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    IPCS INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY
    Health and Safety Guide No. 109



    VINYL CHLORIDE





    UNITED NATIONS ENVIRONMENT PROGRAMME

    INTERNATIONAL LABOUR ORGANISATION

    WORLD HEALTH ORGANIZATION




    IPCS

    Health and Safety Guide No. 109

    VINYL CHLORIDE HEALTH AND SAFETY GUIDE

         This is a companion volume to Environmental Health Criteria 215:
    Vinyl 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) and produced within the framework
    of the Inter-Organization Programme for the Sound Management of
    Chemicals



    WORLD HEALTH ORGANIZATION, GENEVA 1999


    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

    Vinyl chloride: health and safety guide.

    (Health and safety guide ; no. 109)

    1.Vinyl chloride - toxicity  2.Environmental exposure 
    3.Occupational exposure  4.Guidelines
    I.International Programme on Chemical Safety II.Series

    ISBN 92 4 151109 5       (NLM Classification: QV 633)
    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 1999

    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. Conversion factors
         1.4. Analytical methods
         1.5. Production and uses

    2. SUMMARY AND EVALUATION
         2.1. Exposure
              2.1.1. General population
              2.1.2. Occupational exposure
         2.2. Uptake, metabolism and excretion
         2.3. Effects on organisms in the environment
         2.4. Effects on experimental animals and  in vitro test systems
         2.5. Effects on humans

    3. RECOMMENDATIONS FOR PROTECTION OF HUMAN HEALTH
         3.1. Public health
         3.2. Occupational health

    4. HUMAN HEALTH HAZARDS, PREVENTION AND PROTECTION, EMERGENCY ACTION
         4.1. Human health hazards, prevention and
              protection, first aid
              4.1.1. Information for physicians
                        4.1.1.1   Signs and symptoms of exposure
                        4.1.1.2   First aid
                        4.1.1.3   Medical treatment
                        4.1.1.4   Effects of chronic exposure
              4.1.2. Health surveillance advice
                        4.1.2.1   Initial medical screening
                        4.1.2.2   Periodic medical examination
              4.1.3. Prevention and protection

         4.2. Explosion and fire hazards
              4.2.1. Explosion hazards
              4.2.2. Fire hazards
         4.3. Handling and storage
         4.4. Spillage

    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. Occupational exposure limit values
         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

    CAS/IUPAC name           Chloroethene

    Chemical formula:        C2H3Cl

    Chemical structure:      H2C=CHCl

    Common synonyms:         Vinyl chloride, VC, VCM, 1-chloroethylene

    CAS registry number:     75-01-4

    EC number:               602-023-007

    EINECS number:           2008310

    RTECS registry number:   KU9625000

    UN transport number      1086 (inhibited)

    1.2  Physical and chemical properties

         At ambient temperature, vinyl chloride (VC) is a colourless,
    compress liquefied flammable gas. It has a slightly sweet odour but
    the odour threshold value is very subjective and is far above the
    present accepted occupational safety threshold values. VC is heavier
    than air. It has relatively low solubility in water but is soluble in
    almost all organic solvents. With air, very explosive peroxides can be
    formed. Combustion of VC in air produces hydrogen chloride. At ambient
    temperatures in the absence of air, dry purified VC is highly stable
    and non-corrosive.

         Other physical and chemical properties of vinyl chloride are
    given in the Summary of Chemical Safety Information (section 6).

    1.3  Conversion factors

         1 ppm = 2.59 mg/m3 at 20C and 101.3 kPa
         1 mg/m3 = 0.386 ppm

    1.4  Analytical methods

         The concentration of VC in air can be monitored by trapping it on
    adsorbents and, after liquid or thermal desorption, analysis by gas
    chromatography (GC). In ambient air measurements, several adsorbents
    in series or refrigerated traps may be needed to increase the
    efficiency of trapping. Peak concentrations at workplaces can be
    measured with direct reading instruments based on, for instance, flame
    ionization detection (FID) or photo-ionization detection (PID). For

    continuous monitoring, infrared and GC/FID analysers combined with
    data logging and processing have been used, whereas, for analysis of
    VC in liquids and solids direct injection, extraction and, more
    increasingly, head space or purge-and-trap techniques are applied.
    Also in these samples, VC is analysed by GC fitted to, for instance,
    FID or mass spectrometry detectors.

