IPCS INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY
    Health and Safety Guide No. 19

    PENTACHLOROPHENOL
    HEALTH AND SAFETY GUIDE

    UNITED NATIONS ENVIRONMENT PROGRAMME

    INTERNATIONAL LABOUR ORGANISATION

    WORLD HEALTH ORGANIZATION

    WORLD HEALTH ORGANIZATION, GENEVA 1989

    This is a companion volume to Environmental Health Criteria
    71: Pentachlorophenol

    Published by the World Health Organization for the International
    Programme on Chemical Safety (a collaborative programme of the United
    Nations Environment Programme, the International Labour Organisation,
    and the World Health Organization)

    This report contains the collective views of an international group of
    experts and does not necessarily represent the decisions or the stated
    policy of the United Nations Environment Programme, the International
    Labour Organisation, or the World Health Organization

    ISBN 92 4 154341 8
    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
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    (c) World Health Organization 1989

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    CONTENTS

    INTRODUCTION

    1. PRODUCT IDENTITY AND USES
         1.1. Identity
               1.1.1. Pentachlorophenol (PCP)
               1.1.2. Sodium pentachlorophenate (Na-PCP)
               1.1.3. Pentachlorophenyl laurate
               1.1.4. Impurities in pentachlorophenol
         1.2. Physical and chemical properties
         1.3. Analytical methods
         1.4. Production and uses

    2. SUMMARY AND EVALUATION
         2.1. Kinetics and metabolism
         2.2. Effects on experimental animals and in vitro test
               systems
         2.3. Evaluation of human health risks
               2.3.1. Occupational exposure
                       2.3.1.1   Exposure levels and routes
                       2.3.1.2   Toxic effects
                       2.3.1.3   Risk evaluation
               2.3.2. Non-occupational exposure
                       2.3.2.1   Exposure levels and routes
                       2.3.2.2   Risk evaluation
               2.3.3. General population exposure
                       2.3.3.1   Exposure levels and routes
                       2.3.3.2   Risk evaluation
         2.4. Evaluation of effects on the environment

    3. CONCLUSIONS AND RECOMMENDATIONS
         3.1. Conclusions
         3.2. 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   Clinical features
                       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
         4.3. Storage
         4.4. Transport
         4.5. Spillage and disposal
               4.5.1. Spillage
               4.5.2. Disposal

    5. HAZARDS FOR THE ENVIRONMENT AND THEIR PREVENTION

    6. INTERNATIONAL CHEMICAL SAFETY CARD

    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. 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 an International Chemical Safety Card
    which should be readily available, and should be clearly explained, to
    all who could come into contact with the chemical. The section on
    regulatory information has been extracted from the legal file of the
    International Register of Potentially Toxic Chemicals (IRPTC) and from
    other United Nations sources.

    The target readership includes 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

    1.1.1  Pentachlorophenol (PCP)

    Chemical structure:      

    Molecular formula:       C6Cl5OH

    CAS chemical name:       pentachlorophenol

    Common synonyms:         chlorophen; PCP; penchlorol; penta;
                             pentachlorofenol; pentachlorofenolo;
                             pentachlorphenol; 2,3,4,5,6-pentachlorophenol

    CAS registry
    number:                  87-86-5

    1.1.2  Sodium pentachlorophenate (Na-PCP)

    Chemical structure:      

    Molecular formula:       C6Cl5ONa
                             C6Cl5ONa.H2O (as monohydrate)

    Common synonyms:         penta-ate; pentachlorophenate sodium;
                             pentachlorophenol, sodium salt;
                             pentachlorophenoxy sodium; pentaphenate;
                             phenol, pentachloro-, sodium derivative
                             monohydrate; sodium PCP; sodium
                             pentachlorophenate; sodium
                             pentachlorophenolate; sodium
                             pentachlorophenoxide

    CAS registry             131-52-2 (Na-PCP);
    number:                  27735-64-4 (Na-PCP monohydrate)

    1.1.3  Pentachlorophenyl laurate

    The molecular formula of pentachlorophenyl laurate is C6Cl5OCOR; R
    is the fatty acid moiety, which consists of a mixture of fatty acids
    ranging in carbon chain length from C6 to C20, the predominant
    fatty acid being lauric acid (C12).

