View source for Clofenotane

{{other uses}}
{{Use mdy dates|date=April 2014}}
{{Chembox new
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 456348813
| Name = DDT
| ImageFile = Clofenotane Chembox.png

| ImageName = Chemical structure of DDT
| IUPACName = 1,1,1-Trichloro-2,2-bis(4-chlorophenyl)ethane
|Section1={{Chembox Identifiers
| PubChem = 3036
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = CIW5S16655
| KEGG_Ref = {{keggcite|correct|kegg}}
| KEGG = D07367
| InChI = 1/C14H9Cl5/c15-11-5-1-9(2-6-11)13(14(17,18)19)10-3-7-12(16)8-4-10/h1-8,13H
| InChIKey = YVGGHNCTFXOJCH-UHFFFAOYAJ
| ChEMBL_Ref = {{ebicite|changed|EBI}}
| ChEMBL = 416898
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/C14H9Cl5/c15-11-5-1-9(2-6-11)13(14(17,18)19)10-3-7-12(16)8-4-10/h1-8,13H
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = YVGGHNCTFXOJCH-UHFFFAOYSA-N
| CASNo = 50-29-3
| CASNo_Ref = {{cascite|correct|CAS}}
| ATCCode_prefix = P03
| ATCCode_suffix = AB01
| ATC_Supplemental = {{ATCvet|P53|AB01}}
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID=2928
| ChEBI_Ref = {{ebicite|correct|EBI}}
| ChEBI = 16130
| SMILES = Clc1ccc(cc1)C(c2ccc(Cl)cc2)C(Cl)(Cl)Cl
 }}
|Section2={{Chembox Properties
| C=14|H=9|Cl=5
| Density = 0.99&nbsp;g/cm<sup>3</sup><ref name="ATSDRc5"/>
| MeltingPtC = 108.5
| BoilingPtC = 260
| Boiling_notes = (decomposes)
| Solubility = 1 μg·<sup>−1</sup> (20 °C)<ref>{{GESTIS|ZVG=12510|CAS=50-29-3|Name=DDT|Date=28 February 2015}}</ref>
 }}
| Section7 ={{Chembox Hazards
| EUClass = {{Hazchem T}} {{Hazchem N}}
| EUIndex =
| MainHazards = Toxic, dangerous to the environment, carcinogenic
| NFPA-H = 2
| NFPA-F = 2
| NFPA-R = 0
| NFPA-S =
| RPhrases={{R25}} {{R40}} {{R48/25}} {{R50/53}}
| SPhrases={{(S1/2)}} {{S22}} {{S36/37}} {{S45}} {{S60}} {{S61}}
| LD50=113 mg/kg (rat)
| PEL = TWA 1 mg/m<sup>3</sup> [skin]<ref name=PGCH>{{PGCH|0174}}</ref>
| IDLH = 500 mg/m<sup>3</sup><ref name=PGCH/>
| REL = Ca TWA 0.5 mg/m<sup>3</sup><ref name=PGCH/>
| FlashPtF = 162-171
| FlashPt_notes = <ref name=PGCH/>
 }}
}}
__NOTOC__
{{SI}}
{{CMG}}
== Overview ==
'''DDT''' ('''dichlorodiphenyltrichloroethane''') is a colorless, [[Crystallinity|crystalline]], tasteless and almost odorless [[organochloride]] known for its [[Insecticide|insecticidal]] properties. DDT has been formulated in almost every conceivable form, including [[solution]]s in [[xylene]] or [[petroleum]] [[Distillation|distillates]], [[Emulsion|emulsifiable]] [[concentrate]]s, water-[[wettable powder]]s, granules, [[aerosol]]s, [[Smoke bomb|smoke candles]] and charges for vaporizers and lotions.<ref name=EHC83>{{EHC-ref | id = 83 | name = DDT and Its Derivatives: Environmental Aspects | date = 1989 | isbn = 92-4-154283-7 }}</ref>

First synthesized in 1874, DDT's insecticidal action was discovered by the Swiss chemist [[Paul Hermann Müller]] in 1939. It was then used in the second half of [[World War II]] to control [[malaria]] and [[typhus]] among civilians and troops. After the war, DDT was made available for use as an agricultural insecticide and its production and use duly increased.<ref name=EHC009>{{EHC-ref | id = 009 | name=DDT and its derivatives | date = 1979 | isbn = 92-4-154069-9 }}</ref> Müller was awarded the [[Nobel Prize in Physiology or Medicine]] "for his discovery of the high efficiency of DDT as a contact poison against several arthropods" in 1948.<ref name=nobel>[http://nobelprize.org/nobel_prizes/medicine/laureates/1948/ NobelPrize.org: The Nobel Prize in Physiology of Medicine 1948], accessed July 26, 2007.</ref>

In 1962, the book ''[[Silent Spring]]'' by American biologist [[Rachel Carson]] was published. It cataloged the environmental impacts of indiscriminate DDT [[Aerial application|spraying]] in the United States and questioned the logic of releasing large amounts of potentially dangerous chemicals into the environment without a sufficient understanding of their effects on [[ecology]] or human health. The book claimed that DDT and other pesticides had been shown to cause [[cancer]] and that their agricultural use was a threat to wildlife, particularly birds. Its publication was a seminal event for the [[Environmentalism|environmental movement]] and resulted in a large public outcry that eventually led, in 1972, to a ban on the agricultural use of DDT in the United States.<ref name="Lear">{{cite book|author=Linda Lear|title=Rachel Carson: Witness for Nature|url=http://books.google.com/books?id=36euz6DjmwUC|date=1 April 2009|publisher=Mariner Books|isbn=978-0-547-23823-4}}</ref> A worldwide ban on its agricultural use was later formalized under the [[Stockholm Convention]], but its limited use in [[Vector (epidemiology)|disease vector]] [[Vector control|control]] continues to this day and remains controversial,<ref name="Larson">{{cite journal |last=Larson |first=Kim |date=December 1, 2007 |title=Bad Blood |journal=On Earth |issue=Winter 2008 |url=http://www.onearth.org/article/bad-blood? |accessdate=June 5, 2008}}</ref><ref name=moyers>{{cite web |last=Moyers |first=Bill |author-link=Bill Moyers |title=Rachel Carson and DDT |date=September 21, 2007 |url=http://www.pbs.org/moyers/journal/09212007/profile2.html |accessdate=March 5, 2011 }}</ref> because of its effectiveness in reducing deaths due to malaria, countered by environmental and health concerns.

Along with the passage of the [[Endangered Species Act]], the US ban on DDT is cited by scientists as a major factor in the comeback of the [[bald eagle]] (the [[national bird of the United States]]) and the [[peregrine falcon]] from near-[[local extinction|extirpation]] in the [[contiguous United States]].<ref name="pmid17588911">{{cite journal | author = Stokstad E | title = Species conservation. Can the bald eagle still soar after it is delisted? | journal = Science | volume = 316 | issue = 5832 | pages = 1689–90 | date = June 2007 | pmid = 17588911 | doi = 10.1126/science.316.5832.1689 | url = http://www.sciencemag.org/cgi/content/summary/316/5832/1689 }}</ref><ref name="test">[http://mdc.mo.gov/sites/default/files/resources/2010/04/4068_1693.pdf Missouri Animals of Conservation Concern], p. 30</ref>

==Properties and chemistry==

DDT is similar in structure to the insecticide [[methoxychlor]] and the [[acaricide]] [[dicofol]]. Being highly [[hydrophobic]], it is nearly [[Solubility|insoluble]] in [[Water (molecule)|water]] but has good solubility in most [[Organic chemistry|organic]] [[solvent]]s, [[fat]]s and [[Oil (liquid)|oils]]. DDT does not occur naturally, but is produced by the reaction of [[trichloroethanal|chloral]] ({{chem|CCl|3|CHO}}) with [[chlorobenzene]] ({{chem|C|6|H|5|Cl}}) in the presence of [[sulfuric acid]] as a [[catalyst]]. Trade names that DDT has been marketed under include Anofex, Cezarex, Chlorophenothane, Clofenotane, Dicophane, Dinocide, Gesarol, Guesapon, Guesarol, Gyron, Ixodex, Neocid, Neocidol and Zerdane.<ref name=EHC009/>

===Isomers and related compounds===
[[File:DDT X.png|left|200px]]
Commercial DDT is a mixture of several closely–related compounds. The major component (77%) is the ''[[Arene substitution patterns|p]]'',''p' '' [[isomer]] which is pictured at the top of this article. The ''o'',''p' '' isomer (pictured to the right) is also present in significant amounts (15%). [[Dichlorodiphenyldichloroethylene]] (DDE) and [[dichlorodiphenyldichloroethane]] (DDD) make up the balance. DDE and DDD are also the major [[metabolite]]s and breakdown products in the environment.<ref name=EHC009/> The term "'''total DDT'''" is often used to refer to the sum of all DDT related compounds (''p,p'-''DDT, ''o,p'-''DDT, DDE, and DDD) in a sample.

