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    IPCS INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY
    Health and Safety Guide No. 9

    ISOBUTANOL
    HEALTH AND SAFETY GUIDE






    UNITED NATIONS ENVIRONMENT PROGRAMME

    INTERNATIONAL LABOUR ORGANISATION

    WORLD HEALTH ORGANIZATION




    WORLD HEALTH ORGANIZATION, GENEVA 1987

    This is a companion volume to Environmental Health Criteria 65:
    Butanols - Four Isomers: 1-Butanol, 2-Butanol,  tert-Butanol,
    Isobutanol

    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

    ISBN 92 4 154665 4
    ISSN 0259-7268

    The World Health Organization welcomes requests for permission to
    reproduce or translate its publications, in part or in full. 
    Applications and enquiries should be addressed to the Office of
    Publications, World Health Organization, Geneva, Switzerland, which
    will be glad to provide the latest information on any changes made to
    the text, plans for new editions, and reprints and translations
    already available.

    (c) World Health Organization 1987

    Publications of the World Health Organization enjoy copyright
    protection in accordance with the provisions of Protocol 2 of the
    Universal Copyright Convention.  All rights reserved.

    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

    IPCS

    HEALTH AND SAFETY GUIDE FOR ISOBUTANOL

    INTRODUCTION

    HOW TO USE THE GUIDE

    1. PRODUCT IDENTITY AND USES

         1.1. Identity
         1.2. Physical and chemical properties
         1.3. Uses

    2. SUMMARY AND EVALUATION

         2.1. Exposure to isobutanol
         2.2. Uptake, metabolism, and excretion
         2.3. Effects on organisms in the environment
         2.4. Effects on animals
         2.5. Effects on human beings

    3. CONCLUSIONS AND RECOMMENDATIONS

    4. HEALTH HAZARDS FOR MAN, PREVENTION AND PROTECTION, EMERGENCY
         ACTION

         4.1. Main hazards for man, prevention and protection, first aid
         4.2. Advice to physicians
         4.3. Health surveillance advice
         4.4. Explosion and fire hazards
               4.4.1. Explosion hazards
               4.4.2. Fire hazards
               4.4.3. Fire-extinguishing agents
         4.5. Storage
         4.6. Transport
         4.7. Spillage and disposal
               4.7.1. Spillage
                       4.7.1.1    Small spillage
                       4.7.1.2    Large spillage
               4.7.2. Disposal

    5. INTERNATIONAL CHEMICAL SAFETY CARD

    6. HAZARDS FOR THE ENVIRONMENT AND THEIR PREVENTION

    7. CURRENT REGULATIONS, GUIDELINES, AND STANDARDS

         7.1. Exposure limit values
         7.2. Specific restrictions
         7.3. Labelling, packaging, and transport
    

    INTRODUCTION

    The International Programme on Chemical Safety is responsible for the
    publication of a series of Environmental Health Criteria documents,
    each of which assesses the existing information on the relationship
    between exposure to a specific chemical, mixture of chemicals, or
    combination of chemicals and physical and biological agents, and man's
    health and the integrity of the environment. The documents provide
    guidelines for setting exposure limits consistent with the protection
    of human health and the environment.

    To facilitate the application of these guidelines in national chemical
    safety programmes, "Health and Safety Guides" are being prepared,
    highlighting the information contained in the documents for those who
    need to know the health and environmental issues involved, but not the
    scientific details. The Guides include advice on preventive and
    protective measures and emergency action.

    Review and revision of the information in this Health and Safety Guide
    will take place in due course, and the eventual aim is to use
    standardized terminology. We should be grateful if you would help by
    telling us of any difficulties encountered in using the information in
    this guide.

    Comments please, addressed to:

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

    HOW TO USE THE GUIDE

    All people in the work-place environment should be given the relevant
    written information in this book, supplemented by a clear, personal
    explanation to ensure that they are fully aware of the dangers and the
    current courses of protective and emergency action.

    The International Chemical Safety Card should be displayed as directed
    and its contents clearly explained to all working personnel. Medical
    staff should be fully conversant with the medical information to
    ensure they can act rapidly and efficiently in an emergency. Posters
    should be used to give impact to basic safety measures.

