IPCS INCHEM Home

    IPCS INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY
    Health and Safety Guide No. 50

    CAPTAN
    HEALTH AND SAFETY GUIDE






    UNITED NATIONS ENVIRONMENT PROGRAMME

    INTERNATIONAL LABOUR ORGANISATION

    WORLD HEALTH ORGANIZATION




    WORLD HEALTH ORGANIZATION, GENEVA 1990

    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

    Captan : health and safety guide.

    (Health and safety guide ; no. 50)

    1. Captan - standards  I. Series

    ISBN 92 4 151050 1          (NLM Classification: WA 240)
    ISSN 0259-7268

    (c) World Health Organization 1990

    Publications of the World Health Organization enjoy copyright
    protection in accordance with the provisions of Protocol 2 of the
    Universal Copyright Convention.  For rights of reproduction or
    translation of WHO publications, in part or  in toto, application
    should be made to the Office of Publications, World Health
    Organization, Geneva, Switzerland.  The World Health Organization
    welcomes such applications.

    The designations employed and the presentation of the material in this
    publication do not imply the expression of any opinion whatsoever on
    the part of the Secretariat of the World Health Organization
    concerning the legal status of any country, territory, city or area or
    of its authorities, or concerning the delimitation of its frontiers or
    boundaries.

    The mention of specific companies or of certain manufacturers'
    products does not imply that they are endorsed or recommended by the
    World Health Organization in preference to others of a similar nature
    that are not mentioned.  Errors and omissions excepted, the names of
    proprietary products are distinguished by initial capital letters.

    CONTENTS

    INTRODUCTION

    1. PRODUCT IDENTITY AND USES
         1.1. Identity
         1.2. Physical and chemical properties
         1.3. Analytical methods
         1.4. Production and uses

    2. SUMMARY AND EVALUATION
         2.1. Human exposure to captan
         2.2. Uptake, metabolism, and excretion
         2.3. Effects on animals
         2.4. Effects on human beings
         2.5. Effects on the environment

    3. CONCLUSIONS AND RECOMMENDATIONS

    4. HUMAN HEALTH HAZARDS, PREVENTION AND PROTECTION, EMERGENCY ACTION
         4.1. Main human health hazards, prevention and protection,
              first aid
              4.1.1. Prevention and protection
              4.1.2. First aid
         4.2. Advice to physicians
         4.3. Explosion and fire hazards
         4.4. Storage and transport
         4.5. Spillage and disposal

    5. HAZARDS FOR THE ENVIRONMENT AND THEIR PREVENTION

    6. CURRENT REGULATIONS, GUIDELINES, AND STANDARDS
         6.1. Exposure limit values
         6.2. Specific restrictions
         6.3. Transport and labelling
    

    INTRODUCTION

    This Health and Safety Guide is not based on an existing Environmental
    Health Criteria document, but on critical national reviews.  The
    hazard evaluation in the Health and Safety Guide was made on the basis
    of carefully selected studies, after scrutiny of the original
    publications.

    In order to assist the peer-review process of the present Health and
    Safety Guide, a background companion document was prepared by the IPCS
    and can be obtained from the Manager on request;  the IPCS does not
    intend that the background document should be published. 

    The first three sections of this Health and Safety Guide present
    essential technical information and the hazard evaluation.  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 sources.

    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.

    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 Manager
    International Programme on Chemical Safety
    Division of Environmental Health
    World Health Organization
    1211 Geneva 27
    Switzerland

    THE INFORMATION IN THIS GUIDE SHOULD BE CONSIDERED AS A STARTING POINT
    TO A COMPREHENSIVE HEALTH AND SAFETY PROGRAMME

    1.  PRODUCT IDENTITY AND USES

    1.1  Identity

    Chemical formula:             C9H8Cl3NO2S

    Chemical structure:

