Health and Safety Guide No. 78






    This is a companion volume to Environmental Health Criteria
    153: Carbaryl

    Published by the World Health Organization for the International
    Programme on Chemical Safety (a collaborative programme of the
    United Nations Environment Programme, the International Labour
    Organisation, and the World Health Organization)

    This report contains the collective views of an international group
    of experts and does not necessarily represent the decisions or the
    stated policy of the United Nations Environment Programme, the
    International Labour Organisation, or the World Health Organization

    WHO Library Cataloguing in Publication Data

    Carbaryl : health and safety guide.

    (Health and safety guide ; no. 78)

    1.Carbaryl - standards 2.Carbaryl - toxicity 3.Environmental exposure
    4.Hazardous substances - standards   I.Series

    ISBN 92 4 151078 1          (NLM Classification: WA 240)
    ISSN 0259-7268

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         1.1. Identity
         1.2. Physical and chemical properties
         1.3. Analytical methods
         1.4. Production and uses

         2.1. Environmental transport, distribution, and
         2.2. Environmental levels and human exposure
         2.3. Kinetics and metabolism
         2.4. Effects on organisms in the environment
         2.5. Effects on experimental animals and  in vitro
              test systems
              2.5.1. Reproduction effects
              2.5.2. Mutagenicity
              2.5.3. Carcinogenicity
              2.5.4. Effects on different organs and systems
              2.5.5. Primary mechanism of toxicity
         2.6. Effects on human beings

         3.1. Conclusions
              3.1.1. General population
              3.1.2. Subpopulations at high risk
              3.1.3. Occupational exposure
              3.1.4. Environmental effects
         3.2. Recommendations

         4.1. Human health hazards, prevention and
              protection, first aid
              4.1.1. Advice to physicians
                Symptoms of poisoning
                edical treatment
              4.1.2. Health surveillance advice
         4.2. Explosion and fire hazards
         4.3. Storage
         4.4. Transport
         4.5. Spillage and disposal
              4.5.1. Spillage
              4.5.2. Disposal


         6.1. Previous evaluations by international bodies
         6.2. Exposure limit values
         6.3. Specific restrictions
         6.4. Labelling, packaging, and transport
         6.5. Waste disposal


    ANNEX. Treatment of carbamate poisoning in man


    The Environmental Health Criteria (EHC) monographs produced by the
    International Programme on Chemical Safety include an assessment of
    the effects on the environment and on human health of exposure to a
    chemical or combination of chemicals, or physical or biological
    agents. They also provide guidelines for setting exposure limits.

    The purpose of a Health and Safety Guide is to facilitate the
    application of these guidelines in national chemical safety
    programmes. The first three sections of a Health and Safety Guide
    highlight the relevant technical information in the corresponding
    EHC. Section 4 includes advice on preventive and protective measures
    and emergency action; health workers should be thoroughly familiar
    with the medical information to ensure that they can act efficiently
    in an emergency. The section on regulatory information has been
    extracted from the legal file of the International Register of
    Potentially Toxic Chemicals (IRPTC) and from other United Nations

    The target readership includes occupational health services, those
    in ministries, governmental agencies, industry, and trade unions who
    are involved in the safe use of chemicals and the avoidance of
    environmental health hazards, and those wanting more information on
    this topic. An attempt has been made to use only terms that will be
    familiar to the intended user. However, sections 1 and 2 inevitably
    contain some technical terms. A bibliography has been included for
    readers who require further background information.

    Revision of the information in this Guide will take place in due
    course, and the eventual aim is to use standardized terminology.
    Comments on any difficulties encountered in using the Guide would be
    very helpful and should be addressed to:

    The Director
    International Programme on Chemical Safety
    World Health Organization
    1211 Geneva 27


    1.1  Identity

    Common name:                  Carbaryl

    Chemical structure:


    Molecular formula:            C12H11NO2

    Common name:                  Carbaryl (BSI)

    CAS chemical name:            1-naphthalenyl methylcarbamate

    IUPAC chemical name:          1-naphthyl methylcarbamate

    Trade names:                  Arylat, Arylam, Atoxan, Bercema,
                                  Carbaryl, Carbamate, Carpolin,
                                  Carbotox, Denapon, Dicarbam, Hexavin,
                                  Monsur, Murrin, Panam, Pamex,
                                  Prosevor, Rayvon, Sevimol, Sevin,
                                  Viaxon, etc.

    CAS registry number:          63-25-2

    RTECS registry number:        FC5950000

    Relative molecular mass:      201

    Conversion factor:            1 mg/m3=8.22 ppm
                                  1 ppm=0.12 mg/m3 at 35 C

    1.2  Physical and chemical properties

    Carbaryl is an odourless, white, crystalline solid, with a low
    volatility. It is practically insoluble in water, but soluble in
    most organic solvents, stable to light and heat up to 70 C, and
    easily hydrolysed by alkaline materials. It is non-corrosive.

    The technical product is principally manufactured in the USA;
    however, small amounts are produced in other parts of the world.

    The technical product, manufactured in the USA, is produced to a
    minimum purity of 99% w/w carbaryl with a specified content of the
    impurity, 2-naphthyl carbamate isomer (sometimes known as
    beta-carbaryl), of <0.05% w/w.

    The Food and Agriculture Organization of the United Nations (FAO)
    specifies a minimum purity of 98% w/w carbaryl with a specified w/w
    content of the impurity, 2-naphthyl carbamate isomer, of <0.05%.

    Some physical properties of carbaryl are given in Table 1.

    Table 1. Physical properties


    Melting point (C)             142
    Boiling point (C)             decomposing
    Solubility in water (30 C)    40 mg/litre
    Specific density (20 C)       1.23
    Relative vapour density        -
    Vapour pressure                1.17 x 10-6-3.1 x 10-7 mmHg at
                                   24-25 C
    Flash point                    193 C
    Octanol/water partition
      coefficient (log Kow)        1.59-2.3
    Flammability (explosive)
      limits                       -
    Relative molecular mass        201

    1.3  Analytical methods

    Product analysis can be carried out using infrared spectroscopy.
    Residues can be determined by GLC and TLC. The Joint FAO/WHO Codex
    Alimentarius Commission has given recommendations for the methods of
    analysis to be used for the determination of carbaryl residues
    (FAO/WHO, 1986a).

