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    IPCS INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY
    Health and Safety Guide No. 36

    VINYLIDENE CHLORIDE
    HEALTH AND SAFETY GUIDE






    UNITED NATIONS ENVIRONMENT PROGRAMME

    INTERNATIONAL LABOUR ORGANISATION

    WORLD HEALTH ORGANIZATION




    WORLD HEALTH ORGANIZATION, GENEVA 1989

    This is a companion volume to Environmental Health Criteria 100:
    Vinylidene Chloride

    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)

    ISBN 92 4 154357 4
    ISSN 0259-7268

    World Health Organization 1989

    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.

    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.

    CONTENTS

    INTRODUCTION

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

    2. SUMMARY AND EVALUATION
         2.1. Exposure to vinylidene chloride
         2.2. Uptake, metabolism, and excretion
         2.3. Effects on animals
         2.4. Effects on human beings

    3. CONCLUSIONS AND RECOMMENDATIONS

    4. HUMAN HEALTH HAZARDS, PREVENTION AND PROTECTION, EMERGENCY ACTION
         4.1. Human health hazards, prevention and protection, first aid
         4.2. Advice to physicians
              4.2.1. Acute poisoning by inhalation
              4.2.2. Oral poisoning
              4.2.3. Skin exposure
              4.2.4. Eye exposure
         4.3. Health surveillance advice
         4.4. Explosion and fire hazards
              4.4.1. Explosion hazards
              4.4.2. Fire hazards
         4.5. Prevention and disposal
              4.5.1. Use
              4.5.2. Storage
              4.5.3. Transport
              4.5.4. Disposal
         4.6. Spillage and fire treatment
              4.6.1. Spillage
              4.6.2. Fire

    5. HAZARDS FOR THE ENVIRONMENT AND THEIR PREVENTION

    6. INTERNATIONAL CHEMICAL SAFETY CARD

    7. CURRENT REGULATIONS, GUIDELINES, AND STANDARDS
         7.1. Exposure limit values
         7.2. Specific restrictions
         7.3. Labelling, packaging, and transport
         7.4. Waste disposal

    BIBLIOGRAPHY
    

    INTRODUCTION

    The Environmental Health Criteria (EHC) documents produced by the
    International Programme on Chemical Safety include an assessment of
    the effects on the environment and human health from exposure to a
    chemical or combinations of chemicals, or to 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.  Within the Guide is an International Chemical Safety Card
    which should be readily available, and should be clearly explained, to
    all who could come into contact with the chemical.  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 people in the occupational health
    services, ministries, governmental agencies, industry, and trade
    unions, who are involved in the safe use of chemicals and the
    prevention of environmental health hazards, and also workers who would
    like more information on this topic.  An attempt has been made to use
    only terms that are familiar to the user.  However, sections 1 and 2
    inevitably contain some technical terms.  A bibliography has been
    included for readers who would like to have further background
    information.

    Revision of the information in this Guide will take place in due
    course.  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:             C2H2Cl2

    Chemical structure:
                                  Cl         H
                                    \       /
                                      C = C
                                    /       \
                                  Cl         H

    Common synonyms:              ethylene,1,1-dichloro;
                                  1,1-dichloroethene; ethene,1,1-dichloro;
                                  VDC; 1,1-DCE

    Common trade name:            Sconatex

    IUPAC systematic name:        1,1-dichloroethylene

    CAS registry number:          75-35-4

    RTECS number:                 KV9275000

    Conversion factor:            1 mg/m3 = 0.25 ppm

                                  1 ppm vinylidene chloride = 4 mg/m3
                                  at 25 °C and 101.3 kPA (760 mmHG).

    1.2  Physical and Chemical Properties

    Vinylidene chloride is a volatile, clear, colourless liquid with a
    "sweet" odour and has a low solubility in water.  It is extremely
    flammable; its vapour can form explosive mixtures with air or oxygen. 
    Some physical and chemical properties of vinylidene chloride are given
    in the International Chemical Safety Card (see section 6).

    1.3  Composition

    Technical vinylidene chloride is more than 99.6% pure.  It is
    stabilized against oxidation and polymerization by the addition  of
    hydroquinone monomethyl ether ( p-methoxyphenol; 180-220 mg/kg).
    Impurities may include water (acidic), chlorinated acetylene,
    peroxides, and halogenated hydrocarbons.