    1.5  Production and uses

         VC is produced industrially by two main reactions: 1) the
    hydrochlorination of acetylene; 2) the thermal cracking (at about
    500C) of 1,2-dichloroethane produced by direct chlorination (ethylene
    and chlorine) or oxychlorination (ethylene, HCl and air/O2) of
    ethylene in the "balanced process". The latter process is most
    commonly used nowadays.

         About 95% of the world production of VC is used for the
    production of polyvinyl chloride (PVC, where  n = 700-1500) and the
    manufacture of co-polymers with monomers such as vinyl acetate or
    vinylidene chloride. The remainder goes into the production of
    chlorinated solvents, primarily 1,1,1-trichloroethane (10 000
    tonnes/year). The world production of PVC (and therefore VC) in 1998
    was about 27 million tonnes. PVC accounts for 20% of plastic material
    usage and is used in most industrial sectors.
    

    2.  SUMMARY AND EVALUATION

    2.1  Exposure

    2.1.1  General population

         There is very little exposure of the general population to VC.

         Atmospheric concentrations of VC in ambient air are low, usually
    less than 3 g/m3. Exposure of the general population may be higher
    in situations where large amounts of VC are accidentally released to
    the environment, such as in a spill during transportation. However,
    such exposure is likely to be transient. Near VC/PVC industry and
    waste disposal sites, much higher concentrations (up to 8000 g/m3
    and 100 g/m3, respectively) have been recorded.

         Indoor air concentrations in houses adjacent to land fills
    reached maximal concentrations of 1000 g/m3.

         VC has occasionally been detected in surface waters, sediment and
    sewage sludges, with maxima of 570 g/litre, 580 g/kg and 62 000
    g/litre, respectively. Soil samples near an abandoned chemical
    cleaning shop contained very high VC concentrations (up to 900 mg/kg).
    Maximal VC concentrations in groundwater or leachate from areas
    contaminated with chlorinated hydrocarbons amounted to 60 000 g/litre
    (or more). High concentrations (up to 200 mg/litre) were detected in
    well water in the vicinity of a PVC plant 10 years after leakages.

         In the majority of drinking-water samples analysed in the past,
    VC was not present at detectable concentrations. The maximum VC
    concentration reported in finished drinking-water was 10 g/litre.
    Although there is a lack of recent data on VC concentrations in
    drinking-water, these levels are expected to be below 10 g/litre. If
    contaminated water is used as the source of drinking-water, higher
    exposures may occur. Some recent studies have identified VC in
    PVC-bottled drinking-water at levels below 1 g/litre. The frequency
    of occurrence of VC in such water is expected to be higher than in tap
    water.

         Packaging with certain PVC materials can result in VC
    contamination of foodstuff, pharmaceutical or cosmetic products,
    including liquors (up to 20 mg/kg), vegetable oils (up to 18 mg/kg),
    vinegars (up to 9.8 mg/kg) and mouthwashes (up to 7.9 mg/kg). Owing to
    the legislative action of many countries, a significant reduction in
    VC levels and/or in the number of positive samples has been achieved
    since the early 1970s.

         Dietary exposure to VC from PVC packages used for food has been
    calculated by several agencies and, based upon estimated average
    intakes in the United Kingdom and USA, an exposure of <0.0004 g/kg
    body weight per day was estimated for the late 1970s and early 1980s.
    An early study identified VC in tobacco smoke at the ng/cigarette
    range.

         The few data available show that VC can be present in the tissues
    of small aquatic invertebrates and fish.

    2.1.2  Occupational exposure

         The main route of occupational exposure is via inhalation and
    occurs primarily in VC/PVC plants. Occupational exposure to VC
    amounted to several thousands of mg/m3 in the 1940s and 1950s and
    several hundreds of mg/m3 in the 1960s and early 1970s. After the
    recognition of the carcinogenic hazards of VC, occupational exposure
    standards were set at approximately 13-26 mg/m3 (5-10 ppm) in most
    countries in the 1970s. Compliance with these guidelines has
    considerably lowered workplace VC concentrations, but even in the
    1990s higher concentrations have been reported and may still be
    encountered in some countries.

