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    IPCS INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY
    Health and Safety Guide No. 63

    HEXACHLOROCYCLO-PENTADIENE
    HEALTH AND SAFETY GUIDE






    UNITED NATIONS ENVIRONMENT PROGRAMME

    INTERNATIONAL LABOUR ORGANISATION

    WORLD HEALTH ORGANIZATION




    WORLD HEALTH ORGANIZATION, GENEVA 1991

    This is a companion volume to Environmental Health Criteria 120:
    Hexachlorocyclopentadiene

    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

    Hexachlorocyclopentadiene : health and safety guide.

    (Health and safety guide ; no. 63)

    1.Hydrocarbons, Chlorinated - adverse effects
    2.Hydrocarbons, Chlorinated - standards
    3.Hydrocarbons, Chlorinated -  toxicity
    4.Environmental exposure
    5.Environmental pollutants I.Series

    ISBN 92 4 151063 3          (NLM Classification: QV 633)
    ISSN 0259-7268

    (c) World Health Organization 1991

    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. Composition
         1.4. Uses

    2. SUMMARY AND EVALUATION
         2.1. Exposure
         2.2. Uptake, metabolism, and excretion
         2.3. Effects on animals
         2.4. Effects on human beings
         2.5. Effects on organisms in 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. Advice to physicians
                     4.1.1.1  Symptoms of poisoning
                     4.1.1.2  Medical advice
              4.1.2. Health surveillance advice
         4.2. Explosion and fire hazards
              4.2.1. Explosion hazards
              4.2.2. Fire hazards
              4.2.3. Prevention
              4.2.4. Extinguishing agents
         4.3. Storage
         4.4. Transport
         4.5. Spillage
         4.6. Disposal

    5. HAZARDS FOR THE ENVIRONMENT AND THEIR PREVENTION

    6. SUMMARY OF CHEMICAL SAFETY INFORMATION

    7. CURRENT REGULATIONS, GUIDELINES, AND STANDARDS
         7.1. Previous evaluations by international bodies
         7.2. Exposure limit values
         7.3. Specific restrictions
         7.4. Labelling, packaging, and transport
         7.5. Other measures
         7.6. 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 on human health of exposure to a
    chemical or combination of chemicals, or physical or biological
    agents.  They also provide guidelines for setting exposure limits.

    The purpose of a Health and Safety Guide is to facilitate the
    application of these guidelines in national chemical safety
    programmes. The first three sections of a Health and Safety Guide
    highlight the relevant technical information in the corresponding EHC. 
    Section 4 includes advice on preventive and protective measures and
    emergency action; health workers should be thoroughly  familiar with
    the medical information to ensure that they can act efficiently in an
    emergency.  Within the Guide is a Summary of Chemical Safety
    Information 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 occupational health services, those in
    ministries, governmental agencies, industry, and trade unions who are
    involved in the safe use of chemicals and the avoidance of
    environmental health hazards, and those wanting more information on
    this topic.  An attempt has been made to use only terms that will be
    familiar to the intended user.  However, sections 1 and 2 inevitably
    contain some technical terms.  A bibliography has been included for
    readers who require further background information.

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

    The 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

    Common name:                  hexachlorocyclopentadiene (HEX)

    Molecular formula:            C5Cl6

    Chemical structure:

    CHEMICAL STRUCTURE 1

    Common synonyms:              perchlorocyclopentadiene (HCCPD)

    Common trade names:           C-56, HRS 1655, Graphlox 

    CAS chemical name:            1,2,3,4,5,5'-hexachloro-1,3-
                                  cyclopentadiene

    CAS registry number:          77-47-4

    EINEC number:                 2010293

    Relative molecular mass:      272.77

    Conversion factor (20C):     1 ppm = 11.3 mg/m3
                                  1 mg/m3 = 0.088 ppm

    1.2  Physical and Chemical Properties

    Pure hexachlorocyclopentadiene (HEX) is a light, lemon-yellow liquid
    that has a pungent, musty odour.  The odour threshold is reported to
    be 0.0014-0.0016 mg/m3.  HEX is highly reactive and volatile at low
    temperatures.  Other physical and chemical properties of HEX are given
    in the Summary of Chemical Safety Information (section 6).

