WORLD HEALTH ORGANIZATION FOOD AND AGRICULTURE ORGANIZATION
ORGANISATION MONDIALE DE LA SANTE ORGANISATION POUR L'ALIMENTATION
DATA SHEET ON PESTICIDES No. 80
Primary Use: Insect repellent
Secondary Use: None
Chemical Group: Substituted toluamide
It must be noted that the issue of a Data Sheet for a
particular pesticide does not imply endorsement of the pesticide by
WHO or FAO for any particular use, or exclude its use for other
purposes not stated. While the information provided is believed to
be accurate according to data available at the time when the sheet
was compiled, neither WHO nor FAO are responsible for any errors or
omissions, or any consequences therefrom.
The issue of this document does Ce document ne constitue pas une
not constitute formal publication. Il ne doit faire
publication. It should not be l'objet d'aucun compte rendu ou
reviewed, abstracted or quoted résumé ni d'aucune citation sans
without the agreement of the l'autorisation de l'Organisation
Food and Agriculture des Nations Unies pour
Organization of the United l'Alimentation et l'Agriculture
Nations or of the World Health ou de l'Organisation Mondiale de
Organization. la Santé.
1.0 GENERAL INFORMATION
1.1 COMMON NAME: Deet (ANSI, ESA, exception BPC, BSI, E-ISO,
IUPAC: N, N-diethyl-m-toluamide
CAS: N, N-diethyl-3-methylbenzamide
CAS Reg. No.: 134-62-3
Molecular formula: C12H17NO
Molecular weight: 191.3
1.1.2 Synonyms: AutanR; DET; DETA; DetamideR; DieltamidR;
diethyltoluamide; diethyl-m-toluamide; ENT 20,218; ENT 22542:
FlypelR; m-DelpheneR; m-Det; m-Deta; MetadelpheneR; MGK;
Naugatuck DETR; OFFR; Repper-DET; Repladin SpecialR.
1.2 SYNOPSIS: Deet is a selected spectrum, non-cumulative substituted
toluamide; an insect repellent of slight toxicity to mammals and
with residual activity. The technical product is listed in WHO
Hazard Class III. Toxicity is not increased after metabolism to
the oxygen analogue. Deet was introduced commercially in 1955.
1.3 SELECTED PROPERTIES
1.3.1 Physical characteristics - The technical product is a nearly
odourless, colourless to amber liquid consisting of 85-95%
meta-isomer. The boiling point is 111°C at 1.0 mm Hg; the
density (d) 244 is 0.996 to 0.998; viscosity 13.3 mPa at 30°C;
the refraction index (n) 25D 1.5206. Deet is not corrosive
1.3.2 Solubility - Practically insoluble in water and glycerin.
Miscible with ethanol, isopropanol, propylene glycol, and other
1.3.3 Stability - Technical deet is relatively stable, highly
hygroscopic and light sensitive. Sensitive to strong acids and
1.3.4 Vapour pressure: - 2.54 x 10-3 mm Hg (25°C)
1.4 AGRICULTURE, HORTICULTURE AND FORESTRY - No recommended uses.
1.5 PUBLIC HEALTH PROGRAMMES - See 1.6
1.6 HOUSEHOLD USE
1.6.1 Common formulations - Deet is commercially available as
emulsifiable concentrate, creams, sticks, lotions and in
pressurized sprays and foams, ranging in concentration from 11.27
to 99.9% deet. It may be formulated with solvents such as
ethanol or isopropanol, or with other pesticides.
1.6.2 Susceptible pests - Blood-sucking insects (including mosquitoes,
blackflies, gnats and other biting fleas), mites and ticks.
1.6.3 Use pattern - World-wide, on human skin to repel insect pests.
Can be used on clothing, household Pets, tents, bedrolls and
1.6.4 Unintended effects - No information available.
2.0 TOXICOLOGY AND RISKS
2.1 TOXICOLOGY - MAMMALS
2.1.1 Absorption routes - Deet is absorbed slowly through the skin,
gastrointestinal tract or by inhalaton of spray mist. Maximum
dermal penetration occurs within 24 hours and depending upon the
vehicle and the species may account for up to 77% of the applied
dose, the remainder being evaporated.
