = live }}{{cite web |last=Guillette |first=Louis J. |name-list-style=vanc |year=2006 |url=http://www.ehponline.org/members/2005/8045/8045.pdf |title=Endocrine Disrupting Contaminants |access-date=February 2, 2007 |archive-url=https://web.archive.org/web/20090325085455/http://www.ehponline.org/members/2005/8045/8045.pdf |archive-date=March 25, 2009 |url-status=dead |df=mdy }}{{cite journal | vauthors = Lundholm CD | title = DDE-induced eggshell thinning in birds: effects of p,p{{'}}-DDE on the calcium and prostaglandin metabolism of the eggshell gland | journal = Comparative Biochemistry and Physiology C | volume = 118 | issue = 2 | pages = 113–128 | date = October 1997 | pmid = 9490182 | doi = 10.1016/S0742-8413(97)00105-9 }} Other evidence indicates that o,p'-DDT disrupts female reproductive tract development, later impairing eggshell quality.{{cite journal | vauthors = Holm L, Blomqvist A, Brandt I, Brunström B, Ridderstråle Y, Berg C | title = Embryonic exposure to o,p{{'}}-DDT causes eggshell thinning and altered shell gland carbonic anhydrase expression in the domestic hen | journal =Environmental Toxicology and Chemistry| volume = 25 | issue = 10 | pages = 2787–2793 | date = October 2006 | pmid = 17022422 | doi = 10.1897/05-619R.1 | s2cid = 9298213 }} Multiple mechanisms may be at work, or different mechanisms may operate in different species.

File:DDT WWII soldier.jpg-carrying lice.]]

File:ASC Leiden - Coutinho Collection - 27 09 - Ziguinchor hospital, Senegal - Cleaning the hospital and the hospital beds - 1973.tif hospital of Ziguinchor, 1973]]

File:The build up of toxins in a food chain.svg is the build up of toxins in a food chain. The DDT concentration is in parts per million. As the trophic level increases in a food chain, the amount of toxic build up also increases. The X's represent the amount of toxic build up accumulating as the trophic level increases. Toxins build up in organism's tissues and fat. Predators accumulate higher toxins than the prey.]]

DDT is an endocrine disruptor.{{cite web |url= http://www.fws.gov/contaminants/issues/endocrinedisruptors.cfm |title= Endocrine (Hormone) Disruptors |work= United States Fish and Wildlife Service |access-date= 8 April 2015 |archive-date= October 8, 2015 |archive-url= https://web.archive.org/web/20151008032722/http://www.fws.gov/contaminants/issues/EndocrineDisruptors.cfm |url-status= dead }}{{cite web | url = http://gewa.mpcer.nau.edu/files/endocrine-disruptors.pdf | title = Endocrine Disruptors |work=National Institute of Environmental Health Sciences | date = 2007 | access-date = April 8, 2015 | archive-url = https://web.archive.org/web/20160305203707/http://gewa.mpcer.nau.edu/files/endocrine-disruptors.pdf | archive-date = March 5, 2016 |via= George Washington Birthplace National Monument}} It is considered likely to be a human carcinogen although the majority of studies suggest it is not directly genotoxic.{{cite web |url=http://www.efsa.europa.eu/sites/default/files/scientific_output/files/main_documents/433.pdf |title=European Food Safety Administration – DDT |access-date=2014-10-29 |archive-date=June 3, 2018 |archive-url=https://web.archive.org/web/20180603023020/http://www.efsa.europa.eu/sites/default/files/scientific_output/files/main_documents/433.pdf |url-status=dead }}{{cite web |url=http://ntp.niehs.nih.gov/ntp/roc/content/profiles/dichlorodiphenyltrichloroethane.pdf |work=National Toxicology Program |title=DDT |access-date=2014-10-29 |archive-date=May 22, 2016 |archive-url=https://web.archive.org/web/20160522013510/http://ntp.niehs.nih.gov/ntp/roc/content/profiles/dichlorodiphenyltrichloroethane.pdf |url-status=live }}{{cite book |url=http://monographs.iarc.fr/ENG/Monographs/vol53/mono53-9.pdf |title=IARC – DDT |year=1992 |isbn=9789283212539 |access-date=2014-10-29 |archive-date=October 29, 2014 |archive-url=https://web.archive.org/web/20141029134721/http://monographs.iarc.fr/ENG/Monographs/vol53/mono53-9.pdf |url-status=live }} DDE acts as a weak androgen receptor antagonist, but not as an estrogen.{{Cite journal|last1=Kelce|first1=William R.|last2=Stone|first2=Christy R.|last3=Laws|first3=Susan C.|last4=Gray|first4=L. Earl|last5=Kemppainen|first5=Jon A.|last6=Wilson|first6=Elizabeth M.|date=1995|title=Persistent DDT metabolite p,p'–DDE is a potent androgen receptor antagonist|url=http://www.nature.com/articles/375581a0|journal=Nature|language=en|volume=375|issue=6532|pages=581–585|doi=10.1038/375581a0|pmid=7791873|bibcode=1995Natur.375..581K|s2cid=4344932|issn=0028-0836|access-date=October 14, 2020|archive-date=November 17, 2020|archive-url=https://web.archive.org/web/20201117150457/https://www.nature.com/articles/375581a0|url-status=live}} p,p{{'}}-DDT, DDT's main component, has little or no androgenic or estrogenic activity.{{cite journal | vauthors = Cohn BA, Wolff MS, Cirillo PM, Sholtz RI | title = DDT and breast cancer in young women: new data on the significance of age at exposure | journal = Environmental Health Perspectives | volume = 115 | issue = 10 | pages = 1406–1414 | date = October 2007 | pmid = 17938728 | pmc = 2022666 | doi = 10.1289/ehp.10260 | bibcode = 2007EnvHP.115.1406C }} The minor component o,p{{'}}-DDT has weak estrogenic activity.

DDT is classified as "moderately toxic" by the U.S. National Toxicology Program (NTP) and "moderately hazardous" by WHO, based on the rat oral {{LD50}} of 113 mg/kg.World Health Organization, [https://www.who.int/ipcs/publications/pesticides_hazard_rev_3.pdf The WHO Recommended Classification of Pesticides by Hazard] {{Webarchive|url=https://web.archive.org/web/20210704154307/https://www.who.int/ipcs/publications/pesticides_hazard_rev_3.pdf |date=July 4, 2021 }}, 2005. Indirect exposure is considered relatively non-toxic for humans.{{cite journal | vauthors = Agarwal A, Aponte-Mellado A, Premkumar BJ, Shaman A, Gupta S | title = The effects of oxidative stress on female reproduction: a review | journal = Reproductive Biology and Endocrinology | volume = 10 | issue = 1 | pages = 49 | date = June 2012 | pmid = 22748101 | pmc = 3527168 | doi = 10.1186/1477-7827-10-49 | quote = In general, incidental human exposure to DDT has been considered relatively non-toxic, but prolonged exposure has long been recognized to adversely affect reproduction. | doi-access = free }}

Primarily through the tendency for DDT to build up in areas of the body with high lipid content, chronic exposure can affect reproductive capabilities and the embryo or fetus.