    1.3  Composition

    Commercially available HEX contains several impurities, depending on
    the method of synthesis.  HEX with a purity exceeding 90% is produced
    by thermal dechlorination of octachlorocyclopentene.  HEX with a
    purity of 75% contains many lower chlorinated cyclopentadienes as well
    as hexachlorobenzene and octachlorocyclopentene.

    1.4  Uses

    HEX is an intermediate in the manufacture of chlorinated cyclodiene
    pesticides, such as heptachlor, chlordane, aldrin, dieldrin, endrin,
    and mirex, and in the manufacture of resins, dyes, and pharmaceutical
    products.  Another major use is in the manufacture of flame
    retardants, including Dechlorane Plus (R) and chlorendic anhydride.

    2.  SUMMARY AND EVALUATION

    2.1  Exposure

    Few data are available on the relative contribution of different
    sources of HEX to the environment.  Human exposure via air, soil, or
    water is expected to be minimal, except for that of persons living in
    the vicinity of manufacturing, shipping, or disposal sites. 
    Occupational exposure is probably the major source of human exposure.

    Short-term laboratory tests have shown that HEX is highly toxic for
    aquatic microorganisms, invertebrates, and fish, and less toxic for
    soil micro-organisms. Information obtained under environmentally
    realistic conditions is limited, but the potential hazard for the
    general environment is expected to be low.

    2.2  Uptake, Metabolism, and Excretion

    Absorption from the gastrointestinal tract is relatively low compared
    with that from the lungs or skin.  HEX appears to be almost completely
    metabolized in the body.  The primary metabolites are described as
    polar compounds, but they have not been identified.  Most of the
    retained HEX and its metabolites are found in the liver and kidneys,
    though after inhalation exposure, the highest tissue concentrations
    are found in the lung and trachea.  The major routes of elimination
    are the urine and faeces.  Excretion in the bile has been shown to
    occur with all routes of exposure.

    2.3  Effects on Animals

    HEX is moderately toxic for animals via the oral and dermal routes of
    exposure, and extremely toxic via inhalation.  The main cause of death
    following acute exposure via any route is respiratory failure,
    suggesting that the respiratory tract is the major target organ of
    toxicity.  HEX is also a primary skin irritant and causes severe eye
    irritation in rabbits.

    Short-term oral exposure (91 days) to HEX resulted in kidney damage. 
    No data have been found on effects associated with long-term oral
    exposure to HEX.

    The inhalation of HEX vapour at concentrations of 4.52 mg/m3
    (0.4 ppm) or more, for 90 days, resulted in respiratory-tract effects,
    including inflammation and respiratory distress, in mice and rats. 
    The inhalation of 5.65 mg/m3 (0.5 ppm) for 6 h/day, 5 days/week,
    over 30 weeks, resulted in lung damage in mice and rats.  No data on
    the effects of long-term inhalation exposure to HEX were available. 

    HEX has not been shown to affect reproduction and development in
    animals.  There is good evidence that HEX is not mutagenic in
    bacterial or mammalian cells, or in the fruit fly.  Data on the
    carcinogenic potential of HEX in experimental animals are not
    currently available.

    2.4  Effects on Human Beings

    There is limited information on human health effects.  Acute exposure
    can result in severe irritation of the eyes, nose, throat, and
    gastrointestinal tract.  In a well-documented incident at a
    waste-water treatment plant, exposed workers exhibited eye irritation,
    headaches, nausea, and eye and throat irritation.  These effects
    persisted for several weeks.  Exposure levels could not be estimated
    accurately, but airborne concentrations in primary treatment areas,
    measured 4 days after closing the facility, ranged from 3.05 to
    10.96 mg/m3 (270 to 970 ppb).

    No excess cancer mortality was reported in an epidemiological study of
    workers employed at a chemical plant producing and processing HEX. 
    Using the criteria of the International Agency for Research on Cancer
    (IARC), the available data on carcinogenicity are classified in
    Group 3, i.e., because of major qualitative or quantitative
    limitations, the available studies cannot be interpreted as showing
    either the presence or absence of a carcinogenic effect.