2.1.2 Mode of action - The exact mode of action of deet is not known.
Circumstantial evidence implicates deet in activities causing
accumulation of potassium in muscle cells and neurons. See
Section 2.1.7. Pharmacological effects.
2.1.3 Excretion products - In seven-day excretion studies in rats,
rabbits and dogs, topically applied radio-labelled deet
(75% m-Deet in ethanol) was found to be excreted primarily
through the urine with the dog having lowest absorption
potential. Of absorbed deet >75% was excreted in the urine
within 24 hours with little accumulation in any tissues for the
three species. Published human studies indicated that most of
absorbed deet is excreted unchanged within one hour with the
remainder being metabolized. The predominant metabolic pathway
in man involves oxidation of the benzylic moiety and
hydroxylation of the side chain yielding m-carboxyl-
N,N-diethybenzoylamide. The monohydroxylation product is
excreted as a glucuronide conjugate rather than a free alcohol.
2.1.4 Toxicity - Single dose
Rat (M) 2.00 g/kg b.w. (meta-isomer)
1.21 g/kg b.w. (ortho-isomer)
2.30 g/kg b.w. (para-isomer)
Administration of technical grade deet to male rats by gastric
intubation led to acute toxicity symptoms including hyperemia at
base of ears, lacrimation, depression, prostration, epileptoid
tremors, asphyxial convulsions, respiratory and cardiac failure
and death. Doses near but below the LD50 caused slight to mild
symptoms. Some rats appeared moribund but recovered completely
within 24 hours. No latent toxic effects were observed.
Mouse (M,F) 4.5 g/kg b.w.
Rat (M,F) >5.0 g/kg b.w.
Rabbit (M) 3.18 g/kg b.w.
Rat (M,F) >5950 mg/m3/8h
Rats exposed to concentrations of 3.15 mg/l/hr for two to six
hours experienced a slight bloody discharge from the nose. After
24 hours the rats appeared normal and showed no significant
physical or histopathological changes.
Rabbit (M,F) >50 mg/kg b.w. (meta-isomer)
All rabbits receiving >75 mg/kg b.w. in a single injection died
within one minute. Rabbits receiving 50 mg/kg b.w. experienced
temporary miosis and respiratory stimulation. Pregnant rabbits
injected intravenously with a radio-labelled m-deet in ethanol
solution on the fifteenth day of gestation did not bioaccumulate
deet; the foetuses contained approximately one-sixth of the
maternal blood level of deet at all sampling intervals.
Eye irritation - Exposure of the rabbit eye to three drops (0.04
mg m-deet/drop) of a 30% and 40% solution of deet in cottonseed
oil and undiluted deet resulted in edema of the nictitating
membrane, lacrimation, conjunctivitis with pus. After 48 hours
mild to moderate conjunctivitis and cloudiness of the cornea were
present. After five days, injury to the eye began to disappear,
leaving no permanent damage.
2.1.5 Toxicity, repeated doses
Oral - Male rats, given 10% ortho-isomer (600 mg/kg b.w.) or
12.5% para-isomer (1125 mg/kg b.w.) for 19 days by gavage showed
no evidence of adverse effects and no histopathological changes.
Male rabbits, given 528 mg/kg b.w. m-deet daily by gavage for 15
days showed progressive weight loss, decreased serum calcium
levels, increased cholesterol and triglyceride levels as well as
increased relative kidney weight.
Dermal - Female rabbits dosed with radio labelled m-deet in
ethanol (75% conc.) throughout gestation in doses ranging from 0
to 500 mg/kg/b.w./day absorbed about 45% of the applied dose.
The degree of absorption was not dose dependant. No
radioactivity was observed in the full term foetuses.
Moderate erythema, desquamation and dryness of skin occurred when
rabbits were dosed with m-deet in cottonseed oil or isopropanol
(50% conc.) at 1.0 g/kg b.w./day for 65 days. Later, the skin
application site became leathery with hard, dry fissures
developing. Three weeks after the final application all rabbits
appeared normal except for occasional scarring and no evidence of
skin sensitization was found.
In a 60 day study horses sprayed with 31 g/day of m-deet in
aerosol formulations (3.75-75.0% conc.) developed hypersteatosis
and dermatosis at >15% conc. The timing of appearance of these
effects was inversely related to dose.