• A review article in The Lancet states: "research has shown that exposure to DDT at amounts that would be needed in malaria control might cause preterm birth and early weaning ... toxicological evidence shows endocrine-disrupting properties; human data also indicate possible disruption in semen quality, menstruation, gestational length, and duration of lactation".
• Other studies document decreases in semen quality among men with high exposures (generally from indoor residual spraying).{{cite journal | vauthors = Jurewicz J, Hanke W, Radwan M, Bonde JP | s2cid = 6681999 | title = Environmental factors and semen quality | journal = International Journal of Occupational Medicine and Environmental Health | volume = 22 | issue = 4 | pages = 305–329 | date = January 2010 | pmid = 20053623 | doi = 10.2478/v10001-009-0036-1 | doi-broken-date = November 11, 2024 }}
• Studies are inconsistent on whether high blood DDT or DDE levels increase time to pregnancy. In mothers with high DDE blood serum levels, daughters may have up to a 32% increase in the probability of conceiving, but increased DDT levels have been associated with a 16% decrease in one study.{{cite journal | vauthors = Eskenazi B, Chevrier J, Rosas LG, Anderson HA, Bornman MS, Bouwman H, Chen A, Cohn BA, de Jager C, Henshel DS, Leipzig F, Leipzig JS, Lorenz EC, Snedeker SM, Stapleton D | title = The Pine River statement: human health consequences of DDT use | journal = Environmental Health Perspectives | volume = 117 | issue = 9 | pages = 1359–1367 | date = September 2009 | pmid = 19750098 | doi = 10.1289/ehp.11748 | quote = Overall, the few studies conducted to date suggest that DDT exposure may affect time to pregnancy, but more research is needed. | pmc=2737010| bibcode = 2009EnvHP.117.1359E }}
• Indirect exposure of mothers through workers directly in contact with DDT is associated with an increase in spontaneous abortions.
• Other studies found that DDT or DDE interfere with proper thyroid function in pregnancy and childhood.{{cite journal | vauthors = Chevrier J, Eskenazi B, Holland N, Bradman A, Barr DB | title = Effects of exposure to polychlorinated biphenyls and organochlorine pesticides on thyroid function during pregnancy | journal = American Journal of Epidemiology | volume = 168 | issue = 3 | pages = 298–310 | date = August 2008 | pmid = 18550560 | pmc = 2727265 | doi = 10.1093/aje/kwn136}}
• Mothers with high levels of DDT circulating in their blood during pregnancy were found to be more likely to give birth to children who would go on to develop autism.{{Cite journal|last=Reardon|first=Sara|date=2018-08-16|title=Autism and DDT: What one million pregnancies can – and can't – reveal|url=https://www.nature.com/articles/d41586-018-05994-1|journal=Nature|doi=10.1038/d41586-018-05994-1|s2cid=81471566|issn=0028-0836|access-date=August 17, 2018|archive-date=August 19, 2018|archive-url=https://web.archive.org/web/20180819095150/https://www.nature.com/articles/d41586-018-05994-1|url-status=live}}{{cite journal | vauthors = Brown AS, Cheslack-Postava K, Rantakokko P, Kiviranta H, Hinkka-Yli-Salomäki S, McKeague IW, Surcel HM, Sourander A | title = Association of Maternal Insecticide Levels With Autism in Offspring From a National Birth Cohort | journal = The American Journal of Psychiatry | volume = 175 | issue = 11 | pages = 1094–1101 | date = November 2018 | pmid = 30111184 | pmc = 6377859 | doi = 10.1176/appi.ajp.2018.17101129 }}

In 2015, the International Agency for Research on Cancer classified DDT as Group 2A "probably carcinogenic to humans".{{Cite web|url=http://www.iarc.fr/en/media-centre/pr/2015/pdfs/pr236_E.pdf|title=IARC Monographs evaluate DDT, lindane, and 2,4-D|access-date=August 13, 2015|archive-date=April 13, 2020|archive-url=https://web.archive.org/web/20200413043943/http://www.iarc.fr/en/media-centre/pr/2015/pdfs/pr236_E.pdf|url-status=live}} Previous assessments by the U.S. National Toxicology Program classified it as "reasonably anticipated to be a carcinogen" and by the EPA classified DDT, DDE and DDD as class B2 "probable" carcinogens; these evaluations were based mainly on animal studies.

A 2005 Lancet review stated that occupational DDT exposure was associated with increased pancreatic cancer risk in 2 case control studies, but another study showed no DDE dose-effect association. Results regarding a possible association with liver cancer and biliary tract cancer are conflicting: workers who did not have direct occupational DDT contact showed increased risk. White men had an increased risk, but not white women or black men. Results about an association with multiple myeloma, prostate and testicular cancer, endometrial cancer and colorectal cancer have been inconclusive or generally do not support an association. A 2017 review of liver cancer studies concluded that "organochlorine pesticides, including DDT, may increase hepatocellular carcinoma risk".{{cite journal | vauthors = VoPham T, Bertrand KA, Hart JE, Laden F, Brooks MM, Yuan JM, Talbott EO, Ruddell D, Chang CH, Weissfeld JL | title = Pesticide exposure and liver cancer: a review | journal = Cancer Causes & Control | volume = 28 | issue = 3 | pages = 177–190 | date = March 2017 | pmid = 28194594 | pmc = 5336347 | doi = 10.1007/s10552-017-0854-6 }}

A 2009 review, whose co-authors included persons engaged in DDT-related litigation, reached broadly similar conclusions, with an equivocal association with testicular cancer. Case–control studies did not support an association with leukemia or lymphoma.

The question of whether DDT or DDE are risk factors in breast cancer has not been conclusively answered. Several meta analyses of observational studies have concluded that there is no overall relationship between DDT exposure and breast cancer risk.{{cite journal | vauthors = Park JH, Cha ES, Ko Y, Hwang MS, Hong JH, Lee WJ | title = Exposure to Dichlorodiphenyltrichloroethane and the Risk of Breast Cancer: A Systematic Review and Meta-analysis | journal = Osong Public Health and Research Perspectives | volume = 5 | issue = 2 | pages = 77–84 | date = April 2014 | pmid = 24955316 | pmc = 4064641 | doi = 10.1016/j.phrp.2014.02.001 }}{{cite journal | vauthors = Ingber SZ, Buser MC, Pohl HR, Abadin HG, Murray HE, Scinicariello F | title = DDT/DDE and breast cancer: a meta-analysis | journal = Regulatory Toxicology and Pharmacology | volume = 67 | issue = 3 | pages = 421–433 | date = December 2013 | pmid = 24021539 | doi = 10.1016/j.yrtph.2013.08.021 | doi-access = free | pmc = 11298241 }} The United States Institute of Medicine reviewed data on the association of breast cancer with DDT exposure in 2012 and concluded that a causative relationship could neither be proven nor disproven.{{cite journal | vauthors = Smith-Bindman R | title = Environmental causes of breast cancer and radiation from medical imaging: findings from the Institute of Medicine report | journal = Archives of Internal Medicine | volume = 172 | issue = 13 | pages = 1023–1027 | date = July 2012 | pmid = 22688684 | pmc = 3936791 | doi = 10.1001/archinternmed.2012.2329 }}

A 2007 case-control study using archived blood samples found that breast cancer risk was increased 5-fold among women who were born prior to 1931 and who had high serum DDT levels in 1963. Reasoning that DDT use became widespread in 1945 and peaked around 1950, they concluded that the ages of 14–20 were a critical period in which DDT exposure leads to increased risk. This study, which suggests a connection between DDT exposure and breast cancer that would not be picked up by most studies, has received variable commentary in third-party reviews. One review suggested that "previous studies that measured exposure in older women may have missed the critical period".{{cite journal | vauthors = Clapp RW, Jacobs MM, Loechler EL | title = Environmental and occupational causes of cancer: new evidence 2005–2007 | journal = Reviews on Environmental Health | volume = 23 | issue = 1 | pages = 1–37 | year = 2008 | pmid = 18557596 | pmc = 2791455 | doi = 10.1515/REVEH.2008.23.1.1 | bibcode = 2008RvEH...23....1C }} The National Toxicology Program notes that while the majority of studies have not found a relationship between DDT exposure and breast cancer that positive associations have been seen in a "few studies among women with higher levels of exposure and among certain subgroups of women".