===Production and use statistics===
From 1950 to 1980, DDT was extensively used in [[agriculture]] – more than 40,000 [[tonnes]] were used each year worldwide<ref name="Geisz">{{cite journal | author = Geisz HN, Dickhut RM, Cochran MA, Fraser WR, Ducklow HW | title = Melting glaciers: a probable source of DDT to the Antarctic marine ecosystem | journal = Environ. Sci. Technol. | volume = 42 | issue = 11 | pages = 3958–62 |date=June 2008  | pmid = 18589951 | doi = 10.1021/es702919n | last2 = Dickhut | last3 = Cochran | last4 = Fraser | last5 = Ducklow }}</ref> – and it has been estimated that a total of 1.8 million tonnes have been produced globally since the 1940s.<ref name="ATSDRc5">[http://www.atsdr.cdc.gov/toxprofiles/tp.asp?id=81&tid=20 ''Toxicological Profile: for DDT, DDE, and DDE.''] [[Agency for Toxic Substances and Disease Registry]], September 2002.</ref> In the U.S., where it was manufactured by some 15 companies including [[Monsanto]],<ref>{{cite web|url=http://www.organicconsumers.org/corp/tokaronwar120902.cfm |title=Agribusiness, Biotechnology and War |publisher=Organicconsumers.org}}</ref> [[Novartis|Ciba]],<ref>{{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|date=July 4, 2008|accessdate=July 7, 2008|archiveurl = http://www.webcitation.org/5uKxNtMeS |archivedate = November 18, 2010|deadurl=no}}</ref> [[Montrose Chemical Corporation of California|Montrose Chemical Company]], Pennwalt<ref name="Oregon DEQ 2009">[http://www.deq.state.or.us/lq/ECSI/ecsidetail.asp?seqnbr=398 Environmental Cleanup Site Information Database for Arkema (former Pennwalt) facility], Oregon DEQ, April 2009.</ref> and [[Velsicol Chemical Corporation]],<ref>{{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 |date=January 27, 2008 |newspaper=Morning Sun |location=Michigan, United States |publisher=[[Journal Register Company]] |accessdate=May 16, 2008 |archiveurl=http://web.archive.org/web/20080705170443/http://www.themorningsun.com/stories/012708/loc_tests.shtml |archivedate=July 5, 2008 }}</ref> production peaked in 1963 at 82,000 tonnes per year.<ref name=EHC009/> More than 600,000 tonnes (1.35 billion lbs) were applied in the U.S. before the 1972 ban. Usage peaked in 1959 at about 36,000 tonnes.<ref name="EPA1975">[http://www.epa.gov/pesticides/factsheets/chemicals/ddt-brief-history-status.htm DDT Regulatory History: A Brief Survey (to 1975)], U.S. EPA, July 1975.</ref>

In 2009, 3314 tonnes were produced for the control of malaria and [[visceral leishmaniasis]]. India is the only country still manufacturing DDT, with China having ceased production in 2007.<ref name=EG.3>Report of the Third Expert Group Meeting on DDT, UNEP/POPS/DDT-EG.3/3, Stockholm Convention on Persistent Organic Pollutants, November 12, 2010. Available [http://chm.pops.int/Programmes/DDT/Meetings/DDTEG32010/tabid/1108/mctl/ViewDetails/EventModID/1421/EventID/116/xmid/4037/language/en-US/Default.aspx here].</ref> India is the largest consumer.<ref name="DDTBP.1/2">{{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|author2=Stockholm Convention|date=October 23, 2008|publisher=[[Stockholm Convention]]/[[United Nations Environment Programme]]|accessdate=November 22, 2008|archiveurl = http://www.webcitation.org/5uKxOub8a |archivedate = November 18, 2010|deadurl=no|authorlink2=Stockholm Convention}}</ref>

===Mechanism of insecticide action===
In insects it opens [[Sodium channel|sodium ion channels]] in [[neuron]]s, causing them to fire spontaneously, which leads to spasms and eventual death. Insects with certain [[mutation]]s in their sodium channel [[gene]] are resistant to DDT and other similar insecticides. DDT resistance is also conferred by up-regulation of genes expressing [[cytochrome P450]] in some insect species,<ref>{{cite journal | author = Denholm I, Devine GJ, Williamson MS | title = Evolutionary genetics. Insecticide resistance on the move | journal = Science | volume = 297 | issue = 5590 | pages = 2222–3 | year = 2002 | pmid = 12351778 | doi = 10.1126/science.1077266 | last2 = Devine | last3 = Williamson }}</ref> as greater quantities of some enzymes of this group accelerate metabolism of the toxin into inactive metabolites.

==History==
[[File:DDT History.png|right|200px]]
DDT was first synthesized in 1874 by [[Othmar Zeidler]] under the supervision of [[Adolf von Baeyer]].<ref name=EHC009/><ref name="augustin">{{cite book |last=Augustin |first=Frank |title=Zur Geschichte des Insektizids Dichlordiphenyltrichloräthan (DDT) unter besonderer Berücksichtigung der Leistung des Chemikers Paul Müller (1899–1965) url=http://books.google.com/books?id=hY5btwAACAAJ |year=1993 |publisher=Medizinische Fakultät der Universität Leipzig |location=Leipzig |pages=1–77}}</ref><!--Augustin claims that Baeyer synthesized it already in 1872--> It was further described in 1929 in a dissertation by W. Bausch and in two subsequent publications in 1930.<ref>{{cite journal | author = 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 | year = 1930 | pmid = | pmc = | doi = 10.1002/prac.19301270114 }}</ref><ref>{{cite journal | author = 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 | year = 1930 | pmid = | pmc = | doi = 10.1002/prac.19301270115 }}</ref> 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.<ref>Wolfgang von Leuthold, Schädlingsbekämpfung. DRP Nr 673246, April 27, 1934</ref> DDT's insecticidal properties were not, however, discovered until 1939 by the [[Swiss (people)|Swiss]] scientist [[Paul Hermann Müller]], who was awarded the 1948 [[Nobel Prize in Physiology and Medicine]] for his efforts.<ref name=nobel/>

===Use in the 1940s and 1950s===
DDT is the best-known of several [[chlorine]]-containing pesticides used in the 1940s and 1950s. With [[pyrethrum]] in short supply, DDT was used extensively during [[World War II]] by the [[Allies of World War II|Allies]] to control the insect [[Vector (epidemiology)|vectors]] of [[typhus]] – nearly eliminating the disease in many parts of [[Europe]]. In the [[Pacific Ocean|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 a high degree of organization and sufficient manpower were also crucial to the success of these programs.<ref name="Dunlap">{{cite book|author=Thomas Dunlap|title=DDT: Scientists, Citizens, and Public Policy|url=http://books.google.com/books?id=PLL_AwAAQBAJ|date=14 July 2014|publisher=Princeton University Press|isbn=978-1-4008-5385-4}}</ref>

In 1945, DDT was made available to farmers as an agricultural insecticide,<ref name=EHC009/> and it played a role in the final elimination of malaria in Europe and [[North America]].<ref name="Larson"/><ref>{{cite journal |author=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=245–6 |date=June 1998  |pmid=9653750 |doi= |url=}}</ref><ref>{{cite web |url=http://www.cdc.gov/malaria/about/history/elimination_us.html |title=CDC - Malaria - About Malaria - History - Elimination of Malaria in the United States (1947-1951) |work= |accessdate=}}</ref>

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.<ref>{{cite journal |author=Mendis K, Rietveld A, Warsame M, Bosman A, Greenwood B, Wernsdorfer WH |title=From malaria control to eradication: The WHO perspective |journal=Trop. Med. Int. Health |volume=14 |issue=7 |pages=802–9 |date=July 2009  |pmid=19497083 |doi=10.1111/j.1365-3156.2009.02287.x |url=}}</ref> The program was initially highly successful, eliminating the disease 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"<ref name="Gladwell">{{cite news |last=Gladwell |first=Malcolm |author-link=Malcolm Gladwell |title=The Mosquito Killer |newspaper=The New Yorker |date=July 2, 2001 |url=http://gladwell.com/the-mosquito-killer/}}</ref> and dramatically reducing mortality in [[Sri Lanka]] and India.<ref name=Gordon/>

However, failure to sustain the program, increasing resistance of mosquito to DDT, and increasing parasite resistance led to a resurgence. In many areas early victories partially or completely reversed, and in some cases rates of transmission even increased.<ref name="pmid7278974">{{cite journal | author = Chapin G, Wasserstrom R | title = Agricultural production and malaria resurgence in Central America and India | journal = Nature | volume = 293 | issue = 5829 | pages = 181–5 | year = 1981 | pmid = 7278974 | doi = 10.1038/293181a0 }}</ref> The program was successful in eliminating malaria only in areas with "high socio-economic status, well-organized healthcare systems, and relatively less intensive or seasonal malaria transmission".<ref name="AmJTrop">{{cite journal | author = Sadasivaiah S, Tozan Y, Breman JG | title = Dichlorodiphenyltrichloroethane (DDT) for Indoor Residual Spraying in Africa: How Can It Be Used for Malaria Control? | journal = Am. J. Trop. Med. Hyg. | volume = 77 | issue = Suppl 6 | pages = 249–263 | date = December 1, 2007 | pmid = 18165500 | url = http://www.ajtmh.org/cgi/content/full/77/6_Suppl/249 }}</ref>