    2.2 Uptake, metabolism and excretion

         VC is rapidly and well absorbed after inhalation or oral
    exposure. The primary route of exposure to VC is inhalation. In animal
    and human studies, under steady-state conditions, approximately 40% of
    inspired VC is absorbed after exposure by inhalation. Animal studies
    showed an absorption of more than 95% after oral exposure. Dermal
    absorption of VC in the gaseous state is not significant.

         Data from oral and inhalation studies on rats indicate rapid and
    widespread distribution of VC. Rapid metabolism and excretion limits
    accumulation of VC in the body. Placental transfer of VC occurs
    rapidly in rats.

         The main route of metabolism of VC involves oxidation by
    cytochrome P-450 (CYP2E1) to form chloroethylene oxide (CEO), a highly
    reactive epoxide which rapidly rearranges to form chloroacetaldehyde
    (CAA). The primary detoxification reaction of these two reactive
    metabolites is conjugation with glutathione catalysed by glutathione
     S-transferase. The conjugation products are further modified to
    substituted cysteine derivatives and excreted via urine, and the CO2
    generated is exhaled.

         After exposure to low doses, VC is metabolically eliminated and
    nonvolatile metabolites are excreted mainly in the urine. After
    exposure by inhalation, the metabolic elimination velocity is lower in
    humans than in laboratory animals on a body weight basis. However, on
    a body surface area basis, the metabolic clearance of VC in humans is
    comparable to that of other mammalian species. With increasing oral or
    inhalation exposure, the major route of excretion in animals is
    exhalation of unchanged VC, indicating the saturation of metabolic
    pathways. Independently of applied dose, the excretion of metabolites
    via faeces is only a minor route.

         With regard to carcinogenicity, CEO is thought to be the most
    important metabolite of VC. CEO reacts with DNA to produce
    promutagenic exocyclic etheno adducts.

    2.3  Effects on organisms in the environment

         There is a lack of standard toxicity data on the survival and
    reproduction of aquatic organisms exposed to VC. Care must be taken
    when interpreting the data that are available, as most of it was
    generated from tests where the exposure concentration was not measured
    and therefore losses due to volatilization were not taken into
    account.

         The lowest concentration of VC that caused an effect in
    microorganisms was 40 mg/litre. This was an EC50 value based upon
    inhibition of respiration in anaerobic microorganisms in a batch assay
    over 3.5 days.

         The lowest concentration that caused an effect in higher
    organisms was 210 mg/litre (48-h LC50 for a freshwater fish); with a
    corresponding no-observed-adverse-effect concentration (NOAEC) of 128
    mg/litre. Effects due to VC have been reported at lower concentrations
    in other species, but the ecological significance of these effects was
    not verified.

         VC concentrations predicted to be non-hazardous to freshwater
    fish were calculated to range from 0.088 to 29 mg/litre.

         There is a paucity of data concerning the effects of VC on
    terrestrial organisms.

    2.4  Effects on experimental animals and in vitro test systems

         VC appears to be of low acute toxicity when administered to
    various species by inhalation. The 2-h LC50 values for rat, mouse,
    guinea-pig and rabbit were reported to be 390 000, 293 000, 595 000
    and 295 000 mg/m3, respectively. VC has a narcotic effect after
    inhalative administration. In rats, mice and hamsters, death by
    respiratory failure was preceded by increased motor activity, ataxia
    and convulsions. In dogs, severe cardiac arrythmias occurred after
    inhalative exposure to 260 000 mg/m3. After acute inhalative exposure
    to VC in rats, pathological findings included congestion of the
    internal organs, particularly lung, liver and kidney, as well as
    pulmonary oedema.

         No studies or relevant data are available for assessing effects
    of dermal exposure, skin irritation or sensitizing property of VC.

         In various species, the main target organ for short-term (up to 6
    months) inhalation toxicity of VC is the liver. Increases in relative
    liver weights and hepatocellular changes were noted in rats at 26
    mg/m3 (the lowest dose level tested); at higher levels (> 260
    mg/m3) more pronounced liver changes occurred in a dose-related

    manner. Other target organs were the kidney, lung and testis. Rats,
    mice and rabbits seem to be more sensitive than guinea-pigs and dogs.