A 2015 case control study identified a link (odds ratio 3.4) between in-utero exposure (as estimated from archived maternal blood samples) and breast cancer diagnosis in daughters. The findings "support classification of DDT as an endocrine disruptor, a predictor of breast cancer, and a marker of high risk".{{cite journal | vauthors = Cohn BA, La Merrill M, Krigbaum NY, Yeh G, Park JS, Zimmermann L, Cirillo PM | title = DDT Exposure in Utero and Breast Cancer | journal = The Journal of Clinical Endocrinology and Metabolism | volume = 100 | issue = 8 | pages = 2865–2872 | date = August 2015 | pmid = 26079774 | pmc = 4524999 | doi = 10.1210/jc.2015-1841 }}

Malaria remains the primary public health challenge in many countries. In 2015, there were 214 million cases of malaria worldwide resulting in an estimated 438,000 deaths, 90% of which occurred in Africa.{{cite web|title=Malaria Fact sheet N°94|url=https://www.who.int/mediacentre/factsheets/fs094/en/|publisher=WHO|access-date=2 February 2016|archive-date=September 3, 2014|archive-url=https://web.archive.org/web/20140903002027/http://www.who.int/mediacentre/factsheets/fs094/en/|url-status=live}} DDT is one of many tools to fight the disease. Its use in this context has been called everything from a "miracle weapon [that is] like Kryptonite to the mosquitoes",{{cite news |first=Kirsten |last=Weir |name-list-style=vanc |title=Rachel Carson's birthday bashing |url=http://www.salon.com/news/feature/2007/06/29/rachel_carson/ |work=Salon.com |date=June 29, 2007 |access-date=July 1, 2007 |archive-date=April 15, 2008 |archive-url=https://web.archive.org/web/20080415165815/http://www.salon.com/news/feature/2007/06/29/rachel_carson/ |url-status=live }} to "toxic colonialism".{{cite journal | last = Paull | first = John | name-list-style = vanc | title = Toxic Colonialism | journal = New Scientist | issue = 2628 | page = 25 | date = November 3, 2007 | volume = 196 | doi = 10.1016/S0262-4079(07)62774-2 | url = https://www.newscientist.com/article/mg19626280.400-toxic-colonialism.html/ | access-date = August 26, 2017 | archive-date = April 24, 2015 | archive-url = https://web.archive.org/web/20150424205340/http://www.newscientist.com/article/mg19626280.400-toxic-colonialism.html | url-status = live }}

Before DDT, eliminating mosquito breeding grounds by drainage or poisoning with Paris green or pyrethrum was sometimes successful. In parts of the world with rising living standards, the elimination of malaria was often a collateral benefit of the introduction of window screens and improved sanitation. A variety of usually simultaneous interventions represents best practice. These include antimalarial drugs to prevent or treat infection; improvements in public health infrastructure to diagnose, sequester and treat infected individuals; bednets and other methods intended to keep mosquitoes from biting humans; and vector control strategies{{cite web | date = 2009 | publisher = World Health Organization | url = http://whqlibdoc.who.int/publications/2009/9789241563901_eng.pdf | title = World Malaria Report | access-date = December 17, 2009 | archive-date = January 12, 2010 | archive-url = https://web.archive.org/web/20100112144947/http://whqlibdoc.who.int/publications/2009/9789241563901_eng.pdf | url-status = live }} such as larviciding with insecticides, ecological controls such as draining mosquito breeding grounds or introducing fish to eat larvae and indoor residual spraying (IRS) with insecticides, possibly including DDT. IRS involves the treatment of interior walls and ceilings with insecticides. It is particularly effective against mosquitoes, since many species rest on an indoor wall before or after feeding. DDT is one of 12 WHO–approved IRS insecticides.

The WHO's anti-malaria campaign of the 1950s and 1960s relied heavily on DDT and the results were promising, though temporary in developing countries. Experts tie malarial resurgence to multiple factors, including poor leadership, management and funding of malaria control programs; poverty; civil unrest; and increased irrigation. The evolution of resistance to first-generation drugs (e.g. chloroquine) and to insecticides exacerbated the situation.{{cite journal | vauthors = Feachem RG, Sabot OJ | title = Global malaria control in the 21st century: a historic but fleeting opportunity | journal = JAMA | volume = 297 | issue = 20 | pages = 2281–2284 | date = May 2007 | pmid = 17519417 | doi = 10.1001/jama.297.20.2281 }} Resistance was largely fueled by unrestricted agricultural use. Resistance and the harm both to humans and the environment led many governments to curtail DDT use in vector control and agriculture. In 2006 WHO reversed a longstanding policy against DDT by recommending that it be used as an indoor pesticide in regions where malaria is a major problem.{{cite news |url=https://www.washingtonpost.com/wp-dyn/content/article/2006/09/15/AR2006091501012.html |title=WHO Urges Use of DDT in Africa |date=September 16, 2006 |newspaper=Washington Post |access-date=August 22, 2017 |archive-date=September 2, 2017 |archive-url=https://web.archive.org/web/20170902230036/http://www.washingtonpost.com/wp-dyn/content/article/2006/09/15/AR2006091501012.html |url-status=live }}

Once the mainstay of anti-malaria campaigns, as of 2019 only five countries used DDT for Indoor Residual Spraying {{cite web |url= https://www.un.org/africarenewal/magazine/january-2022/widespread-use-ddt-malaria-control-worries-environmentalist|title=Widespread use of DDT for malaria control worries environmentalist|work=Africa Renewal|date=January 5, 2022 }}

When it was introduced in World War II, DDT was effective in reducing malaria morbidity and mortality. WHO's anti-malaria campaign, which consisted mostly of spraying DDT and rapid treatment and diagnosis to break the transmission cycle, was initially successful as well. For example, in Sri Lanka, the program reduced cases from about one million per year before spraying to just 18 in 1963{{cite book|title=The Coming Plague: Newly Emerging Diseases in a World Out of Balance|page=51|last=Garrett|first=Laurie|url=https://books.google.com/books?id=v9RY2PVOtOMC&pg=PA51|year=1994|publisher=Farrar, Straus and Giroux|isbn=978-1-4299-5327-6|access-date=August 29, 2022|archive-date=October 19, 2021|archive-url=https://web.archive.org/web/20211019223243/https://books.google.com/books?id=v9RY2PVOtOMC&pg=PA51|url-status=live}}{{cite news | url = https://www.nytimes.com/2010/12/28/health/28global.html | title = Malaria: A Disease Close to Eradication Grows, Aided by Political Tumult in Sri Lanka | first = Donald G. | last = McNeil | name-list-style = vanc | work = The New York Times | date = December 27, 2010 | access-date = February 7, 2017 | archive-date = January 4, 2017 | archive-url = https://web.archive.org/web/20170104050535/http://www.nytimes.com/2010/12/28/health/28global.html | url-status = live }} and 29 in 1964. Thereafter the program was halted to save money and malaria rebounded to 600,000 cases in 1968 and the first quarter of 1969. The country resumed DDT vector control but the mosquitoes had evolved resistance in the interim, presumably because of continued agricultural use. The program switched to malathion, but despite initial successes, malaria continued its resurgence into the 1980s.{{cite book|name-list-style=vanc|title=Mosquitoes, Malaria, and Man: A History of the Hostilities Since 1880|isbn=978-0-525-16025-0|first=Gordon A.|last=Harrison|url=https://books.google.com/books?id=mfkBr2oskyEC|year=1978|publisher=Dutton|access-date=August 29, 2022|archive-date=October 19, 2021|archive-url=https://web.archive.org/web/20211019210418/https://books.google.com/books?id=mfkBr2oskyEC|url-status=live}}{{cite journal | vauthors = Karunaweera ND, Galappaththy GN, Wirth DF | title = On the road to eliminate malaria in Sri Lanka: lessons from history, challenges, gaps in knowledge and research needs | journal = Malaria Journal | volume = 13 | page = 59 | year = 2014 | pmid = 24548783 | pmc = 3943480 | doi = 10.1186/1475-2875-13-59 | doi-access = free }}

DDT remains on WHO's list of insecticides recommended for IRS. After the appointment of Arata Kochi as head of its anti-malaria division, WHO's policy shifted from recommending IRS only in areas of seasonal or episodic transmission of malaria, to advocating it in areas of continuous, intense transmission.