DDT was less effective in tropical regions due to the continuous life cycle of mosquitoes and poor infrastructure. It was not applied at all in [[sub-Saharan Africa]] due to these perceived difficulties. 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]]''.{{Citation needed|date=June 2014}}

The goal of eradication was abandoned in 1969 and attention was 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.<ref name="pmid7278974"/> Efforts shifted from spraying to the use of [[Mosquito net|bednets]] impregnated with insecticides and other interventions.<ref name="AmJTrop"/><ref name="pmid16125595">{{cite journal | author = 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 = 763–73 | year = 2005 | pmid = 16125595 | doi = 10.1016/S0140-6736(05)67182-6 }}</ref>

===U.S. ban===
As early as the 1940s, scientists in the U.S. had begun expressing concern over possible hazards associated with DDT, and in the 1950s the government began tightening some of the regulations governing its use.<ref name=EPA1975/> However, these early events received little attention, and it was not until 1957, when the ''[[New York Times]]'' reported an unsuccessful struggle to restrict DDT use in [[Nassau County, New York]], that the issue came to the attention of the popular naturalist-author, [[Rachel Carson]]. [[William Shawn]], editor of ''[[The New Yorker]]'', urged her to write a piece on the subject, which developed into her famous book ''[[Silent Spring]]'', published in 1962. The book argued that [[pesticide]]s, including DDT, were poisoning both wildlife and the environment and were also endangering human health.<ref name="Lear"/> ''Silent Spring'' was a best seller, and public reaction to it launched the modern [[environmentalism|environmental movement]] in the United States. The year after it appeared, [[John F. Kennedy|President Kennedy]] ordered his Science Advisory Committee to investigate Carson's claims. The report the committee issued "add[ed] up to a fairly thorough-going vindication of Rachel Carson’s Silent Spring thesis," in the words of the journal ''[[Science (journal)|Science]]'',<ref name="pmid17810673">{{cite journal | author = Greenberg DS | title = Pesticides: White House Advisory Body Issues Report Recommending Steps to Reduce Hazard to Public | journal = Science | volume = 140 | issue = 3569 | pages = 878–9 | date = May 1963 | pmid = 17810673 | doi = 10.1126/science.140.3569.878 | url = http://www.sciencemag.org/cgi/pmidlookup?view=long&pmid=17810673 }} cited in {{cite journal |last=Graham Jr. |first=Frank |title=Nature's Protector and Provocateur |journal=Audubon Magazine |url=http://audubonmagazine.org/books/editorchoice0709.html}} {{dead link|date=November 2010}}</ref> and recommended a phaseout of "persistent toxic pesticides".<ref name="Michaels2008">{{cite book |last=Michaels |first=David |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}}</ref> DDT became a prime target of the growing anti-chemical and anti-pesticide movements, and in 1967 a group of scientists and lawyers founded the [[Environmental Defense|Environmental Defense Fund]] (EDF) with the specific goal of winning a ban on DDT. [[Victor Yannacone]], Charles Wurster, [[Art Cooley]] and others associated with inception of EDF had all witnessed bird kills or declines in bird populations and suspected that DDT was the cause. In their campaign against the chemical, EDF petitioned the government for a ban and filed a series of lawsuits.<ref>{{cite news |title=Sue the Bastards |url=http://www.time.com/time/magazine/article/0,9171,910111-2,00.html |work=[[TIME (magazine)|TIME]] |date=October 18, 1971 |archiveurl=http://www.webcitation.org/5uKxR0D6f |archivedate=November 18, 2010 |deadurl=no}}</ref> Around this time, [[toxicologist]] [[David Peakall]] was measuring [[Dichlorodiphenyldichloroethylene|DDE]] levels in the eggs of [[peregrine falcons]] and [[California condor]]s and finding that increased levels corresponded with thinner shells.

In response to an EDF suit, the U.S. District Court of Appeals in 1971 ordered the [[United States Environmental Protection Agency|EPA]] to begin the de-registration procedure for DDT. After an initial six-month review process, [[William Ruckelshaus]], the Agency's first [[Administrator of the Environmental Protection Agency|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 to human health and wildlife.<ref name=EPA1975/> However, the findings of these staff members were criticized, as they were performed mostly by [[economic entomologist]]s inherited from the [[United States Department of Agriculture]], who many environmentalists felt were biased towards agribusiness and tended to minimize concerns about human health and wildlife. The decision not to ban thus created public controversy.<ref name=Dunlap/>

The EPA then held seven months of hearings in 1971–1972, with scientists giving evidence both for and against the use of DDT. The hearings produced a 113-page decision, in which Hearing Examiner Edmund Sweeney wrote: “DDT is not a carcinogenic, mutagenic, or teratogenic hazard to man. The uses under regulations involved here do not have a deleterious effect on fresh water fish, estuarine organisms, wild birds, or other wildlife. The evidence in this proceeding supports the conclusion that there is a present need for essential uses of DDT.” <ref>Lehr, Jay and Janet, ''Standard Handbook of Environmental Science, Health, and Technology'', McGraw Hill Professional, 2000, p. 6</ref>

In the summer of 1972, Ruckelshaus announced the cancellation of most uses of DDT – an exemption allowed for public health uses under some conditions.<ref name=EPA1975/> He later wrote, in a letter to American Farm Bureau President Allan Grant, that “in such decisions the ultimate judgement remains political.”<ref>W. Ruckelshaus, letter to [[American Farm Bureau]] President Allan Grant,April 26, 1979</ref> Immediately after the cancellation was announced, both EDF and the DDT manufacturers filed suit against the EPA, with the industry seeking to overturn the ban, and EDF seeking a comprehensive ban. The cases were consolidated, and in 1973 the [[U.S. Court of Appeals for the District of Columbia]] ruled that the EPA had acted properly in banning DDT.<ref name=EPA1975/>

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]].<ref name="urlAEI – Short Publications – The Rise, Fall, Rise, and Imminent Fall of DDT">{{cite web |url=http://www.aei.org/outlook/27063 |title=AEI – Short Publications – The Rise, Fall, Rise, and Imminent Fall of DDT |archiveurl = http://www.webcitation.org/5uKxRwUwH |archivedate = November 18, 2010|deadurl=no}}</ref> DDT also continued to be produced in the US for foreign markets until as late as 1985, when over 300 tons were exported.<ref name="ATSDRc5"/>

===Restrictions on usage===
In the 1970s and 1980s, agricultural use was banned in most developed countries, beginning with [[Hungary]] in 1968<ref>{{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}}</ref> then in [[Norway]] and [[Sweden]] in 1970, [[Germany]] and the United States in 1972, but not in the [[United Kingdom]] until 1984. By 1991 total bans on the use of DDT, including in disease control, were in place in at least 26 countries; for example Cuba in 1970, Singapore in 1984, Chile in 1985 and the Republic of Korea in 1986.<ref>{{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.}}</ref>

The [[Stockholm Convention]], which took effect in 2004, outlawed several [[persistent organic pollutant]]s, and restricted DDT use to [[vector control]]. The Convention has been ratified by more than 170 countries and is endorsed by most environmental groups. Recognizing that total elimination in many malaria-prone countries is currently unfeasible because there are few affordable or effective alternatives, the convention exempts public health use within World Health Organization (WHO) guidelines from the ban.<ref>{{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.}}</ref> Resolution 60.18 of the World Health Assembly commits the World Health Organization to the Stockholm Convention's aim of reducing and ultimately eliminating the use of DDT.<ref>{{cite web |url=http://www.who.int/ipcs/capacity_building/ddt_statement/en/ |title=WHO. Strengthening malaria control while reducing reliance on DDT. 2011.}}</ref> 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."<ref>{{cite web |url=http://www.malaria.org/DDTpage.html |title=MFI second page |publisher=Malaria Foundation International |accessdate=March 15, 2006 |archiveurl=http://www.webcitation.org/5uKxTLPxl |archivedate=November 18, 2010 |deadurl=no}}</ref>

Despite the worldwide ban, agricultural use continued in India,<ref>{{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 |accessdate=May 5, 2008 |archiveurl= http://web.archive.org/web/20081206120016/http://www.kanglaonline.com/index.php?template=headline&newsid=42015&typeid=1 |archivedate=December 6, 2008}}</ref> North Korea, and possibly elsewhere as of 2008.<ref name="DDTBP.1/2"/>

Today, about 3,000 to 4,000 [[tonnes]] of DDT are produced each year for disease [[vector control]].<ref name=EG.3/> 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.<ref>{{cite web |url=http://www.malaria.org/DDTcosts.html |title=Is DDT still effective and needed in malaria control? |publisher=Malaria Foundation International |accessdate=March 15, 2006 |archiveurl=http://www.webcitation.org/5uKxTzvxt |archivedate=November 18, 2010 |deadurl=no}}</ref> For comparison, treating {{convert|40|ha|acre}} of cotton during a typical U.S. growing season requires the same amount of chemical as roughly 1,700 homes.<ref name="Roberts 1997">{{cite journal | author = 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 | url = http://www.cdc.gov/ncidod/eid/vol3no3/roberts.htm }}</ref>