         Long-term inhalation exposure to VC resulted in increased
    mortality in some strains of rats at a dose as low as 260 mg/m3, in
    mice at 130 mg/m3 and in hamsters at 520 mg/m3. Rats exposed to
    130 mg/m3 showed reduced body weight and increased relative spleen
    weight, hepatocellular degeneration and proliferation of cells lining
    the liver sinusoids. Exposure to higher levels produced degenerative
    alteration in the testis, tubular nephrosis and focal degeneration of
    the myocardium in rats. For rats and mice exposed via inhalation, the
    no-observed-adverse-effect level (NOAEL) concerning non-neoplastic
    effects is below 130 mg/m3.

         Long-term feeding studies showed increased mortality, increased
    liver weights and morphological alteration of the liver. In rats,
    liver cell polymorphism (variation in size and shape of hepatocytes
    and their nuclei) could be seen at levels as low as 1.3 mg/kg body
    weight, and the NOAEL was 0.13 mg/kg body weight.

         Long-term feeding studies in rats with VC in PVC granules yielded
    significantly increased incidences of angiosarcoma of the liver (ASL)
    at 5.0 mg/kg body weight per day and neoplastic liver nodules
    (females) and hepatocellular carcinoma (HCC) (males) at 1.3 mg/kg body
    weight per day.

         In inhalation studies with VC in Sprague-Dawley rats, a clear
    dose-response relationship was observed for ASL and, at high
    concentrations, Zymbal gland carcinomas. No clear dose-dependency for
    hepatoma or extrahepatic angiosarcoma, nephroblastomas,
    neuroblastomas, or mammary malignant tumours was observed. In mice,
    the spectrum of tumours induced by long-term inhalation exposure was
    similar to that observed in rats, but an increase in lung tumours was
    only observed in mice. In hamsters, increased incidences of ASL,
    mammary gland and acoustic duct tumours, melanomas, stomach and skin
    epithelial tumours were reported.

         The mutagenic and genotoxic effects of VC have been detected in a
    number of  in vitro test systems, predominantly after metabolic
    activation. VC is mutagenic in the Ames test in  Salmonella
     typhimurium strains TA100, TA1530 and TA1535 but not in TA98, TA1537
    or TA1538, indicating mutations as a result of base-pair substitution
    rather than frameshift mutations.

         Other gene mutation assays in bacteria, yeast cells, plant
     (Tradescantia) cuttings and mammalian cells have revealed positive
    results in the presence of metabolic activation. VC induced gene
    conversion in  Saccharomyces cerevisiae, unscheduled DNA synthesis in
    rat hepatocytes and sister-chromatid exchanges (SCE) in human
    lymphocytes in the presence of a metabolic activation system. Cell
    transformation assays revealed positive results with and without
    metabolic activation.

         VC exposure induced gene mutation and mitotic recombination in
     Drosophila melanogaster but not gene mutations in mammalian germ
    cells  in vivo. VC showed clastogenic effects in rodents, increased
    SCE in hamsters and induced DNA breaks in mice. VC also induced gene
    conversion and forward mutations in yeast in host-mediated assays in
    rats.

    2.5  Effects on humans

         Concentrations of VC in the region of 2590 mg/m3 (1000 ppm),
    which were not unusual prior to 1974, over periods ranging from 1
    month to several years, have been reported to cause a specific
    pathological syndrome found in VC workers called the "vinyl chloride
    illness". Symptoms described were earache and headache, dizziness,
    unclear vision, fatigue and lack of appetite, nausea, sleeplessness,
    breathlessness, stomachache, pain in the liver/spleen area, pain and
    tingling sensation in the arms/legs, cold sensation at the
    extremities, loss of libido and weight loss. Clinical findings
    included scleroderma-like changes in the fingers with subsequent bony
    changes in the tips of the fingers described as acroosteolysis,
    peripheral circulatory changes identical with the classical picture of
    Raynaud's disease and enlargement of the liver and spleen with a
    specific histological appearance, and respiratory manifestations.

         Studies in humans have not been adequate to confirm effects on
    the reproductive system. A few morbidity studies have reported
    elevated incidence of circulatory diseases among vinyl chloride
    workers. However, large cohort studies have found lower cardiovascular
    disease mortality.

         There is strong and consistent evidence from epidemiological
    studies that VC exposure causes the rare tumour, angiosarcoma of the
    liver. Brain tumours and hepatocellular carcinoma of the liver may
    also be associated with VC, although the evidence cannot be considered
    definitive. Other cancer sites reported to be in excess, but less
    consistently, include lung, lymphatic and haematopoietic tissue, and
    skin.