    CHEMICAL STRUCTURE 1

    Relative molecular mass:      300.57

    Common trade names:           Aacaptan; Agrosol S; Agrox 2-WAY and
                                  3-WAY; Amercide; Bangton; Bean Seed
                                  Protectant; Captab; Captaf; Captaf 85W;
                                  Capteneet 26,538;  Captane;
                                  Captan-Streptomycin 7.5-0.1 Potato Seed
                                  Piece Protectant; Captan 50W; Captex;
                                  ENT 26,538; Esso Fungicide 406; Flit
                                  406; Fungus Ban Type II; Glyodex 3722;
                                  Granox PFM; Gustafson Captan 30-DD;
                                  Hexacap; Isotox Seed Treater "D" and
                                  "F"; Kaptan; Malipur; Merpan;
                                  Micro-Check 12; Neracid; NA 9099;
                                  NCI-C00077; Orthocide; Orthocide 7.5;
                                  Orthocide 50; Orthocide 406; Osocide;
                                  SR406; Stauffer CAPTAN; Vancide 89;
                                  Vancide 89RE; Vancide P-75; Vangard K;
                                  Vanguard K; Vanicide; Vondcaptan

    CAS chemical name:            1H-isoindole-1,3(2H)-dione,3a,4,7,7a-
                                  tetra-hydro-2-[(trichloromethyl)-thio]-

    Synonyms:                     4-cyclohexene-1,2-dicarboximide,
                                   N-(trichloromethyl) thio-;
                                  1H-isoindole-1,3(2H)-dione, 3a,4,7,7a-
                                  tetrahydro-2-((trichloromethyl)-thio)-;
                                  3a,4,7,7a-tetrahydro- N-(trichloro-
                                  methanesulphenyl)phthalimide;
                                  1,2,3,6-tetrahydro- N-(trichloro-
                                  methylthio)phthalimide; 
                                   N-(trichlormethylthio)-phthalimide;
                                   N-trichloromethylmercapto-4-
                                  cyclohexene-1,2-dicarboximide;
                                   N-(trichloromethylmercapto)-delta
                                  (sup4)-tetrahydrophthalimide; 
                                   N-trichloromethylthio-cyclohex-4-ene-
                                  1,2-dicarboximide;
                                   N-trichloromethylthio-cis-delta(sup4)-
                                  cyclohexene-1,2-dicarboximide;
                                   N-((trichloromethyl)thio)-4-
                                  cyclohexene-1,2-dicarboximide; 
                                  trichloromethyl-thio-1,2,5,6-tetra-
                                  hydrophthalamide; 
                                   N-((trichloromethyl)-thio)
                                  tetrahydrophthalimide;
                                   N-trichloromethylthio-3a,4,7,7a-tetra-
                                  hydrophthalimide

    CAS registry number:          133-06-2

    RTECS registry number:        GW5075000

    Technical captan is usually 90-95% pure.  Tetrahydrophthalimide
    (4-cyclohexene-1,2-dicarboximide) and sodium chloride are the main
    impurities.

    1.2  Physical and Chemical Properties

    Pure captan is an odourless white crystalline solid.  The technical
    product is an amorphous powder that is colourless to beige with a
    pungent odour.  Since captan decomposes slowly when heated to its
    melting point, a melting point range of 158-170 C has been reported
    for the technical product.  At 25C, the vapour pressure of the pure
    compound is less than 0.133 mPa.  At 25C, it is practically insoluble
    in water (3.3 mg/litre), and soluble in acetone (21 g/litre),
    chloroform (70 g/litre), cyclohexanone (23 g/litre), isopropanol
    (1.7 g/litre), and xylene (20 g/litre).  It is slightly soluble in
    petroleum oils.

    In the dry state, captan is stable at room temperature.  However, in
    aqueous solution, it is hydrolysed at a rate that is dependent on the
    pH.  In alkaline solution, the breakdown is rapid.

    1.3  Analytical Methods

    Capillary gas-liquid chromatography with electron-capture detection is
    a multi-residue method suitable for the routine determination of five
    fungicides including captan, folpet, captafol, vinclozolin, and
    iprodione.

    1.4  Production and Uses

    Captan was introduced in 1949 and world production in 1983 was
    estimated to be 13 000 tonnes.

    It is a broad spectrum fungicide used in the cultivation of both food
    and non-food crops, and also as an industrial fungicide.  It has no
    insecticidal or acaricidal activity.  Captan is applied as a
    preharvest treatment, particularly to the foliage of fruit and
    vegetable crops.  It is also used for seed treatment, as a pre-plant
    application to the soil, and for post-harvest application.  Other uses
    include as an agent for cotton-seed treatment and as a therapeutic
    agent against fungal infections of the skin.

    Captan is also incorporated into plastics, oil-based paints, textiles,
    paper, and cosmetics, and is used as a mould- and mildew-proofing
    agent in coatings intended for contact with certain types of foods.