                                  * * *

    Further copies of the Health and Safety Guide and, for those requiring
    more detailed scientific information, the relevant Environmental
    Health Criteria publication, are available to order.

    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:        C4H10O

    Chemical structure:      CH3
                              \
                               CH - CH2OH
                              /
                             CH3
    Primary constituent:     isobutanol

    Common synonyms:         isobutyl alcohol, isopropylcarbinol,
                             2-methyl-l-propanol, 2-methylpropyl
                             alcohol

    CAS registry number:     78-83-1

    1.2  Physical and Chemical Properties

    Some physical and chemical properties of isobutanol are given in the
    Sample International Chemical Safety Card.

    1.3  Uses

    The major use of isobutanol is in the manufacture of isobutyl acetate
    for use in the lacquer industry. It is also used as a flavouring agent
    in butter, cola, fruit, liquor, rum, and whisky. Further applications
    include use as a solvent in paint and varnish removers and in the
    manufacture of isobutyl esters, which serve as solvents, plasticizers,
    flavourings, and perfumes. Average maximum levels at which it is used
    in the USA range between 7 and 30 mg/kg.

    Natural isobutanol is produced by the fermentation of carbohydrates.
    It is found in brandy, cider, gin, coffee, cherries, raspberries,
    blackberries, grapes, apples, hop oil, bread, and Cheddar cheese. It
    can also result from decay in municipal waste plants.

    2.  SUMMARY AND EVALUATION

    2.1  Exposure to Isobutanol

    Levels of exposure of the general population to isobutanol through
    food and beverages are not available, and occupational exposure levels
    are inadequate.

    2.2  Uptake, Metabolism, and Excretion

    In animals, isobutanol is absorbed through the skin, lungs, and
    gastrointestinal tract. It is metabolized by alcohol dehydrogenase to
    isobutyric acid via the aldehyde and may enter the tricarboxylic acid
    cycle. Small amounts of isobutanol are excreted unchanged (<0.5% of
    the dose) or as the glucuronide (< 5% of the dose) in the urine. In
    rabbits, metabolites found in the urine included acetaldehyde, acetic
    acid, isobutylaldehyde, and isovaleric acid.

    2.3  Effects on Organisms in the Environment

    Few quantitative data relating to levels in the general environment
    are available, but, because isobutanol is readily biodegradable,
    substantial concentrations are only likely to occur locally in the
    case of major spillages. It does not bioaccumulate.

    At background concentrations likely to occur in the environment,
    isobutanol is not directly toxic for fish, amphibia, crustacea, or
    algae. Protozoa will be tolerant to levels of isobutanol likely to be
    found in the environment.

    Isobutanol should be managed in the environment as a slightly toxic
    compound. It poses an indirect hazard for the aquatic environment,
    because it is readily biodegradable, which may lead to oxygen
    depletion.

    2.4  Effects on Animals

    Oral LD50 values (2.5 - 3.1 g/kg body weight) and inhalation LC50
    values (19.2 g/m3) for the rat classify isobutanol as slightly toxic
    according to the scale of Hodge & Sterner. Acute toxic effects are
    alcoholic intoxication and narcosis. Isobutanol is severely irritating
    for the eyes and moderately irritating for the skin. A group of rats
    given a 1 mol/litre solution of isobutanol as their sole drinking
    liquid for 4 months did not show any adverse effects on the liver;
    another group given a 2 mol/litre solution as their sole drinking
    liquid for 2 months showed a reduction in fat, glycogen, RNA content,
    and overall size of the cells in the liver. Continuous inhalation
    exposure of rats to a concentration of 3 mg/m3 for 4 months resulted

    in depression of leg withdrawal response to electrical stimulation,
    and minor changes in formed elements of the blood and in serum
    enzymes. The estimated no-observed-adverse-effect level was
    0.1 mg/m3.

    In a life-time carcinogenicity study, groups of rats received
    isobutanol subcutaneously (0.05 ml/kg body weight, twice a week) or
    orally (0.2 mg/kg body weight, twice a week). The animals exhibited
    toxic liver damage ranging from steatosis to cirrhosis. The total
    numbers of animals showing malignant rumours were 3 in the oral group,
    8 in the subcutaneous group, and 0 in the control group. The majority
    of treated animals also showed hyperplasia of blood-forming tissues.