         VC is mutagenic and clastogenic in humans. Frequencies of
    chromosomal aberrations (CA), micronuclei (MN) and sister-chromatid
    exchanges (SCE) in the peripheral blood lymphocytes of workers exposed
    to high levels of VC have been shown to be raised compared to
    controls. Although in many studies the exposure concentrations and
    duration of exposure were only estimated, a dose-response relationship
    and a "normalization" of genotoxic effects with time after reduction
    of exposure can be seen.

         Point mutations have been detected in  p53 and  ras genes in
    liver angiosarcoma from highly exposed autoclave workers and in
    hepatocellular carcinoma from another exposed worker.

         Biological markers that have been investigated as indicators for
    VC exposure or VC-induced effects include: a) excretion of VC
    metabolites (e.g., thiodiglycolic acid); b) genetic assays (e.g.,
    chromosomal abnormalities or micronucleus assay); c) levels of enzymes
    (e.g., in liver function tests); d) serum oncoproteins (p21 and p53)
    and/or their antibodies.

         Children living near landfill sites and other point sources may
    be at increased risk based on suggestive evidence of early
    life-sensitivity in animal studies. However, there is no direct
    evidence in humans.

         In epidemiological studies, a clear dose-response relationship is
    only evident for ASL alone or in combination with other liver tumours.
    Only one epidemiological study has sufficient data for quantitative
    dose-response estimation.
    

    3.  RECOMMENDATIONS FOR PROTECTION OF HUMAN HEALTH

    3.1  Public health

         The following measures should be taken:

    *    worldwide application of production technologies leading to low
         residual VC levels in PVC;

    *    implementation and enforcement worldwide of steps that guarantee
         minimal emissions of VC at production sites;

    *    identification, surveillance and emission and exposure control of
         contaminated areas such as landfill sites.

    3.2  Occupational health

         Since VC is a genotoxic carcinogen, exposures should be kept as
    low as possible, using the best available technology worldwide.

         More information, education and training of workers potentially
    exposed to VC regarding the risks involved and safe working procedures
    and habits is required.

         Monitoring and record-keeping of exposure and record-keeping of
    exposed workers are needed.
    

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

    4.1  Human health hazards, prevention and protection, first aid

    4.1.1  Information for physicians

    4.1.1.1  Signs and symptoms of exposure

         Exposure to levels of VC above 25 900 mg/m3 (10 000 ppm) causes
    acute effects on the central nervous system, e.g., dizziness,
    disorientation and narcosis, and higher concentrations in air may
    prove fatal.

    4.1.1.2  First aid

    a)  Eye contact

         Immediately flush with large amounts of water for at least 15
    min, occasionally lifting upper and lower lids. Seek medical attention
    immediately. VC is stored under pressure; exposure to escaping gas may
    cause frostbite.

    b)  Skin contact

         Quickly remove victim from source of contamination and
    flush/immerse affected part in warm water. Seek medical attention.
    Exposure to escaping compress liquefied gas may cause frostbite.

    c)  Breathing

         Remove the person from exposure.

         Begin artificial respiration if breathing has stopped and
    cardio-pulmonary resuscitation if heart action has stopped.

         Transfer immediately to a medical facility.

    4.1.1.3  Medical treatment

         In case of intoxication the treatment is supportive. Death may
    result from central nervous system depression and/or cardiac
    arrhythmia.

    4.1.1.4  Effects of chronic exposure

         Chronic health effects observed after exposure to high levels of
    VC monomer gas are angiosarcoma of the liver and obstructive disease
    of peripheral arteries, which may appear as Raynaud's phenomenon,
    scleroderma-like disease or acro-osteolysis.

         Possible other effects at similar levels of exposure include
    tumours of the brain and hepatocellular carcinoma.

         VC may also cause liver toxicity.

    4.1.2  Health surveillance advice

    4.1.2.1  Initial medical screening

         Liver function tests form the basis of initial medical screening.

    4.1.2.2  Periodic medical examination

         The primary method of prevention is by monitoring of exposure.
    When low levels of exposure cannot be guaranteed, medical screening
    may be useful. It should be directed towards assessment of the
    peripheral vascular system and the function of the liver.

          Ad hoc cytogenetic studies can be performed.

    4.1.3  Prevention and protection

         VC is a human carcinogen. There may be no safe level of exposure,
    so all contact should be reduced to the lowest possible level. Odour
    is an inadequate warning of excessive exposure.

