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    IPCS INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY
    Health and Safety Guide No. 84

    HEXACHLOROBUTADIENE
    HEALTH AND SAFETY GUIDE






    UNITED NATIONS INTERNATIONAL

    ENVIRONMENT PROGRAMME LABOUR ORGANISATION

    WORLD HEALTH ORGANIZATION




    WORLD HEALTH ORGANIZATION, GENEVA 1993

    This is a companion volume to Environmental Health Criteria 156:
    Hexachlorobutadiene

    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

    Health and safety guide for hexachlorobutadiene.

    (Health and safety guide ; no. 84)

    1.Butadienes - standards  I.Series

    ISBN 92 4 151084 6          (NLM Classification: WA 240)
    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 1993

    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

    INTRODUCTION

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

    2. SUMMARY AND EVALUATION
         2.1. Environmental fate
         2.2. Exposure
         2.3. Kinetics and metabolism
         2.4. Effects on organisms in the environment
         2.5. Effects animals

    3. CONCLUSIONS
         3.1. Human health
         3.2. Environment

    4. HUMAN HEALTH HAZARDS, PREVENTION AND PROTECTION, EMERGENCY ACTION
         4.1. Human health hazards, prevention and protection, first aid
         4.2. Advice to physicians
         4.3. Health surveillance advice
         4.4. Explosion and fire hazards, prevention
              4.4.1. Explosion and fire hazards
              4.4.2. Prevention
              4.4.3. Fire extinguishing agents
         4.5. Storage
         4.6. Transport
         4.7. Spillage and disposal
              4.7.1. Spillage
              4.7.2. Disposal

    5. HAZARDS FOR THE ENVIRONMENT AND THEIR PREVENTION

    6. SUMMARY OF CHEMICAL SAFETY INFORMATION

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

    The purpose of a Health and Safety Guide is to facilitate the
    application of these guidelines in national chemical safety
    programmes. The first three sections of a Health and Safety Guide
    highlight the relevant technical information in the corresponding EHC. 
    Section 4 includes advice on preventive and protective measures and
    emergency action; health workers should be thoroughly  familiar with
    the medical information to ensure that they can act efficiently in an
    emergency. 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 Director
    International Programme on Chemical Safety
    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:                  hexachlorobutadiene

    Chemical structure:

    CHEMICAL STRUCTURE 1

    Chemical formula:             C4Cl6

    Common synonyms:              1,3-hexachlorobutadiene, 
                                  1,1,2,3,4,4-hexachloro-1,3-butadiene,
                                  perchlorobutadiene

    Common trade names:           C-46, Dolen-pur, GP40-66: 120, UN2279

    Common abbreviation:          HCBD

    CAS registry number:          87-68-3

    RTECS registry number:        EJ 0700000

    Relative molecular mass:      260.8

    Conversion factors:           1 ppm of hexachlorobutadiene 
                                    = 10.67 mg/m3 air, and 
                                  1 mg of hexachlorobutadiene per m3 air
                                    = 0.094 ppm 
                                  at 25 C and 101.3 kPa (760 mm Hg).

    1.2  Physical and Chemical Properties

    Hexachlorobutadiene is a non-flammable, incombustible, clear,
    colourless, oily liquid at ordinary temperature and pressure. Its
    odour is described as turpentine-like. The compound is poorly soluble
    in water, but miscible with ether and ethanol.

    Some physical and chemical data on hexachlorobutadiene are presented
    in the Summary of Chemical Safety Information (section 6).

    1.3  Analysis

    The substance can be detected and determined quantitatively by gas
    chromatographic methods. Detection limits are 0.03 g/m3 in air,
    0.001 g/dm3 in water, 0.7 g/kg wet weight in soil or sediment, and
    0.02 g/dm3 in blood. No odour threshold for the compound in air was
    found. In water an odour threshold of 0.006 mg/dm3 was reported.