==Environmental impact==
[[File:DDT Env.png|right|200px]]

DDT is a [[persistent organic pollutant]] that is readily adsorbed to [[soil]]s and [[sediment]]s, which can act both as sinks and as long-term sources of exposure contributing to terrestrial organisms.<ref name=EHC83/> Depending on conditions, its soil [[half life]] can range from 22 days to 30 years. Routes of loss and degradation include runoff, volatilization, [[photolysis]] and [[aerobic organism|aerobic]] and [[Anaerobic digestion|anaerobic]] [[biodegradation]]. Due to [[hydrophobic]] properties, in [[aquatic ecosystem]]s DDT and its metabolites are absorbed by aquatic organisms and adsorbed on suspended particles, leaving little DDT dissolved in the water itself. Its breakdown products and metabolites, DDE and DDD, are also highly persistent and have similar chemical and physical properties.<ref name="ATSDRc5"/> DDT and its breakdown products are transported from warmer regions of the world to the [[Arctic]] by the phenomenon of [[global distillation]], where they then accumulate in the region's [[food web]].<ref>{{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}}{{dead link|date=November 2009}}</ref>

Because of its [[Lipophilicity|lipophilic]] properties, DDT has a high potential to [[bioaccumulate]], especially in [[predatory birds]].<ref>{{cite book |title=Introduction to Ecotoxicology |publisher=Blackwell Science |year=1999 |isbn=0-632-03852-7 |page=68 |url=http://books.google.com/books?id=X-ik73-vnXAC&pg=PA68 | last1=Connell | first = D. |author2=et al. }}</ref> DDT, DDE, and DDD [[biomagnification|magnify]] through the [[food chain]], with [[apex predator]]s such as [[raptor birds]] concentrating more chemicals than other animals in the same environment. They are very lipophilic and are stored mainly in body [[fat]]. DDT and DDE are very 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 in the US.<ref name="PineRiver">{{cite journal | author = 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|Environ. Health Perspect.]]  | volume = 117 | issue = 9 | pages = 1359–67 | year = 2009 | pmid = 19750098 | pmc = 2737010 | doi = 10.1289/ehp.11748 }}</ref> Estimated dietary intake has also declined,<ref name="PineRiver"/> although FDA food tests commonly detect it.<ref>USDA, ''Pesticide Data Program Annual Summary Calendar Year 2005'', November 2006.</ref>

Marine macroalgae ([[seaweed]]) help [[Bioremediation|reduce]] soil toxicity by up to 80% within six weeks.<ref>{{cite journal |doi=10.1002/jctb.1032 |last1 = Kantachote |first1=D |year=2004 |last2=Naidu |first2=R |last3=Williams |first3=B |last4=McClure |first4=N |last5=Megharaj |first5=M |last6=Singleton |first6=I |title=Bioremediation of DDT-contaminated soil: enhancement by seaweed addition |journal=Journal of Chemical Technology & Biotechnology |volume=79 |issue=6 |pages=632–8 }}</ref>

===Effects on wildlife and eggshell thinning===
DDT is toxic to a wide range of living organisms, including marine animals such as [[crayfish]], [[daphnia|daphnids]], [[shrimp|sea shrimp]] and many species of [[fish]]. DDT, through its metabolite DDE ([[dichlorodiphenyldichloroethylene]]), caused eggshell thinning and resulted in severe population declines in multiple North American and European [[bird of prey]] species.<ref name="Vos">{{cite journal | author = 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 = Crit Rev Toxicol | volume = 30 | issue = 1 | pages = 71–133 | year = 2000 | pmid = 10680769 | doi = 10.1080/10408440091159176 }}</ref> Eggshell thinning lowers the reproductive rate of certain bird species by causing egg breakage and embryo deaths. DDE related eggshell thinning is considered a major reason for the decline of the [[bald eagle]],<ref name="pmid17588911"/> [[brown pelican]],<ref>"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}}</ref> [[peregrine falcon]], and [[osprey]].<ref name="ATSDRc5"/> However, different groups of birds vary greatly in their sensitivity to these chemicals.<ref name=EHC83/> [[Birds of prey]], [[waterfowl]], and [[passerine|song birds]] are more susceptible to [[eggshell]] thinning than [[chicken]]s and [[Galliformes|related species]], and DDE appears to be more potent than DDT.<ref name="ATSDRc5"/> Even in 2010, more than forty years after the U.S. ban, [[California condor]]s which feed on sea lions at [[Big Sur]] which in turn feed in the Palos Verdes Shelf area of the [[Montrose Chemical Corporation of California|Montrose Chemical]] [[Superfund]] site seemed to be having continued thin-shell problems. Scientists with the [[Ventana Wildlife Society]] and others are intensifying studies and remediations of the condors' problems.<ref>Moir, John, [http://www.nytimes.com/2010/11/16/science/16condors.html?hpw "New Hurdle for California Condors May Be DDT From Years Ago"], ''The New York Times'', November 15, 2010. Retrieved November 15, 2010.</ref>

The biological thinning mechanism is not entirely known, but there is strong evidence that p,p'-DDE inhibits [[calcium ATPase]] in the [[Biological membrane|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.<ref name="ATSDRc5"/><ref>{{cite book | last1 = Walker | first1 = C.H. |author2=et al.  |title=Principles of ecotoxicology |publisher=CRC/Taylor & Francis |location=Boca Raton, FL |year=2006 |isbn=978-0-8493-3635-5 |edition=3rd}}</ref><ref name="Guillette, 2006">{{cite web |last=Guillette |first=Louis J., Jr. |year=2006 |url=http://www.ehponline.org/members/2005/8045/8045.pdf |format=PDF |title=Endocrine Disrupting Contaminants |accessdate=February 2, 2007 |archiveurl=http://www.webcitation.org/5uKxWWYm0 |archivedate=November 18, 2010 |deadurl=no}}</ref><ref name="Lundholm, 1997">{{cite journal | author = Lundholm CD | title = DDE-induced eggshell thinning in birds | journal = Comp Biochem Physiol C Pharmacol Toxicol Endocrinol | volume = 118 | issue = 2 | pages = 113–28 | year = 1997 | pmid = 9490182 | doi = 10.1016/S0742-8413(97)00105-9 }}</ref> There is also evidence that o,p'-DDT disrupts female reproductive tract development, impairing eggshell quality later.<ref name="pmid17022422">{{cite journal | author = 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 = Environ. Toxicol. Chem. | volume = 25 | issue = 10 | pages = 2787–93 | date = October 2006 | pmid = 17022422 | doi = 10.1897/05-619R.1 }}</ref> Multiple mechanisms may be at work, or different mechanisms may operate in different species.<ref name="ATSDRc5"/> Some studies show that although DDE levels have fallen dramatically, eggshell thickness remains 10–12 percent thinner than before DDT was first used.<ref>[http://www.fws.gov/contaminants/examples/AlaskaPeregrine.cfm Contaminants and Birds. Monitoring Contaminants in Arctic and American Peregrine Falcons in Alaska], U.S. Fish & Wildlife service, Division of Environmental Quality, Skip Ambrose, Northern Alaska Field Office, Fairbanks, Alaska</ref>

==Effects on human health==
[[File:DDT Eff.png|right|200px]]

DDT is an endocrine disruptor.<ref>{{cite web |url= http://www.fws.gov/contaminants/issues/endocrinedisruptors.cfm |title= Endocrine (Hormone) Disruptors |work= [[United States Fish and Wildlife Service]] |accessdate= 8 April 2015}}</ref><ref>{{cite paper |url= http://gewa.mpcer.nau.edu/files/endocrine-disruptors.pdf |title= Endocrine Disruptors |work= [[National Institute of Environmental Health Sciences]] |date= February 2007 |accessdate= April 2015}}</ref> It is considered likely to be a human carcinogen although the majority of studies suggest it is not directly [[Genotoxicity|genotoxic]].<ref>{{cite web |url=http://www.efsa.europa.eu/en/efsajournal/doc/433.pdf |title=European Food Safety Administration - DDT |accessdate=2014-10-29 }}</ref><ref>{{cite web |url=http://ntp.niehs.nih.gov/ntp/roc/content/profiles/dichlorodiphenyltrichloroethane.pdf |title=National Toxicology Program - DDT |accessdate=2014-10-29 }}</ref><ref>{{cite web |url=http://monographs.iarc.fr/ENG/Monographs/vol53/mono53-9.pdf |title=IARC - DDT |accessdate=2014-10-29 }}</ref> The DDT metabolite [[Dichlorodiphenyldichloroethylene|DDE]] acts as an [[antiandrogen]], but not as an [[estrogen]]. p,p'-DDT, DDT's main component, has little or no androgenic or estrogenic activity.<ref name="Cohn07">{{cite journal | author = 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 = Environ. Health Perspect. | volume = 115 | issue = 10 | pages = 1406–14 | date = October 2007 | pmid = 17938728 | pmc = 2022666 | doi = 10.1289/ehp.10260 }}</ref> The minor component o,p'-DDT has weak estrogenic activity.