    1.4  Production and uses

    Carbaryl is used as a broad spectrum contact and stomach insecticide
    with some systemic properties on crops, trees, and ornamentals. It
    is also used in public health and veterinary practice. In
    agriculture, the usual application rate is 0.25-2 kg/ha, but for
    tree fruit, up to 10 kg/ha.

    Formulations of carbaryl include dusts (1.75-50%), wettable powders
    (50-85%), oil- and water-based liquid suspensions (40-50%), granules
    (5 and 10%), and baits.


    2.1  Environmental transport, distribution, and transformation

    Under most conditions, carbaryl is not persistent in the
    environment. In water, the hydrolysis half-life is dependent on
    temperature, pH, and the initial concentration, and varies from
    several minutes to several weeks. The major degradation product is

    Accumulation of carbaryl, expressed as a bioconcentration factor in
    the aquatic environment, has been found to be in the range of 14-75
    for freshwater fish. Carbaryl is adsorbed more readily on soil with
    a high organic content than on sandy soils. At the usual application
    rates, under "good agricultural practice", dissipation is rapid,
    with a half-life of 8 days-1 month, under normal conditions.
    Carbaryl may occasionally be carried, by rainfall and soil
    cultivation, from the surface of the soil, into the subsoil (one
    metre from the surface).

    Carbaryl contaminates vegetation either during spraying or by
    migrating through contaminated soil into plants.

    The degradation of carbaryl in the environment is determined by the
    extent of the volatilization, photodecomposition, and chemical and
    microbial degradation that occur in the soil, water, and plants. The
    rate of decomposition is more rapid under hot climatic conditions.

    2.2  Environmental levels and human exposure

    Food represents the major source of carbaryl intake for the general
    population. Residues in total dietary samples are relatively low,
    ranging from trace amounts to 0.05 mg/kg. In the USA, the daily
    intake during the first years of carbaryl application was 0.15
    mg/day per person (in 7.4% of the composites) and decreased to 0.003
    mg/day per person in 1969 (in only 0.8% of the composites). During
    the carbaryl application period, it may be found occasionally in
    surface water and reservoirs.

    The general population can be exposed to carbaryl during pest
    control operations in the home and in recreation areas.

    Workers can be exposed to carbaryl during its manufacture,
    formulation, packing, transportation, storage, and during and after
    application. Concentrations in the working-air environment during
    production varied from <1 mg/m3 to 30 mg/m3. Significant dermal
    exposure of industrial and agricultural workers may occur, if
    protective measures are inadequate.

    2.3  Kinetics and metabolism

    Carbaryl is rapidly absorbed in the lungs and digestive tract. In
    human volunteers, dermal absorption of 45% of an applied dose in
    acetone occurred in 8 h. However,  in vitro dermal penetration data
    and toxicity data indicate that dermal absorption usually occurs at
    a much lower rate.

    The principal metabolic pathways of carbaryl are ring hydroxylation
    and hydrolysis. As a result, numerous metabolites are formed and
    subjected to conjugation, with the formation of water-soluble
    sulfates, glucuronides, and mercapturates, which are excreted in the
    urine. Hydrolysis results in the formation of 1-naphthol, carbon
    dioxide, and methylamine. Hydroxylation produces 4-hydroxycarbaryl,
    5-hydroxycarbaryl,  N-hydroxy-methylcarbaryl,
    5-6-dihydro-5-6-dihydroxycarbaryl, and 1,4-naphthalendiol. The
    principal metabolite in human beings is 1-naphthol.

    Under normal exposure conditions, accumulation of carbaryl in
    animals is unlikely. Carbaryl is excreted primarily via the urine,
    since its product of hydrolysis, 1-naphthol, is mainly detoxified to
    water-soluble conjugates. Enterohepatic cycling of carbaryl
    metabolites is also considerable, especially after oral

    The hydrolysis product,  N-naphthol carbamic acid, is spontaneously
    decomposed to methylamine and carbon dioxide. The methylamine moiety
    is later demethylated to carbon dioxide and formate, the latter
    being mainly excreted in the urine.

    Carbaryl metabolites are also present in a small percentage of the
    absorbed doses in saliva and milk.

    2.4  Effects on organisms in the environment

    LC50 values for crustacea vary from 5 to 9 g/litre (water fleas,
    mysid shrimps), 8 to 25 g/litre (scud), and 500 to 2500 g/litre
    (crayfish). Aquatic insects have a similar range of sensitivity.
    Plecoptera and Ephemeroptera (stoneflies and mayflies) are the most
    sensitive groups. Molluscs are less susceptible with EC50s in the
    range of a few mg/litre. For fish, most LC50 values are between 1-
    30 mg/litre. Salmonids are the most sensitive group.

    The acute toxicity of carbonyl for birds is low. The LD50 for
    waterfowl and game birds is >1000 mg/kg. The red-winged blackbird
    is the most susceptible bird tested (LD50=56 mg/kg). There was no
    evidence for field effects on birds in forest areas sprayed with 1.1
    kg carbaryl/ha.

    Carbaryl is very toxic for earthworms and honey bees, the oral
    LD50 for the latter being 0.18 g/bee (about 1-2 mg/kg).

    There are indications that carbaryl may temporarily influence the
    species composition of both terrestrial and aquatic ecosystems. For
    instance, one study showed that effects on certain terrestrial
    invertebrate communities may persist for at least 10 months
    following a single application.

    2.5  Effects on experimental animals and  in vitro test systems

    The acute toxicity, expressed as the LD50, varies considerably
    according to species, formulation, and vehicle. Estimates for the
    oral LD50 for rats range from 200 to 850 mg/kg. Cats are more
    sensitive, with an LD50 of 150 mg/kg. Pigs and monkeys are less
    sensitive, with an LD50 of >1000 mg/kg.