    1.4  Analytical Methods

    Vinylidene chloride can be trapped by an absorbent column and desorbed
    thermally. It can be measured by gas chromatography, preferably with
    an electron-capture detector, although electrolytic conductivity and
    flame ionization detectors have also been used. Gas chromatography/
    mass spectroscopy is a very accurate technique.

    1.5  Production and Uses

    Vinylidene chloride does not occur naturally in the environment.  It
    is synthesized on a large scale to be used in the production of
    1,1,1-trichloroethane and in the formation of modacrylic fibres and
    copolymers.

    2.  SUMMARY AND EVALUATION

    2.1  Exposure to Vinylidene Chloride

    Up to an estimated 5% of the manufactured vinylidene chloride is
    emitted annually into the atmosphere where it is expected to have a
    half-life of approximately 2 days.  Low levels are detectable in the
    air, particularly in industrial areas.  Levels in water and soil are
    low unless contaminated by an accidental release.  Vinylidene chloride
    may reach drinking water or food, but only in trace amounts, from the
    environment, packing materials, and possibly from water treatment.

    Occupational exposure to vinylidene chloride results mainly from
    inhalation, but skin and eye contamination may also occur.

    2.2  Uptake, Metabolism, and Excretion

    Vinylidene chloride is readily absorbed in animals by inhalation and
    ingestion.  The extent of absorption by the skin is unknown.  Absorbed
    vinylidene chloride is widely distributed, but does not persist,
    within the body.  It is eliminated unchanged via the breath, and as
    metabolites in the bile and urine. Metabolism is more rapid in mice
    than in rats.  The major routes of metabolism involve oxidation and
    conjugation with glutathione and/or with phosphatidyl ethanolamine
    prior to further conversions.  Metabolites bind covalently to tissue
    macromolecules and can cause glutathione depletion.  Covalent binding
    is greater in mice than in rats and greater in the kidneys than in the
    liver.

    2.3  Effects on Animals

    Vinylidene chloride is highly toxic in animals after inhalation (the
    LC50 is as low as 460 mg/m3 for a 4-h exposure) and after
    ingestion (the LD50 ranges from 200 to 1500 mg/kg body weight).
    Inhalation causes irritation of mucous membranes, depression of the
    central nervous system, and cardiotoxicity. Fasting markedly increases
    its toxicity. Both inhalation and ingestion can cause toxicity in the
    liver, kidneys, and lungs.  In mice, which are more susceptible than
    rats to the hepatotoxicity and renal toxicity of vinylidene chloride,
    kidney damage was caused by exposure as low as 10 ppm (40 mg/m3) for
    6 h.

    Although vinylidene chloride is genotoxic in a number of  in vitro
    assays, including mammalian cells, there is only limited evidence for
    genetic toxicity in whole animals.  In chronic studies in three animal
    species tested, a clear carcinogenic effect was seen in mouse kidneys
    and only at dose levels associated with cytotoxicity in the critical
    organ.  Some other tumour types were observed in mice and rats, but
    their significance is uncertain.

    No effect on fertility has been observed and no fetal abnormalities
    occur, other than those associated with maternal toxicity. Embryo and
    fetal toxicity and fetal abnormalities were observed only at
    concentrations that were maternally toxic, as seen by reduced weight
    gain.

    Vinylidene chloride can be toxic to aquatic organisms. The mean LC50
    values for 96-h exposures range from 74 to 250 mg/litre.

    2.4  Effects on Human Beings

    People severely overexposed to vinylidene chloride exhibit depression
    of the central nervous system and may become unconscious.  Kidney,
    liver, and cardiovascular damage has been reported for subanaesthetic,
    prolonged, or repeated short-term exposures.

    Stabilized vinylidene chloride is also an irritant to the respiratory
    tract, skin, and eyes.

    Epidemiological studies have shown no evidence of carcinogenicity in
    human beings, but were not adequate to evaluate vinylidene chloride's
    carcinogenic risk.

    3.  CONCLUSIONS AND RECOMMENDATIONS

    More accurate estimates of vinylidene chloride's worldwide annual
    production and emission levels are needed.  Data in human beings are
    not adequate to establish a potential for carcinogenicity.  There are
    limited data on carcinogenicity in laboratory animals (particularly
    kidney adenocarcinoma in mice) and genetic toxicity.  On the basis of
    currently available experimental toxicity and epidemiological data,
    the level at which no-observed-adverse effects will occur cannot be
    predicted.

