4,4'-DDT

Molecular Structure:

Molecular Formula: C₁₄H₉Cl₅
Molecular Weight: 354.4863
IUPAC Name: 1-Chloro-4-[2,2,2-trichloro-1-(4-chlorophenyl)ethyl]benzene
Synonyms of DDT (CAS NO.50-29-3): 1,1,1-Trichloro-2,2-bis(p-chlorophenyl)ethane ; Benzene, 1,1'-(2,2,2-trichloroethylidene)bis(4-chloro- ; Clofenotane ; Ethane, 1,1,1-trichloro-2,2-bis(p-chlorophenyl)- ; p,p'-DDT ; 4,4'-DDT ; DDT ; DDT and metabolites ; DDT, p,p'- ; Dichlorodiphenyltrichloroethane ; RCRA waste no. U061
CAS NO: 50-29-3
Classification Code: Agricultural Chemical ; Human Data ; Insecticide ; Mutation data ; Reproductive Effect ; TSCA Flag S [Substance is identified in a proposed or final SNUR (Significant New Use Rule) under TSCA] ; Tumor data
Melting point: 107-110 °C  
Index of Refraction: 1.608
Molar Refractivity: 84.5 cm³
Molar Volume: 244.1 cm³
Surface Tension: 46.8 dyne/cm
Density: 1.451 g/cm³
Flash Point: 203.9 °C
Enthalpy of Vaporization: 64.34 kJ/mol
Boiling Point: 416.2 °C at 760 mmHg
Vapour Pressure: 9.42E-07 mmHg at 25°C

 DDT (CAS NO.50-29-3) was synthesized in 1874. During World War II, it was available for controling mosquitoes spreading malaria and lice transmitting typhus among civilians and troops. After the war, it was widely used as an agricultural insecticide. In 1962, Silent Spring was published, which resulted in spread awareness in environmental issues and eventually led to most uses of it being banned in the US in 1972. Subsequently, it was banned for agricultural use worldwide under the Stockholm Convention.

From 1950 to 1980,  DDT (CAS NO.50-29-3) was extensively used in agriculture. It has been estimated that a total of 1.8 million tonnes of it have been produced globally since the 1940s. More than 600,000 tonnes were applied in the U.S. before the 1972 ban. Today, India, China, and North Korea are the only countries still producing and exporting it, and production is reportedly on the rise.

NTP 10th Report on Carcinogens. IARC Cancer Review: Group 2B IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 7 (1987),p. 186.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) ; Animal Sufficient Evidence IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 5 (1974),p. 83.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) ; Human Inadequate Evidence IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 5 (1974),p. 83.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) . NCI Carcinogenesis Bioassay (feed); No Evidence: mouse, rat NCITR*    National Cancer Institute Carcinogenesis Technical Report Series. (Bethesda, MD 20014) No. NCI-CG-TR-131 ,1978. . Reported in EPA TSCA Inventory. EPA Genetic Toxicology Program.

Hazard Codes of DDT (CAS NO.50-29-3): T,N,Xi,F
Risk Statements: 25-40-48-50-36/37/38-11-39-23/24/25-52/53 
R25: Toxic if swallowed. 
R40: Limited evidence of a carcinogenic effect. 
R48: Danger of serious damage to health by prolonged exposure. 
R50: Very toxic to aquatic organisms. 
R36/37/38: Irritating to eyes, respiratory system and skin. 
R11: Highly flammable. 
R39: Danger of very serious irreversible effects. 
R23/24/25: Toxic by inhalation, in contact with skin and if swallowed. 
R52/53: Harmful to aquatic organisms, may cause long-term adverse effects in the aquatic environment.
Safety Statements: 22-36/37-45-60-61-33-26-16-7 
S22: Do not breathe dust. 
S36/37: Wear suitable protective clothing and gloves. 
S45: In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.) 
S60: This material and its container must be disposed of as hazardous waste. 
S61: Avoid release to the environment. Refer to special instructions / safety data sheets. 
S33: Take precautionary measures against static discharges. 
S26: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. 
S16: Keep away from sources of ignition. 
S7: Keep container tightly closed.
RIDADR: UN 2811 6.1/PG 3
WGK Germany: 3
RTECS: KJ3325000
HazardClass: 6.1(b)
PackingGroup: III
Confirmed carcinogen with experimental carcinogenic, neoplastigenic, tumorigenic, and teratogenic data. Human poison by ingestion. Experimental poison by ingestion, skin contact, subcutaneous, intravenous, and intraperitoneal routes. Experimental reproductive effects. Human systemic effects by ingestion: anesthetic, convulsions, headache, analgesia, cardiac arrhythmias, nausea or vomiting, sweating, and unspecified pulmonary changes. Human mutation data reported. An insecticide. When heated to decomposition it emits toxic fumes of Cl⁻. See also CHLORINATED HYDROCARBONS, AROMATIC.
A dose of 20 g has proved highly dangerous though not fatal to a human. This dose was taken by 5 persons who vomited an unknown portion of the material and even so recovered only incompletely after 5 weeks. Smaller doses produced less important symptoms with relatively rapid recovery. Experimental ingestion of 1.5 g resulted in great discomfort and moderate neurological changes including paresthesia, tremor, moderate ataxia, exaggeration of part of the reflexes, headache, and fatigue. Vomiting followed only after 11 hours. Recovery was complete on the following day. The fatal dose of DDT for humans is not known. Judging from the literature, no one has ever been killed by DDT in the absence of other insecticides and/or a variety of toxic solvents. However, these common solvent formulations are highly fatal when taken in small doses, partly because of the toxicity of the solvent, and perhaps because of the increased absorbability of the DDT; several fatal cases in humans have been reported. Little is known of the hazard of chronic DDT poisoning. Human volunteers have ingested up to 35 mg/day for 21 months with no ill effects.=
DDT and some of its degradation products, particularly DDE, are stored in fat. This storage effect leads to a concentration of DDT at higher levels of the food chain. DDT stored in the fat is at least largely inactive since a greater total dose may be stored in an experimental animal than is sufficient as a lethal dose for that same animal if given at one time. A study based on 75 human cases reported an average of 5.3 ppm of DDT stored in the fat. A higher content of DDT and its derivatives (up to 434 ppm of DDE and 648 ppm of DDT) was found in workers who had very extensive exposure. Without exception, the samples were taken from persons who were either asymptomatic or suffering from some disease completely unrelated to DDT. Careful hospital examination of workers who had been very extensively exposed and who had volunteered for examination revealed no abnormality that could be attributed to DDT. Much higher levels have been found in humans than have been observed in the fat of experimental animals that were apparently asymptomatic. DDT stored in the fat is eliminated only very gradually when further dosage is discontinued. However, weight loss can speed the release of this stored DDT (and DDE) into the blood. After a single dose, the secretion of DDT in the milk and its excretion in the urine reach their height within a day or two and continue at a lower level thereafter.

OSHA PEL: TWA 1 mg/m³ (skin)
ACGIH TLV: TWA 1 mg/m³; Animal Carcinogen
NIOSH REL: (DDT) TWA 0.5 mg/m³; avoid skin contact
DFG MAK: 1 mg/m³