    2.  SUMMARY AND EVALUATION

    2.1  Human Exposure to Captan

    The highest human exposure to captan is associated with its
    manufacture and its occupational use.  Because of the widespread use
    of captan, exposure of the general population through residues in food
    may also be significant.  However, the compound is extensively
    hydrolysed during thermal and other food processing.  Captan residues
    in fresh vegetables and fruit can be reduced by such treatments as
    washing, blanching, and peeling.  Outside the working environment,
    exposure through non-agricultural uses is minor.

    2.2  Uptake, Metabolism, and Excretion

    Captan may be absorbed by ingestion as well as by inhalation, and, to
    a very limited extent, by skin exposure.  After oral administration,
    captan is metabolized to tetrahydrophthalimide (THPI; 4-cyclo-hexene-
    1,2-dicarboximide) and the derivatives of the trichloromethylthio
    (TMS) side chain.  The latter compounds are reactive substances that
    are bound to glutathion and further metabolized.  Both captan and its
    metabolites accumulate in the tissues of animals, and are rapidly
    eliminated (> 90% within 24 h).  The metabolism of captan differs
    between the rat and the mouse in that a greater proportion of a high
    dose of captan reaches the small intestine of the mouse compared with
    the rat.

    2.3  Effects on Animals

    The toxicological properties of captan have, in general, been
    thoroughly investigated.  The acute oral toxicity of the compound is
    low.  Thus, the acute oral LD50 for the rat has been reported to be
    in the range of 9000-12 500 mg/kg body weight.  There are indications
    that ruminants are more sensitive to captan than some other mammalian
    species.  Furthermore, experimental animal studies have demonstrated
    that protein deprivation may increase oral toxicity.  The acute
    inhalation toxicity appears to be considerably higher than the oral
    toxicity.  Captan is irritating to the skin and to the mucous
    membranes of the respiratory tract, and also to the eye; it may cause
    eye damage.

    Long-term administration of high dietary levels of captan to mice
    resulted in the induction of benign and malignant tumours of the small
    intestine.  The situation regarding carcinogenicity in the rat is less
    clear; in one study on the rat, a slight increase in the incidence of
    kidney tumours was found.  However, the carcinogenic potential in
    rodents relative to other experimental carcinogens is low.  Captan,
    which is an alkylating agent, has demonstrated genotoxic properties in
    several  in vitro systems, but not  in vivo. Thus, though captan may
    be able to induce genotoxic events in somatic cells, the results
    obtained seem to indicate that the potential for causing heritable

    effects in mammals is extremely low.  There is also no evidence that
    captan constitutes a teratogenic hazard, though it may cause fetotoxic
    effects at doses toxic for the mother.

    2.4  Effects on Human Beings

    Captan has caused allergic dermatitis and eye irritation in man.  No
    other serious adverse health effects have been identified.

    2.5  Effects on the Environment

    Captan is not acutely toxic for birds but is highly toxic for fish; a
    96-h LC50 range of 0.03-0.7 mg/litre has been reported for various
    species.  Captan is moderately toxic for freshwater invertebrates,
    such as  Daphnia (48-h LC50 between 1 and 8 mg/litre).  Captan is
    not persistent, and its use is not considered to be a threat to
    terrestrial wildlife.  It is not toxic for bees.  The environmental
    impact of the pesticide is likely to be limited by its high rate of
    hydrolysis and the lack of any tendency to bioaccumulate.  The
    half-life in lake water is 7 h at 12 C and 1 h at 25 C.  However,
    because of its demonstrated high toxicity, exposure of aquatic
    organisms to captan through drift and/or run-off is a cause for
    concern.

    3.  CONCLUSIONS AND RECOMMENDATIONS

    At high exposure levels, captan has been shown to induce tumours in
    mice and it causes mutations in a number of in vitro systems. 
    Although the carcinogenic potential of captan is considered to be low,
    it is, nevertheless, recommended that this pesticide should be applied
    with caution, particularly where residues in food can result. 
    Occupational exposure should be kept to a minimum.

    Captan is highly toxic for both freshwater and marine fish and
    moderately to highly toxic for freshwater invertebrates.  Because of
    this high toxicity, it is recommended that adequate precautions should
    be taken to prevent contamination of surface and ground water.