    2.5  Effects on Organisms in the Environment

    HEX is highly toxic for aquatic organisms.  There is a lack of
    information on the effects of HEX on animals and vegetation.

    3.  CONCLUSIONS AND RECOMMENDATIONS

    (i)   Environmental monitoring is needed to examine the persistence
    and fate of HEX in all media near production, processing, and disposal
    sites, and also hazardous waste incinerators.  Monitoring data are
    needed for HEX in drinking-water, and surface, shower, and ground
    waters.

    (ii)  Biomarker techniques should be developed to indicate the
    possible past or current actions of HEX.  Such biomarkers could be
    stable metabolites derived from HEX, or the contaminants present in
    the original preparation.

    (iii) Research is needed on the metabolic, degradation, and reactive
    products, to understand the fate of HEX in humans and the environment.

    (iv)  Further study of the apparent disparity between degradation
    under laboratory conditions and that observed in the environment is
    needed.

    (v)   The efficacy and safety of current disposal methods should be
    evaluated, and their present and future health impacts assessed.

    (vi)  Developmental and reproductive studies on HEX need to be
    conducted, with emphasis on the inhalation route of exposure.

    (vii) Methods for the early warning of the presence of HEX should be
    developed.

    (viii) Occupational exposure to HEX should be minimized by the use of
    closed systems.  Guidelines should be followed on the disposal of HEX
    and HEX wastes.

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

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

    HEX is toxic via all routes of exposure, but is particularly dangerous
    via inhalation.  This chemical is extremely irritating to the mucous
    membranes, eyes, and skin, causing lacrimation, sneezing, and
    salivation.  Contact with the skin can result in discoloration,
    blisters, and burns.  Inhalation or ingestion can result in nausea,
    vomiting, diarrhoea, headaches, lethargy, breathing difficulties, and
    liver and kidney damage.  Inhalation exposure may cause severe
    irritation to the throat, respiratory tract, and the lungs.  The human
    health hazards associated with certain types of exposure, as well as
    preventive and protective measures and first-aid recommendations, are
    presented in the Summary of Chemical Safety Information (section 6).

    4.1.1  Advice to physicians

    Following the ingestion of HEX, oxygen should be administered, if
    respiration is depressed.  Toxic symptoms resulting from inhalation
    exposure should be treated symptomatically and supportively.  Oxygen
    should be administered as needed. In the case of eye contact, the eyes
    should be washed immediately with large amounts of water for at least
    15 minutes, to remove any remaining chemical.  The eyes should then be
    irrigated with physiological saline solution for 30-60 minutes, or
    until the pH returns to normal.  Following dermal contact, the
    affected area should be washed immediately with soap and large amounts
    of water.  If blistering develops, the skin should be covered with
    loosely wrapped sterile bandages.

    4.1.2  Health surveillance advice

    Persons employed in the manufacture, transportation, or disposal of
    HEX should undergo periodic medical examinations.

    4.2  Explosion and Fire Hazards

    4.2.1  Explosion hazards

    HEX is not explosive.  However, containers may explode in the heat of
    fires. Furthermore, HEX may form explosive mixtures with sodium.

    4.2.2  Fire hazards

    HEX is not flammable.  However, toxic fumes, such as hydrogen
    chloride, chlorine, and phosgene, are formed in fires.

    4.2.3  Prevention

    Enclosed processing equipment, local exhaust, or ventilation that is
    adequate to meet published exposure limits, should be provided.

    4.2.4  Extinguishing agents

    For fires, dry chemical powder, carbon dioxide, water spray, or
    standard foam is recommended.  If possible, containers should be moved
    away from the fire.  Water used to control fires should be contained,
    or diked, for later disposal.

    4.3  Storage

    HEX should be stored in tightly closed containers, labelled as
    corrosive, and stored in a cool, dry place, away from moisture, heat,
    and strong oxidizing agents.

    4.4  Transport

    HEX can be transported at ambient temperatures and does not require an
    inert atmosphere; it is stable under normal conditions.  For shipping,
    55-gallon (250-litre) drums or tank cars are recommended.  Label as
    corrosive.