    1.1.4  Impurities in pentachlorophenol

    Technical PCP has been shown to contain a large number of impurities,
    depending on the manufacturing method. These consist of other
    chlorophenols, particularly isomeric tetrachlorophenols, and several
    microcontaminants, mainly polychlorodibenzodioxins (PCDDs),
    polychlorodibenzofurans (PCDFs), polychlorodiphenyl ethers,
    polychlorophenoxyphenols, chlorinated cyclohexenons and
    cyclohexadienons, hexachlorobenzene, and polychlorinated biphenyls
    (PCBs).

    1.2  Physical and Chemical Properties

    Pure pentachlorophenol consists of light tan to white, needle-like
    crystals and is relatively volatile. It is soluble in most organic
    solvents, but practically insoluble in water at the slightly acidic pH
    generated by its dissociation (pKa 4.7). However, its salts, such as
    sodium pentachlorophenate (Na-PCP), are readily soluble in water. At
    the approximately neutral pH of most natural waters, PCP is more than
    99% ionized.

    Some physical and chemical properties of PCP and Na-PCP are given in
    the International Chemical Safety Card.

    1.3  Analytical Methods

    Most of the analytical methods used today involve acidification of the
    sample to convert PCP to its non-ionized form, extraction into an
    organic solvent, possible cleaning by back-extraction into a basic
    solution, and determination by gas chromatography with
    electron-capture detector or other chromatographic methods as ester or
    ether derivatives (e.g., acetyl-PCP). Depending on sampling procedures
    and matrices, detection limits as low as 0.05 µg/m3 in air or
    0.01 µg/litre in water can be achieved.

    1.4  Production and Uses

    World production of PCP is estimated to be of the order of 30 000
    tonnes per year. Because of their efficiency, broad spectrum, and low
    cost, PCP and its salts have been used as algicides, bactericides,
    fungicides, herbicides, insecticides, and molluscicides with a variety
    of applications in the industrial, agricultural, and domestic fields.
    However, in recent years, most developed countries have restricted the
    use of PCP, especially for agricultural and domestic applications (see
    section 7.3).

    PCP is mainly used as a wood preservative, particularly on a
    commercial scale. The domestic use of PCP is of minor importance in
    the overall PCP market, but has been of particular concern because of
    possible health hazards associated with the indoor application of wood
    preservatives containing PCP.

    2.  SUMMARY AND EVALUATION

    2.1  Kinetics and Metabolism

    PCP is readily absorbed through the intact skin and the respiratory
    and gastrointestinal tracts, and is distributed in the tissues.
    Highest levels are observed in liver and kidney, and lower levels are
    found in body fat, brain, and muscle tissue. There is only a slight
    tendency to bioaccumulate, and so relatively low PCP concentrations
    are found in tissues. In rodent species, detoxification occurs through
    the oxidative conversion of PCP to tetrachlorohydroquinone and, to a
    lesser extent, to trichlorohydroquinone, as well as through
    conjugation with glucuronic acid. In rhesus monkeys, no specific
    metabolites have been detected. In man, metabolism of PCP to
    tetrachlorohydroquinone seems to occur only to a small extent.

    Rats, mice, and monkeys eliminate PCP and their metabolites, either
    free or conjugated with glucuronic acid, mainly in the urine and to a
    lesser extent with the faeces.

    Some animal data indicate that there may be long-term accumulation and
    storage of small amounts of PCP in human beings. The fact that urine-
    or blood-PCP levels do not completely disappear in some occupationally
    exposed people, even after a long absence of exposure, seems to
    confirm this, though the biotransformation of hexachlorobenzene and
    related compounds provides an alternative explanation of this
    phenomenon. However, there is a lack of data concerning the long-term
    fate of low PCP levels in animals as well as in man. Furthermore, no
    data are available on the accumulation and effects of
    microcontaminants taken up by man together with PCP.

    2.2  Effects on Experimental Animals and In Vitro Test Systems

    In the main, mammalian studies have been relatively consistent in
    their demonstration of the effects of exposure to PCP. In rats, lethal
    doses induce an increased respiratory rate, a marked rise in
    temperature, tremors, and a loss of righting reflex. Asphyxial spasms
    and cessation of breathing occur just before cardiac arrest, which is
    in turn followed by a rapid, intense rigor morris.