    With the information available, it is doubtful that people who come in
    contact with vinylidene chloride will be at risk if exposure levels in
    the workplace and general environment are kept as low as possible and
    within the prescribed control limits. In some countries, however, the
    margin between the control limit and the concentration of vinylidene
    chloride capable of producing toxicity in animals should be
    re-evaluated.

    Because of vinylidene chloride's irritant effect, contact with the
    skin and eyes should be avoided.

    The general population is exposed to detectable but very low levels of
    vinylidene chloride in drinking water, food, and ambient air.

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

    4.1  Human Health Hazards, Prevention and Protection, First Aid

    The health hazards associated with different types of exposure to
    vinylidene chloride are given in section 2.4.

    4.2  Advice to Physicians

    Since vinylidene chloride is an irritant, the lungs, skin, and eyes
    should be examined carefully and frequently.  Liver and kidney
    function, the heart, and the central nervous system, should also be
    monitored.  Severe hypotension, although unlikely, may be treated by
    transfusions of blood or plasma expanders.  Epinephrine should not be
    given.

    4.2.1  Acute poisoning by inhalation

    Move the patient to fresh air and remove contaminated clothing. If
    breathing stops, give artificial respiration.  Obtain medical
    attention. Keep the patient under observation for 48 h because
    pulmonary oedema may develop.

    4.2.2  Oral poisoning

    If the patient is conscious, rinse his/her mouth thoroughly with
    water, and give 500 ml water to drink.  Keep the patient quiet. If
    severely affected, admit to hospital.

    Gastric lavage and/or the oral administration of activated charcoal or
    liquid paraffin may help to reduce the bioavailability of vinylidene
    chloride only if given early (e.g., preferably within approximately
    1 h of ingestion, but it may be beneficial up to 4 h of ingestion). 
    To prevent aspiration of the stomach contents into the lungs, do not
    induce vomiting.

    Wherever exposure to vinylidene chloride is possible, a water supply,
    and first-aid and physicians' treatment kits, should always be easily
    accessible.  The kits should contain eye washes, oxygen masks,
    activated charcoal, and liquid paraffin.

    4.2.3  Skin exposure

    Remove contaminated clothing.  Irrigate and wash contaminated skin
    thoroughly with soap and water.

    4.2.4  Eye exposure

     Act immediately. Irrigate eyes with appropriate sterile eyewash
    solution or clean tap water for at least 15 min. If severely affected,
    obtain medical attention.

    4.3  Health Surveillance Advice

    Anyone who is potentially exposed to vinylidene chloride should
    undergo periodic medical examinations, with special attention to liver
    and kidney function, lungs, and cardiovascular and central nervous
    systems. Carcinogenicity resulting from exposure to vinylidene
    chloride is possible.

    Hygiene standards in the workplace should be maintained.

    4.4  Explosion and Fire Hazards

    4.4.1  Explosion hazards

    Vinylidene chloride reacts vigorously after exposure to oxidizing
    agents or free radical initiators, or when heated.  In the presence of
    oxygen, pure uninhibited vinylidene chloride forms an explosive
    peroxide at temperatures as low as -40 °C.  Vapour-air mixtures may be
    formed that can explode if they come in contact with an ignition
    source, even at sub-zero temperatures.  It is essential to have an
    adequate amount of stabilizer present in the monomer.

    4.4.2  Fire hazards

    Vinylidene chloride is an extremely flammable liquid.  Toxic products,
    particularly phosgene, may be released in a fire.

    4.5  Prevention and Disposal

    4.5.1  Use

    In the work area, use closed systems with continuous ventilation and
    prohibit the use of potential sources of ignition. Use spark-proof
    equipment. The monitoring of vinylidene chloride emissions during
    distribution operations is recommended.

    4.5.2  Storage

    Vinylidene chloride should be covered with inert gas and stored below
    -10 °C in hermetically sealed, properly labelled steel containers. It
    should be protected from light, air, free radical initiators, copper,
    and aluminium.  Only inhibited (stabilized) vinylidene chloride should
    be stored, and only for a limited time.