{{cite web | url =https://www.who.int/mediacentre/news/releases/2006/pr50/en/index.html | archive-url =https://web.archive.org/web/20060918220144/http://www.who.int/mediacentre/news/releases/2006/pr50/en/index.html | url-status =dead | archive-date =September 18, 2006 | publisher = World Health Organization | title = Who gives indoor use of DDT a clean bill of health for controlling malaria }} WHO reaffirmed its commitment to phasing out DDT, aiming "to achieve a 30% cut in the application of DDT world-wide by 2014 and its total phase-out by the early 2020s if not sooner" while simultaneously combating malaria. WHO plans to implement alternatives to DDT to achieve this goal.{{cite web | url =https://www.who.int/mediacentre/news/releases/2009/malaria_ddt_20090506/en/index.html | archive-url =https://web.archive.org/web/20090506212626/http://www.who.int/mediacentre/news/releases/2009/malaria_ddt_20090506/en/index.html | url-status =dead | archive-date =May 6, 2009 | title = Countries move toward more sustainable ways to roll back malaria | publisher = World Health Organization }}

South Africa continues to use DDT under WHO guidelines. In 1996, the country switched to alternative insecticides and malaria incidence increased dramatically. Returning to DDT and introducing new drugs brought malaria back under control.{{cite journal | vauthors = Yamey G | title = Roll Back Malaria: a failing global health campaign | journal = BMJ | volume = 328 | issue = 7448 | pages = 1086–1087 | date = May 2004 | pmid = 15130956 | pmc = 406307 | doi = 10.1136/bmj.328.7448.1086 }} Malaria cases increased in South America after countries in that continent stopped using DDT. Research data showed a strong negative relationship between DDT residual house sprayings and malaria. In a research from 1993 to 1995, Ecuador increased its use of DDT and achieved a 61% reduction in malaria rates, while each of the other countries that gradually decreased its DDT use had large increases.{{cite journal | vauthors = Griffing SM, Gamboa D, Udhayakumar V | title = The history of 20th century malaria control in Peru | journal = Malaria Journal | volume = 12 | page = 303 | year = 2013 | pmid = 24001096 | pmc = 3766208 | doi = 10.1186/1475-2875-12-303 | doi-access = free }}{{cite journal | vauthors = Curtis CF | title = Should the use of DDT be revived for malaria vector control? | journal = Biomédica | volume = 22 | issue = 4 | pages = 455–461 | date = December 2002 | pmid = 12596442 | doi = 10.7705/biomedica.v22i4.1171| doi-access = free }}

In some areas, resistance reduced DDT's effectiveness. WHO guidelines require that absence of resistance must be confirmed before using the chemical."

[http://whqlibdoc.who.int/hq/2006/WHO_HTM_MAL_2006.1112_eng.pdf Indoor Residual Spraying: Use of Indoor Residual Spraying for Scaling Up Global Malaria Control and Elimination] {{Webarchive|url=https://web.archive.org/web/20081002173139/http://whqlibdoc.who.int/hq/2006/WHO_HTM_MAL_2006.1112_eng.pdf |date=October 2, 2008 }}". World Health Organization, 2006. Resistance is largely due to agricultural use, in much greater quantities than required for disease prevention.

Resistance was noted early in spray campaigns. Paul Russell, former head of the Allied Anti-Malaria campaign, observed in 1956 that "resistance has appeared after six or seven years". Resistance has been detected in Sri Lanka, Pakistan, Turkey and Central America and it has largely been replaced by organophosphate or carbamate insecticides, e.g. malathion or bendiocarb.{{cite web | vauthors = Curtis CF | url = http://ipmworld.umn.edu/chapters/curtiscf.htm | title = Control of Malaria Vectors in Africa and Asia | archive-url = https://web.archive.org/web/20071002124232/http://ipmworld.umn.edu/chapters/curtiscf.htm | archive-date = October 2, 2007 | url-status = dead | date = February 1996 | publisher = University of Minnesota }}

In many parts of India, DDT is ineffective.{{cite journal | vauthors = Sharma VP | title = Current scenario of malaria in India | journal = Parassitologia | volume = 41 | issue = 1–3 | pages = 349–353 | date = September 1999 | pmid = 10697882 }} Agricultural uses were banned in 1989 and its anti-malarial use has been declining. Urban use ended.{{cite journal |title=No Future in DDT: A case study of India |last=Agarwal |first=Ravi | name-list-style = vanc | journal=Pesticide Safety News |date=May 2001}} One study concluded that "DDT is still a viable insecticide in indoor residual spraying owing to its effectivity in well supervised spray operation and high excito-repellency factor."{{cite journal | vauthors = Sharma SN, Shukla RP, Raghavendra K, Subbarao SK | title = Impact of DDT spraying on malaria transmission in Bareilly District, Uttar Pradesh, India | journal = Journal of Vector Borne Diseases | volume = 42 | issue = 2 | pages = 54–60 | date = June 2005 | pmid = 16161701 }}

Studies of malaria-vector mosquitoes in KwaZulu-Natal Province, South Africa found susceptibility to 4% DDT (WHO's susceptibility standard), in 63% of the samples, compared to the average of 87% in the same species caught in the open. The authors concluded that "Finding DDT resistance in the vector An. arabiensis, close to the area where we previously reported pyrethroid-resistance in the vector An. funestus Giles, indicates an urgent need to develop a strategy of insecticide resistance management for the malaria control programmes of southern Africa."{{cite journal | vauthors = Hargreaves K, Hunt RH, Brooke BD, Mthembu J, Weeto MM, Awolola TS, Coetzee M | title = Anopheles arabiensis and An. quadriannulatus resistance to DDT in South Africa | journal = Medical and Veterinary Entomology | volume = 17 | issue = 4 | pages = 417–422 | date = December 2003 | pmid = 14651656 | doi = 10.1111/j.1365-2915.2003.00460.x | s2cid = 22748077 }}