    The maximum achievable aerosol concentration of carbaryl of 792 mg
    a.i./m3, over a 4-h exposure, resulted in the death of 1 out of 5
    female rats. A single 4-h exposure to carbaryl aerosol, at a
    concentration of 20 mg/m3, decreased cholinesterase (ChE) activity
    in cats. However, this concentration did not produce any observable
    effects in rats.

    Carbaryl is a mild eye irritant and has little or no sensitizing
    potential. In long-term studies, the NOEL for rats was 10 mg/kg body
    weight (200 mg/kg diet), and that for dogs, 1.8 mg/kg body weight
    (100 mg/kg diet). The long-term inhalation NOEL for cats was 0.16
    mg/m3. The cumulative potential of carbaryl is low.

    2.5.1  Reproduction effects

    Carbaryl has been shown to affect mammalian reproduction and
    perinatal development adversely in a number of species. Effects on
    reproduction include impairment of fertility, decreased litter size,
    and reduced postnatal viability. Developmental toxicity is seen as
    increased  in  utero death, reduced fetal weight, and the
    occurrence of malformation. With the exception of a small number of
    studies, all adverse reproductive and developmental effects have
    been noted only at doses that cause overt maternal toxicity; in a
    number of cases, the maternal animal is more sensitive to carbaryl
    than the conceptus. The maternal toxic effects include lethality,
    decreased growth, and dystocia. Data indicate that the reproductive
    and developmental processes of mammals are not especially sensitive
    to carbaryl when compared to the susceptibility of the adult

    2.5.2  Mutagenicity

    Carbaryl has been evaluated for its potential mutagenicity in a
    number of  in vitro and  in vivo tests, including tests on
    bacterial, yeast, plant, insect, and mammalian systems, with a
    variety of end-points.

    The available evidence indicates that carbaryl does not have any
    DNA-damaging properties. There are no confirmed reports of the
    induction of mitotic recombination, gene conversion, and UDS in
    prokaryotes ( H. influenzae, B. subtilis) and eukaryotes ( S.
     cerevisiae, A. nidulans, cultured human lymphocytes, and rat
    hepatocytes)  in vitro.

    Tests for gene mutations in a large number of bacterial assays, with
    the exception of 2 cases, have given negative results. In several
    studies of gene mutations in mammalian cells  in vitro, carbaryl
    only produced one equivocal positive result in a cell culture study.
    However, the study had several shortcomings and the result has not
    been confirmed in any other comparable studies.

    Chromosomal damage with high dosages of carbaryl, has been reported
    in  in vitro studies on human, rat, and hamster cells and in
    plants. No such effects have been observed in mammalian tests  in
    vivo, even at doses as high as 1000 mg/kg.

    Carbaryl has been shown to induce disturbances in the spindle fibre
    mechanism in plant and mammalian cells  in vitro. The relevance of
    plant assays for extrapolation to humans is unclear.

    It can be concluded that the available data do not support the
    presumption that carbaryl poses a risk of inducing genetic changes
    in either somatic or germinal tissue of humans.

    The nitrosated product of carbaryl,  N-nitrosocarbaryl, is capable
    of inducing mitotic recombination and gene conversion in prokaryotes
    ( H.  influenzae, B. subtilis) and eukaryotes ( S. cerevisiae), in
    vitro, and gives positive results in  Escherichia coli spot tests.
    Furthermore, experimental results indicate that  N-nitrosocarbaryl
    binds to DNA, causing alkali-sensitive bonds and single-strand

    Nitrosocarbaryl has not been established as a clastogen  in vivo
    (bone marrow and germ cells), even at high toxic doses.

    2.5.3  Carcinogenicity

    Carbaryl has been studied for its carcinogenic potential in numerous
    studies on rats and mice. The results of most of these studies were
    negative, but the studies are old and do not meet contemporary
    standards. However, new studies meeting modern standards are in
    progress on mice and rats. The latest IARC evaluation (IARC, 1987)
    concluded that, as there are no data on cancer in humans, and
    evidence of carcinogenicity in experimental animals is inadequate,
    carbaryl could not be classified as to its carcinogenicity for
    humans (Group 3).

     N-nitrosocarbaryl has been shown to induce tumours locally in rats
    (either sarcoma at the site of injection or forestomach squamous
    cell carcinoma, when given by the oral route). Given the human
    chemistry of carbaryl, the risk of  N-nitrosocarbaryl
    carcinogenicity from carbaryl exposure can be judged as negligible.

    2.5.4  Effects on different organs and systems

    (a)  Nervous sysytem

    The effects of carbaryl on the nervous system are primarily related
    to cholinesterase inhibition and are usually transitory. The effect
    on the central nervous system was studied in rats and monkeys. Oral
    doses of 10-20 mg carbaryl/kg for 50 days have been reported to
    disrupt learning and performance in rats.

    In a small study on pigs, carbaryl (150 mg/kg body weight)
    administered in the diet for 72-82 days, was reported to produce a
    number of neuromuscular effects. Reversible leg weakness was noticed
    in chickens that were given high doses of carbaryl. No evidence of
    demyelination was observed in brain, sciatic nerve, or in spinal
    cord sections examined microscopically. Similar effects were not
    observed in long-term rodent studies.

    (b)  Immune system

    Carbaryl, when administered  in vivo at doses causing overt
    clinical signs, has been reported to produce a variety of effects on
    the immune system. Many of the effects described were detected at
    doses close to the LD50. Most studies on rabbits and mice, at
    doses permitting survival, have not produced significant effects on
    the immune system. Shortcomings of several of these studies were a
    lack of consistency and sometimes overt contradiction between
    results, which prevents the description of a defined immunotoxic

    (c)  Blood

    Carbaryl has been reported to affect coagulation, but there are
    conflicts in the direction of the effect. In glucose-6-phosphate
    dehydrogenase deficient sheep erythrocytes, carbaryl produces a
    dose-dependent increase in Met-Hb formation. Human serum albumin
    reacts  in vitro with the ester group of carbaryl. Carbaryl binds
    free blood amino acids.

    (d)  Liver metabolism

    Disturbances in the carbohydrate metabolism and protein synthesis
    and detoxification function of the liver in mammals have been
    reported. Carbaryl is a weak inducer of hepatic microsomal
    drug-metabolizing activity. It reduces phenobarbital sleeping time.