    4.5  Spillage

    In the case of a spill or leak, earth, sand, or some other
    noncombustible absorbent material (cement powder or soda ash) can be
    used to absorb the chemical.  This material is then placed in a clean,
    dry, covered container for later disposal.  Dry spills can be removed
    using a clean shovel.  For large spills, the liquid should be
    contained, or diked, at a distance from the spill for later disposal. 
    In the case of an air release, vapours should be knocked down with a
    water spray.  Persons should remain upwind of the vapour cloud.  Water
    spills can be trapped at the bottom of deep water pockets (since HEX
    is heavier than water), in excavated holding areas, or within sandbag
    barriers, to avoid contamination of sewers and surface waters. 
    Damaged containers should be destroyed to prevent further use. 
    Suction hoses can then be used to remove the spilled material.

    4.6  Disposal

    HEX can be incinerated after mixing with a combustible fuel.  This
    mixture should be completely combusted to prevent the formation of
    phosgene.  An acid scrubber should be used to remove the halo acids
    produced.  HEX can be buried in specially designated chemical
    landfills.  However, HEX and organic solvents should not be disposed
    of in the same landfill area, to prevent possible migration of HEX
    from the disposal site.  Dumping into sewer systems is not an
    acceptable method of disposal.  Deep well injection can be used.

    5.  HAZARDS FOR THE ENVIRONMENT AND THEIR PREVENTION

    Since environmental pollution is expected to occur as a result of
    releases during the production, processing, and disposal of HEX,
    contamination can be avoided by the use of proper methods of storage,
    transport, handling, and waste disposal (sections 4.3, 4.4, and 4.6). 
    In the case of spillage, the clean-up methods described in section 4.5
    should be used.

    When the fate and transport of HEX in the atmosphere was modelled on
    the basis of available laboratory data, a tropospheric residence time
    of approximately 5 h was calculated.  The atmospheric transport of HEX
    has been reported from an area where waste was stored, and from wet
    wells during the treatment of industrial wastes.

    In water, HEX may undergo photolysis, hydrolysis, and biodegradation. 
    In shallow water, it has a photolytic half-life of <1 h.  In deeper
    water, where photolysis was precluded, the hydrolytic half-life of HEX
    ranged from several days to approximately 3 months; biodegradation is
    predicted to occur more slowly.  HEX is known to volatilize from
    surface water, and its volatilization is affected by turbulence and by
    sorption on to sediments.

    Because of its low solubility in water, HEX should be relatively
    immobile in soil; however, HEX has been found in ground water. 
    Volatilization, which is likely to occur primarily at the soil
    surface, is inversely related to the levels of organic matter in the
    soil.  From laboratory studies, chemical hydrolysis and microbial
    metabolism, both aerobic and anaerobic, would be expected to reduce
    HEX levels in soils.

    Low concentrations of HEX have been shown to be toxic for aquatic
    life.  Lethality in acute exposures (48-96 h) was observed in both
    freshwater and saltwater crustaceans and fish at nominal
    concentrations of 32-180 g/litre in static exposure systems where the
    water was not renewed during the test.  As the photolytic half-life is
    <1 h, the concentration of the HEX would have decreased substantially
    during the 48-96 h of exposure.

    In aqueous media, HEX is toxic for many other microorganisms at
    nominal concentrations of 0.2-10 mg/litre, or levels substantially
    higher than those needed to kill most aquatic animals or plants.  HEX
    appears to be less toxic for microorganisms in the soil than in
    aquatic media, probably because of the sorption of HEX on to the soil
    matrix.

    Although exposure is expected to be low, data currently available are
    insufficient to determine the effects of HEX exposure on terrestrial
    vegetation or wildlife.

    6.  SUMMARY OF CHEMICAL SAFETY INFORMATION

     This summary should be easily available to all health workers
     concerned with, and users of, hexachlorocyclopentadiene. It should be
     displayed at, or near, entrances to areas where there is potential
     exposure to hexachlorocyclopentadiene, and on processing equipment
     and containers.  The summary should be translated into the
     appropriate language(s).  All persons potentially exposed to the
     chemical should also have the instructions in the summary clearly
     explained.