Studies done on ortho- and para-isomers of deet showed similar
results to the meta-isomer. Dermal application of 200 mg/kg
b.w./day to rabbits for 65 days resulted in mild interstitial
nephritis and more extensive inflammatory kidney lesions with the
Inhalation - Groups of rats exposed to air saturated with m-deet.
100 mg/1.4m3 for 40 hours (eight hours/day, five days per week
and for seven weeks) showed slight hyperemia of ears, feed and
tail and increased motor activity. Some rats showed slight
bleeding from the nose. At the end of the study there were no
significant physiological or histopathological findings.
2.1.6 Dietary studies
Short-term - In a 200-day rat feeding study with dose levels of
100-10000 mg/kg diet, no effect levels were established at 500
mg/kg/diet for males and 5000 mg/kg/diet for females. The male
no effect level was due to induced hypertrophy of the testes.
Hypertrophy of the liver and kidneys was observed in both sexes.
No histopathological changes were reported.
2.1.7 Supplementary studies
Carcinogenicity - Lifetime studies of female mice and male and
female rabbits dosed twice a week with deet in acetone (100, 50
and 10% conc.) at a volume of 0.02 ml showed no carcinogenic
activity in either species and no local changes in mice.
Mutagenicity - Deet had no mutagenic potential in the
metabolically activated and non-activated Ames
Salmonella/mammalian microsome mutagenicity assay, nor in tests
involving Escherischia coli.
Additionally, a dominant lethal assay in male mice using m-deet
in corn oil yielded no statistically significant results.
Teratogenicity - No evidence of teratogenic activity was found
when female rabbits were repeatedly dosed dermally throughout
gestation a 75% solution of m-deet in concentrations ranging from
50 to 1000 mg/kg b.w./day. In a rat combined reproduction and
teratogenicity study, dermal applications of 100 or 1000 mg/kg
b.w./day of m-deet for the duration of gestation caused no
observed teratologic effects.
Parent effects - Male rats inhaling 1500 mg m-deet/m3 of air for
six hours/day, five days/week for 13 weeks had sperm head
abnormalities and reduced sperm motility. Untreated females
mated with these males had a decreased pregnancy rate.
In female rats dermally dosed with m-deet at 100 and 1000 mg/kg
b.w./day for the duration of pregnancy, increased pre- and post-
implantation losses and decreased foetal viability and foetal
weight were observed at the highest dose level. At 100
mg/kg/day, only the viability of foetuses was adversely affected.
These adverse effects were confirmed in a second study, using
similar doses for a period of one to six months prior to mating.
In addition, adverse testicular effects and decreased sperm
motility were reported in treated males at both dose levels. In
another different study, groups of male rats dermally dosed with
m-deet at doses up to 1000 mg/kg b.w./day, five days/week for
nine weeks showed no alteration in sperm count, sperm morphology,
sperm viability, body weight or food consumption at any dose
Pup Effects - When female rats were dosed dermally with m-deet
retarded development of the newborns was observed at the 1000
mg/kg, the highest dose level tested.
Neurotoxicity - When the mice were injected once,
intraperitoneally with 40% m-deet in alcohol they showed motor
excitement, disturbed coordination, convulsive twitching of
limbs, depression and death. Dogs administered 100-300 mg/kg
b.w./day of m-deet for 13 weeks experienced mild CNS stimulation
and occasional emesis. Temporary miosis was reported in rabbits
following a single intravenous injection of 50 mg/kg b.w.
Sensitization and skin irritation - Deet was not found to cause a
photo-chemical irritation reaction when applied dermally to
rabbits prior to UV light exposure. No evidence of sensitization
was observed in guinea pigs following dermal application of 1.0
ml of 10% m-deet solution.
Behavioural changes - Minor behavioural changes in passive and
quick avoidance, tactile sensitivity, endurance, balance and
level of activity, were seen in a 65 day rat inhalation study of
m-deet at all dose levels from 250-1500 mg/m3.
Pharmacological effects - A 40% emulsion of m-deet (in vegetable
lecithin, ethanol and distilled water) had no effect on isolated
rat uterus at a dilution of 1:10000. A dilution of 1:5000
depressed the amplitude of rhythmic contraction in the uterus
while a dilution of 1:2500 completely abolished contraction and
muscle tone. All effects were reversible when the m-deet
emulsion was removed or upon additional treatment with
acetylcholine or barium chloride. The effects, therefore, are
consistent with increased intracellular potassium levels.