===Acute toxicity===
DDT is classified as "moderately toxic" by the United States [[National Toxicology Program]] (NTP)<ref>[http://pesticideinfo.org/Detail_Chemical.jsp?Rec_Id=PC33482 Pesticideinfo.org]</ref> and "moderately hazardous" by the [[World Health Organization]] (WHO), based on the rat oral {{LD50}} of 113&nbsp;mg/kg.<ref name = "zvgfrt">
World Health Organization, [http://www.who.int/ipcs/publications/pesticides_hazard_rev_3.pdf ''The WHO Recommended Classification of Pesticides by Hazard''], 2005.</ref> DDT has on rare occasions been administered orally as a treatment for [[barbiturate]] poisoning.<ref><!--not about toxicity?:-->{{cite journal | author = Rappolt RT | title = Use of oral DDT in three human barbiturate intoxications: hepatic enzyme induction by reciprocal detoxicants | journal = Clin Toxicol | volume = 6 | issue = 2 | pages = 147–51 | year = 1973 | pmid = 4715198 | doi = 10.3109/15563657308990512 }}</ref>

===Chronic toxicity===

====Developmental toxicity====
DDT and DDE, like other organochlorines, have been shown to have [[estrogen|xenoestrogenic]] activity, meaning they are chemically similar enough to estrogens to trigger hormonal responses in animals. This [[endocrine disruptor|endocrine disrupting]] activity has been observed in [[mouse|mice]] and [[rat]] toxicological studies, and available [[epidemiological]] evidence indicates that these effects may be occurring in humans as a result of DDT exposure. The US [[United States Environmental Protection Agency|Environmental Protection Agency]] states that DDT exposure damages the reproductive system and reduces reproductive success. These effects may cause developmental and reproductive toxicity:
* 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 disruptor|endocrine-disrupting]] properties; human data also indicate possible disruption in semen quality, menstruation, gestational length, and duration of lactation."<ref name="pmid16125595"/>
* Other studies document decreases in semen quality among men with high exposures (generally from IRS).<ref name="pmid20053623">{{cite journal | author = Jurewicz J, Hanke W, Radwan M, Bonde JP | title = Environmental factors and semen quality | journal = Int J Occup Med Environ Health | volume = 22 | issue = 4 | pages = 1–25 | date = January 2010 | pmid = 20053623 | doi = 10.2478/v10001-009-0036-1 | last2 = Hanke | last3 = Radwan | last4 = Bonde }}</ref>
* Studies generally find that high blood DDT or DDE levels do not increase time to pregnancy (TTP.){{mcn|date=October 2014}} There is some evidence that the daughters of highly exposed women may have more difficulty getting pregnant (i.e. increased TTP).{{mcn|date=October 2014}}
* DDT is associated with early pregnancy loss, a type of [[miscarriage]]. A prospective cohort study of Chinese textile workers found "a positive, monotonic, exposure-response association between preconception serum total DDT and the risk of subsequent early pregnancy losses."{{mcn|date=October 2014}} The median serum DDE level of study group was lower than that typically observed in women living in homes sprayed with DDT.{{mcn|date=October 2014}}
* A Japanese study of [[congenital hypothyroidism]] concluded that ''in utero'' DDT exposure may affect [[thyroid]] [[hormone]] levels and "play an important role in the incidence and/or causation of [[cretinism]]."{{mcn|date=October 2014}} Other studies have also found that DDT or DDE interfere with proper thyroid function.{{mcn|date=October 2014}}

===Carcinogenicity===
In 2002, the Centers for Disease Control reported that "Overall, in spite of some positive associations for some cancers within certain subgroups of people, there is no clear evidence that exposure to DDT/DDE causes cancer in humans."<ref name="ATSDRc5"/> The NTP classifies it as "reasonably anticipated to be a carcinogen," the [[International Agency for Research on Cancer]] classifies it as a "possible" human carcinogen, and the EPA classifies DDT, DDE, and DDD as class B2 "probable" [[carcinogen]]s. These evaluations are based mainly on the results of animal studies.<ref name="ATSDRc5"/><ref name="pmid16125595"/>

A Lancet review of epidemiological studies concluded that that DDT causes cancers [[Liver cancer|of the liver]], and [[Pancreatic cancer|pancreas]], that there is mixed evidence that it causes cancers of the testes, and that it probably does not contribute to cancers of the rectum, prostate, endometrium, lung, or stomach.<ref name="pmid16125595"/> A second review, whose co-authors included persons engaged in DDT-related litigation, reached broadly similar conclusions, but also found possible associations with breast cancer, leukemia, lymphoma, and testicular cancer.<ref name="PineRiver"/>

====Breast cancer====
The question of whether DDT or DDE are [[Risk factors for breast cancer|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.<ref>{{cite journal |author=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 Res Perspect |volume=5 |issue=2 |pages=77–84 |date=April 2014  |pmid=24955316 |pmc=4064641 |doi=10.1016/j.phrp.2014.02.001 |url=|last2=Cha |last3=Ko |last4=Hwang |last5=Hong |last6=Lee }}</ref><ref>{{cite journal |author=Ingber SZ, Buser MC, Pohl HR, Abadin HG, Murray HE, Scinicariello F |title=DDT/DDE and breast cancer: a meta-analysis |journal=Regul. Toxicol. Pharmacol. |volume=67 |issue=3 |pages=421–33 |date=December 2013  |pmid=24021539 |doi=10.1016/j.yrtph.2013.08.021 |url=|last2=Buser |last3=Pohl |last4=Abadin |last5=Murray |last6=Scinicariello }}</ref> 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.<ref>{{cite journal |author=Smith-Bindman R |title=Environmental causes of breast cancer and radiation from medical imaging: findings from the Institute of Medicine report |journal=Arch. Intern. Med. |volume=172 |issue=13 |pages=1023–7 |date=July 2012  |pmid=22688684 |pmc=3936791 |doi=10.1001/archinternmed.2012.2329 |url=}}</ref>

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."<ref name="PineRiver"/><ref name="pmid18557596">{{cite journal | author = Clapp RW, Jacobs MM, Loechler EL | title = Environmental and occupational causes of cancer: new evidence 2005–2007 | journal = Rev Environ Health | volume = 23 | issue = 1 | pages = 1–37 | year = 2008 | pmid = 18557596 | pmc = 2791455 | doi = 10.1515/REVEH.2008.23.1.1 | last2 = Jacobs | last3 = Loechler }}</ref> A second review suggested a cautious approach to the interpretation of these results given methodological weaknesses in the study design.<ref>{{cite journal |author=Verner MA, Charbonneau M, López-Carrillo L, Haddad S |title=Physiologically based pharmacokinetic modeling of persistent organic pollutants for lifetime exposure assessment: a new tool in breast cancer epidemiologic studies |journal=Environ. Health Perspect. |volume=116 |issue=7 |pages=886–92 |date=July 2008  |pmid=18629310 |pmc=2453156 |doi=10.1289/ehp.10917 |url=|last2=Charbonneau |last3=López-Carrillo |last4=Haddad }}</ref> 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"<ref>{{cite web |url=http://ntp.niehs.nih.gov/ntp/roc/content/profiles/dichlorodiphenyltrichloroethane.pdf |title=NTP |accessdate=2014-10-14 }}</ref>

==Use against malaria==
[[Malaria]] remains a major public health challenge in many countries. 2008 WHO estimates were 243 million cases, and 863,000 deaths. About 89% of these deaths occur in [[Africa]], and mostly to children under the age of 5.<ref name="wmr09">2009 WHO [http://whqlibdoc.who.int/publications/2009/9789241563901_eng.pdf World Malaria Report 2009]</ref>  DDT is one of many tools that public health officials use to fight the disease. Its use in this context has been called everything from a "miracle weapon [that is] like [[Kryptonite]] to the mosquitoes,"<ref name=salon/> to "toxic colonialism."<ref>{{cite journal | last = Paull | first = John |title=Toxic Colonialism |journal=New Scientist |issue=2628 |page=25 |date=November 3, 2007 |url=http://www.newscientist.com/article/mg19626280.400-toxic-colonialism.html/}}</ref>

Before DDT, eliminating mosquito breeding grounds by drainage or poisoning with [[Paris green]] or [[pyrethrum]] was sometimes successful in fighting malaria. 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.<ref name="Gladwell"/> Today, a variety of usually simultaneous interventions is the norm. These include [[antimalarial drugs]] to prevent or treat infection; improvements in public health infrastructure to quickly diagnose, sequester, and treat infected individuals;  [[mosquito net|bednets]] and other methods intended to keep mosquitoes from biting humans; and [[vector control]] strategies<ref name=wmr09/> such as [[larvacide|larvaciding]] 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 all interior walls and ceilings with insecticides, and 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.