    The hepatic levels of cytochrome P-450 and b5 are increased.
    Changes in liver metabolism may account, in part, for the trifold
    increase of the carbaryl LD50 in carbaryl pretreated rats.

    (e)  Gonadotropic function

    Carbaryl has been reported to increase the gonadotropic function of
    the hypophysis in rats.

    2.5.5  Primary mechanism of toxicity

    Carbaryl is an inhibitor of cholinesterase activity. This effect was
    dose-related and quickly reversible. There was no aging of the
    carbamylated cholinesterase. All identified metabolites of carbaryl
    are appreciably less active as cholinesterase inhibitors than
    carbaryl itself.

    2.6  Effects on human beings

    Carbaryl is easily absorbed through inhalation and via the oral
    route, but less readily absorbed via the dermal route. Since the
    inhibition of cholinesterase (ChE) is the principal mechanism of
    carbaryl action, the clinical picture of intoxication is dominated
    by ChE inhibition symptoms, such as: increased bronchial secretion,
    excessive sweating, salivation, and lacrimation; pinpoint pupils,
    bronchoconstriction, abdominal cramps (vomiting and diarrhoea);
    bradycardia; fasciculation of fine muscles (in severe cases,
    diaphragm and respiratory muscles also involved); tachycardia;
    headache, dizziness, anxiety, mental confusion, convulsions, and
    coma; and depression of the respiratory centre. Signs of
    intoxication develop quickly after absorption and disappear rapidly
    after exposure ends.

    In controlled studies on human volunteers, single doses of less than
    2 mg/kg were well-tolerated. A single dose of 250 mg (2.8 mg/kg)
    produced moderate ChE inhibition symptoms (epigastric pain and
    sweating) within 20 min. Complete recovery occurred within 2 h of
    treatment with atropine sulfate.

    In cases of occupational overexposure to carbaryl, mild symptoms are
    observed long before a dangerous dose is absorbed, which is why
    severe cases of occupational intoxication with carbaryl are rare.
    During agricultural application, dermal exposure may play an
    important role. Local irritative effects are not usually observed;
    however, the appearance of a skin rash after accidental splashing
    with carbaryl formulations has been described.

    There are conflicting data about effects of carbaryl on sperm count
    and changes in sperm morphology in plant workers. No adverse effect
    on reproduction has been reported.

    The most sensitive biological indicator of carbaryl exposure is the
    appearance of 1-naphthol in the urine and the decrease of ChE
    activity in the blood. Levels of 1-naphthol in the urine can be used
    as a biological indicator, if there is no 1-naphthol in the working
    environment. During occupational exposure, 40% of the urine samples
    contained more than 10 mg total 1-naphthol/litre. In one case of
    acute intoxication, a level of 31 mg/litre was found in the urine.
    The hazard level is >10 mg 1-naphthol/litre and the symptomatic
    level, 30 mg/litre, in urine (WHO, 1978).

    Measurement of the ChE activity can be a very sensitive test for
    monitoring, provided that measurement is conducted soon after


    3.1  Conclusions

    The health hazard of carbaryl for human beings is judged to be low,
    because of its low vapour pressure, rapid degradation, the rapid
    spontaneous recovery of inhibited cholinesterase, and the fact that
    symptoms usually appear well before a dangerous dose has accumulated
    in the body. Good carcinogenicity studies, which meet modern
    standards, are not yet available.

    3.1.1  General population

    Residue levels of carbaryl in food and drinking-water, remaining
    after its normal use in agriculture, are far below the ADI (0.01
    mg/kg body weight per day), and not likely to produce health hazards
    in the general population.

    3.1.2  Subpopulations at high risk

    Use of carbaryl for public health purposes in the home or in
    recreation areas may create overexposure, if the rules for its
    application are neglected.

    3.1.3  Occupational exposure

    By enforcing reasonable work practices, including safety
    precautions, personal protection, and proper supervision,
    occupational exposure during the manufacture, formulation, and
    application of carbaryl will not create hazards. Undiluted
    concentrations must be handled with great care, because improper
    work practices may cause skin contamination. Work air concentrations
    should not exceed 5 mg/m3.

    3.1.4  Environmental effects

    Carbaryl is toxic for honey bees and earthworms and should not be
    applied to crops during flowering.

    With normal use, carbaryl should not cause environmental concern.
    Carbaryl is adsorbed on soil particles to a great extent and does
    not readily leach into groundwater. It is rapidly degraded in the
    environment and therefore is not persistent. Use of carbaryl should
    not result in harmful short-term effects on the ecosystem.

    3.2  Recommendations

    *    The handling and application of carbaryl should be accomplished
         with the care given to all pesticides. Instructions for proper
         usage, provided on the package containing the chemical, should
         be carefully followed.

    *    Manufacture, formulation, use, and disposal of carbaryl should
         be carefully managed to minimize contamination of the

    *    Regularly exposed workers should receive periodic health

    *    Application of carbaryl should be timed to avoid effects on
         non-target species.

    *    Carcinogenicity studies, which meet modern standards, should be


    4.1  Human health hazards, prevention and protection, first aid

    Carbaryl is a carbamate insecticide with anticholinesterase
    activity. It is moderately toxic and hazardous (the acute oral
    LD50 for the rat is approximately 300 mg/kg (WHO, 1990). It can be
    absorbed via the gastrointestinal tract and through inhalation, and,
    to a lesser extent, through the skin. Because of its rapid
    metabolism and excretion, it does not accumulate in tissues. It can
    be hazardous for human beings if handled incorrectly and carelessly.
    It is, therefore, essential that the correct precautions should be
    observed during handling and use.

    The human health hazards associated with certain types of exposure
    to carbaryl, together with preventive and protective measures and
    first aid and are listed in Table 2.