DDT can still be effective against resistant mosquitoes and the avoidance of DDT-sprayed walls by mosquitoes is an additional benefit of the chemical. For example, a 2007 study reported that resistant mosquitoes avoided treated huts. The researchers argued that DDT was the best pesticide for use in IRS (even though it did not afford the most protection from mosquitoes out of the three test chemicals) because the other pesticides worked primarily by killing or irritating mosquitoes – encouraging the development of resistance.{{cite journal | vauthors = Grieco JP, Achee NL, Chareonviriyaphap T, Suwonkerd W, Chauhan K, Sardelis MR, Roberts DR | title = A new classification system for the actions of IRS chemicals traditionally used for malaria control | journal = PLOS ONE | volume = 2 | issue = 8 | page = e716 | year = 2007 | pmid = 17684562 | pmc = 1934935 | doi = 10.1371/journal.pone.0000716 | doi-access = free | editor1-last = Krishna | editor1-first = Sanjeev | bibcode = 2007PLoSO...2..716G }} Others argue that the avoidance behavior slows eradication.{{cite journal|vauthors=Mabaso ML, Sharp B, Lengeler C|date=August 2004|title=Historical review of malarial control in southern African with emphasis on the use of indoor residual house-spraying|journal=Tropical Medicine & International Health|volume=9|issue=8|pages=846–856|doi=10.1111/j.1365-3156.2004.01263.x|pmid=15303988|doi-access=free|s2cid=10018052}} Unlike other insecticides such as pyrethroids, DDT requires long exposure to accumulate a lethal dose; however its irritant property shortens contact periods. "For these reasons, when comparisons have been made, better malaria control has generally been achieved with pyrethroids than with DDT." In India outdoor sleeping and night duties are common, implying that "the excito-repellent effect of DDT, often reported useful in other countries, actually promotes outdoor transmission".{{cite journal |title=DDT: The fallen angel |first=V. P. |last=Sharma |name-list-style=vanc |journal=Current Science |volume=85 |pages=1532–1537 |issue=11 |date=December 2003 |url=http://www.ias.ac.in/currsci/dec102003/1532.pdf |url-status=dead |archive-url=https://web.archive.org/web/20050518063647/http://www.ias.ac.in/currsci/dec102003/1532.pdf |archive-date=May 18, 2005 |df=mdy-all }}

{{Main|Indoor residual spraying#Residents' opposition to IRS}}

IRS is effective if at least 80% of homes and barns in a residential area are sprayed. Lower coverage rates can jeopardize program effectiveness. Many residents resist DDT spraying, objecting to the lingering smell, stains on walls, and the potential exacerbation of problems with other insect pests."[http://www.mindfully.org/Health/Malaria-New-Strain.htm In Malaria War, South Africa Turns To Pesticide Long Banned in the West]" {{webarchive|url=https://web.archive.org/web/20071013113406/http://mindfully.org/Health/Malaria-New-Strain.htm |date=October 13, 2007 }}, Roger Thurow, The Wall Street Journal, July 26, 2001 Pyrethroid insecticides (e.g. deltamethrin and lambda-cyhalothrin) can overcome some of these issues, increasing participation.

A 1994 study found that South Africans living in sprayed homes have levels that are several orders of magnitude greater than others. Breast milk from South African mothers contains high levels of DDT and DDE. It is unclear to what extent these levels arise from home spraying vs food residues. Evidence indicates that these levels are associated with infant neurological abnormalities.

Most studies of DDT's human health effects have been conducted in developed countries where DDT is not used and exposure is relatively low.{{cite news |url=https://www.sciencedaily.com/releases/2009/05/090504122058.htm |title=Unprecedented Use Of DDT Concerns Experts |last=Science Daily |date=May 9, 2009 |publisher=ScienceDaily.com |access-date=May 30, 2009 |archive-date=May 14, 2009 |archive-url=https://web.archive.org/web/20090514171439/http://www.sciencedaily.com/releases/2009/05/090504122058.htm |url-status=live }}

Illegal diversion to agriculture is also a concern as it is difficult to prevent and its subsequent use on crops is uncontrolled. For example, DDT use is widespread in Indian agriculture,{{cite news|url=http://economictimes.indiatimes.com/Markets/Commodities/Pesticide-level-in-veggies-fruits-rises/articleshow/4637527.cms|title=Pesticide level in veggies, fruits rises|last=Jayashree|first=Jayashree|name-list-style=vanc|date=10 June 2009|newspaper=The Economic Times|access-date=10 June 2009|archive-date=July 11, 2018|archive-url=https://web.archive.org/web/20180711064205/https://economictimes.indiatimes.com/Markets/Commodities/Pesticide-level-in-veggies-fruits-rises/articleshow/4637527.cms|url-status=live}} particularly mango production{{cite journal|last=Sanjana|date=June 13, 2009|title=A Whole Fruit|journal=Tehelka |volume=6|issue=23|url=http://www.tehelka.com/story_main42.asp?filename=cr130609a_whole.asp|access-date=June 8, 2009|archive-url=https://web.archive.org/web/20120405075828/http://www.tehelka.com/story_main42.asp?filename=cr130609a_whole.asp|archive-date=April 5, 2012|url-status=dead}} and is reportedly used by librarians to protect books.{{cite news|url=http://www.indianexpress.com/news/State-public-libraries-gasp-for-breath/472785|title=State public libraries gasp for breath|last=Chakravartty|first=Anupam|name-list-style=vanc|date=8 June 2009|newspaper=Indian Express|access-date=June 8, 2009|archive-date=April 13, 2020|archive-url=https://web.archive.org/web/20200413043945/http://archive.indianexpress.com/news/State-public-libraries-gasp-for-breath/472785|url-status=live}} Other examples include Ethiopia, where DDT intended for malaria control is reportedly used in coffee production,{{cite journal | last = Katima | first = Jamidu | name-list-style = vanc | date = June 2009 | title = African NGOs outline commitment to malaria control without DDT | url = http://www.pan-uk.org/pestnews/Issue/pn84/PN84_5.pdf | journal = Pesticides News | issue = 84 | page = 5 | url-status = dead | archive-url = https://web.archive.org/web/20160224231607/http://www.pan-uk.org/pestnews/Issue/pn84/PN84_5.pdf | archive-date = February 24, 2016 | df = mdy-all }} and Ghana where it is used for fishing.{{cite web|url=http://www.ghananewsagency.org/s_social/r_9596/ |title=Ministry moves to check unorthodox fishing methods |last=Ghana News Agency |date=November 17, 2009 |publisher=Ghana News Agency |access-date=November 18, 2009 |archive-url=https://web.archive.org/web/20120118212645/http://www.ghananewsagency.org/s_social/r_9596/ |archive-date=January 18, 2012 |url-status=live |df=mdy }}{{cite news|url=http://news.myjoyonline.com/news/201004/45316.asp|title=Northern fisherfolks complain of committee's harassment|last=Appiah|first=Samuel|name-list-style=vanc|date=27 April 2010|publisher=Joy Online|access-date=April 27, 2010|url-status=dead|archive-url=https://web.archive.org/web/20100429002159/http://news.myjoyonline.com/news/201004/45316.asp|archive-date=April 29, 2010|df=mdy-all}} The residues in crops at levels unacceptable for export have been an important factor in bans in several tropical countries. Adding to this problem is a lack of skilled personnel and management.

Restrictions on DDT usage have been criticized by some organizations opposed to the environmental movement, including Roger Bate of the pro-DDT advocacy group Africa Fighting Malaria and the libertarian think tank Competitive Enterprise Institute; these sources oppose restrictions on DDT and attribute large numbers of deaths to such restrictions, sometimes in the millions.{{cite news |title=Rachel Carson Didn't Kill Millions of Africans |first=William |last=Souder |name-list-style=vanc |date=September 4, 2012 |work=Slate |url=http://www.slate.com/articles/health_and_science/science/2012/09/silent_spring_turns_50_biographer_william_souder_clears_up_myths_about_rachel_carson_.html |access-date=September 5, 2012 |archive-date=April 22, 2014 |archive-url=https://web.archive.org/web/20140422025120/http://www.slate.com/articles/health_and_science/science/2012/09/silent_spring_turns_50_biographer_william_souder_clears_up_myths_about_rachel_carson_.html |url-status=live }}{{cite book |last1=Oreskes |first1=Naomi |author-link1=Naomi Oreskes |last2=Conway |first2=Erik M. |author-link2=Erik M. Conway |title=Merchants of Doubt |publisher=Bloomsbury |location=New York |year=2010 |isbn=978-1-59691-610-4 |title-link=Merchants of Doubt|page=217}}{{cite journal|last=Baum|first=Rudy M.|date=June 4, 2007|title=Rachel Carson|journal=Chemical and Engineering News|volume=85|issue=23|page=5|url=http://pubs.acs.org/isubscribe/journals/cen/85/i23/html/8523editor.html}} These arguments were rejected as "outrageous" by former WHO scientist Socrates Litsios. May Berenbaum, University of Illinois entomologist, says, "to blame environmentalists who oppose DDT for more deaths than Hitler is worse than irresponsible". More recently, Michael Palmer, a professor of chemistry at the University of Waterloo, has pointed out that DDT is still used to prevent malaria, that its declining use is primarily due to increases in manufacturing costs, and that in Africa, efforts to control malaria have been regional or local, not comprehensive.{{cite web |url=http://www.science.uwaterloo.ca/~mpalmer/stuff/DDT-myth.pdf |title=The ban of DDT did not cause millions to die from malaria |first=Michael |last=Palmer |date=29 September 2016 |publisher=University of Waterloo |access-date=August 14, 2018 |archive-date=June 16, 2021 |archive-url=https://web.archive.org/web/20210616080102/http://science.uwaterloo.ca/~mpalmer/stuff/DDT-myth.pdf |url-status=live }}