         Engineering controls are the most effective way of reducing
    exposure. The best protection is to enclose operations and provide
    local exhaust ventilation at the site of chemical release.

         Protective clothing and, where necessary, an approved
    air-purifying respirator should be used. When the level of exposure is
    not known or the airborne exposure guidelines may be exceeded, an
    approved positive-pressure breathing apparatus should be used. Safety
    glasses should be worn.

         A pit or tank must never be entered without adhering to the
    following safety procedures: never alone, always with a lifeline, and
    always with a positive pressure supply of fresh air.

         Continuous exposure monitoring and record keeping is necessary.

    4.2  Explosion and fire hazards

    4.2.1  Explosion hazards

         VC forms explosive mixtures with air. It can also form
    shock-sensitive peroxides on exposure to air.

         Heat and contact with oxidizing agents, oxygen, air, sunlight and
    other polymerization catalysts must be avoided.

         VC vapour polymerizes in the presence of air and may block
    ventilation systems, leading to a risk of explosion and/or fire
    hazard.

    4.2.2  Fire hazards

         VC is a highly flammable liquid or gas and a dangerous fire
    hazard. Hazardous decomposition products (hydrogen chloride, phosgene
    and others) are formed on complete or incomplete combustion.

         A fire involving VC should be controlled with alcohol foam, dry
    chemical or carbon dioxide. Water must not be used.

         Containers may explode in case of fire. Water spray should be
    used to keep fire-exposed containers cool.

    4.3  Handling and storage

         VC should be stored in cool well-ventilated areas, out of direct
    sunlight. It is usually stored under pressure and handled as a liquid.
    It must be kept away from sparks, flames and other ignition sources.

         VC vapour is heavier than air and will tend to collect in low
    areas. It should not be used in confined spaces.

    4.4  Spillage

         Leaks should be stopped as soon as possible. All sources of
    ignition must be eliminated. VC vapour can travel to an ignition
    source and flash back causing a flash fire. Because of the explosive
    hazard, fire at a leak must not be extinguished unless the leak is
    simultaneously closed.

         In the event of a spillage, liquid should be contained and
    discharges to streams or sewer system prevented. People performing the
    clean-up should have full protective equipment and positive-pressure
    breathing apparatus.
    

    5.  HAZARDS FOR THE ENVIRONMENT AND THEIR PREVENTION

         There is very limited information on the environmental effects of
    VC. Laboratory tests indicate that it has low toxicity for aquatic
    organisms. If released to soil or surface water, volatilization is
    likely to take place. Biodegradation is possible but very slow in
    anaerobic environments. VC is not expected to hydrolyse, adsorb to
    organic fractions of soils or sediments, or to biomagnify. VC has been
    found to leach into groundwater and has been found there as a
    degradation product of trichloroethylene and related solvents, where
    it may remain under certain conditions.
    

    6.  SUMMARY OF CHEMICAL SAFETY INFORMATION

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


        SUMMARY OF CHEMICAL SAFETY INFORMATION
                                                                                                                                       
    Vinyl chloride
    CAS Registry No. 75-01-4
    C2H3Cl

    PHYSICAL PROPERTIES                                                 OTHER CHARACTERISTICS
                                                                                                                                       

    Relative molecular mass                62.5                         Colourless flammable gas with a slightly sweet odour. It is
    Boiling point (C)                     -13                          heavier than air and may travel along the ground. It can
    Melting point (C)                     -154                         under specific circumstances form peroxides, initiating
    Relative density (water = 1)           0.9                          explosive polymerization. It will polymerize readily due to
    Solubility in water                    none                         heating, under the influence of air, light, and on contact
    Relative vapour density (air = 1)      2.2                          with a catalyst, strong oxidizing agents and metals such as
    Flash point (closed cup) (C)          -78                          copper and aluminium, with fire or explosion hazard. It
    Auto-ignition temperature (C)         472                          decomposes on burning producing toxic and corrosive fumes
    Explosive limits, vol % in air         3.6-33                       (hydrogen chloride and phosgene).


    HAZARDS/SYMPTOMS                       PREVENTION AND PROTECTION    FIRST AID
                                                                                                                                       

    EYES: irritation, redness,             Wear safety goggles.         Rinse with plenty of water for at least 15 min (remove contact
          pain                                                          lenses) obtain medical attention immediately.