WHO's anti-malaria campaign of the 1950s and 1960s relied heavily on DDT and the results were promising, though temporary. Experts tie the resurgence of malaria 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.<ref name="DDTBP.1/2"/><ref>{{cite journal | author = Feachem RG, Sabot OJ | title = Global malaria control in the 21st century: a historic but fleeting opportunity | journal = JAMA | volume = 297 | issue = 20 | pages = 2281–4 | year = 2007 | pmid = 17519417 | doi = 10.1001/jama.297.20.2281 | last2 = Sabot }}</ref> Resistance was largely fueled by often unrestricted agricultural use. Resistance and the harm both to humans and the environment led many governments to restrict or curtail the use of DDT in vector control as well as agriculture.<ref name="pmid7278974"/> In 2006 the 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.<ref>{{cite news |url=http://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}}</ref>

Once the mainstay of anti-malaria campaigns, as of 2008 only 12 countries used DDT, including India and some southern African states,<ref name=wmr09/> though the number is expected to rise.<ref name="DDTBP.1/2"/>

===Initial effectiveness of DDT against malaria===
When it was first introduced in World War II, DDT was very effective in reducing malaria [[morbidity]] and [[mortality rate|mortality]].<ref name=Dunlap/> The WHO's anti-malaria campaign, which consisted mostly of spraying DDT and rapid treatment and diagnosis to break the transmission cycle, was initially very 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<ref>{{cite book |title=The Coming Plague |publisher=Virago Press |year=1994 |isbn=1-86049-211-8 |page=51 | last = Garrett | first = Laurie }}</ref><ref>[http://www.nytimes.com/2010/12/28/health/28global.html Malaria: A Disease Close to Eradication Grows, Aided by Political Tumult in Sri Lanka], Donald G. McNeil Jr, ''The New York Times'', December 27, 2010.</ref> 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.<ref name="Gordon">{{cite book|last=Harrison|first=Gordon A|title=Mosquitoes, Malaria, and Man: A History of the Hostilities Since 1880|publisher=Dutton|year=1978|isbn=978-0-525-16025-0}}</ref><ref>{{cite journal |author=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=Malar. J. |volume=13 |issue= |pages=59 |year=2014 |pmid=24548783 |pmc=3943480 |doi=10.1186/1475-2875-13-59 |url=}}</ref>

Today, DDT remains on the WHO's list of insecticides recommended for IRS. Since the appointment of [[Arata Kochi]] as head of its anti-malaria division, WHO's policy has shifted from recommending IRS only in areas of seasonal or episodic transmission of malaria, to also advocating it in areas of continuous, intense transmission.<ref>
[http://www.who.int/mediacentre/news/releases/2006/pr50/en/index.html WHO |WHO gives indoor use of DDT a clean bill of health for controlling malaria]</ref> The WHO has reaffirmed its commitment to eventually 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. The WHO plans to implement alternatives to DDT to achieve this goal.<ref>[http://www.who.int/mediacentre/news/releases/2009/malaria_ddt_20090506/en/index.html Countries move toward more sustainable ways to roll back malaria]</ref>

South Africa is one country that 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.<ref>{{cite journal | author = Yamey G | title = Roll Back Malaria: a failing global health campaign | journal = BMJ | volume = 328 | issue = 7448 | pages = 1086–1087 | date = May 8, 2004 | pmid = 15130956 | pmc = 406307 | doi = 10.1136/bmj.328.7448.1086 }}</ref> Malaria cases increased in [[South America]] after countries in that continent stopped using DDT. Research data shows a significantly strong negative relationship between DDT residual house sprayings and malaria rates. In a research from 1993 to 1995, Ecuador increased its use of DDT and resulted in a 61% reduction in malaria rates, while each of the other countries that gradually decreased its DDT use had large increase in malaria rates.<ref name="Roberts 1997"/><ref>{{cite journal |author=Griffing SM, Gamboa D, Udhayakumar V |title=The history of 20th century malaria control in Peru |journal=Malar. J. |volume=12 |issue= |pages=303 |year=2013 |pmid=24001096 |pmc=3766208 |doi=10.1186/1475-2875-12-303 |url=}}</ref><ref>{{cite journal |author=Curtis CF |title=Should the use of DDT be revived for malaria vector control? |journal=Biomedica |volume=22 |issue=4 |pages=455–61 |date=December 2002  |pmid=12596442 |doi= |url=}}</ref>

===Mosquito resistance===
In some areas resistance has greatly reduced DDT's effectiveness. WHO guidelines require that absence of resistance must be confirmed before using the chemical.<ref name="IRS-WHO">
[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.] World Health Organization, 2006.</ref> 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, a former head of the [[Allies of World War II|Allied]] Anti-Malaria campaign, observed in 1956 that "resistance has appeared after six or seven years."<ref name="Gladwell"/> 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]].<ref name="Curtis">C.F. Curtis, [http://ipmworld.umn.edu/chapters/curtiscf.htm Control of Malaria Vectors in Africa and Asia]</ref>

In many parts of [[India]], DDT has also largely lost its effectiveness.<ref>{{cite journal | author = Sharma VP | title = Current scenario of malaria in India | journal = Parassitologia | volume = 41 | issue = 1–3 | pages = 349–53 | year = 1999 | pmid = 10697882 }}</ref> Agricultural uses were banned in 1989 and its anti-malarial use has been declining. Urban use has halted completely.<ref>{{cite journal |title=No Future in DDT: A case study of India |last=Agarwal |first=Ravi |journal=Pesticide Safety News |date=May 2001}}</ref> Nevertheless, DDT is still manufactured and used,<ref>{{cite web |url=http://www.unce.unr.edu/publications/files/nr/2003/SP0316.pdf |title=DDT and DDE: Sources of Exposure and How to Avoid Them| first1 = Art | last1 = Fisher | first2 = Mark | last2 = Walker | first3 = Pam | last3 = Powell |format=PDF |accessdate=December 2, 2010}}</ref> and one study had 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."<ref name="mrc">{{cite journal | author = Sharma SN, Shukla RP, Raghavendra K, Subbarao SK | title = Impact of DDT spraying on malaria transmission in Bareilly District, Uttar Pradesh, India | journal = J Vector Borne Dis | volume = 42 | issue = 2 | pages = 54–60 | date = June 2005 | pmid = 16161701 | last2 = Shukla | last3 = Raghavendra | last4 = Subbarao }}</ref>

Studies of malaria-vector mosquitoes in [[KwaZulu-Natal Province]], [[South Africa]] found susceptibility to 4% DDT (the WHO susceptibility standard), in 63% of the samples, compared to the average of 86.5% 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."<ref name="Hargreaves">{{cite journal | author = 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 = Med. Vet. Entomol. | volume = 17 | issue = 4 | pages = 417–22 | year = 2003 | pmid = 14651656 | doi = 10.1111/j.1365-2915.2003.00460.x | last2 = Hunt | last3 = Brooke | last4 = Mthembu | last5 = Weeto | last6 = Awolola | last7 = Coetzee }}</ref>

DDT can still be effective against resistant mosquitoes,<ref name=PLoS1/> and the avoidance of DDT-sprayed walls by mosquitoes is an additional benefit of the chemical.<ref name="mrc"/> 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 others pesticides worked primarily by killing or irritating mosquitoes – encouraging the development of resistance to these agents.<ref name="PLoS1">{{cite journal | author = 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 = 1 | pages = e716 | year = 2007 | pmid = 17684562 | pmc = 1934935 | doi = 10.1371/journal.pone.0000716 | editor1-last = Krishna | editor1-first = Sanjeev | last2 = Achee | last3 = Chareonviriyaphap | last4 = Suwonkerd | last5 = Chauhan | last6 = Sardelis | last7 = Roberts }} {{open access}}</ref> Others argue that the avoidance behavior slows the eradication of the disease.<ref name="Musawenkosi"/> 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."<ref name="Curtis"/> In India, with its outdoor sleeping habits and frequent night duties, "the excito-repellent effect of DDT, often reported useful in other countries, actually promotes outdoor transmission."<ref>{{cite journal |title=DDT: The fallen angel | first=V. P. |last=Sharma |journal=Current Science |volume=85 |pages=1532–7 |issue=11 |date=December 2003 |url=http://www.ias.ac.in/currsci/dec102003/1532.pdf |format=PDF}}</ref>  Genomic studies in the model genetic organism ''Drosophila melanogaster'' have revealed that high level DDT resistance is polygenic, involving multiple resistance mechanisms.<ref>{{cite journal | author = Pedra JH, McIntyre LM, Scharf ME, Pittendrigh BR | title = Genome-wide transcription profile of field- and laboratory-selected dichlorodiphenyltrichloroethane (DDT)-resistant Drosophila | journal = Proc. Natl. Acad. Sci. U.S.A. | volume = 101 | issue = 18 | pages = 7034–9 | date = May 2004 | pmid = 15118106 | pmc = 406461 | doi = 10.1073/pnas.0400580101 | url = http://www.pnas.org/cgi/pmidlookup?view=long&pmid=15118106 | last2 = McIntyre | last3 = Scharf | last4 = Pittendrigh }}</ref>

===Residents' concerns===
{{main|Indoor residual spraying#Residents's opposition to IRS}}
IRS is effective if at least 80% of homes and barns in a residential area are sprayed.<ref name="IRS-WHO"/> 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.<ref name="Curtis"/><ref name="Musawenkosi">{{cite journal | author = Mabaso ML, Sharp B, Lengeler C | title = Historical review of malarial control in southern African with emphasis on the use of indoor residual house-spraying | journal = Trop. Med. Int. Health | volume = 9 | issue = 8 | pages = 846–56 | year = 2004 | pmid = 15303988 | doi = 10.1111/j.1365-3156.2004.01263.x | last2 = Sharp | last3 = Lengeler }}</ref><ref name="Thurow">[http://www.mindfully.org/Health/Malaria-New-Strain.htm In Malaria War, South Africa Turns To Pesticide Long Banned in the West], Roger Thurow, [[Wall Street Journal]], July 26, 2001</ref> [[Pyrethroid]] insecticides (e.g. [[deltamethrin]] and [[lambda-cyhalothrin]]) can overcome some of these issues, increasing participation.<ref name="Curtis"/>