    The Task Group could not determine whether isobutanol was a
    genetically active compound because of a lack of mutagenicity studies.
    The findings in the carcinogenicity study are a cause for concern.
    Because of methodological inadequacies and the manner of reporting the
    data, it could not be determined whether isobutanol should be regarded
    as an animal carcinogen. Therefore, it is not possible to extrapolate
    from this study to possible long-term effects in man.

    From the animal studies available, it is not possible to determine a
    no-observed-adverse-effect level for long-term exposure. Adequate data
    are not available to assess the mutagenicity or teratogenicity of
    isobutanol or its effects on reproduction.

    2.5  Effects on Human Beings

    Exposure of the general population to isobutanol through food and
    beverages is unlikely to lead to acute toxic effects. The only
    reported observations in man relate to the production of vertigo under
    conditions of severe and prolonged exposure to vapour mixtures of
    isobutanol and 1-butanol. It was not possible from this study to
    attribute the vertigo to a single cause.

    3.  CONCLUSIONS AND RECOMMENDATIONS

    1.   On the basis of available data, the Task Group considered it
         unlikely that isobutanol would pose a serious acute health risk
         for the general population, under normal exposure conditions.
         However, the Task Group was unable to make an assessment of the
         long-term health risks of isobutanol for the general population.
         It was concluded that the results of the carcinogenicity study
         need verification by a bioassay of modem standards.

    2.   The Task Group considered that the data available were inadequate
         to establish guidelines for setting occupational exposure limits.
         In line with good manufacturing practice, exposure to isobutanol
         should be minimized.

    3.   The ecotoxicological data available indicate that the impact of
         background concentrations of isobutanol on the aquatic
         environment can be expected to be minimal.

    4.   The Task Group noted that animal data were inadequate to
         determine a no-observed-adverse-effect level. Relevant studies
         should be conducted so that this can be achieved.

    5.   The Task Group considered that adequate studies should be
         conducted to assess the mutagenicity and carcinogenicity of
         isobutanol.

    6.   Epidemiological studies, including precise exposure data, would
         enable a better assessment of the occupational hazards of
         isobutanol to be made.

    7.   Additional information on environmental pathways (notably
         emission and leaching) and residues are desirable.

    From:  Environmental Health Criteria 65: Butanols - Four Isomers:
           1-Butanol, 2-Butanol,  tert-Butanol, Isobutanol

    4.  HEALTH HAZARDS FOR MAN, PREVENTION AND PROTECTION, EMERGENCY
        ACTION

    4.1  Main Hazards for Man, Prevention and Protection, First Aid

    Liquid isobutanol is moderately irritating to the skin and severely
    irritating to the eyes. It is irritating to the mucous membranes of
    the respiratory tract. At high concentrations, its vapour can cause
    narcosis. It has been shown to be hepatoxic in both human beings and
    animals and is a questionable carcinogen.

    The human health hazards associated with certain types of exposure to
    isobutanol, together with preventive and protective measures and first
    aid recommendations are listed in the following table.

    GOLDEN RULES

     1.  Do not smoke, drink, or eat in the work-place.

     2.  In case of overexposure, the victim should leave, or be removed
     from, the contaminated area to fresh air as rapidly as possible.

     3.  Remove contaminated clothing and shoes and wash with plenty of
     water and soap.

     4.  Flush affected eye(s) with water for at least 15 minutes.

    4.2  Advice to Physicians

    Treat by observation and supportive measures as indicated by the
    patient's condition.

    4.3  Health Surveillance Advice

    In view of its hepatotoxicity and its irritation potential, regular
    medical surveillance may be advisable at the discretion of a medical
    adviser after taking into account the likely extent of exposure.

    4.4  Explosion and Fire Hazards

    4.4.1  Explosion hazards

    Explosive vapour-air mixtures are formed at temperatures exceeding
    27C.

    4.4.2  Fire hazards

    Isobutanol is flammable.