Rabbits showed circulatory and respiratory responses to m-deet
including a slight but evanescent fall in blood pressure when
intravenously administered at 5 mg/kg b.w.
2.2 TOXICOLOGY - MAN
2.2.1 Absorption route - See 2.1.1
2.2.2 Dangerous doses - No published information available. Probable
oral lethal dose 0.5 to 5.0 g/kg b.w. Dermal lowest toxic dose
35 mg/kg b.w./five days.
2.2.3 Observations of occupationally exposed workers - Contact
dermatitis developed on facial skin of 2.3% of workers using m-
deet lotion. Hyperemia and pronounced edema of fingers, dryness
and superficial cracks, tenderness in region of the fingers and
periodic numbness followed by the sensation of pain in the
fingers were common observations.
2.2.4 Observations of volunteers - In 1966, three preparations of deet
were tested in 85 men aged 19 to 27 years for adverse dermal
effects. Deet (40%) in alcohol was applied to hands, forearms,
face and neck at a daily dose of 4 to 6 ml for three to four
weeks. Effects included seborrhea (three cases), contact
dermatitis (one case), acne-like eruptions (one case), and
conjunctivitis (one case).
A group of 232 human volunteers' clothing was sprayed once every
three to five days for one to one and one half months with a deet
formulation including deet and Neopynamin or Sumithrin. No side
effects were seen on the skin.
Five human volunteers were tested with a 50% solution of deet.
One ml was applied to the face and 2 ml were applied to each arm
daily for five days. Tingling and mild desquamation occurred
around the nose. No systemic effects were observed. Desquamation
cleared after two days.
2.2.5 Observations of the general population - No published information
available. Bystander exposure is not likely to occur when
recommended application procedures are used. However, extra care
should be taken to avoid unintentional exposure of young children
and other sensitive individuals through mouth or skin contact
with liberally treated persons or objects (e.g. clothing,
bedding, toys, etc.).
2.2.6 Reported Mishaps - The majority of adult mishaps reported between
1961-1981 produced only mild syptoms of irritation. Most
individuals remained asymptomatic. Contact urticaria has been
reported in several cases in the general population.
Ten soldiers experienced bullous eruptions in the antecubital
fossae, 18 to 24 hours after application, prior to sleep, of a
50% m-deet repellent formulation to their skin. Observations
included burning sensation, erythema, blisters, ulceration and
Mishaps in which deet may have been concerned, produced severe
toxic encephalopathy occurred in female children; two of nine
poisonings were fatal. An 18 month old girl was hospitalized
following ingestion of a small amount of 10% deet formulation.
Recovery was slow, after six weeks of treatment the patient was
discharged to a second hospital for further convalescence. No
further details about her recovery are available.
A five year old girl, sprayed nightly for three months with a
formulation (10% deet) died 24 days after admission to hospital
for symptoms of toxic encephalopathy. At autopsy, edema of the
brain and congestion of the meninges were observed.
A three and one half year old girl was admitted to hospital with
symptoms of toxic encephalopathy after cumulative exposure to
approximately 180 mg of deet (15%) over a two week period.
Improvement followed vigorous medical treatiaent, including
anticonvulsant therapy. The patient was discharged after three
days in hospital.
A six year old girl died seven days after admission to hospital
presenting toxic encephalopathy following repeated exposures to a
15% deet formulation. This patient was also a presumed
heterozygote for ornithine carbamoyl transferase deficiency.
2.3 TOXICITY TO NON-MAMMALIAN SPECIES
2.3.1 Fish - LC50 (24 and 48 hr. exposure)
Gambusia affinis (Mosquito fish) 235 mg/l in stagnant water. The
fish appeared to become tranquilized in one to three minutes
exhibiting no response to external stimulus. Surviving fish, if
placed in fresh water, fully recover.
2.3.2 Birds - Deet had teratogenic and embryotoxic effects in white
leghorn chicken embryos when 1.27 micromoles of deet were applied
to the chorio-allantoic membrane at various times during the
second incubation day. Forty-one percent of embryos survived and
of these thirty-three percent exhibited gross malformations.