===Human exposure===
A 1994 study found that compared to contemporaries living where DDT is not used, [[South Africa]]ns living in sprayed homes have levels that are several orders of magnitude greater.<ref name="PineRiver"/> [[Breast milk]] from South African mothers contains high levels of DDT and DDE.<ref name="PineRiver"/> It is unclear to what extent these levels arise from home spraying vs. residues in food. There is some evidence that these levels are associated with neurological abnormalities in babies.<ref name="Curtis"/>

Most studies of DDT's human health effects have been conducted in developed countries where DDT is not used and exposure is relatively low. Many experts urge that alternatives be used instead of IRS.<ref name="pmid16125595"/><ref name="PineRiver"/><ref>{{cite news |url=http://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 |accessdate=May 30, 2009}}</ref>

Illegal diversion to agriculture is also a concern as it is almost impossible to prevent and its subsequent use on crops is uncontrolled. For example, DDT use is widespread in Indian agriculture,<ref>{{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|date=June 10, 2009|publisher=Economic Times|accessdate=June 10, 2009}}</ref> particularly [[mango]] production,<ref>{{cite journal|last=Sanjana|date=June 13, 2009|title=A Whole Fruit|journal=Tehelka Magazine|volume=6|issue=23|url=http://www.tehelka.com/story_main42.asp?filename=cr130609a_whole.asp}}</ref> and is reportedly used by librarians to protect books.<ref>{{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|date=June 8, 2009|publisher=Indian Express|accessdate=June 8, 2009}}</ref> Other examples include Ethiopia, where DDT intended for malaria control is reportedly being used in coffee production,<ref>{{cite journal |last=Katima |first=Jamidu |date=June 2009 |title=African NGOs outline commitment to malaria control without DDT |journal=Pesticides News |issue=84 |page=5}}</ref> and Ghana where it is used for fishing."<ref>{{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|accessdate=November 18, 2009|archiveurl=http://www.webcitation.org/5uKxjHSId |archivedate=November 18, 2010|deadurl=no}}</ref><ref>{{cite news|url=http://news.myjoyonline.com/news/201004/45316.asp|title=Northern fisherfolks complain of committee’s harassment|last=Appiah|first=Samuel |date=April 27, 2010|publisher=Joy Online|accessdate=April 27, 2010}}</ref> The residues in crops at levels unacceptable for export have been an important factor in recent bans in several tropical countries.<ref name="Curtis"/> Adding to this problem is a lack of skilled personnel and supervision.<ref name="Musawenkosi"/>

===Criticism of restrictions on DDT use===
Critics argue that limitations on DDT use for public heath purposes have caused unnecessary morbidity and mortality from vector borne diseases, with some claims of malaria deaths ranging as high as the hundreds of thousands,<ref>{{cite news |url=http://query.nytimes.com/gst/abstract.html?res=F40B1EFB3F580C718DDDAA0894DD404482&n=Top%252fOpinion%252fEditorials%2520and%2520Op%252dEd%252fOp%252dEd%252fColumnists%252fNicholas%2520D%2520Kristof |publisher=New York Times |date=March 12, 2005 |title=I Have a Nightmare |first=Nicholas D. |last=Kristof |pages=Section A, Page 15 , Column 1 |nopp=true}}</ref> and millions. Robert Gwadz of the US [[National Institutes of Health]] said in 2007, "The ban on DDT may have killed 20 million children."<ref>{{cite news |authorlink = Michael Finkel | last = Finkel | first = Michael |title=Malaria |url=http://www7.nationalgeographic.com/ngm/0707/feature1/text4.html |publisher=National Geographic |date=July 2007}}</ref> In his novel ''[[State of Fear]]'', author [[Michael Crichton]] wrote "Banning DDT killed more people than Hitler."<ref name="Crichton">{{cite news |title=Rachel Carson Didn’t Kill Millions of Africans | first = William | last = Souder |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 |accessdate=September 5, 2012}}</ref> These arguments have been dismissed 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."<ref name="salon">{{cite news | first = Kirsten | last = Weir |title=Rachel Carson's birthday bashing |url=http://www.salon.com/news/feature/2007/06/29/rachel_carson/ |publisher=Salon.com |date=June 29, 2007 |accessdate=July 1, 2007}}</ref> Investigative journalist Adam Sarvana and others characterize this notion as a "myth" promoted principally by [[Roger Bate]] of the pro-DDT advocacy group [[Africa Fighting Malaria]] (AFM).<ref name="NRNS">{{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|date=May 28, 2009|publisher=Natural Resources New Service|accessdate=June 2, 2009}}</ref><ref name="Guts">{{cite book|last=Gutstein|first=Donald|title=Not a Conspiracy Theory: How Business Propaganda Hijacks Democracy|publisher=Key Porter Books|date=November 24, 2009|isbn=978-1-55470-191-9}}. Relevant excerpt at {{cite news |url=http://thetyee.ca/Mediacheck/2010/01/22/DDTPropaganda/ |title=Inside the DDT Propaganda Machine |last=Gutstein |first=Donald |date=January 22, 2010 |publisher=The Tyee |accessdate=January 22, 2010}}</ref>

Criticisms of a DDT "ban" often specifically reference the 1972 US ban (with the erroneous implication that this constituted a worldwide ban and prohibited use of DDT in vector control). Reference is often made to [[Rachel Carson]]'s ''Silent Spring,'' even though she never pushed for a ban on DDT specifically. [[John Quiggin]] and Tim Lambert wrote, "the most striking feature of the claim against Carson is the ease with which it can be refuted."<ref name="quig">{{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/}}</ref>

It has also been alleged that donor governments and agencies have refused to fund DDT spraying, or made aid contingent upon not using DDT. According to a report in the ''British Medical Journal'', use of DDT in [[Mozambique]] "was stopped several decades ago, because 80% of the country's health budget came from donor funds, and donors refused to allow the use of DDT."<ref>{{cite journal | author = Sidley P | title = Malaria epidemic expected in Mozambique | journal = BMJ | volume = 320 | issue = 7236 | page = 669 | year = 2000 | pmid = 10710569 | pmc = 1117705 | doi = 10.1136/bmj.320.7236.669 }}</ref> Roger Bate asserts, "many countries have been coming under pressure from international health and environment agencies to give up DDT or face losing aid grants: Belize and Bolivia are on record admitting they gave in to pressure on this issue from [USAID]."<ref>{{cite journal |url=http://www.cid.harvard.edu/cidinthenews/articles/nr_051401.html |date=May 14, 2001 |journal=National Review|volume=LIII |issue=9 |first=Roger |last=Bate |title=A Case of the DDTs: The war against the war against malaria|archiveurl=http://www.webcitation.org/5uKxmunGp |archivedate=November 18, 2010|deadurl=no}}</ref>

The [[United States Agency for International Development]] (USAID) has been the focus of much criticism. While the agency is currently funding the use of DDT in some African countries,<ref name="USAID">{{cite web |url=http://www.usaid.gov/our_work/global_health/id/malaria/techareas/irs.html |title=USAID Health: Infectious Diseases, Malaria, Technical Areas, Prevention and Control, Indoor Residual Spraying |publisher=USAID |accessdate=October 14, 2008 |archiveurl=http://www.webcitation.org/5uKxoMqlg |archivedate=November 18, 2010 |deadurl=no}}</ref> in the past it did not. When [[John Stossel]] accused USAID of not funding DDT because it wasn't "politically correct," Anne Peterson, the agency's assistant administrator for global health, replied that "I believe that the strategies we are using are as effective as spraying with DDT ... So, politically correct or not, I am very confident that what we are doing is the right strategy."<ref>{{cite news|url=http://abcnews.go.com/2020/Stossel/story?id=1898820|title=Excerpt: 'Myths, Lies, and Downright Stupidity'|last=Stossel|first=John|date=November 16, 2007|publisher=ABC News|accessdate=October 14, 2008}}</ref> USAID's Kent R. Hill states that the agency has been misrepresented: "USAID strongly supports spraying as a preventative measure for malaria and will support the use of DDT when it is scientifically sound and warranted."<ref>{{cite web|url=http://www.hillnews.com/thehill/export/TheHill/Comment/LetterstotheEditor/111505.html |title=USAID isn’t against using DDT in worldwide malaria battle | first = Kent R. | last = Hill |accessdate=April 3, 2006|year=2005 |archiveurl=http://web.archive.org/web/20060331190237/http://www.hillnews.com/thehill/export/TheHill/Comment/LetterstotheEditor/111505.html  |archivedate=March 31, 2006|authorlink=Kent R. Hill }}</ref> The Agency's website states that "USAID has never had a 'policy' as such either 'for' or 'against' DDT for IRS. The real change in the past two years [2006/07] has been a new interest and emphasis on the use of IRS in general – with DDT or any other insecticide – as an effective malaria prevention strategy in tropical Africa."<ref name=USAID/> The website further explains that in many cases alternative malaria control measures were judged to be more cost-effective that DDT spraying, and so were funded instead.<ref>{{cite web |url=http://transition.usaid.gov/our_work/global_health/id/malaria/news/afrmal_ddt.html |title=USAID Health: Infectious Diseases, Malaria, News, Africa Malaria Day, USAID Support for Malaria Control in Countries Using DDT |accessdate=March 15, 2006 |year=2005|archiveurl=http://www.webcitation.org/5uKxp31Ck |archivedate=November 18, 2010|deadurl=no}}</ref>