    4.1.1  Advice to physicians  Symptoms of poisoning

    Carbaryl is a short-acting anticholinesterase agent, with the
    important characteristic of rapid reversibility of enzyme
    inhibition. It inactivates cholinesterase, resulting in the
    accumulation of acetylcholine at synapses in the nervous system, at
    neuromuscular junctions of the skeletal and smooth muscles, and in
    secretory glands. Signs and symptoms of overexposure may include
    headache, tiredness, pinpoint pupils, blurred vision, lacrimation,
    excessive nasal discharge or salivation, sweating, dizziness,
    stomach pain, nausea, vomiting, diarrhoea, tremor, difficulties in
    breathing, cyanosis, convulsions,and unconsciousness. Symptoms
    appear immediately or within 12 h of exposure.

    For a more complete treatise on the mode of action and the effects
    of carbamate pesticides, especially their effects on the nervous
    system, refer to  EHC 64: Carbamate pesticides - a general
     introduction (WHO, 1986).  Medical treatment

    If more than 1 g carbaryl equivalent has been ingested (unless the
    patient is vomiting) rapid gastric lavage should be performed using
    5% sodium bicarbonate, if available. In case of skin contact, the
    skin should be washed with soap and water. Contaminated eyes should
    be washed with isotonic saline or water. Since the symptoms of
    poisoning with carbaryl disappear comparatively rapidly, atropine
    treatment is often not necessary by the time the patient reaches the
    place where the antidote is available. In case of accidental
    poisoning or of manifest symptoms, 2 mg of atropine (adult dose) may
    be given im, or even iv, and repeated if necessary. Care should be

    taken to avoid overdosage with atropine in the case of carbaryl
    poisoning, especially in children. Mechanical respiratory assistance
    with oxygen may be required in extreme cases, if the patient is
    unconscious or in respiratory distress.

    Oximes, such as pralidoxime, barbiturates, and central
    stimulants of all kinds are contraindicated.

    If the acute toxic effect is survived, the chances of complete
    recovery are very good.

    More information on the treatment of carbamate pesticide poisoning
    is given in the Annex to this Guide.

    4.1.2  Health surveillance advice

    Pre-exposure, and annual, general medical examinations should be
    carried out on workers exposed to carbaryl. In the pre-employment
    examinations, medical fitness for work with carbamates and a
    baseline cholinesterase level should be established.

    Overexposure to carbamates can be monitored by the measurement of
    erythrocyte- and whole blood-ChE activity, but, in the case of
    carbamates, return to normal values is generally rapid. Moreover,
    physiological variations in erythrocyte- and whole blood-ChE values
    occur in healthy persons.

    In exposed workers, the urinary excretion of 1-naphthol should be
    monitored; 1.5-4 mg/litre can be considered as acceptable. A hazard
    level is >10 mg/litre, and, at >30 mg/litre, toxic signs and
    symptoms can be expected.

    Table 2. Health hazards, prevention and protection, first aid


    GENERAL: Readily absorbed
    via skin, ingestion, and
    inhalation; may cause carbamate
    poisoning: excessive sweating, 
    headache, weakness, giddiness, 
    nausea, vomiting, stomach pains,
    blurred vision, slurred speech,
    tremors, and convulsions

    SKIN: Irritation; skin rash           Wear impervious clothing, gloves,      Remove contaminated clothing and shoes;
                                          face shields                           wash the skin with plenty of water and soap
                                                                                 (or mild detergent); get medical attention
                                                                                 attention immediately

    EYES: Irritation                      Wear face shield or safety goggles     Wash eyes immediately with clean water for at
                                                                                 least 15 min, lifting the lower and upper
                                                                                 lids occasionally; if irritation persists, get
                                                                                 medical attention immediately

    INHALATION: Irritation                Use proper exhaust ventilation         Move the exposed person to fresh air at once;
                                          and suitable respiratory protection    if breathing has stopped, perform artificial
                                                                                 respiration; keep the affected person warm and
                                                                                 at rest; get medical attention immediately

    INGESTION: May lead to severe         Do not eat, drink, or smoke when       Obtain medical attention immediately; in case
    poisoning                             working with the compound              of accidental or intentional ingestion, and if
                                                                                 the patient is still conscious, induce vomiting
                                                                                 immediately: if breathing has stopped, apply
                                                                                 artificial respiration

    4.2  Explosion and fire hazards

    Technical grade material will not burn, but formulations in organic
    solvents may be highly flammable. Use dry powder, carbon dioxide, or
    alcohol-resistant foam, sand, or earth for dealing with fires.
    If carbaryl is involved in a major fire or in a fire involving other
    products, advise the fire service that protective clothing and
    breathing apparatus should be worn, because toxic decomposition
    products, such as nitrogen oxides, methylamine, and carbon monoxide
    may be formed. Also, warn the authorities that carbaryl is toxic for
    fish, and that the use of water should be confined to the cooling of
    unaffected stock, thus avoiding the accumulation of polluted run-off
    from the site.

    4.3  Storage

    Formulations should be stored in locked buildings, preferably
    dedicated to insecticides. They should be kept in clearly labelled,
    leakproof containers.

    Keep formulations and dilutions out of reach of children and
    unauthorized persons. Do not store near foodstuffs or animal feed.

    4.4  Transport

    Comply with any local requirements regarding the movement of
    hazardous goods. Do not load with foodstuffs or animal feed. Before
    dispatch, check that containers are sound and labels undamaged.

    4.5  Spillage and disposal

    4.5.1  Spillage

    Avoid exposure, if possible, by the use of appropriate protective
    clothing and masks.

    Empty any product remaining in damaged or leaking containers into a
    clean, empty drum, and label.

    Absorb spillage with lime, damp sawdust, sand, or earth and dispose
    of safely (see below). If spillage is large, contain it by building
    a barrier of earth or sandbags.

    Decontaminate empty, damaged, or leaking containers with a 10%
    sodium carbonate solution added at the rate of at least 1 litre per
    20-litre drum. Puncture and crush containers to prevent reuse.

    4.5.2  Disposal

    Waste that contains carbaryl should be burned in a high-temperature
    incinerator with effluent gas scrubbing.