Cardiovascular, musculoskeletal and CNS defects were common.
2.3.3 Other species - No information.
3.0 FOR REGULATORY AUTHORITIES - RECOMMENDATIONS ON REGULATION OF
3.1 RECOMMENDED RESTRICTIONS ON AVAILABILITY - (For definitions of
categories, see Introduction). All liquid formulation above 10%,
and solid formulations above 40%, category 4. All other
formulations, category 5.
3.2 TRANSPORT AND STORAGE
Formulations in category 4 - Should be transported and stored in
clearly labelled, rigid and leakproof containers, secure from
access by children and other unauthorized persons. No food or
drink should be transported or stored in the same compartment.
Formulations in category 5 - Should be transported and stored in
clearly labelled leakproof containers out of reach of children,
away from food and drink.
Formulations in category 4 - Skin protection (see 4.1.3) should be
used by all persons handling the concentrate for prolonged or
repeated time periods. Adequate washing facilities should be
available at all times during the handling and should be close to
the site of handling. Eating, drinking and smoking should be
prohibited during handling and before washing of hands and face.
Formulations in category 5 - No facilities other than those needed
for the handling of any other chemical are required.
3.4 DISPOSAL AND/OR DECONTAMINATION OF CONTAINER
Containers may be decontaminated prior to disposal.
Decontaminated containers should not be used for storage of food
or drink. If not decontaminated, large empty containers should be
crushed and buried below topsoil. Care must be taken to avoid
subsequent contamination of water resources.
3.5 SELECTION, TRAINING AND MEDICAL SUPERVISION OF WORKERS
Formulations in category 4 - Pre-employment medical examination of
workers is desirable. Workers suffering from active hepatic or
renal disease or dermatitis should be excluded from contact.
Special account should be taken of workers' mental ability to
comprehend and follow instructions. Training of workers in
techniques to avoid contact is advisable.
Formulations in category 5 - No pre-employment medical examination
for workers is necessary. Warning to workers to minimize skin
contact is essential.
3.6 ADDITIONAL REGULATIONS RECOMMENDED IF DISTRIBUTED BY AIRCRAFT -
Formulations in category 4 - Minimum cautionary statement
Deet is a substituted toluamide of low mammalian toxicity and
should not be used by people under medical advice not to work with
such compounds. Avoid all eye contact, mouth contact, excessive
skin contact, or inhalation of aerosol mist. Wash splashes from
skin and eyes immediately. Wash hands before eating or smoking
after handling the pesticide.
Do not contaminate food and animal feedstuffs, food preparation
surfaces or utensils.
Store pesticide in the original container, tightly closed and in a
safe place away from children. Dispose of empty container
safely. Do not contaminate ponds, waterways, ditches or ground
water with either the chemical directly or the used container.
Avoid prolonged use on children and do not apply to areas of deep
skin folds. If signs of poisoning occur after overexposure, take
the patient to a physician.
Formulations in category 5 - minimum cautionary statement -
This formulation contains deet. Avoid all eye, mouth and
excessive skin contact, or inhalation of the spray mist. Wash
hands after use. Store in the original container in a safe place
away from children and pets. Avoid prolonged use on children and
do not apply to areas of deep skin folds. In addition, for
aerosol preparations do not apply directly to face as a spray.
Keep container away from heat (including sun). Do not puncture or
incinerate aerosol cans even when empty. Dispose of all empty
containers safely. Do not contaminate food, food utensils or food
3.8 RESIDUES IN FOOD - Not applicable.
4.0 PREVENTION OF POISONING IN MAN AND EMERGENCY AID
4.1 PRECAUTIONS IN USE
4.1.1 General - Deet is a substituted toluamide insect repellent of
moderate mammalian toxicity.
4.1.2 Manufacture and formulation - T.L.V.: No information. Closed
systems and forced ventilation may be required to reduce as much
as possible the exposure of workers to the chemical.
4.1.3 Mixers - When opening the container and when mixing, care should
be taken to avoid contact with the skin, mouth and eyes. If
necessary, a facial visor and gloves should be worn. Splashes
should be washed immediately from the skin or eyes with large
quantities of water. Before eating, drinking or smoking, hands
and exposed skin should be washed. If contaminated, clothing
should be washed at the end of a working day.