    4.5.3  Transport

    Only stabilized vinylidene chloride should be transported under the
    conditions described in section 4.5.2. The transport vehicle should be
    equipped with a first-aid kit and a waterspray system to cool the
    tanks in the event of a fire.

    If an accident occurs, stop the engine and remain upwind.  Remove all
    sources of ignition including lighted cigarettes.  Keep everyone at a
    distance and place hazard signs on the road.  In case of spillage or
    fire, use the methods described in section 4.6. Notify the police and
    fire brigade immediately.

    4.5.4  Disposal

    Waste should be incinerated and not disposed of in sewers.  Complete
    combustion is necessary to prevent the formation of phosgene and an
    acid scrubber is required to remove harmful halo-acids.  Dangerous
    vinylidene chloride-derived peroxides can be destroyed to some extent
    by water that is at room temperature.  Peroxides soluble in the
    monomer can be inactivated by treatment with mild reducing agents
    (ferrous sulfate or acidified potassium iodide).  The peroxides should
    not be allowed to undergo polymerisation since extremely dangerous
    peroxide polymers will result.

    4.6  Spillage and Fire Treatment

    4.6.1  Spillage

    If a leak occurs, remove all sources of ignition and evacuate the
    area.  Then evaporate the vinylidene chloride. If a large leak occurs,
    control the evaporation with an expansion synthetic foam.  Use
    water-spray curtains to evaporate the vinylidene chloride from the
    foam.  Personnel should wear full protective clothing and breathing
    apparatus.

    4.6.2  Fire

    In the event of a fire, cool sealed containers with a waterspray
    system. However, if vinylidene chloride ignites, do not use a water
    hose because it could spread the fire.  Instead, use alcohol or
    aqueous foams, carbon dioxide, or powder.  The fire brigade should
    wear breathing apparatus.

    5.  HAZARDS FOR THE ENVIRONMENT AND THEIR PREVENTION

    The physico-chemical properties of vinylidene chloride allow it to
    evaporate and disperse into the atmosphere where it does not persist.
    Bioaccumulation is therefore expected to be low.

    If an accidental spillage occurs, contaminated water may cause
    toxicity in aquatic organisms; otherwise, environmental concentrations
    are very low and well below those that cause toxicity.

    Adequate safety measures should prevent leakage into the environment
    during use, storage, transport, and disposal (see section 4.5).

    6. INTERNATIONAL CHEMICAL SAFETY CARD

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

     Space is available on the card for insertion of the National
     Occupational Exposure Limit, the address and telephone number of the
     National Poison Control Centre, and for local trade names.


        VINYLIDENE CHLORIDE

    (VDC, 1,1-dichloroethene)
    C2H2Cl2
    IUPAC systematic name: 1,1-dichloroethylene
    CAS registry number: 75-35-4
    RTECS number: KV9275000

                                                                                                                                         

    PHYSICAL PROPERTIES                                                   OTHER CHARACTERISTICS
                                                                                                                                         

    Relative molecular mass                        96.95                  Clear, colourless, volatile liquid that has
    Boiling point (°C)                             31.56                  a "sweet" odour and can have adverse effects
    Solubility in water (g/litre) (21 °C)          2.5 g/kg               well below the odour threshold; vinylidene
    Specific density (20 °C)                       1.213 g/cm3            chloride reacts vigorously with oxidizing
    Relative vapour density                                               materials and is extremely flammable when
     (air = 1, 20 °C)                              3.34                   exposed to heat or flame; it polymerizes
    Vapour pressure (mmHg) (20 °C)                 495                    readily above 0 °C in the presence of oxygen,
    Flash point (°C) (closed cup)                  -19                    and in the absence of a stabilizer can form
    Flash point (°C) (open cup)                    -15                    explosive peroxides at temperatures as low as
    Flammability (explosive) limits                5.6-16                 -40 °C; the vapour is heavier than air and may
    Log  n-octanol/water partition                                         travel along the ground and collect at the
     coefficient                                   1.66                   lowest point.

                                                                                                                                         

    HAZARDS/SYMPTOMS                        PREVENTION AND PROTECTION                    FIRST AID
                                                                                                                                         
    SKIN: Causes irritation and             Avoid exposure; wear impervious              Remove contaminated clothing and
    redness; may enter body                 protective clothing, gloves, and face        shoes; wash affected area with soap
    through the skin.                       mask. Do not wear leather.                   and large amounts of water.