    1.4  Production and Uses

    Hexachlorobutadiene has not been reported to occur as a natural
    product. The compound was, and is, chiefly produced as a by-product
    in the manufacture of chlorinated hydrocarbons, where it occurs in
    the heavy fractions (Hex-waste). The annual world production of
    the compound in heavy fractions was estimated, in 1982, to be
    10 000 tonnes.

    The compound can be used for the recovery of chlorine-containing gas
    in chlorine plants and as a wash liquor for removing certain volatile
    organic compounds from gas streams. It has further been used as a
    fluid in gyroscopes, as a heat transfer, transformer-insulating, and
    hydraulic fluid, as a solvent for elastomers, an intermediate, and as
    a fumigant.

    2.  SUMMARY AND EVALUATION

    2.1  Environmental Fate

    The main pathways of entry into the environment are emissions from
    waste, and dispersive use.  Intercompartmental transport occurs
    chiefly by volatilization, adsorption on particulate matter, and
    subsequent deposition or sedimentation. The compound does not migrate
    rapidly in soil and accumulates in sediment. It is considered
    persistent in water, unless there is high turbulence. Hydrolysis does
    not occur. The substance seems to be biodegradable aerobically, though
    biodegradability has not been investigated thoroughly. The compound
    photolyzes. In addition to deposition, reaction with hydroxyl radicals
    is assumed to be an important sink of hexachlorobutadiene in the
    troposphere with an estimated atmospheric half-life of up to 2.3
    years. The substance has a high bioaccumulating potential, as has been
    confirmed by both laboratory and field observations. Average,
    steady-state bioconcentration factors of 5800 and 17 000, based on wet
    weight, have been experimentally determined in rainbow trout.
    Biomagnification has not been observed in either the laboratory or the
    field. 

    2.2  Exposure

    Hexachlorobutadiene has been measured in urban air: in all cases,
    levels have been below 0.5 g/m3. In remote areas, concentrations
    were below 1 pg/m3. In lakes and rivers in Europe, concentrations of
    up to 1000 ng/dm3 have been recorded, mean levels usually being
    below 100 ng/dm3. In the Great Lakes area, Canada, much lower levels
    of around 1 ng/dm3 have been measured. Bottom sediment levels here
    can be as high as 120 g/kg dry weight. Older sediment layers, from
    around 1960, contained higher concentrations of up to 550 g/kg wet
    weight. The sediment concentration was shown to increase with the size
    of the fraction of sediment particles. 

    Concentrations of hexachlorobutadiene in aquatic organisms, birds, and
    mammals indicate bioaccumulation, but no biomagnification. In polluted
    waters, levels of over 1000 g/kg wet weight have been measured in
    several species and 120 mg/kg (lipid base) in one species. Generally,
    however, present levels remain below 100 g/kg wet weight.

    The compound has been detected in the urine, blood, and tissues of
    humans.

    Certain food items containing a high lipid fraction were found to
    contain up to about 40 g hexachlorobutadiene/kg and, in one case,
    over 1000 g/kg.

    In a single study on workers, occupational exposure levels of
    1.6-16.9 mg hexachlorobutadiene/m3 were recorded.

    2.3  Kinetics and Metabolism

    Hexachlorobutadiene is rapidly absorbed following oral administration
    to experimental animals. The rate of absorption following inhalation
    or dermal exposure has not been investigated. In rats and mice, the
    compound is mainly distributed to the liver, kidneys, and adipose
    tissue. It is rapidly excreted. Binding to liver and kidney protein
    and nucleic acids has been demonstrated.

    The biotransformation of the compound in experimental animals appears
    to be a saturable process, which mainly proceeds through a glutathione
    mediated pathway in which hexachlorobutadiene is initially converted
    to glutathione conjugates. These conjugates can be metabolized
    further, especially in the brush border membrane of renal tubular
    cells to a reactive sulfur metabolite, which probably accounts for the
    observed nephrotoxicity, genotoxicity, and carcinogenicity. 