                                                                                                                                           
    ROUTE                HEALTH HAZARDS                         PREVENTION AND PROTECTION          FIRST AID
                                                                                                                                       

    SINGLE EXPOSURE

    SKIN                 Moderately irritating                  Minimize exposure,                 Remove contaminated clothing;
                                                                wear protective clothing           rinse skin with water; if skin
                                                                                                   irritation persists, seek medical
                                                                                                   attention
                                                                                                                                       

    EYES                 Potentially moderately                 Minimize exposure,                 Flush eyes immediately with
                         irritating                             wear goggles or face shield        water for at least 15 minutes;
                                                                                                   seek medical attention
                                                                                                                                       

    INHALATION           Irritant; high vapour                  Minimize exposure,                 Remove patient to fresh air;
                         concentrations may cause               use adequate ventilation           if breathing has stopped, apply
                         narcosis                               or suitable respiratory            artificial respiration; seek medical
                                                                protection                         attention immediately
                                                                                                                                       

    INGESTION            Unlikely occupational hazard;          Apply normal hygienic              Do not induce vomiting; seek
                         it may be absorbed and cause           practices                          medical attention immediately
                         systemic effects such as alcohol
                         poisoning and hepatoxicity
                                                                                                                                       

    (cont'd)
                                                                                                                                       
    REPEATED EXPOSURE

    INHALATION           As for single exposure                 Minimize exposure,
                                                                apply normal hygienic practices

    INGESTION            Long-term consumption                  Apply normal hygienic practices;
                         (present in most alcoholic             moderation
                         beverages) may result in liver
                         damage
                                                                                                                                       
    
    4.4.3  Fire-extinguishing agents

    Dry chemical powder extinguishers are recommended. These are
    particularly useful when fires involve "live" electrical equipment,
    because the powder is non-conducting.

    For a small fire, use carbon dioxide, dry chemical powder, alcohol-
    resistant foam, sand, earth, or water spray. Do not use water in a
    jet. For a large fire, use alcohol-resistant foam, or water fog.

    4.5  Storage

    Store drums away from sources of heat and out of direct sunlight.

    4.6  Transport

    Treat as for flammable liquids; otherwise, no special measures
    indicated.

    4.7  Spillage and Disposal

    4.7.1  Spillage

    Extinguish naked flames. Do not smoke. Avoid sparks. Avoid contact
    with skin, eyes, and clothing. Wear gloves, goggles or face shield,
    and boots. Avoid breathing the vapour.

    4.7.1.1  Small spillage

    Absorb the spilt liquid with sand, earth, sawdust, or other suitable
    absorbant material. Shovel up and remove all material to a safe area
    for subsequent disposal by burning or burying. Flush the contaminated
    area with plenty of water.

    4.7.1.2  Large spillage

    Prevent spilt liquid from spreading by the use of sand or earth. If
    possible, transfer the liquid to a salvage tank. Otherwise, treat as
    for a small spillage. Inform the local authorities (particularly the
    fire service) at once, if the spilt liquid enters the surface drains,
    since a potential explosive hazard will be created.

    4.7.2  Disposal

    Incineration is the recommended method. Wastes should be sprayed into
    the furnace. Incineration is more efficient if the wastes are mixed
    with a more flammable liquid.

    5.  INTERNATIONAL CHEMICAL SAFETY CARD

     This card should be easily available to all health workers concerned
     with, and users of, isobutanol. It should be displayed at, or near,
     entrances to areas where there is potential exposure to isobutanol,
     and on processing equipment and containers.

     The card should be translated into the appropriate language(s). All
     persons potentially exposed to the chemical should also have the
     instructions on the chemical safety card clearly explained.


        ISOBUTANOL
    (2-methyl-1-propanol, isopropylcarbinol, isobutyl alcohol) [(CH3)2CHCH2OH]
                                                                                                                                              
    PHYSICAL PROPERTIES                                                                  OTHER CHARACTERISTICS
                                                                                                                                              

    Boiling point (C)                              108                                  Colourless liquid with characteristic odour; reacts
    Melting point (C)                              -108                                 with strong oxidants and alkali metals to form
    Flash point (C)                                27                                   combustible gas (hydrogen); attacks many plastics
    Autoignition temperature (C)                   430                                  substance may be absorbed into the body by inhalation
    Relative density (water = 1)                    0.8
    Relative vapour density                         2.6
    (air = 1)
    Vapour pressure in mbar (20C)                  12
    Solubility in water                             95
    (g/litre at 20C)
    Explosive limits (vol. % in air)                1.2-10.9
    Relative molecular mass                         74.1
                                                                                                                                              