    EYES: Both liquid and vapour            Avoid exposure; wear safety goggles.         Irrigate eyes with cold water for at
    cause irritation and redness;                                                        least 15 min; seek medical attention if
    liquid splashes may cause                                                            severely affected.
    corneal damage.

    INHALATION: Causes irritation           Avoid exposure; use exhaust                  Seek medical attention; keep patient
    of respiratory tract, depression        ventilation and/or breathing protection.     warm, in semi-prone position in fresh
    of the central nervous system,                                                       air; keep airway clear; if breathing
    unconsciousness; may cause liver,                                                    has stopped, give artificial 
    lung, or kidney damage.                                                              respiration.

    INGESTION: Causes oral and              Do not eat, drink, or smoke when             Seek medical attention; rinse mouth
    gastrointestinal tract                  working with vinylidene chloride; do         with water; do not induce vomiting.
    irritation, depression of the           not store food or drink in areas with
    central nervous system,                 potential exposure.
    unconsciousness; may cause liver,
    lung, or kidney damage.

    Carcinogenic potential                  Avoid exposure

                                                                                                                                         

    SPILLAGE                                STORAGE                                      FIRE AND EXPLOSION
                                                                                                                                         
    Remove ignition sources;                Vinylidene chloride should be                Extremely flammable; do not expose to
    evacuate area; equip personnel with     inhibited, covered with inert gas, and       oxidizing materials, free radical 
    protective clothing and                 stored below -10 °C in hermetically          initiators, heat, flame, or sparks; vapour/air
    breathing apparatus; evaporate          sealed, properly labelled steel              mixtures can explode on ignition even
    vinylidene chloride with an expansion   containers, and protected from light,        below 0 °C. If a fire occurs, cool sealed
    synthetic foam and a waterspray         air, free radical initiators, copper,        containers with a water-spray; if not
    curtain.                                and aluminium.                               sealed, use alcohol or aqueous foams,
                                                                                         carbon dioxide, or powder.

                                                                                                                                         

    WASTE DISPOSAL                          NATIONAL INFORMATION
                                                                                                                                         

    Incineration with complete              National Occupational Exposure Limit:
    combustion is necessary to prevent
    formation of phosgene; an acid          National Poison Contol Centre:
    scrubber is required for removal
    of harmful halo-acids.                  Local Trade Names:

    FIGURE 1

                                                                                                                                         
    

    7.  CURRENT REGULATIONS, GUIDELINES, AND STANDARDS

    The information in this section has been extracted from the
    International Register of Potentially Toxic Chemicals (IRPTC) legal
    file and other UN sources.  It is a representative but non-exhaustive
    overview of current regulations, guidelines, and standards.

    Regulations and guidelines about chemicals can be fully understood
    only within the framework of a country's legislation, and are always
    subject to change.  Therefore, they should always be verified with the
    appropriate authorities.

    There are restrictions, limitations, and safety precautions in some of
    the countries where vinylidene chloride has been registered.  They
    should always be consulted before this substance is used.

    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 shown, indicated by (r).

    7.1  Exposure Limit Values

    Some exposure limit values are given in the table on pages 24-25.

    7.2  Specific Restrictions

    The Commission of the European Communities classifies vinylidene
    chloride as harmful (Class IIB), and requires appropriate packaging
    and labelling.  The substance must not be used in cosmetics.

    In the Federal Republic of Germany (FRG) and in the USA, vinylidene
    chloride is listed as a potential carcinogen and regulations for such
    substances apply.

    In the FRG, the compound is a Class I emission. The air emission must
    not exceed (as the sum of all compounds in this class) 20 mg/m3 at a
    mass flow of 0.1 kg/h or more. Handling of vinylidene chloride by
    adolescents and pregnant and nursing women is prohibited or restricted
    (effective date, 1980).

    In the USA, the vapour emitted through a spray booth must not exceed
    25% of the explosive limit, which is 5.9% vinylidene chloride by
    volume in air.  The European Communities are proposing a limit of
    5 mg/kg in food contact plastics and 50 µg/kg in food.

    7.3  Labelling, Packaging, and Transport

    In the European Economic Community, containers of vinylidene chloride
    should be labelled:

          Extremely flammable; harmful; harmful by inhalation; possible
          risks of irreversible effects; keep container tightly closed;
          keep away from sources of ignition - no smoking; do not empty
          into drains.