{{Quote box

|quote = The question that ... malaria control experts must ask is not "Which is worse, malaria or DDT?" but rather "What are the best tools to deploy for malaria control in a given situation, taking into account the on-the-ground challenges and needs, efficacy, cost, and collateral effects{{snd}}both positive and negative{{snd}}to human health and the environment, as well as the uncertainties associated with all these considerations?"

|width = 50%

|author = Hans Herren & Charles Mbogo{{cite journal | vauthors = Herren HR, Mbogo C | title = The role of DDT in malaria control | journal = Environmental Health Perspectives | volume = 118 | issue = 7 | pages = A282–A283; author reply A283 | date = July 2010 | pmid = 20601331 | doi = 10.1289/ehp.1002279 | pmc=2920925}}

}}

Criticisms of a DDT "ban" often specifically reference the 1972 United States ban (with the erroneous implication that this constituted a worldwide ban and prohibited use of DDT in vector control). Reference is often made to Silent Spring, even though Carson never pushed for a DDT ban. John Quiggin and Tim Lambert wrote, "the most striking feature of the claim against Carson is the ease with which it can be refuted".{{cite news |first1=John |last1=Quiggin |first2=Tim |last2=Lambert |title=Rehabilitating Carson |newspaper=Prospect |date=May 2008 |url=http://www.prospectmagazine.co.uk/magazine/rehabilitatingcarson/ |name-list-style=vanc |access-date=June 22, 2012 |archive-date=April 13, 2020 |archive-url=https://web.archive.org/web/20200413043951/http://www.prospectmagazine.co.uk/magazine/rehabilitatingcarson |url-status=live }}

Investigative journalist Adam Sarvana and others characterize these notions as "myths" promoted principally by Roger Bate of the pro-DDT advocacy group Africa Fighting Malaria (AFM).{{cite news |url=http://www.nrns.org/index.php?option=com_content&view=article&id=51:bate-and-switch-how-a-free-market-magician-manipulated-two-decades-of-environmental-science- |title=Bate and Switch: How a free-market magician manipulated two decades of environmental science |last=Sarvana |first=Adam |name-list-style=vanc |date=May 28, 2009 |publisher=Natural Resources New Service |access-date=June 2, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20100524144406/http://www.nrns.org/index.php?option=com_content&view=article&id=51%3Abate-and-switch-how-a-free-market-magician-manipulated-two-decades-of-environmental-science- |archive-date=May 24, 2010 |df=mdy }}{{cite book|last=Gutstein|first=Donald|name-list-style=vanc|title=Not a Conspiracy Theory: How Business Propaganda is Hijacking Democracy|url=https://books.google.com/books?id=zDRePgAACAAJ|year=2009|publisher=Key Porter Books |isbn=978-1-55470-191-9|access-date=August 29, 2022|archive-date=October 19, 2021|archive-url=https://web.archive.org/web/20211019223230/https://books.google.com/books?id=zDRePgAACAAJ|url-status=live}}. Relevant excerpt at {{cite magazine |url=https://thetyee.ca/Mediacheck/2010/01/22/DDTPropaganda/ |title=Inside the DDT Propaganda Machine |last=Gutstein |first=Donald |name-list-style=vanc |date=January 22, 2010 |magazine=The Tyee |access-date=January 22, 2010 |archive-date=January 25, 2010 |archive-url=https://web.archive.org/web/20100125172424/http://thetyee.ca/Mediacheck/2010/01/22/DDTPropaganda/ |url-status=live }}

{{Main|Indoor residual spraying}}

Organophosphate and carbamate insecticides, e.g. malathion and bendiocarb, respectively, are more expensive than DDT per kilogram and are applied at roughly the same dosage. Pyrethroids such as deltamethrin are also more expensive than DDT, but are applied more sparingly (0.02–0.3 g/m² vs 1–2 g/m²), so the net cost per house per treatment is about the same. DDT has one of the longest residual efficacy periods of any IRS insecticide, lasting 6 to 12 months. Pyrethroids will remain active for only 4 to 6 months, and organophosphates and carbamates remain active for 2 to 6 months. In many malaria-endemic countries, malaria transmission occurs year-round, meaning that the high expense of conducting a spray campaign (including hiring spray operators, procuring insecticides, and conducting pre-spray outreach campaigns to encourage people to be home and to accept the intervention) will need to occur multiple times per year for these shorter-lasting insecticides.{{Cite web|url=https://apps.who.int/iris/bitstream/handle/10665/69386/WHO_HTM_MAL_2006.1112_eng.pdf?sequence=1|title=Indoor Residual Spraying|date=2019|website=World Health Organization|access-date=March 14, 2019|archive-date=July 29, 2020|archive-url=https://web.archive.org/web/20200729031424/https://apps.who.int/iris/bitstream/handle/10665/69386/WHO_HTM_MAL_2006.1112_eng.pdf?sequence=1|url-status=live}}

In 2019, the related compound difluorodiphenyltrichloroethane (DFDT) was described as a potentially more effective and therefore potentially safer alternative to DDT.{{cite journal |last1=Zhu |first1=Xiaolong |last2=Hu |first2=Chunhua T. |last3=Yang |first3=Jingxiang |last4=Joyce |first4=Leo A. |last5=Qiu |first5=Mengdi |last6=Ward |first6=Michael D. |last7=Kahr |first7=Bart |title=Manipulating Solid Forms of Contact Insecticides for Infectious Disease Prevention |journal=Journal of the American Chemical Society |volume=141 |issue=42 |pages=16858–16864 |date=11 October 2019 |doi=10.1021/jacs.9b08125|pmid=31601104 |bibcode=2019JAChS.14116858Z |s2cid=204244148 }}{{cite news |last1=Chang |first1=Kenneth |title=A Nazi Version of DDT Was Forgotten. Could It Help Fight Malaria? |url=https://www.nytimes.com/2019/10/17/science/nazi-ddt-malaria.html |archive-url=https://ghostarchive.org/archive/20220101/https://www.nytimes.com/2019/10/17/science/nazi-ddt-malaria.html |archive-date=2022-01-01 |url-access=limited |access-date=18 October 2019 |work=The New York Times |date=17 October 2019}}{{cbignore}}

Before DDT, malaria was successfully eliminated or curtailed in several tropical areas by removing or poisoning mosquito breeding grounds and larva habitats, for example by eliminating standing water. These methods have seen little application in Africa for more than half a century.{{cite journal | vauthors = Killeen GF, Fillinger U, Kiche I, Gouagna LC, Knols BG | title = Eradication of Anopheles gambiae from Brazil: lessons for malaria control in Africa? | journal = The Lancet. Infectious Diseases | volume = 2 | issue = 10 | pages = 618–627 | date = October 2002 | pmid = 12383612 | doi = 10.1016/S1473-3099(02)00397-3 }} According to CDC, such methods are not practical in Africa because "Anopheles gambiae, one of the primary vectors of malaria in Africa, breeds in numerous small pools of water that form due to rainfall ... It is difficult, if not impossible, to predict when and where the breeding sites will form, and to find and treat them before the adults emerge."{{cite web |url=https://www.cdc.gov/malaria/malaria_worldwide/reduction/vector_control.html |title=Malaria Worldwide – How Can Malaria Cases and Deaths Be Reduced? – Larval Control and Other Vector Control Interventions |website=CDC.gov |date=January 29, 2019 |access-date=September 9, 2017 |archive-date=July 9, 2017 |archive-url=https://web.archive.org/web/20170709190523/https://www.cdc.gov/malaria/malaria_worldwide/reduction/vector_control.html |url-status=live }}

The relative effectiveness of IRS versus other malaria control techniques (e.g. bednets or prompt access to anti-malarial drugs) varies and is dependent on local conditions.