    HAZARDS/SYMPTOMS                                PREVENTION                           FIRST AID
                                                                                                                                              

    INHALATION: Sore throat, coughing,              Minimize exposure,                   Fresh air; rest in half upright position;
    shortness of breath, dullness, headache         use ventilation, local exhaust       seek medical attention, if necessary
                                                    or breathing protection

    SKIN: May be absorbed; redness                  Minimize exposure,                   Remove contaminated clothing; rinse skin
                                                    wear protective gloves               with plenty of water or shower

    EYES: Redness, pain, blurred vision             Minimize exposure,                   First rinse with plenty of water; then seek
                                                    wear safety goggles                  medical attention

    INGESTION: Abdominal pain, vomiting,                                                 Rinse mouth; give plenty of water to drink;
    dullness                                                                             seek medical attention or transport to hospital

    GENERAL: Alcoholic beverages may
    enhance the toxic effects
                                                                                                                                              

    (cont'd)
                                                                                                                                              
    SPILLAGE                                        STORAGE                              FIRE AND EXPLOSION
                                                                                                                                              

    Collect leaking liquid in sealable              Fireproof                            Flammable; above 27C, explosive vapour-air mixtures
    containers; absorb spilt liquid                                                      may be formed; no open flames, no sparks, and no
    in sand or inert absorbent and                                                       smoking; above 27C, use closed systems, ventilation,
    remove to safe place                                                                 explosion-proof electrical equipment; in case of fire,
                                                                                         keep drums cool by spraying with water; extinguish
                                                                                         fire with powder, AFFF, foam, halons, or carbon
                                                                                         dioxide
                                                                                                                                              
    WASTE DISPOSAL
                                                                                                                                              

                                                    National Occupational Exposure       UN: 1212
                                                    Limit:

                                                    National Poison Control Centre:

    FIGURE 1
                                                                                                                                              

    Adapted from:  Handling Chemicals Safely (1980) Published by the Dutch Association of Safety Experts, the Dutch Chemical Industry
    Association, and the Dutch Safety Institute, The Hague.
    
    6.  HAZARDS FOR THE ENVIRONMENT AND THEIR PREVENTION

    Isobutanol should be managed in the environment as a compound that is,
    at most, slightly toxic, but that poses an indirect hazard for the
    aquatic environment, because of ready biodegradation, which may lead
    to oxygen depletion. Thus, in the case of spillage in surface water,
    consider dilution or (artificial) re aeration.

    Minimize contamination of water. Avoid gross contamination of soil.
    Spilled material should be contained and removed as far as possible.
    Final traces can be dispersed with water.

    Disposal should be acceptable within the requirements of operative
    legislation; if necessary, consult local authorities.

    7.  REGIONS, GUIDELINES, AND STANDARDS

    The information given in this paragraph has been extracted from the
    International Register of Potentially Toxic Chemicals (IRPTC) legal
    file.

    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. A full reference to the
    original national document from which the information was extracted
    can be obtained from the IRPTC.a

    When no effective date appears in the IRPTC legal file, the year of
    the reference from which the data are taken is shown, indicated by
    (r).

    7.1  Exposure Limit Values

    For some exposure limit values, see the following table.

    7.2  Specific Restrictions

    Isobutanol can be used in the USA as a component of adhesives in
    articles intended for use in packaging, transporting, or holding of
    food.

    7.3  Labelling, Packaging, and Transport

    Isobutanol is classified as a flammable liquid (Hazard Class 3) by the
    United Nations Committee of Experts on the Transport of Dangerous
    Goods, as "a toxic waste" in the USA, and as a flammable liquid by the
    International Maritime Organization (Hazard Class 3.2). The following
    symbol should be used:

    Background: red     FIGURE 2

                 

    a  International Register of Potentially Toxic Chemicals, Palais des
       Nations, 1211 Geneva 10, Switzerland (Telephone No. 988400-985850).

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

    FIGURE 3

    The label must read: flammable - harmful by inhalation; keep away from
    sources of ignition - no smoking.