4.1.4 Other associated workers - All persons exposed to the concentrate
should observe the precautions described above in 4.1.3 under
"Mixers and applicators".
4.1.5 Other populations likely to be affected - With recommended usage
the general population should not be exposed to hazardous amounts
of deet. Caution should be exercised when children are treated
for prolonged periods.
4.2 ENTRY OF PERSONS INTO TREATED AREAS - Not applicable.
4.3 DECONTAMINATION OF SPILLAGE AND CONTAINERS - Residues in large
concentrate containers should be emptied in diluted form into a
shallow pit taking care to avoid contamination of groundwaters.
The empty containers may be decontaminated by rinsing two or three
times with water and scrubbing the sides. An additional rinse
should be carried out with a 5% sodium hydroxide solution which
should remain in the container overnight. Impermeable gauntlets
should be worn during the work and soakage pit should be provided
for the rinsings. Decontaminated containers should not be used
for storage of food and drink. Spillage of deet and its
formulations should be removed by washing with 5% sodium hydroxide
solution and then rinsing with large quantities of water.
4.4 EMERGENCY AID
4.4.1 Early symptoms of poisoning - Symptoms of early systemic
poisoning may include respiratory difficulty, confusion, abnormal
reflexes and convulsions; ataxia and coma may also occur. Skin
contact may result in itchiness, a burning sensation, red patches
and blisters on exposed skin surfaces.
4.4.2 Treatment before a person is seen by a physician, if these
symptoms appear following exposure - For skin contact, the person
should remove contaminated clothing, wash contaminated skin with
soap and water and flush with large quantities of water.
Vomiting should not be induced following ingestion, inhalation of
the solvent must be avoided.
5.0 FOR MEDICAL AND LABORATORY PERSONNEL
5.1 MEDICAL DIAGNOSIS AND TREATMENT IN CASE OF POISONING
5.1.1 General information - Deet is a substituted toluamide insect
repellent of slight mammalian toxicity which may be absorbed from
the gastrointestinal tract, through the intact skin, and by
5.1.2 Symptoms and signs - Symptoms of acute systemic poisoning typical
of toxic encephalopathy include respiratory difficulty, shaking
spells stimulated by noise or pain, abnormal reflexes, confusion
and loss of sense of balance, followed by ataxia and convulsions;
coma may also occur. Skin contact may result in hypersteatosis
or acute dermatitis, followed in some cases by ulceration in body
creases and scarring.
5.1.3 Laboratory - No published information.
5.1.4 Treatment - Treatment is symptomatic. If a potentially lethal
dose has been ingested, unless the patient is vomiting, rapid
gastric lavage should be performed. For skin contact resulting
in toxicity, the skin should be washed with soap and water. If
the compound has entered the eyes, they should be washed with
isotonic saline or large quantities of water.
5.1.5 Prognosis - If the acute toxic effect is survived and adequate
respiratory support was given, the chances of full recovery are
5.1.6 References to previously reported cases
1. Gryboski, J., Weinstein, D., Ordway, N. K.
N. Engl. J. Med., 264:289, 1961
2. Heick, H. M. C., Shipman, R. T., Norman, M. G., James, W.
J. Pedidtr. 97(3), 471-473, 1980
3. Konovalov, G. A., Ramanov.,
Anesteziol Reanimatol, 2, 54-5, 1980.
4. Maibach, H. I., Johnson, H. L. Arch. Dermatol. 111,
5. PIMS (1980) Summary of Reported Pesticide Incidents
Involving Deet. Pesticide Incident Monitoring System
Report No. 365. US EPA 1980.
6. Reuveni, H., Yaqupsky, P. Arch. Dermatol., 118 (8)
7. Zadikoff, C. M. J. Pediatr. 95(1) 140-142, 1979.
5.2 SURVEILLANCE TESTS
Urinary levels of deet and/or metabolites can be used to determine
the degree of exposure.
5.3 LABORATORY METHODS
5.3.1 Detection and assay of compound -
Wu, A., Pearson, M. L., Shekoski, D. L., Soto, R. J., Stewart, R.
D., J. High Resolute Chromatogr. Chromatog. Commun. 2(9)
5.3.2 Other tests in case of poisoning - No published information.
DEET (PIM 170)