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


        HEXACHLOROCYCLOPENTADIENE (C5Cl6)

                                                                                                                                         

    PHYSICAL PROPERTIES                                                   OTHER CHARACTERISTICS
                                                                                                                                         

    Relative molecular mass            272.77                             Reacts slowly with water to form 
    Appearance                         lemon-yellow liquid                hydrochloric acid; may form explosive 
    Odour threshold                    0.00019 mg/m3                      mixture with sodium; corrosive to iron 
    Odour                              pungent, musty                     and other metals, in the presence of
    Melting point (C)                 -9.6                               moisture
    Boiling point (C)                 239
    Solubility in water (25C)         1.03-1.25 mg/litre
    Relative vapour density (air =1)   9.42
    Density (25C)                     1.702
    Vapour pressure (25C)             0.08 mmHg
    Electronegativity                  ND
    Flame colouration test             ND
    Octanol/water partition
      coefficient (Kow)                1.1 x 105

                                                                                                                                         

    HAZARDS/SYMPTOMS                        PREVENTION AND PROTECTION                    FIRST AID
                                                                                                                                         

    SKIN: Severe irritation; burns,         Avoid exposure; wear protective              Remove contaminated clothing and shoes;
    blisters; readily absorbed through      clothing and rubber gloves and               flush skin with plenty of water; cover burns 
    intact skin                             shoes                                        with sterile bandages, loosely wrapped

    EYES: Severe irritation;                Wear a face-shield if there is a             Flush the eyes with plenty of water for
    redness; pain                           possibility of eye contact                   15 minutes, making sure to remove any
                                                                                         remaining chemical; seek medical attention

    INHALATION:  Severe irritation          Avoid exposure by using                      Fresh air, rest; if breathing has 
    to mucous membranes and upper           ventilation, local exhaust, or               stopped, apply artificial respiration;
    respiratory tract; sore throat,         respiratory protection, such as a            administer oxygen, if required; seek 
    coughing, shortness of breath,          self-contained breathing                     medical attention immediately
    headache, vomiting, lacrimation,        apparatus and a face-shield
    pulmonary oedema, degenerative
    changes in lung, liver, and kidney;
    death may occur from respiratory
    failure

    INGESTION:  Salivation,                 Do not eat, drink, or smoke when             Rinse mouth; seek medical
    diarrhoea, lethargy, shortness of       handling the compound                        attention
    breath or difficulty in breathing,
    degenerative changes in the lung,
    liver, kidney, adrenal glands,
    heart, and brain 

    HEX is highly toxic to aquatic          Do not contaminate surface
    environments                            waters or sewers

                                                                                                                                         

    SPILLAGE                                STORAGE                                      FIRE AND EXPLOSION
                                                                                                                                         

    Do not touch spilled material;          Store in a cool, dry place in                Negligible fire hazard; hydrogen 
    for dry spills, using clean shovel      tightly closed containers                    chloride, chlorine, and phosgene 
    place material into a clean, dry                                                     may be formed in the heat of 
    container; for small liquid spills,                                                  fires; closed containers may 
    take up with sand or other                                                           explode in the heat of fires
    absorbent material and place into
    containers for disposal; for large
    liquid spills, dike far ahead of
    spill for later disposal

                                                                                                                                         

    WASTE DISPOSAL                          NATIONAL INFORMATION
                                                                                                                                         

    Incinerate after mixing with            National Occupational Exposure               Code of Federal Regulations:  
    combustible fuel; take care to          Limit:                                       Poison, Class B 
    ensure complete combustion;
    apply acid scrubbers; can also be       National Poison Control Centre:
    disposed of in specially designated
    chemical landfill; care should be       Local trade names:
    taken to avoid disposal together
    with organic solvents

                                                                                                                                         
        7.  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.

    7.1  Previous Evaluations by International Bodies

    Data are insufficient to assess the carcinogenic potential of HEX in
    humans.  No previous evaluations have been carried out by
    international bodies.

    7.2  Exposure Limit Values

    See table on pages 24-25.

    7.3  Specific Restrictions

    No specific restrictions were found.

    7.4  Labelling, Packaging, and Transport

    The United Nations Committee of Experts on the Transport of Dangerous
    Goods classifies HEX as a poisonous substance (Hazard Class 6.1), and
    as a very dangerous substance (Packing Group I) with regard to
    packing.