    2.4  Effects on Organisms in the Environment

    Hexachlorobutadiene is moderately to very toxic for aquatic organisms.
    Crustaceans and fish species were found to be most sensitive, 96-h
    LC50 values ranging from 0.032 to 1.2 mg/dm3 and 0.09 to
    approximately 1.7 mg/dm3 for fish and crustaceans, respectively. The
    kidney was demonstrated to be an important target organ in fish. 

    On the basis of several long-term tests on algae and fish species, a
    no-observed-effect concentration (NOEC) of 0.003 mg/dm3 could be
    established, classifying the compound as very toxic for aquatic
    species. End-points investigated include general toxicity,
    neurotoxicity, biochemistry, haematology, pathology, and reproductive
    parameters. In one 28-day early life-stage test on the fathead minnow,
    reproduction was not affected at concentrations of up to
    0.017 mg/dm3, whereas increased mortality and a decreased body
    weight were observed at 0.013 and 0.017 mg/dm3. The NOEC was
    0.0065 mg/dm3.

    In a 90-day test on Japanese quail receiving a diet containing the
    compound at concentrations from 0.3 up to 30 mg/kg diet, the survival
    of chicks was decreased at 10 mg/kg diet only. No further reproductive
    effects were found.

    2.5  Effects on Animals

    Hexachlorobutadiene is slightly to moderately toxic for adult rats,
    moderately toxic for male weanling rats, and highly toxic for female
    weanling rats following a single oral dose (based on the WHO pesticide
    toxicity classification). The kidney is the major target organ and, to
    a much lesser extent, the liver.

    In the kidneys of rats, mice, and rabbits, hexachlorobutadiene caused
    a dose-dependent necrosis of the renal proximal tubules. Young rats
    and mice are more sensitive than adults, but adult female rats are
    highly suceptible. The lowest, single, intraperitoneal dose at which
    renal necrosis was induced in adult female rats was 25 mg/kg body
    weight, and in adult male and female mice 6.3 mg/kg body weight. Other
    routes have not been investigated with respect to renal toxicity.
    Biochemical changes and distinct functional alterations in the kidneys
    occurred at similar, or higher, doses than those at which necrosis was
    observed. 

    In short-term oral tests, 2 reproductive studies, and 1 long-term diet
    study on rats, the kidney also appeared to be the major target of
    hexachlorobutadiene. Dose-related effects included a decreased
    relative renal weight and tubular epithelial degeneration. The
    no-observed-adverse-effect level (NOAEL) for renal toxicity in rats
    and mice was 0.2 mg/kg body weight per day. In both species, adult
    females were more susceptible than males. 

    In one short-term inhalation test, similar effects on the kidneys were
    observed with exposure to a vapour concentration of 267 mg/m3,
    nominally. The NOAEL was 53 mg/m3.

    On the basis of animal data, the vapour of hexachlorobutadiene should
    be regarded as irritating to mucous membranes and the liquid as
    corrosive. The substance should also be regarded as a sensitizing
    agent.

    Two reproduction diet studies on rats at doses up to 20 and 75 mg/kg
    body weight per day, respectively, revealed reduced pup weight at
    doses of 7.5 and 20 mg/kg body weight. A highly toxic dose of 75 mg/kg
    body weight per day was sufficient to prevent implantation of eggs.
    Skeletal abnormalities were not observed.

    In two teratogenicity tests on rats receiving 10 mg/kg body weight per
    day, intraperitoneally, from days 1 to 15 of pregnancy, or exposed to
    vapour concentrations of between 21 and 160 mg/m3 for 6 h per day
    from days 6 to 20 of pregnancy, respectively, fetuses showed retarded
    development but no malformations. The retarded development was
    observed at levels that were also toxic to the dams.