    Where no incinerator is available, contaminated absorbents or
    surplus products should be decomposed by hydrolysis at pH12 or
    above. Contact with a suitable hydrolysing agent is required to
    ensure the degradation of the active ingredient to a safe level. For
    emulsifiable material: 5% sodium hydroxide (caustic soda) solution
    or saturated (7-10%) sodium carbonate (washing soda) solution can be
    used. For non-emulsifiable material, use a 1:1 mixture (by volume)
    of either of the above solutions and a water/oil-soluble solvent,
    such as denatured alcohol, monoethylene glycol, hexylene glycol, or
    isopropanol. Cover the material with a hydrolysing agent and put
    aside for 24 h. Before disposal of the resultant waste, the material
    must be analysed to ensure that the active ingredient has been
    degraded to a safe level.

    Never pour untreated waste or surplus products into public sewers or
    where there is any danger of run-off or seepage into streams,
    watercourses, open waterways, ditches, fields with drainage systems,
    or the catchment areas of boreholes, wells, springs, or ponds.


    At worst, carbaryl has only limited persistence in the environment.
    In water, it is easily degraded under most conditions; the half-life
    ranges from a few minutes to several weeks. In soil, the half-life
    ranges from a few days to several weeks. Carbaryl is adsorbed on
    soil and leaching into water is not of great significance.

    There is no evidence of general phytotoxicity when used at
    recommended rates, but damage to apples, pears, and water-melons has
    been reported. Excessive application may retard the germination of

    Carbaryl is toxic for earthworms. It is hazardous for honey bees and
    it should not be applied to crops during flowering.

    Avoid spraying over bodies of water. Do not contaminate ponds,
    waterways, or ditches with the product or used containers, as
    carbaryl has some toxicity for some aquatic species.

    In case of spillage, use the methods advised in section 4.5.1.


    The information given in this section has been extracted from the
    International Register of Potentially Toxic Chemicals (IRPTC) legal
    file and other United Nations sources. A full reference to the
    original national document from which the information was extracted
    can be obtained from IRPTC.

    The reader should be aware that regulatory decisions about chemicals
    taken in a certain country can only be fully understood in the
    framework of the legislation of that country. Furthermore, the
    regulations and guidelines of all countries are subject to change
    and should always be verified with the appropriate regulatory
    authorities before application.

    6.1  Previous evaluations by international bodies

    The Joint FAO/WHO Meeting on Pesticide Residues (JMPR) evaluated
    carbaryl at its meetings in 1963, 1965, 1966, 1967, 1968, 1969,
    1970, 1971, 1973, 1975, 1976, 1977, 1979, and 1984. In 1973, an
    Acceptable Daily Intake (ADI) of 0-0.01 mg/kg body weight was
    established. In addition, Maximum Residue Limits (MRLs) have been
    set for specified crops (see Table 3).

    The International Agency for Research on Cancer (IARC), evaluated
    carbaryl in 1976 and concluded that the available data did not allow
    an evaluation of the carcinogenicity of carbaryl to be made.

    In the WHO recommended classification of pesticides by hazard,
    technical carbaryl is classified in Class II as moderately hazardous
    in normal use. WHO has issued a data sheet on carbaryl (No. 3).

    6.2  Exposure limit values

    Some exposure limit values are given in the Table 3.

    6.3  Specific restrictions

    Carbaryl is approved for use as a pesticide in many countries, in
    each of which, specific uses are defined, as well as limitations and

    Table 3. Exposure limit values


    Medium         Specification  Country/           Exposure limit descriptiona                Value                 Effective
                                  organization                                                                        date

    AIR            Workplace      Argentina          Maximum permissible concentration (MPC)                          1979
                                                     - time-weighted average (TWA)              5 mg/m3
                                                     - short-term exposure limit                10 mg/m3

                                  Bulgaria           Maximum permissible concentration (MPC)    1 mg/m3               1971

                                  Germany            Maximum work-site concentration (MAK)                            1986
                                                     - 8-h time-weighted averageb (TWA)         5 mg/m3

                                  Hungary            Maximum acceptable concentration (MAK)     1 mg/m3               1988

                                  United             Occupational exposure standard (OES)                             1989
                                    Kingdom          - 8-h time-weighted average (TWA)          5 mg/m3
                                                     - 10-min short-term exposure level (STEL)  10 mg/m3

                                  USA (OSHA)         Permissible exposure limit (PEL)                                 1989
                                                     - 8-h time-weighted average (TWA)          5 mg/m3

                                  USA (NIOSH)        Recommended exposure limit (REL)
                                                     - time-weighted average (TWA)              5 mg/m3               1976

                                  USA (ACGIH)        Threshold limit value (TLV)                                      1986
                                                     - 8-h time weighted average (TWA)          5 mg/m3

                                  USSR               Ceiling value (aerosol)                    1 mg/m3               1977

                                  WHO                Maximum permissible concentrationb         5 mg/m3               1982
                                                     (MPC) (tentative)


    Medium         Specification  Country/           Exposure limit descriptiona                Value                 Effective
                                  organization                                                                        date

    AIR            Ambient        USSR               Maximum allowable concentration                                  1977
                                                     - average per day                          0.01 mg/m3
                                                     - once per day                             0.02 mg/m3

    WATER          Surface        USSR               Maximum allowable concentration (MAC)      0.1 mg/litre          1983

                   Surface for    USSR               Maximum allowable concentration (MAC)      0.0005 mg/litre       1983

    SOIL                          USSR               Maximum allowable concentration (MAC)      0.05 mg/kg            1973

    FOOD           Intake         FAO/WHO            Acceptable daily intake (ADI)              0-0.01 mg/kg          1973
                                                                                                body weight

                   Residues       FAO/WHO            Maximum residue limit (MRL)
                                  (Codex             (in specified products):                   0.1-100 mg/kg         1986
                                  Alimentarius)      animal feedstuffs (green), alfalfa, bean
                                                     and pea vines, colver corn, forage
                                                     cowpea, foliage, grasses, peanut hay,
                                                     sorghum forage, soybean foliage,
                                                     sugarbeet tops                             100 mg/kg