    The European Community legislation on labelling of solvant
    preparations classifies isobutanol in class  II d for the purpose of
    determining the label for preparations containing isobutanol and other
    active ingredients (1980).


        SOME EXPOSURE LIMIT VALUES
                                                                                                                                    
    MEDIUM    SPECIFICATION    COUNTRY/                         EXPOSURE LIMIT DESCRIPTIONa                 VALUE         EFFECTIVE
                               ORGANIZATION                                                                                 DATE
                                                                                                                                    

    AIR       Occupational     Argentina                        Maximum permissible concentration (MPC)                     1979
                                                                - Time-weighted average                     150 mg/m3
                                                                - Short-term exposure level (STEL)          225 mg/m3
                               Australia                        Threshold limit value (TLV)                                 1983 (r)
                                                                - Time-weighted average                     300 mg/m3
                               Belgium                          Threshold limit value (TLV)                 150 mg/m3
                               Finland                          Maximum permissible concentration (MPC)                     1982 (r)
                                                                - Time-weighted average                     300 mg/m3
                               Germany, Federal Republic of     Maximum allowable concentration (MAC)                       1985 (r)
                                                                - 8-h time-weighted average                 300 mg/m3
                                                                - Short-term exposure limit (STEL)          600 mg/m3
                                                                  (30 min, 4 x per shift)
                                                                  (average value)
                               Italy                            Threshold limit value (TLV)                 150-225 mg/m3
                               Netherlands                      Maximum limit                                               1985 (r)
                                                                - Time-weighted average                     150 mg/m3
                               Romania                          Maximum permissible concentration (MPC)                     1975 (r)
                                                                - Time-weighted average                     200 mg/m3
                                                                - Ceiling value                             300 mg/m3
                               Sweden                           Maximum tolerable concentration (MTC)                       1984 (r)
                                                                - One-day time-weighted average             700 mg/m3
                                                                - Short-term exposure limit (STEL)          1000 mg/m3
                                                                  (15-min time-weighted average)
                               Switzerland                      Maximum work-site concentration (MAK)                       1984 (r)
                                                                - Time-weighted average                     150 mg/m3
                               United Kingdom                   Recommended limit                                           1985 (r)
                                                                - 8-h time-weighted average                 150 mg/m3
                                                                - Short-term exposure limit (STEL)          225 mg/m3
                                                                  (10-min time-weighted average)
                                                                                                                                    

    (cont'd)
                                                                                                                                    
    MEDIUM    SPECIFICATION    COUNTRY/                         EXPOSURE LIMIT DESCRIPTIONa                 VALUE         EFFECTIVE
                               ORGANIZATION                                                                                 DATE
                                                                                                                                    

                               USA (ACGIH)b                     Threshold limit value (TLV)                                 1984 (r)
                                                                - Time-weighted average                     150 mg/m3
                                                                - Short-term exposure limit (STEL)          225 mg/m3
                               USA (OSHA)                       Permissible exposure limits (PEL)                           1981 (r)
                                                                - Time-weighted average                     300 mg/m3
                               USSR                             Maximum allowable concentration (MAC)                       1980 (r)
                                                                - Ceiling value for vapour                  10 mg/m3
                               Yugoslavia                       Maximum allowable concentration (MAC)                       1971 (r)
                                                                - Time-weighted average                     200 mg/m3

    AIR       Ambient          USSR                             Maximum allowable concentration (MAC)                       1984
                                                                - One time per day                          0.1 mg/m3
                                                                - Average per day                           0.1 mg/m3

    FOOD      Plant            USA                              Exempted from tolerance requirements                        1981 (r)
                                                                in plant products when used according
                                                                to good agricultural practice as inert
                                                                ingredient of pesticides for some
                                                                specific use

    WATER     Surface          USSR                             Maximum allowable concentration (MAC)       0.15 mg/litre   1983
                                                                                                                                    

    a  Unless otherwise defined, time-weighted average is over one working day (usually 8 h).
    b  Value recommended by the American Conference of Government Industrial Hygienists.
        


    See Also:
       Toxicological Abbreviations
       Isobutanol (ICSC)
       Isobutanol (SIDS)