    Hexachlorobutadiene and, to a much greater extent, its sulfur
    metabolites induced gene mutations in the Ames Salmonella test under
    special conditions favouring the formation of glutathione conjugation
    products. In one study of exposure to hexachlorobutadiene by
    inhalation or oral administration, an increased frequency of
    chromosomal aberrations was observed in mouse bone marrow cells. There
    is limited evidence for the genotoxicity of hexachlorobutadiene in
    mammals, but insufficient evidence in humans.

    Long-term administration of hexachlorobutadiene to rats at doses of
    0.02, 2, and 20 mg/kg body weight per day resulted in the induction of
    renal tubular neoplasms at the highest dose level, and also marked
    nephrotoxicity. The evidence for the carcinogenicity of the compound
    in experimental animals is considered limited (one study in one rodent
    strain) and, for humans, insufficient.

    The margin of safety between the estimated no-observed-adverse-effect
    level (NOAEL) and the estimated, maximum, total daily human intake is
    considered sufficient to protect the general population against the
    adverse effects of hexachlorobutadiene.

    The maximum predicted environmental concentration (PEC), away from
    point sources, is twice the extrapolated Environmental Concern Level.
    Aquatic organisms therefore may be at risk in polluted surface waters.
    Adverse effects on benthic organisms and fish-eating mammals cannot be
    excluded.

    3.  CONCLUSIONS AND RECOMMENDATIONS

    3.1  Human Health

    Exposure of the general public mainly occurs indirectly via
    drinking-water and food with a high lipid content.

    No human effect data are available: the evaluation is based entirely
    on experimental animal data.

    On the basis of acute, oral studies on adult rats hexachlorobutadiene
    is slightly to moderately toxic; on the basis of acute, oral
    experiments with weanling rats, it is moderately to highly toxic.

    On the basis of limited data, the vapour should be regarded as
    irritating to mucous membranes of humans and the liquid should be
    regarded as corrosive. The compound should be regarded as a
    sensitizing agent.

    Adverse reproductive effects have not been found in studies on rats.
    In two teratogenicity studies, developmental toxicity was observed in
    rat fetuses at levels that were also toxic to the dams.

    There is limited evidence of the genotoxicity or carcinogenicity of
    hexachlorobutadiene in animals, but insufficient evidence in humans.

    Direct exposure is considered too low to cause adverse health effects
    in the general population. 

    3.2  Environment

    Overall, the compound can be regarded as persistent. Because of a
    strong potential for adsorption on organic matter, the compound
    accumulates in sediment and does not migrate rapidly in soils.

    Field and laboratory data also support a high bioaccumulation
    potential in aquatic and benthic organisms. No evidence has been
    obtained for biomagnification.

    Hexachlorobutadiene is moderately to very toxic for aquatic organisms.
    Aquatic organisms may be at risk in very polluted surface waters.

    Adverse effects on benthic organisms cannot be excluded. Consumption
    of benthic or aquatic organisms by other species in polluted surface
    water may give cause for concern.

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

    4.1  Human Health Hazards, Prevention and Protection, First Aid

    The human health hazards associated with certain types of exposure to
    hexachlorobutadiene, together with preventive and protective measures
    and first aid recommendations are shown in the Summary of Chemical
    Safety Information (section 6).

    4.2  Advice to Physicians

    No specific antidote is known. Treat symptomatically.

    4.3  Health Surveillance Advice

    Human beings frequently potentially exposed to hexachlorobutadiene at
    levels near, or above, the exposure limit should undergo periodic
    medical examination, with emphasis on skin, eyes, and kidneys.

    4.4  Explosion and Fire Hazards, Prevention

    4.4.1  Explosion and fire hazards

    Hexachlorobutadiene is not flammable. The autoignition temperature of
    hexachlorobutadiene is 610 C. The substance decomposes above 600 C,
    or when involved in a fire, with the formation of a noxious gas
    (phosgene) and corrosive vapour (hydrochloric acid). Cylinders may
    explode in the heat of a fire. The compound reacts with aluminium,
    with the production of heat, and attacks rubber and certain plastics. 