===Alternatives===

====Other insecticides====
{{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. [[Pyrethroid]]s such as [[deltamethrin]] are also more expensive than DDT, but are applied more sparingly (0.02–0.3&nbsp;g/m<sup>2</sup> vs 1–2&nbsp;g/m<sup>2</sup>), so the net cost per house is about the same over 6 months.<ref name="AmJTrop"/>

====Non-chemical vector control====
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 filling or applying oil to standing water. These methods have seen little application in Africa for more than half a century.<ref>{{cite journal | author = Killeen GF, Fillinger U, Kiche I, Gouagna LC, Knols BG | title = Eradication of Anopheles gambiae from Brazil: lessons for malaria control in Africa? | journal = Lancet Infect Dis | volume = 2 | issue = 10 | pages = 618–27 | year = 2002 | pmid = 12383612 | doi = 10.1016/S1473-3099(02)00397-3 | last2 = Fillinger | last3 = Kiche | last4 = Gouagna | last5 = Knols }}</ref> According to the United States 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."<ref>{{cite web |url=http://www.cdc.gov/malaria/malaria_worldwide/reduction/vector_control.html |title=CDC - Malaria - Malaria Worldwide - How Can Malaria Cases and Deaths Be Reduced? - Larval Control and Other Vector Control Interventions |work= |accessdate=}}</ref>

The relative effectiveness of IRS (with DDT or alternative insecticides) versus other malaria control techniques (e.g. bednets or prompt access to anti-malarial drugs) varies greatly and is highly dependent on local conditions.<ref name="AmJTrop"/>

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 Rwanda and Ethiopia, countries with high malaria burdens. IRS with DDT did not play an important role in mortality reduction in these countries.<ref>[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.</ref><ref>[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], David Brown (Washington Post), ''SF Chronicle'', A-February 12, 1, 2008.</ref>

[[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.<ref>[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.]</ref>

In Mexico, effective and affordable chemical and non-chemical strategies against malaria have been so successful that the Mexican DDT manufacturing plant ceased production due to lack of demand.<ref name="PMC1119118">{{cite web |url=http://www.ipen.org/ipenweb/documents/work%20documents/ddt_ipenreport_english.pdf |title=DDT & Malaria |accessdate=March 11, 2009 |archiveurl=http://www.webcitation.org/5pt5PazSh |archivedate=May 21, 2010 |deadurl=no}}</ref>

A review of fourteen studies on the subject 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 gross lack of information on the costs and effects of many interventions, the very small number of cost-effectiveness analyses available, 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; furthermore, the resulting estimates may not be good predictors of cost-effectiveness in current programs.<ref>{{cite journal | author = 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 | year = 1999 | pmid = 10787646 | doi = 10.1093/heapol/14.4.301 | url = http://heapol.oxfordjournals.org/cgi/reprint/14/4/301.pdf | format = PDF | last2 = Mills }}</ref>

However, a study in Thailand found the cost per malaria case prevented of DDT spraying ($1.87 US) to be 21% greater than the cost per case prevented of [[lambda-cyhalothrin]]–treated nets ($1.54 US),<ref>{{cite journal | author = 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 = American Journal of Tropical Medicine and Hygiene | volume = 65 | issue = 4 | pages = 279–84 | year = 2001 | pmid = 11693869 | last2 = Butraporn | last3 = Prasittisuk | last4 = Prasittisuk | last5 = Indaratna }}</ref> at very least casting some doubt on the unexamined assumption that DDT was the most cost-effective measure to use in all cases. The director of Mexico's malaria control program finds similar results, declaring that it is 25% cheaper for Mexico to spray a house with synthetic pyrethroids than with DDT.<ref name="PMC1119118"/> However, another study in South Africa found generally lower costs for DDT spraying than for impregnated nets.<ref>{{cite journal | author = 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 = Trop. Med. Int. Health | volume = 6 | issue = 4 | pages = 280–95 | year = 2001 | pmid = 11348519 | doi = 10.1046/j.1365-3156.2001.00700.x | last2 = Mnzava | last3 = Dlamini | last4 = Sharp | last5 = Mthembu | last6 = Gumede }}</ref>

A more comprehensive approach to measuring cost-effectiveness or efficacy of malarial control would not only measure the cost in dollars of the project, as well as the number of people saved, but would also consider ecological damage and negative aspects of insecticide use on human health. One preliminary study regarding the effect of DDT found that it is likely the detriment to human health approaches or exceeds the beneficial reductions in malarial cases, except perhaps in malarial epidemic situations. It is similar to the earlier mentioned study regarding estimated theoretical infant mortality caused by DDT and subject to the criticism also mentioned earlier.<ref>{{cite journal |url=http://www.jcu.edu.au/jrtph/vol/v04corin.pdf |format=PDF |last1=Corin |first1=S.E. |last2=Weaver |first2=S.A. |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}}</ref>

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."<ref>{{cite journal | author = 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 = Am. J. Trop. Med. Hyg. | volume = 71 | issue = 2 Suppl | pages = 214–23 | year = 2004 | pmid = 15331840 | url = http://www.ajtmh.org/cgi/content/full/71/2_suppl/214 | last2 = Bakote'e | last3 = Velayudhan | last4 = Wilikai | last5 = Graves }}</ref>

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."<ref>{{cite journal | author = Barat LM | title = Four malaria success stories: how malaria burden was successfully reduced in Brazil, Eritrea, India, and Vietnam | journal = Am. J. Trop. Med. Hyg. | volume = 74 | issue = 1 | pages = 12–6 | year = 2006 | pmid = 16407339 }}</ref>

DDT resistant mosquitoes have generally proved susceptible to pyrethroids. Thus far, pyrethroid resistance in ''Anopheles'' has not been a major problem.<ref name="Curtis"/>

==See also==
* [[DDT in Australia]]
* [[DDT in New Zealand]]
* [[DDT in the United States]]
* [[Mickey Slim]], a short-lived cocktail that combined [[gin]] with a pinch of DDT.
* [[Operation Cat Drop]]
* [[Biomagnification]]

==References==
{{reflist|colwidth=30em}}

==Further reading==
* David Kinkela. ''DDT and the American Century: Global Health, Environmental Politics, and the Pesticide That Changed the World'' (University of North Carolina Press, 2011).

==External links==
{{Commons category|DDT}}
;Chemistry
* [http://www.periodicvideos.com/videos/mv_DDT.htm DDT] at ''[[The Periodic Table of Videos]]'' (University of Nottingham)

;Toxicity
* [http://npic.orst.edu/factsheets/ddttech.pdf DDT Technical Fact Sheet – National Pesticide Information Center]
* [http://npic.orst.edu/factsheets/ddtgen.pdf DDT General Fact Sheet – National Pesticide Information Center]
* [http://extoxnet.orst.edu/pips/ddt.htm EXTOXNET: Pesticide Information Profiles – DDT]
* [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]
* [http://www.cdc.gov/niosh/npg/npgd0174.html CDC – NIOSH Pocket Guide to Chemical Hazards – DDT]

;Politics and DDT
* [http://reason.com/archives/2004/01/07/ddt-eggshells-and-me DDT, Eggshells, and Me] Article from [[Reason magazine]] by [[Ronald Bailey]], January 7, 2004.
* [http://www.fair.org/index.php?page=3186 ''Rachel Carson, Mass Murderer?: The creation of an anti-environmental myth.''] [[Aaron Swartz]], ''Extra!'', September/October 2007.

;Malaria and DDT
* [http://www.washingtonpost.com/wp-dyn/content/article/2005/06/04/AR2005060400130.html "If Malaria's the Problem, DDT's Not the Only Answer"], a ''[[Washington Post]]'' column by [[entomologist]] May Berenbaum
* [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
* [http://www.abc.net.au/news/stories/2008/05/31/2261160.htm Ugandan farmers push for DDT ban. Dated 31 May 2008 ABC News]

{{Insecticides}}
{{Carcinogen}}
{{Consumer Food Safety}}

[[Category:drug]]
[[Category:DDT| ]]
[[Category:Pesticides]]
[[Category:Endocrine disruptors]]
[[Category:Environmental effects of pesticides]]
[[Category:IARC Group 2B carcinogens]]
[[Category:Malaria]]
[[Category:Persistent Organic Pollutants under the Stockholm Convention]]
[[Category:Persistent Organic Pollutants under the Convention on Long-Range Transboundary Air Pollution]]
[[Category:Environmental controversies]]