                                                                                                                                       

    SKIN: contact with compressed          Avoid skin contact. Wear     In the event of frostbite, rinse with plenty of water. 
          liquid causes frostbite          protective clothing and      Do not remove clothes.
                                           protective
                                           (cold-insulating) gloves.

                                                                                                                                       

    INHALATION: can cause dizziness,       Apply ventilation local      Remove victim to fresh air and place in half-sitting
                drowsiness, headache,      exhaust or breathing         position; obtain medical attention immediately.
                unconsciousness            protection; avoid
                                           inhalation of vapour.

    SUMMARY OF CHEMICAL SAFETY INFORMATION (continued)
                                                                                                                                       

    INGESTION:                             Do not eat, drink or smoke
                                           during work. Wash hands
                                           before eating.
                                                                                                                                       

    SPILLAGE                               STORAGE                      FIRE AND EXPLOSION
                                                                                                                                       

    Evacuate the danger area. Wear         Store in a cool and          Extremely flammable; gives off irritating or
    complete protective clothing,          fireproofed area, separated  toxic fumes in a fire; gas/air mixtures are
    including self-contained breathing     from incompatible materials  explosive. In case of fire, extinguish with
    apparatus to clean up the spill.       (see under "Other            powder, carbon dioxide; keep cylinders cool
                                           characteristics").           by spraying with water.

                                                                                                                                       

    WASTE DISPOSAL                         PACKAGING & LABELLING
                                                                                                                                       

    Incinerate at high temperatures;       EU Classification
    complete combustion necessary to       Symbol:     F+, T
    avoid formation of phosgene; acid      R:          45-12
    scrubber needed to remove halo         S:          53-45
    acids formed.                          Note:       D
                                           UN Classification
                                           UN TDG Hazard Class: 2.1
                                                                                                                                       
        


    7.  CURRENT REGULATIONS, GUIDELINES AND STANDARDS

    7.1  Previous evaluations by international bodies

         Vinyl chloride was evaluated by the International Agency for
    Research on Cancer (IARC, 1979) and updated in Supplement 7 (IARC,
    1987). There was  sufficient evidence for carcinogenicity of vinyl
    chloride in humans and  sufficient evidence for carcinogenicity in
    animals. The overall evaluation was that vinyl chloride is
    carcinogenic to humans (Group 1).

         Using results from the rat bioassay of Til et al. (1983) and
    applying the linearized multistage model, the human lifetime exposure
    for a 10-5 excess risk of ASL was calculated to be 20 g per day in
    the Guidelines for Drinking-water Quality (WHO, 1996). It was assumed
    that, in humans, the number of cancers at other sites may equal that
    of ASL, so that a correction (factor of 2) for cancers other than ASL
    was justified. A concentration in drinking-water of 5 g/litre was
    calculated as being associated with an excess risk of 10-5.

    7.2  Occupational exposure limit values

         Some examples of present exposure limit values are given in the
    table on the next page.

    7.3  Labelling, packaging and transport

         EU labelling

         Symbol:   F+, T
         R: 45-12  45 = may cause cancer
                   12 = extremely flammable
         S: 53-45  53 = avoid exposure - obtain special instruction before
                        use
                   45 = in case of accident or if you feel unwell,
                        seek medical advice immediately (show the
                        label where possible)

         Note:      D
         UNTDG hazard class 2.1

    7.4  Waste disposal

         Waste material containing vinyl chloride should be disposed of by
    incineration.
    


        CURRENT REGULATIONS, GUIDELINES AND STANDARDS
                                                                                                                                

    Exposure limit values

    Country/organization       Exposure limit descriptiona     Value                Value                  Referenceb
                                                               (ppm)                (mg/m3)
                                                                                                                                

    Europe                     personal (8-h TWA)              7                    18.2                   CEC (1978)

        United Kingdom                                                                                     HSC (1995)
        Germany                                                                                            BIA (1997)
        Finland                                                5                    12.8                   Gov. Res. (1992)

    Europe                     working-area (annual)           3                    8                      CEC (1978)

        United Kingdom                                                                                     HSC (1995)
        Germany                                                                                            BIA (1997)
        Finland                                                                                            Gov. Res. (1992)
        Czech Republic         MACK                                                 10                     Bencko & Ungvry (1994)
        Slovakia
        Hungary
        Poland