    4.4.2  Prevention

    Do not use hexachlorobutadiene near open fires and hot surfaces, or
    when welding. Do not smoke. Avoid contact between the compound and
    incompatible materials (see section 4.4.1).

    Caution must be applied in approaching fire and applying water.
    Fire-fighters should use a full-face mask, and self-contained
    breathing apparatus.

    4.4.3  Fire extinguishing agents

    Extinguishing agents include dry chemical powder, foam, water spray,
    and carbon dioxide. Water may cause frothing if it gets below the
    surface of liquids, and turn to steam; water-fog, applied gently to
    the surface, will cause frothing that will extinguish fire.

    4.5  Storage

    Hexachlorobutadiene should be stored away from foodstuffs and
    incompatible materials (see section 4.4.1) in a cool, dark,
    fire-proof, and well-labelled room, with ventilation across the floor.

    4.6  Transport

    In case of an accident, stop the engine, extinguish any naked lights,
    and do not smoke. Keep bystanders at a distance and mark the roads.
    Keep upwind. In case of spillage or fire, use the methods advised in
    sections 4.7 and 4.4, respectively. Notify the police and the fire
    service, immediately. In case of poisoning, follow the advice in
    section 4.1.

    4.7  Spillage and Disposal

    4.7.1  Spillage

    Evacuate and ventilate the area. Collect leaking liquid in a sealable
    container. Do not touch spilled material. Absorb spilled liquid in
    sand or an inert absorbent and remove to a safe place. Ensure personal
    protection. The vapour is invisible, heavier than air, and spreads
    along ground. If the substance has entered a water-course or sewer, or
    has contaminated soil or vegetation, advise the police.

    4.7.2  Disposal

    Spray into a furnace with after-burner and alkali-scrubber.
    Incineration will become easier by mixing with a flammable solvent.

    5.  HAZARDS FOR THE ENVIRONMENT AND THEIR PREVENTION

    Overall, the compound can be regarded as persistent, with a high
    bioaccumulation potential in aquatic and benthic organisms.

    Hexachlorobutadiene is moderately to very toxic for aquatic organisms.
    Aquatic organisms may be at risk in polluted surface waters. Adverse
    effects on benthic organisms cannot be excluded. Consumption of
    benthic or aquatic organisms by other species in polluted surface
    water gives cause for concern.

    Contamination of soil, water, and the atmosphere can be avoided by
    proper methods of storage, transport, and waste disposal. In case of
    spillage, apply the methods recommended in section 4.7.1. Use closed
    systems where feasible.

    6.  SUMMARY OF CHEMICAL SAFETY INFORMATION

     This summary should be easily available to all health workers
     concerned with, and users of, hexachlorobutadiene. It should be
     displayed at, or near, entrances to areas where there is potential
     exposure to hexachlorobutadiene, 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 for local trade names.

        HEXACHLOROBUTADIENE 

    (perchlorobutadiene)

    C4Cl6

                                                                                                                                         

    PHYSICAL PROPERTIES                                               OTHER CHARACTERISTICS
                                                                                                                                         

    Relative molecular mass                     260.8                 Nonflammable, combustible, clear, colourless liquid with
    Melting point (C)                          -19 to -22            a turpentine-like odour. The substance decomposes above
    Boiling point (C)                          215                   600 C, or when involved in a fire, with the formation of a
    Water solubility (mg/dm3, 20 C)            3.2                   noxious gas (phosgene) and corrosive vapour (hydrochloric acid).
    Specific density (20 C)                    1.5542                The vapour is heavier than air and spreads along the ground.
    Relative vapour density                     9.0                   Reacts with aluminium, with the production of heat. Attacks
    Vapour pressure (kPa)(20 C)                0.02                  rubber and certain plastics.
    Autoignition temperature (C)               610                   Renal damage may develop following high, acute exposure 
                                                                      and following prolonged exposure. The substance should be
                                                                      regarded as a possible carcinogen. 