    4.  HUMAN HEALTH HAZARDS, PREVENTION AND PROTECTION, EMERGENCY ACTION

    4.1  Main Human Health Hazards, Prevention and Protection, First Aid

    The acute oral toxicity of technical captan for human beings is low,
    but the compound may cause dermatitis and eye irritation.

    In view of the carcinogenicity induced in experimental animals with
    long-term dietary administration of captan, albeit observed only at
    high exposure levels, exposure of human beings should be kept at a
    minimum.

    4.1.1  Prevention and protection

    The following precautions should be observed during handling and use,
    in order to reduce the risk of accidental contamination:

    (a)  Avoid contact with skin and eyes.

    (b)  Do not smoke, drink, or eat in the work-place.  Wash hands and
    any exposed skin before eating, drinking, and smoking, and after work.

    (c)  Avoid raising a dust cloud when handling wettable powder
    formulations.

    (d)  Avoid breathing the dust from powder products.

    (e)  When unloading and handling containers, wear protective PVC or
    neoprene gloves.

    (f)  When handling leaking containers or when dealing with leaks and
    spills, wear overalls, PVC or neoprene gloves, boots, and eye/face
    protection.  If overalls become contaminated, change and wash them
    thoroughly before re-use.

    (g)  Store products in closed original containers, out of reach of
    children, and away from food, drink, and animal feed.

    4.1.2  First Aid

    Acute poisoning by captan is unlikely, unless large amounts are
    ingested.  In case of over-exposure, apply routine first-aid measures. 
    If the compound has been spilled on the skin, remove the patient
    immediately from the source of contamination, remove all contaminated
    clothing, and wash affected areas with soap and running water.  If the
    material is in the eyes, flush with clean water for at least 15
    minutes.  In case of ingestion of significant quantities, if the
    patient is conscious, give several glasses of water and do not induce
    vomiting.  In serious cases, medical attention should be sought.

    4.2  Advice to Physicians

    The acute oral toxicity of captan for human beings is low.  There is
    no specific antidote.  Treat symptomatically when required.  In cases
    of ingestion of large amounts, gastric lavage may be indicated.

    4.3  Explosion and Fire Hazards

    Captan is not flammable, but, on heating, may produce toxic fumes,
    such as sulfur dioxide, hydrochloric acid, and phosgene.

    Extinguish small fires with carbon dioxide, dry powder, or
    alcohol-resistant foam.  Water spray can be used for larger fires and
    for the cooling of unaffected stock, but avoid the accumulation of
    polluted run-off from the site.

    Beware:  Some liquid formulations may be highly flammable and require
    alcohol-resistant foam as an extinguishing agent.

    4.4  Storage and Transport

    All products should be stored in secure buildings, out of reach of
    children and animals, and local regulations should be complied with. 
    Containers should be sound and adequately labelled.

    4.5  Spillage and Disposal

    Avoid contact with solid or dust.  Keep spectators away from any
    leakage.  This pesticide is highly toxic for fish.  Prevent
    contamination of other goods or cargo, and nearby vegetation and
    waterways.

    Absorb spilled liquid products with earth or sand.  If available,
    sawdust, peat moss, or straw are also suitable absorbents; sweep up
    and place in separate container.  Empty any product remaining in
    damaged or leaking containers into a clean empty container, which
    should be suitably labelled.  Sweep up any spilled powder with damp
    sawdust, taking care not to raise a dust cloud (use vacuum cleaner). 
    Remove trapped material with suction hoses.  Place in separate
    container for subsequent disposal.  Use mechanical dredges or lifts to
    remove immobilized masses of pollutants and precipitates.

    Before disposal, captan can be concentrated by gravity separation
    followed by dual media filtration and activated carbon adsorption. 
    Alkaline treatment of captafol leads to the formation of much less
    toxic degradation products.  For the treatment of large spills, or for
    equipment decontamination, the use of an aqueous solution of
    commercial low-foaming, hard-water detergent in 5% trisodium
    phosphate, or 10-25% sodium hydroxide, is recommended.  During
    neutralization, hydrogen sulfide may be formed, if insufficient alkali
    is used.

    Do not deposit captan in a landfill.  It is not amenable to biological
    treatment at municipal sewage plants.