A WHO study released in January 2008 found that mass distribution of insecticide-treated mosquito nets and artemisinin–based drugs cut malaria deaths in half in malaria-burdened Rwanda and Ethiopia. IRS with DDT did not play an important role in mortality reduction in these countries."[https://web.archive.org/web/20080215004936/http://www.who.int/malaria/docs/ReportGFImpactMalaria.pdf Impact of long-lasting insecticidal-treated nets (LLINs) and artemisinin-based combination therapies (ACTs) measured using surveillance data in four African countries]". World Health Organization, January 31, 2008.[http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2008/02/01/MN4EUPS3D.DTL&type=health Malaria deaths halved in Rwanda and Ethiopia Better drugs, mosquito nets are the crucial tools] {{Webarchive|url=https://web.archive.org/web/20080210024708/http://www.sfgate.com/cgi-bin/article.cgi?f=%2Fc%2Fa%2F2008%2F02%2F01%2FMN4EUPS3D.DTL&type=health |date=February 10, 2008 }}, David Brown (Washington Post), SF Chronicle, A-12, February 1, 2008.

Vietnam has enjoyed declining malaria cases and a 97% mortality reduction after switching in 1991 from a poorly funded DDT-based campaign to a program based on prompt treatment, bednets and pyrethroid group insecticides."[http://www.afronets.org/files/malaria.pdf World Health Organization, A story to be shared: The successful fight against malaria in Vietnam]", November 6, 2000. {{webarchive |url=https://web.archive.org/web/20080226224853/http://www.afronets.org/files/malaria.pdf |date=February 26, 2008 }}

In Mexico, effective and affordable chemical and non-chemical strategies were so successful that the Mexican DDT manufacturing plant ceased production due to lack of demand.{{cite web |url=http://www.ipen.org/ipenweb/documents/work%20documents/ddt_ipenreport_english.pdf |title=DDT & Malaria |access-date=March 11, 2009 |archive-url=https://web.archive.org/web/20110726185356/http://www.ipen.org/ipenweb/documents/work%20documents/ddt_ipenreport_english.pdf |archive-date=July 26, 2011 |url-status=dead |df=mdy }}

A review of fourteen studies in sub-Saharan Africa, covering insecticide-treated nets, residual spraying, chemoprophylaxis for children, chemoprophylaxis or intermittent treatment for pregnant women, a hypothetical vaccine and changing front–line drug treatment, found decision making limited by the lack of information on the costs and effects of many interventions, the small number of cost-effectiveness analyses, the lack of evidence on the costs and effects of packages of measures and the problems in generalizing or comparing studies that relate to specific settings and use different methodologies and outcome measures. The two cost-effectiveness estimates of DDT residual spraying examined were not found to provide an accurate estimate of the cost-effectiveness of DDT spraying; the resulting estimates may not be good predictors of cost-effectiveness in current programs.{{cite journal | vauthors = Goodman CA, Mills AJ | title = The evidence base on the cost-effectiveness of malaria control measures in Africa | journal = Health Policy and Planning | volume = 14 | issue = 4 | pages = 301–312 | date = December 1999 | pmid = 10787646 | doi = 10.1093/heapol/14.4.301 | doi-access = free }}

However, a study in Thailand found the cost per malaria case prevented of DDT spraying (US$1.87) to be 21% greater than the cost per case prevented of lambda-cyhalothrin–treated nets (US$1.54),{{cite journal | vauthors = Kamolratanakul P, Butraporn P, Prasittisuk M, Prasittisuk C, Indaratna K | title = Cost-effectiveness and sustainability of lambdacyhalothrin-treated mosquito nets in comparison to DDT spraying for malaria control in western Thailand | journal = The American Journal of Tropical Medicine and Hygiene | volume = 65 | issue = 4 | pages = 279–284 | date = October 2001 | pmid = 11693869 | doi = 10.4269/ajtmh.2001.65.279 | doi-access = free }} casting some doubt on the assumption that DDT was the most cost-effective measure. The director of Mexico's malaria control program found similar results, declaring that it was 25% cheaper for Mexico to spray a house with synthetic pyrethroids than with DDT. However, another study in South Africa found generally lower costs for DDT spraying than for impregnated nets.{{cite journal | vauthors = Goodman CA, Mnzava AE, Dlamini SS, Sharp BL, Mthembu DJ, Gumede JK | title = Comparison of the cost and cost-effectiveness of insecticide-treated bednets and residual house-spraying in KwaZulu-Natal, South Africa | journal = Tropical Medicine & International Health | volume = 6 | issue = 4 | pages = 280–295 | date = April 2001 | pmid = 11348519 | doi = 10.1046/j.1365-3156.2001.00700.x | s2cid = 28103584 | doi-access = free }}

A more comprehensive approach to measuring the cost-effectiveness or efficacy of malarial control would not only measure the cost in dollars, as well as the number of people saved, but would also consider ecological damage and negative human health impacts. One preliminary study found that it is likely that the detriment to human health approaches or exceeds the beneficial reductions in malarial cases, except perhaps in epidemics. It is similar to the earlier study regarding estimated theoretical infant mortality caused by DDT and subject to the criticism also mentioned earlier.{{cite journal |url=http://www.jcu.edu.au/jrtph/vol/v04corin.pdf |vauthors=Corin SE, Weaver SA |year=2005 |title=A risk analysis model with an ecological perspective on DDT and malaria control in South Africa |journal=Journal of Rural and Tropical Public Health |volume=4 |issue=4 |pages=21–32 |access-date=January 30, 2006 |archive-date=March 6, 2006 |archive-url=https://web.archive.org/web/20060306003634/http://www.jcu.edu.au/jrtph/vol/v04corin.pdf |url-status=live }}

A study in the Solomon Islands found that "although impregnated bed nets cannot entirely replace DDT spraying without substantial increase in incidence, their use permits reduced DDT spraying".{{cite journal | vauthors = Over M, Bakote'e B, Velayudhan R, Wilikai P, Graves PM | title = Impregnated nets or DDT residual spraying? Field effectiveness of malaria prevention techniques in solomon islands, 1993–1999 | journal = The American Journal of Tropical Medicine and Hygiene | volume = 71 | issue = 2 Suppl | pages = 214–223 | date = August 2004 | pmid = 15331840 | doi = 10.4269/ajtmh.2004.71.214 | doi-access = free }}