                                                                                                                                         

    HAZARDS/SYMPTOMS                        PREVENTION AND PROTECTION                    FIRST AID
                                                                                                                                         

    SKIN: Corrosive, burns, redness,        Wear clean, impervious clothing,             Remove contaminated clothing and
    pain                                    gloves, and shoes                            shoes instantly; wash with plenty of
                                                                                         water for at least 15 minutes;
                                                                                         obtain medical attention immediately

    EYES: Corrosive, redness, pain,         Wear safety goggles or face shield           Rinse with plenty of water for at
    lacrimation                                                                          least 15 minutes; obtain medical
                                                                                         attention immediately

    INHALATION: Irritation of all           Apply ventilation, local exhaust, or         Remove victim to fresh air and keep 
    exposed mucosae; painful sensation      breathing protection by a suitable           quiet and warm; if breathing has
    in nose and throat; at higher           respirator                                   stopped, apply artificial
    exposures pulmonary oedema                                                           respiration; obtain medical
                                                                                         attention immediately

    INGESTION: Irritation or                Do not eat, drink, chew, or smoke            Rinse mouth; give large quantities
    corrosion of mouth, throat, and         during work; do not keep food in             of water to drink; do NOT induce
    gastrointestinal tract                  areas with potential exposure; keep          vomiting; obtain medical attention
                                            out of reach of children                     immediately

    ENVIRONMENT: May present                Contamination of water, soil,
    a risk to aquatic and benthic           and atmosphere can be avoided by
    organisms and to species                proper methods of storage, transport,
    consuming these organisms               and waste disposal

                                                                                                                                         

    SPILLAGE                                STORAGE                                      FIRE AND EXPLOSION
                                                                                                                                         

    Evacuate and ventilate the area;        Store away from foodstuffs and               Hexachlorobutadiene decomposes above
    collect leaking liquid in a sealable    incompatible materials in a cool,            600 C, or in open fires, with the
    container; absorb spilt liquid in       dark, fire-proof, and well labelled          formation of toxic gases; cylinders 
    sand or inert material; ensure          room, with ventilation across the            may explode in the heat; do not use 
    personal protection                     floor; containers must be labelled,          near open fires and hot surfaces or close
                                            tightly closed, and kept in a good           to welding sites; extinguish fires with
                                            condition                                    dry powder, foam, water spray, or
                                                                                         carbon dioxide

                                                                                                                                         

    WASTE DISPOSAL
                                                                                                                                         

    Incineration: spray into a furnace      National occupational exposure               UN 1092
    with after-burner and                   limit:                                       Labelling:
    alkali-scrubber

                                            National Poison Control Centre:

                                                                                                                                         
        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. The file contains regulatory data on chemicals from 12 countries
    and recommendations by 6 international organizations. 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).

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

    7.1  Exposure Limit Values

    Some values for exposure limit are shown in the table on the next
    page.

    7.2  Specific Restrictions

    In the USSR, the substance was approved as a fungicide for
    agricultural use; application dose and mode, and treatment frequency
    were specified (effective date: 1981). A later regulation stipulates
    that the substance is severely restricted for use as a pesticide: it
    may be used on vines only for quarantine (not harvesting) purposes
    (effective date: 1986 (r)). 

    7.3  Labelling, Packaging, and Transport

    The United Nations Committee of Experts on the Transportation of
    Dangerous Goods classifies hexachlorobutadiene as a poisonous
    substance (Hazard Class 6.1). Hexachlorobutadiene is also classified
    as a substance presenting minor danger for packing purposes (Packing
    Group III). Packing methods and labels are recommended (effective
    date: 1986 (r)).

    In Germany, hexachlorobutadiene is classified as harmful to water
    (Class 2). In order to protect water, appropriate security measures
    should be taken during storage, loading, and transport (effective
    date: 1985 (r)).