                                                     bran                                       20 mg/kg

                                                     apricots, asparagus, blackberries,
                                                     boysenberries, cherries, kiwi fruit
                                                     leafy vegetables (except brassicas),
                                                     nectarines, nuts (whole), okra, olives
                                                     (fresh), peaches, plums, raspberries,
                                                     sorghum grain                              10 mg/kg


    Medium         Specification  Country/           Exposure limit descriptiona                Value                 Effective
                                  organization                                                                        date

                                                     blueberries, citrus fruit, cranberries
                                                     strawberries                               7 mg/kg

                                                     apples, aubergines, bananas, barley,
                                                     beans, brassicas, grapes, oats, pears,
                                                     peas (including pod), peppers, poultry
                                                     (skin), rice (in husks and hulled), 
                                                     rye, tomatoes, wheat                       5 mg/kg

                                                     cucurbits (including melons)               3 mg/kg

                                                     peanuts (whole), root crops (beets,
                                                     carrots, parsnips, radishes, rutabagas),
                                                     wholemeal flour                            2 mg/kg

                                                     cottonseed (whole), cowpeas, nuts (shelled),
                                                     olives (processed), soybeans, (dry),
                                                     sweetcorn (kernels)                        1 mg/kg

                                                     eggs (shell-free), poultry meat            0.5 mg/kg

                                                     meat of cattle, goats and sheep,           0.2 mg/kg
                                                     potatoes, sugarbeet, wheat flour (white)

                                                     milk and milk products                     0.1 mg/kg


    a TWA - time-weighted average over one working day (usually 8 h).
    b Skin absorption.
    6.4  Labelling, packaging, and transport

    The United Nations Committee of Experts on the Transport of
    Dangerous Goods classifies carbaryl in:

    -    Hazard Class 6.1: poisonous substances

    -    Packing Group III: a substance that has a relatively low risk
         of poisoning during transport (solid >30%; liquid >10%).

    The following label should be used:

    FIGURE 1

    The European Community legislation requires labelling as a dangerous
    substance using the symbol:

    FIGURE 2

    The label must read:

          Harmful by inhalation and if swallowed; irritating to
          respiratory system; keep out of reach of children; keep away
          from food, drink, and animal feeding stuffs.

    Pesticide preparations that contain carbaryl are classified in Class
    IIA, i.e., when solid: as harmful at concentrations >5%, and when
    liquid as toxic at concentrations >50% and as harmful at 2.5-50%.
    Member States should ensure that they cannot be placed on the market
    unless their packaging, fastenings, and labels comply with the
    requirements laid down.

    The FAO specifications for plant protection products containing
    carbaryl specify the composition and purity of the technical product
    and its formulations. They also advise on methods for checking this.

    6.5  Waste disposal

    In the USA, permits are required for the discharge of carbaryl from
    any point source into national waters. This requirement contains
    detailed instructions.


    CEC (1987)  Legislation on dangerous substances - Classification and
     labelling in the European Communities. Vol. 1 & 2. Commission of
    the European Communities, London, Graham & Trotman, Ltd.

    FAO (1985a)  Guidelines for the packaging and storage of pesticides.
    Rome, Food and Agriculture Organization of the United Nations.

    FAO (1985b)  Guidelines for the disposal of waste pesticides and
     pesticide containers on the farm. Rome, Food and Agriculture
    Organization of the United Nations.

    FAO (1985c)  Guidelines on good labelling practice for pesticides.
    Rome, Food and Agriculture Organization of the United Nations.

    FAO (1986)  International code of conduct on the distribution and
    use  of pesticides. Rome, Food and Agriculture Organization of the
    United Nations.

    FAO (1988)  Carbaryl, FAO specifications for plant protection
     products. Rome, Food and Agriculture Organization of the United

    FAO/WHO (1964-present)  Evaluation of some pesticide residues in
     food, Rome, Food and Agriculture Organization of the United

    FAO/WHO (1986a)  Guide to Codex recommendations concerning pesticide
     residues. Part 8.  Recommendations for methods of analysis of
     pesticide residues. 3rd ed. Rome, Codex Alimentarius Committee on
    Pesticide Residues.

    FAO/WHO (1986b)  Codex Alimentarius Commission Codex maximum limits
     for pesticide residues. Joint FAO/WHO Food Standards Programme,
    FAO, CAC Vol. XIII, ed. 2. Rome, Food and Agriculture Organization
    of the United Nations.

    GIFAP (1982)  Guidelines for the safe handling of pesticides during
     their formulation, packing, storage, and transport. Brussels,
    Groupement International des Associations Nationales des Fabricants
    de Produits Agrochimiques.

    GIFAP (1983)  Guidelines for the safe and effective use of
     pesticides. Brussels, Groupement International des Associations
    Nationales des Fabricants de Produits Agrochimiques.

    GIFAP (1984)  Guidelines for emergency measures in cases of
    pesticide  poisoning. Brussels, Groupement International des
    Associations Nationales des Fabricants de Produits Agrochimiques.

    GIFAP (1987)  Guidelines for the safe transport of pesticides.
    Brussels, Groupement International des Associations Nationales des
    Fabricants de Produits Agrochimiques.

    HAYES, W.J., Jr. & LAWS, E.R., Jr. (1991)  Handbook of pesticide
     toxicology. 3 vol. New York, Academic Press.

    IARC (1972-present)  IARC Monographs on the evaluation of
    carcinogenic  risk of chemicals to man. Lyon, International Agency
    for Research on Cancer.

    IRPTC (1985)  IRPTC file on treatment and disposal methods for waste
     chemicals. Geneva, International Register for Potentially Toxic
    Chemicals, United Nations Environment Programme.

    IRPTC (1987)  IRPTC legal file 1986. Geneva, International Register
    for Potentially Toxic Chemicals, United Nations Environment

    ILO (1991) Safety and health in the use of agro-chemicals - a guide.
    Geneva, International Labour Office.

    PLESTINA, R. (1984)  Prevention, diagnosis, and treatment of
     insecticide poisoning. Geneva, World Health Organization
    (unpublished document VBC/84.889).

    SAX, N.I. (1984)  Dangerous properties of industrial materials. New
    York, Van Nostrand Reinhold Company, Inc.