    If the substance is not stabilized, it should be labelled:

          Vinylidene chloride, non-stabilized.

    The United Nations and the International Maritime Organization
    classify vinylidene chloride as "3 = Inflammable liquid" and as a
    "very dangerous substance" (Packing Group 1).

    7.4  Waste Disposal

    In the USA, for purposes of discharge, vinylidene chloride is
    designated as a hazardous substance under the Federal Water Pollution
    Control Act and permits are required for its discharge into US waters. 
    The US Government must be notified of any discharge of this substance
    into navigable waters that adjoin shorelines or the contiguous zone in
    any amounts equal to or greater than 2270 kg in any 24-h period. Such
    a discharge is a violation of the Federal Water Pollution Control Act.

    A discharge above the following levels must be reported:

    -    100 µg/litre
    -    5 times the maximum concentration stated in the application for
         the permit
    -    the level established by the EPA director.


        EXPOSURE LIMIT VALUES

                                                                                                                                         

    Medium      Specification       Country/            Exposure limit description                   Value                Effective
                                    organization                                                                          date
                                                                                                                                         

    AIR         Occupational        Belgium             Threshold limit value (TLV)                                       1987 (r)
                                                        - Time-weighted average (TWA)                 20 mg/m3
                                                        - Short-term exposure limit (STEL)            80 mg/m3

                                    Brazil              Acceptable limit (AC)                         31 mg/m3            1982 (r)
                                                          (48 h/week)

                                    Germany,            Maximum work-site concentration (MAK)                             1987 (r)
                                    Federal             - Time-weighted average (TWA)                  8 mg/m3
                                    Republic of         - Short-term exposure limit (STEL;            16 mg/m3
                                                          30 min)

                                    Netherlands         Maximum limit (MXL)                                               1987 (r)
                                                        - Time-weighted average (TWA)                 40 mg/m3
                                                          (notice of intended change)                 20 mg/m3

                                    Poland              Maximum permissible concentration (MPC)                           1985 (r)
                                                        - Ceiling value (CLV)                         50 mg/m3

                                    Romania             Maximum permissible concentration (MPC)                           1985 (r)
                                                        - Time-weighted average (TWA)                500 mg/m3
                                                        - Ceiling value (CLV)                        700 mg/m3

                                    Sweden              Threshold limit value (TLV)                                       1985
                                                        - Time-weighted average (TWA)                 20 mg/m3
                                                        - Short-term exposure limit (STEL)            40 mg/m3

                                    Switzerland         Maximum work-site concentration (MAK)                             1987 (r)
                                                        - Time-weighted average (TWA)                  8 mg/m3

                                                                                                                                         

    Medium      Specification       Country/            Exposure limit description                   Value                Effective
                                    organization                                                                          date
                                                                                                                                         

                                    United              Recommended limit                                                 1987 (r)
                                    Kingdom             - Time-weighted average (TWA)                 40 mg/m3

                                    USA                 Permissible exposure limit (PEL)                                  1987 (r)
                                    (ACGIH)             - Time-weighted average (TWA)                 20 mg/m3
                                                        - Short-term exposure limit (STEL)            80 mg/m3

                                    USA                 Recommended exposure limit (REL)             lowest reliable      1987 (r)
                                    (NIOSH)                                                          detectable
                                                                                                     concentration

                                    USSR                Maximum allowable concentration (MAC)                             1977
                                                        - Ceiling value (CLV)                        50 mg/m3

    WATER       Surface             USSR                Maximum allowable concentration (MAC)        0.0006               1983
                                                                                                     mg/litre

                Drinking            World Health        Guideline value                              0.0003               1983 (r)
                water               Organization                                                     mg/litre

    FOOD                            EEC                 Proposed limit                               5 mg/kg
    PACKAGING

    FOOD                            EEC                 Proposed limit                               50  g/kg

                                                                                                                                         
    

    BIBLIOGRAPHY

    BRETHERICK, L. (1981)  Hazards in the chemical laboratory, 3rd ed.
    London, The Royal Society of Chemistry.

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    See Also:
       Toxicological Abbreviations
       Vinylidene chloride (EHC 100, 1990)
       Vinylidene chloride (ICSC)
       Vinylidene Chloride  (IARC Summary & Evaluation, Volume 71, 1999)