                                                                                                                                             

    Country             Type                 Media                    Level/remarka                                        Date
                                                                                                                                         

    Australia           recommendation       air/occupational         TLV/TWA = 0.1 mg/m3 (0.01 ppm)                       1983
                                                                      STEL = 0.3 mg/m3 (0.03 ppm)

    Belgium             recommendation       air/occupational         TLV/TWA = 0.1 mg/m3 (0.01 ppm)                       1988

    Canada              regulation           air/occupational         TLV/TWA = 0.01 ppm (0.1 mg/m3)                       1980

    Canada              regulation           transport                specific transportation regulations                  1987

    Finland             recommendation       air/occupational         TWA = 1.0 mg/m3 (0.1 ppm)                            1989
                                             skin                     STEL = 3.0 mg/m3 (0.3 ppm)                           1989

    Germany,            regulation           waste                    "toxic waste" subject to specific handling,          1981
      Federal                                                         transport, treatment, storage, and disposal
      Republic of                                                     regulation/permits

    Netherlands         recommendation       air/occupational         TWA/OCC = 0.11 mg/m3 (0.01 ppm)                      1986

    Switzerland         regulation           air/occupational         TWA = 0.1 mg/m3 (0.01 ppm)                           1987

    USA                 regulation           water                    1 g/litre ambient                                   1980
                                                                      water quality criteria (organoleptic) 

    USA (ACGIH)         recommendation       air/occupational         TWA = 0.1 mg/m3 (0.01 ppm)                           1980

    USA                 regulation           air/occupational         TWA = 0.1 mg/m3 (0.01 ppm)                           1989

    USA                 regulation           water/land               notification of spill of 1 lb (0.454 kg)             1983
                                                                      in 24-h period

    USA                 regulation           waste/transport          "toxic waste" subject to specific handling,          1980
                                                                      transport, treatment, storage, and disposal
                                                                      regulation/permits

                                                                                                                                         

    Country             Type                 Media                    Level/remarka                                        Date
                                                                                                                                         

    USA                 draft
                        recommendation       drinking-water           7 g/kg per day (lifetime)                           1990

    USSR                regulation           air/occupational         TLV = 0.01 mg/m3 (0.01 ppm vapour)                   1989

    USSR                regulation           water                    MAC = 0.001 mg/ml (organoleptic)                     1985

    USSR                regulation           air/ambient              STEL = 0.001 mg/m3                                   1987

    Yugoslavia          regulation           air/occupational         TWA = 0.1 mg/m3 (skin)                               1985

                                                                                                                                         

    a TLV = threshold limit value; TWA = time-weighted average; STEL = short-term exposure level; OCC = occupational;
      MAC = maximum allowable concentration.
    

    The US Code of Federal Regulations lists HEX as a Class B poison and
    recommends that the label presented below be placed on packaging. 
    Label as a corrosive.

    FIGURE 1

    7.5  Other Measures

    None found.

    7.6  Waste Disposal

    The US EPA classifies HEX as a toxic pollutant and is required to set
    effluent limitations and pretreatment standards for 21 major
    industries.  Permits are required for the discharge of any pollutant
    from any point source into US waters.  Applicants who have reason to
    believe that HEX is contained in any of the outfalls produced, or
    applicants using specific industrial processes listed in the Code of
    Federal Regulations (40 CFR 122.53; 1981), must report quantitative
    data for HEX.  Inspecting, monitoring, and reporting requirements are
    specified after the permit is issued.  Discharge of the  substance
    must be reported, regardless of permit requirements, if levels exceed
    10 g/litre, five times the maximum concentration reported in the
    application, or the level established by the US EPA administrator. 
    The US EPA further classifies certain specified industrial solid
    wastes containing HEX as hazardous substances.

    BIBLIOGRAPHY

    ACGIH (1986)  Documentation of the threshold limit values and
     biological exposure indices. 5th ed. Cincinnati, Ohio, American
    Conference of Governmental Industrial Hygienists, pp. 300.

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    See Also:
       Toxicological Abbreviations
       Hexachlorocyclopentadiene (EHC 120, 1991)
       Hexachlorocyclopentadiene (ICSC)