    UNEP/IEO (1990)  Storage of hazardous materials: a technical guide
    for  safe warehousing of hazardous materials. Paris, United Nations
    Environment Programme - Industry and Environment Office, 80 pp.

    UNITED NATIONS (1986)  Recommendations on the transport of dangerous
     goods. 4th ed. New York, United Nations.

    UNITED NATIONS (1991)  Consolidated list of products whose
    consumption  and/or sale have been banned, withdrawn, severely
    restricted or not  approved by governments. 4th ed. New York,
    United Nations.

    US NIOSH/OSHA (1981)  Occupational health guidelines for chemical
     hazards. 3 vol., Washington DC, US Department of Health and Human
    Services, US Department of Labor (Publication No. DHHS (NIOSH)

    WHO (1986)  EHC 64: Carbamate pesticides - a general introduction.
    Geneva, World Health Organization, 137 pp.

    WHO (1992)  The WHO recommended classification of pesticides by
    hazard  and guidelines to classification 1992-93. Geneva, World
    Health Organization (Unpublished document WHO/PCS/92.14).

    WHO (1993)  EHC No. 153: Carbaryl. Geneva, World Health

    WHO/FAO (1978)  Data sheets on pesticides: No. 3: Carbaryl.
    (Unpublished WHO document VBC/DS/75.3, rev. 1).

    WORTHING, C.R. & HANCE, R.J. (1991)  The pesticide manual. 9th ed.
    Old Woking, Surrey, British Crop Protection Council, Unwin Brothers


    Treatment of carbamate pesticide poisoning in man

    All cases of carbamate poisoning should be dealt with as an
    emergency and the patient should be hospitalized as quickly as

    Extensive descriptions of the treatment of poisoning by
    anticholinesterase agents are given in several major references
    (Kagan, 1977; Taylor, 1980; Plestina, 1984).

    The treatment is based on:

    (a) minimizing the absorption;

    (b) general supportive treatment; and

    (c) specific pharmacological treatment.

    Minimizing the absorption

    When dermal exposure occurs, decontamination procedures include
    removal of contaminated clothes and washing of the skin with
    alkaline soap or with a sodium bicarbonate solution. Particular care
    should be taken in the cleaning of the skin area where venupuncture
    is performed. Blood might be contaminated with carbamates and
    therefore inaccurate measures of ChE inhibition might result.
    Extensive eye irrigation with water or saline should also be
    performed. In the case of ingestion, vomiting can be induced, if the
    patient is conscious, by the administration of ipecacuanha syrup
    (10-30 ml) followed by 200 ml of water. However, this treatment is
    contraindicated in the case of pesticides dissolved in hydrocarbon
    solvents. Gastric lavage (with the addition of bicarbonate solution
    or activated charcoal) can also be performed, particularly in
    unconscious patients, taking care to prevent aspiration of fluids
    into the lungs (i.e., only after a tracheal tube has been put in

    The volumes of the fluids introduced in the stomach should be
    recorded and samples of gastric lavage frozen and stored for
    subsequent chemical analysis. If the formulation of the pesticide
    involved is available, it should also be stored for further analysis
    (i.e., detection of toxicologically relevant impurities). A purge to
    remove the ingested compound can be administered.


    a From: EHC 64:  Carbamate pesticides - a general introduction.
      Geneva, World Health Organization, 1968.

    General supportive treatment

    Artificial respiration (via a tracheal tube) should be started at
    the first sign of respiratory failure and maintained for as long as

    Cautious administration of fluids is advised, as well as general
    supportive and symptomatic pharmacological treatment and absolute

    Special pharmacological treatment


    Atropine should be given, beginning with 2 mg iv repeated at 15-
    30-min intervals. The dose and the frequency of atropine treatment
    vary from case to case, but should maintain the patient fully
    atropinized (dilated pupils, dry mouth, skin flushing, etc.).

     Oxime reactivators

    There is no rational basis for using these drugs. Furthermore, some
    unconfirmed reports suggest an increased toxicity of carbamates when
    oximes have been administered.


    Diazepam should be included in the therapy of all but the mildest
    cases. Besides relieving anxiety it appears to counteract some
    aspects of CNS-derived symptoms that are not affected by atropine.
    Doses of 10 mg sc or iv are appropriate and may be repeated as

    Other centrally acting drugs and drugs that may depress respiration
    are not usually recommended in the absence of artificial respiration

    References to Annex

    KAGAN, J.S. (1977)  The toxicity of organophosphorus pesticides.
    Moscow (in Russian).

    PLESTINA, R. (1984)  Prevention, diagnosis, and treatment of
     insecticide poisoning. Geneva, World Health Organization.
    (Unpublished document VBC/84.889).

    TAYLOR, P. (1980) Anticholinesterase agents. In: Goodman, L.S. &
    Gilman, A., ed.  The pharmacological basis of therapeutics. 6th ed.
    New York, Macmillan Publishing Co., pp. 100-119.

    See Also:
       Toxicological Abbreviations
       Carbaryl (EHC 153, 1994)
       Carbaryl (ICSC)
       Carbaryl (PIM 147)
       Carbaryl (FAO Meeting Report PL/1965/10/1)
       Carbaryl (FAO/PL:CP/15)
       Carbaryl (FAO/PL:1967/M/11/1)
       Carbaryl (FAO/PL:1968/M/9/1)
       Carbaryl (FAO/PL:1969/M/17/1)
       Carbaryl (AGP:1970/M/12/1)
       Carbaryl (WHO Pesticide Residues Series 3)
       Carbaryl (WHO Pesticide Residues Series 5)
       Carbaryl (Pesticide residues in food: 1976 evaluations)
       Carbaryl (Pesticide residues in food: 1977 evaluations)
       Carbaryl (Pesticide residues in food: 1979 evaluations)
       Carbaryl (Pesticide residues in food: 1984 evaluations)
       Carbaryl (Pesticide residues in food: 1996 evaluations Part II Toxicological)
       Carbaryl (JMPR Evaluations 2001 Part II Toxicological)
       Carbaryl (IARC Summary & Evaluation, Volume 12, 1976)