    USA                        15 min                          5                    12.8                   OSHA (1998)
                               8 h                             1                    2.6                    OSHA (1998)
                                                               0                                           NIOSH (1997)
                                                               (no detectable
                                                               exposure levels)
                               TLV TWA (8 h)                                        2.6                    ACGIH (1999)
                                                                                                                                

    a TWA = time-weighted average; TLV = threshold limit value; MAKK = maximal allowable concentration (k indicates the
       carcinogenic properties of VC).
    b OSHA = US Occupational Safety and Health Administration; ACGIH = US American Conference of Governmental and Industrial
       Hygienists Inc.; HSC = UK Health and Safety Commission; BIA = German Professional Associations' Institute for Occupational
       Safety; Gov. Res. = Finnish Government Resolution
    

    BIBLIOGRAPHY

    ACGIH (1999) Threshold limit values for chemical substances and
    physical agents and biological exposure indices. Cincinnati, American
    Conference of Governmental and Industrial Hygienists.

    BIA (1997) List of hazardous substances. German Professional
    Associations' Institute for Occupational Safety, Sankt Augustin,
    Germany, 592-593 (in German).

    CEC (1978) Council directive of 29 June 1978 on the approximation of
    the laws, regulations and administrative provisions of the Member
    States on the protection of the health of workers exposed to vinyl
    chloride monomer. Official Journal of the European Communities L197,
    22 July 1978, 12-18.

    CEC (1987) Legislation on dangerous substances. Classification and
    labelling in the European Communities, Vol.2. Brussels, Commission of
    the European Communities.

    CEC/IPCS (1991) International Chemical Safety Card 0082: Vinyl
    chloride. Luxembourg, Commission of the European Communities.

    Gov. Res. (1992) Finnish Government Resolution 919, 4 pp (in Finnish).

    HSG (1995) Control of vinyl chloride at work: Approved code of
    practice. UK Health and Safety Commission, Sudbury, Suffolk, UK Health
    and Safety Executive, 10 pp.

    IARC (1979) Vinyl chloride, polyvinyl chloride and vinyl
    chloride-vinyl acetate copolymers. Lyon, International Agency for
    Research on Cancer, pp 377-438 (IARC Monographs on the Evaluation of
    Carcinogenic Risks to Humans, Volume 19).

    IARC (1987) Overall evaluations of carcinogenicity: An updating of
    IARC monographs, Volumes 1 to 42. Lyon, International Agency for
    Research on Cancer, pp 373-376 (IARC Monographs on the Evaluation of
    Carcinogenic Risks to Humans, Supplement 7).

    IPCS (1993) Poisons Information Monograph No. 558 Vinyl chloride.
    Geneva, World Health Organization. 22 pp.

    IPCS (1999) Environmental Health Criteria 215: Vinyl chloride. Geneva,
    World Health Organization.

    NIOSH (1997) Pocket guide to chemical hazards. Cincinnati, Ohio,
    National Institute for Occupational Safety and Health (US Department
    of Health and Human Services) p 330-331

    OSHA (1990) US Department of Labour, Occupational Safety and Health
    Administration: Title 29, Code of Federal Regulations, Part 1910,
    1910.1017 to end, pp.138-143.

    Til HP, Immel HP & Feron FJ (1983) Lifespan oral carcinogenicity study
    of vinyl chloride in rats. In: TNO (Netherlands organization for
    applied scientific research) ed. TNO Report V83.285/291099. Zeist, TNO
    pp 1-29.

    United Nations (1997) Recommendations on the transport of dangerous
    goods. Model regulations, 10th rev. ed. New York and Geneva, United
    Nations, 573 pp.

    WHO (1996) Guidelines for drinking-water quality. Geneva, World Health
    Organization.
    


    See Also:
       Toxicological Abbreviations
       Vinyl Chloride (EHC 215, 1999)
       Vinyl chloride (ICSC)
       Vinyl chloride (WHO Food Additives Series 19)
       VINYL CHLORIDE (JECFA Evaluation)
       Vinyl chloride (PIM 558)
       Vinyl chloride (SIDS)
       Vinyl Chloride  (IARC Summary & Evaluation, Supplement7, 1987)
       Vinyl Chloride (IARC Summary & Evaluation, Volume 7, 1974)