A comparison of four successful programs against malaria in Brazil, India, Eritrea and Vietnam does not endorse any single strategy but instead states, "Common success factors included conducive country conditions, a targeted technical approach using a package of effective tools, data-driven decision-making, active leadership at all levels of government, involvement of communities, decentralized implementation and control of finances, skilled technical and managerial capacity at national and sub-national levels, hands-on technical and programmatic support from partner agencies, and sufficient and flexible financing."{{cite journal | vauthors = Barat LM | title = Four malaria success stories: how malaria burden was successfully reduced in Brazil, Eritrea, India, and Vietnam | journal = The American Journal of Tropical Medicine and Hygiene | volume = 74 | issue = 1 | pages = 12–16 | date = January 2006 | pmid = 16407339 | doi = 10.4269/ajtmh.2006.74.12 | doi-access = free }}

DDT resistant mosquitoes may be susceptible to pyrethroids in some countries. However, pyrethroid resistance in Anopheles mosquitoes is on the rise with resistant mosquitoes found in multiple countries.{{cite journal | vauthors = Mint Mohamed Lemine A, Ould Lemrabott MA, Niang EH, Basco LK, Bogreau H, Faye O, Ould Mohamed Salem Boukhary A | title = Pyrethroid resistance in the major malaria vector Anopheles arabiensis in Nouakchott, Mauritania | journal = Parasites & Vectors | volume = 11 | issue = 1 | pages = 344 | date = June 2018 | pmid = 29895314 | pmc = 5998517 | doi = 10.1186/s13071-018-2923-4 | doi-access = free }}

• DDT in New Zealand
• Operation Cat Drop
• Environmental hazard
• Index of pesticide articles
• Pest control
• Pesticide
• Pesticide residue
• Pesticide standard value
• WHO Pesticide Evaluation Scheme
• Mosquito control

{{Reflist}}

• Berry-Cabán, Cristóbal S. "DDT and silent spring: fifty years after". Journal of Military and Veterans' Health 19 (2011): 19–24. [https://jmvh.org/wp-content/uploads/2012/12/JMVH-Vol19-No4_Cristobal.pdf online]
• Conis, Elena. "Debating the health effects of DDT: Thomas Jukes, Charles Wurster, and the fate of an environmental pollutant". Public Health Reports 125.2 (2010): 337–342. [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2821864/ online]
• Davis, Frederick Rowe. "Pesticides and the perils of synecdoche in the history of science and environmental history". History of Science 57.4 (2019): 469–492. {{doi|10.1177/0073275319848964}}
• "DDT Banning" in Richard L. Wilson, ed. Historical Encyclopedia of American Business, Vol I. Accounting Industry – Google, (Salem Press: 2009) p. 223 {{ISBN|978-1587655180}}. {{OCLC|430057855}}
• Dunlap, Thomas, ed. DDT, Silent Spring, and the Rise of Environmentalism (University of Washington Press, 2008). {{oclc|277748763}}
• Dunlap, Thomas, ed. DDT, Silent Spring, and the Rise of Environmentalism: Classic texts (University of Washington Press, 2015). {{ISBN|978-0295998947}}. {{OCLC|921868876}}
• {{cite journal | author = Jarman Walter M., Ballschmiter Karlheinz | year = 2012 | title = From coal to DDT: the history of the development of the pesticide DDT from synthetic dyes till Silent Spring | journal = Endeavour | volume = 36 | issue = 4| pages = 131–142 | doi = 10.1016/j.endeavour.2012.10.003 | pmid = 23177325 }}
• Kinkela, David. DDT and the American Century: Global Health, Environmental Politics, and the Pesticide That Changed the World (University of North Carolina Press, 2011). {{ISBN|978-0807835098}}. {{OCLC|934360239}}
• Morris, Peter J. T. (2019). "Chapter 9: A Tale of Two Nations: DDT in the United States and the United Kingdom". Hazardous Chemicals: Agents of Risk and Change, 1800–2000. Environment in History: International Perspectives 17. Berghahn Books. 294–327. {{doi|10.2307/j.ctv1850hst.15}} (book: {{doi|10.2307/j.ctv1850hst}}; {{JSTOR|j.ctv1850hst}}).

{{Commons}}

{{wikiquote}}

{{External links|section|date=April 2023}}

;Chemistry

• [http://www.periodicvideos.com/videos/mv_DDT.htm DDT] at The Periodic Table of Videos (University of Nottingham)

;Toxicity

• {{cite web |title=DDT Technical Fact Sheet |publisher=National Pesticide Information Center |url=http://npic.orst.edu/factsheets/ddttech.pdf |archive-url=https://web.archive.org/web/20030629051317/http://npic.orst.edu/factsheets/ddttech.pdf |archive-date=2003-06-29 |url-status=live }}
• {{cite web |title=DDT General Fact Sheet |publisher=National Pesticide Information Center |url=http://npic.orst.edu/factsheets/ddtgen.pdf |archive-url=https://web.archive.org/web/20030322172257/http://npic.orst.edu/factsheets/ddtgen.pdf |archive-date=2003-03-22 |url-status=live }}
• [http://www.scorecard.org/chemical-profiles/summary.tcl?edf_substance_id=50-29-3 Scorecard: The Pollution Information Site – DDT]
• [http://www.loe.org/shows/shows.htm?programID=07-P13-00040 Interview] with Barbara Cohn, PhD about DDT and breast cancer
• [http://www.inchem.org/documents/jmpr/jmpmono/v00pr03.htm Pesticide residues in food 2000 : DDT]

;Politics and DDT

• {{cite web |first=Aaron |last=Swartz |author-link=Aaron Swartz |title=Rachel Carson, Mass Murderer?: The creation of an anti-environmental myth |date=September–October 2007 |publisher=Extra! |url=http://www.fair.org/index.php?page=3186}}
• {{cite news |last1=Tierney |first1=John |title=Fateful Voice of a Generation Still Drowns Out Real Science |url=https://www.nytimes.com/2007/06/05/science/earth/05tier.html |work=The New York Times |date=June 5, 2007}}

;Malaria and DDT

• {{cite news |first=May |last=Berenbaum | name-list-style = vanc |author-link=May Berenbaum |title=If Malaria's the Problem, DDT's Not the Only Answer |newspaper=Washington Post |date=4 June 2005 |url=https://www.washingtonpost.com/wp-dyn/content/article/2005/06/04/AR2005060400130.html}}
• [http://www.vega.org.uk/video/programme/87 'Andrew Spielman, Harvard School of Public Health, discusses environmentally friendly control of Malaria and uses of DDT] Freeview video provided by the Vega Science Trust
• {{cite news |title=Ugandan farmers push for DDT ban |work=ABC News |publisher=Australian Broadcasting Commission |date=31 May 2008 |url=http://www.abc.net.au/news/stories/2008/05/31/2261160.htm|archive-url=https://web.archive.org/web/20090623074758/http://www.abc.net.au/news/stories/2008/05/31/2261160.htm|url-status=dead|archive-date=June 23, 2009}}

;DDT in popular culture

• {{Skeptoid | id= 4230| number= 230| title=DDT: Secret Life of a Pesticide | date= November 2, 2010| last= Dunning| first= Brian| access-date=}}
• [https://digital.sciencehistory.org/collections/mg74qm28w Phil Allegretti Pesticide Collection] consisting of ephemera and 3-D objects, including cans, sprayers, and diffusers, related to DDT pesticide and insecticide in the United States in the mid-20th century (all images freely available for download in variety of formats from Science History Institute Digital Collections at [https://web.archive.org/web/20190202042542/https://digital.sciencehistory.org/ digital.sciencehistory.org]).

{{Insecticides}}

{{Carcinogen}}

{{Consumer Food Safety}}

{{Androgen receptor modulators}}

{{Estrogen receptor modulators}}

{{Authority control}}

Category:4-Chlorophenyl compounds

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Category:Persistent organic pollutants under the Convention on Long-Range Transboundary Air Pollution

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Category:Trichloromethyl compounds