    In Canada, the substance is classified for transport as hazardous to
    the environment (Class 9.2). Special provisions for transport are
    prescribed (effective date: 1987).


        Table 2. Some exposure limit values

                                                                                                                                         

    Medium      Specification       Country/            Exposure limit descriptiona                  Value                Effective
                                    organization                                                                          date
                                                                                                                                         
    Air         Occupational        Australia           Threshold limit value (TWA)                  0.24 mg/m3 b         1983 (r)

                                    Brasil              Acceptable limit (48 h/week)                 1720 mg/m3           1980 (r)

                                    Canada              Threshold limit value (TWA)                  0.24 mg/m3           1980

                                    Germany             Maximum worksite concentration (TWA)         - c,d                1988(r)

                                    Netherlands         Maximum limit (TWA)                          0.24 mg/m3           1989(r)

                                    Switzerland         Maximum worksite concentration (TWA)         0.24 mg/m3 e         1987 (r)

                                    USA (ACGIH)         Threshold limit value (TWA)                  0.24 mg/m3           1987 (r)

                                    USSR                Ceiling value                                5 g/m3              1983 

    Air         Ambient             USSR                Maximum allowable concentration
                                                          average per day                            0.2 mg/m3            1978 (r)
                                                          once per day                               1 mg/m3              1978 (r)

    Water       Surface             USSR                Maximum allowable concentration              0.01 mg/dm3          1983

    Soil                            USSR                Maximum allowable concentration              0.5 mg/kg            1981

    Food                            USSR                Maximum residue limit(specified food)        0.01 mg/kg           1983
                                                        Acceptable daily intake (calculated)         0.001 mg/kg          1983
              
    a TWA = time-weighted-average over one working day (usually 8 h).
    b Suspected carcinogen.
    c Suspected carcinogen; cutaneous absorption.
    d No value established because of carcinogenic potential.
    e Cutaneous absorption.
        7.4  Waste Disposal

    In the USA, any solid waste (except domestic) containing
    hexachlorobutadiene must be listed as hazardous waste, subject to
    handling, transport, treatment, storage, and disposal requirements,
    unless it is found the waste cannot pose a threat to human health or
    the environment when improperly managed (effective date: 1980). If the
    substance is a commercial chemical product, it is identified as "toxic
    waste", subject to handling, transport, treatment, storage, and
    disposal regulations and permit and notification requirements
    (effective date: 1980).  An owner or operator of a hazardous waste
    incinerator must achieve 99.99% destruction and removal efficiency for
    the substance, if it is designated as a principal organic hazardous
    constituent in its Environmental Protection Agency (EPA) permit
    (effective date: 1981).

    In the USA, permits are required for discharge of hexachlorobutadiene
    from any point source into USA waters (effective date: 1980). EPA is
    required to set, or has set, effluent limitations and pretreatment
    standards for 21 major industries regarding hexachlorobutadiene
    (effective date: 1981 (r)).

    BIBLIOGRAPHY

    Anonymous (1989)  [Chemical cards. Handling chemicals safely.] 5th
    edition. The Netherlands, NIA, VNCI, Samson Tjeenk-Willink. (in Dutch)

    Chemical Industry Association (1979)  CEFIC TREMcards, Reference
    edition. London, England, Chemical Industry Association.

    INRS (1977)  Fiche toxicologique no 121. Hexachlorobutadiene.
    Institut National de Recherche Scientifique, Paris, France.

    IRPTC (1990)  Data profile for hexachlorobutadiene. Geneva,
    Switzerland, International Register of Potentially Toxic Chemicals,
    United Nations Environment Programme.

    


    See Also:
       Toxicological Abbreviations
       Hexachlorobutadiene (EHC 156, 1994)
       Hexachlorobutadiene (ICSC)
       Hexachlorobutadiene  (IARC Summary & Evaluation, Volume 20, 1979)
       Hexachlorobutadiene  (IARC Summary & Evaluation, Volume 73, 1999)