    5.  HAZARDS FOR THE ENVIRONMENT AND THEIR PREVENTION

    Captan is not persistent and small quantities of the compound are
    readily hydrolysed in soil and surface waters.  However, it is highly
    toxic for aquatic organisms.  Contamination of ponds, waterways, and
    ditches with captan should be avoided.  In case of spills, and for
    decontamination of equipment and containers, apply methods recommended
    in section 4.5.

    6.  CURRENT REGULATIONS, GUIDELINES, AND STANDARDS

    The information given in this section has been extracted from the
    International Register of Potentially Toxic Chemicals (IRPTC) legal
    file. A full reference to the original national document from which
    the information was extracted can be obtained from IRPTC.  When no
    effective date appears in the IRPTC legal file, the year of the
    reference from which the data are taken is indicated by (r).

    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 appropriate regulatory authorities
    before application.

    6.1  Exposure Limit Values

    The threshold limit value (TWA) recommended by the US ACGIH for captan
    is 5 mg/m3 in air.  This value is also enforced in some other
    countries, e.g., Argentina, Australia, Canada, the Netherlands, and
    the United Kingdom.

    On the basis of reproduction studies, a reference dose, RfD (ADI), of
    0.013 mg/kg per day for non-neoplastic effects has been established by
    the US Environmental Protection Agency.  The Joint FAO/WHO Meeting on
    Pesticide Residues has established an ADI of 0-0.1 mg/kg body weight. 
    Using the same data base, the EEC calculated the same ADI value at
    0.013 mg/kg per day.  Some tolerances for food and animal feed are
    given in the table on page 20.

    6.2  Specific Restrictions

    In the USA, captan constitutes a hazardous chemical under the Clean
    Water Act as well as under the Water Pollution Control Act, signifying
    that spills must be notified and a permit required for discharge.

    As of 1 January 1988, the use of captan as an ingredient in cosmetic
    products has been prohibited within the European Economic Community.

    In the USSR, the use of captan for the treatment of certain food
    commodities is prohibited.  Intentions to ban, or severely restrict,
    the uses of captan have been announced by control authorities in
    Canada, the Federal Republic of Germany, and the USA.

    6.3  Transport and Labelling

    Conveyance labelling should be as follows:

    FIGURE 1

     Supply and use labelling

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

    FIGURE 2

    The label must read:

    R20             Harmful by inhalation

    R36/37/38       Irritating to eyes, respiratory system and skin

    S2              Keep out of reach of children

    S13             Keep away from food, drink, and animal feeding stuffs

    S21             When using do not smoke

    S22             Do not breathe dust

    S24/25          Avoid contact with skin and eyes

    S36/37/39       Wear suitable protective clothing gloves and eye/face
                    protection 


        TOLERANCES AND MAXIMUM RESIDUE LIMITS FOR FOOD PRODUCTS

                                                                                                                                         

    Country             Food product                       Exposure limit description              Value             Effective
                                                                                                   (mg/kg)           date
                                                                                                                                         

    Brazil              Specified plant products           Acceptable limit                        10-40

    Canada              Raw agricultural products          Acceptable residue limit                5.0               valid 1986

    Czechoslovakia      Plant products                     Maximum residue limit                   10-20             October 1978

    EEC                 Plant, general products            Maximum residue limit                   0.1-3.0           1989

    Sweden              Fruits and vegetables              Maximum acceptable                      5.0-15.0          June 1985
                                                           concentration

    USA                 Raw agricultural products          Tolerance                               0.05-100          September 1983

                                                                                                                                         

    


    See Also:
       Toxicological Abbreviations
       Captan (ICSC)
       Captan (PIM 098)
       Captan (FAO/PL:1969/M/17/1)
       Captan (WHO Pesticide Residues Series 3)
       Captan (WHO Pesticide Residues Series 4)
       Captan (Pesticide residues in food: 1977 evaluations)
       Captan (Pesticide residues in food: 1978 evaluations)
       Captan (Pesticide residues in food: 1980 evaluations)
       Captan (Pesticide residues in food: 1982 evaluations)
       Captan (Pesticide residues in food: 1984 evaluations)
       Captan (Pesticide residues in food: 1984 evaluations)
       Captan (Pesticide residues in food: 1990 evaluations Toxicology)
       Captan (Pesticide residues in food: 1995 evaluations Part II Toxicological & Environmental)
       Captan (IARC Summary & Evaluation, Volume 30, 1983)