    PCP is highly toxic, regardless of the route, length, and frequency of
    exposure. Oral LD50 values for a variety of species range between 27
    and 205 mg/kg body weight according to the different solvent vehicles
    and grades of PCP. There is limited evidence that the most dangerous
    route of exposure to PCP is through inhalation.

    PCP is also an irritant for exposed epithelial tissue, especially the
    mucosal tissues of the eyes, nose, and throat. Other localized acute
    effects include swelling, skin damage, and hair loss, as well as
    flushed skin areas where PCP affects surface blood vessels. Exposure

    to technical formulations of PCP may produce chloracne. Comparative
    studies indicate that this is a response to microcontaminants,
    principally PCDDs, present in the commercial product. The parent
    molecule appears to be responsible for the immediate acute effects,
    including irritation and the uncoupling of oxidative phosphorylation,
    with a resultant elevated temperature.

    The results of short- and long-term studies indicate that purified PCP
    has a fairly limited range of effects in test organisms, primarily
    rats. Exposure to fairly high concentrations of PCP may reduce growth
    rates and serum-thyroid hormone levels, and increase liver weights
    and/or the activity of some liver enzymes. In contrast, technical
    formulations of PCP, usually at much lower concentrations, can
    decrease growth rates, increase the weights of liver, lungs, kidneys,
    and adrenals, increase the activity of a number of liver enzymes,
    interfere with porphyrin metabolism, alter haematological and
    biochemical parameters, and interfere with renal function. Apparently,
    microcontaminants are the principal active moieties in the non-acute
    toxicity of commercial PCP.

    PCP is fetotoxic, delaying the development of rat embryos and reducing
    litter size, neonatal body weight, neonatal survival, and the growth
    of weanlings. The no-observed-adverse-effect level for technical PEP
    is a maternal dose of 5 mg/kg body weight per day during
    organogenesis. In one study, it was reported that purified PCP was
    slightly more embryo/fetotoxic than technical PCP, presumably because
    contaminants induced enzymes that detoxified the parent compound.

    PCP is not considered teratogenic, though, in one instance, birth
    defects arose as an indirect result of maternal hyperthermia. The
    no-observed-adverse-effect level in rat reproduction studies was
    3 mg/kg body weight per day. This value is remarkably close to the
    value mentioned in the previous paragraph, but there are no
    corroborating studies in other mammalian species.

    PCP has also proved to be immunotoxic for mice, rats, chickens, and
    cattle; at least part of this effect is caused by the parent molecule.

    Neurotoxic effects have also been reported, but the possibility that
    these are due to microcontaminants has not been excluded.

    PCP is not considered carcinogenic for rats. Mutagenicity studies
    support this conclusion in as much as pure PCP has not been found to
    be highly mutagenic. However, its carcinogenicity remains questionable
    because of shortcomings in these studies. The presence of at least one
    carcinogenic microcontaminant (H6CDD) suggests that the potential
    for technical PCP to cause cancer in laboratory animals cannot be
    completely ruled out.

    2.3  Evaluation of Human Health Risks

    In this subsection, PCP and Na-PCP are referred to as PCP.

    2.3.1  Occupational Exposure

    2.3.1.1  Exposure levels and routes

    Occupational exposure to technical PCP mainly occurs through
    inhalation and dermal contact. Virtually all workers exposed to
    airborne concentrations take up PCP through the lungs and skin. In
    addition, workers handling treated lumber or maintaining
    PCP-contaminated equipment would be exposed dermally to PCP in
    solution, and may take up from one-half (based on urinary-PCP
    concentrations) to two-thirds (using serum levels) of their total PCP
    burden through the skin.

    The actual concentrations to which workers have been exposed are
    seldom measured but, where they have been monitored, they have been
    predictably high. Airborne levels at PCP-production and
    wood-preservation facilities have ranged from several mg/m3 to more
    than 500 mg/m3 in some work areas. The outer layer of treated wood
    can contain up to several hundred mg/kg, though levels are usually
    less than 100 mg/kg.

    These exposures result in concentrations of PCP in the serum and urine
    that are 1-2 orders of magnitude higher than those found in the
    general population without known exposure. Mean/median urinary-PCP
    concentrations of approximately 1 mg/litre are typical for workers in
    contact with PCP, compared with urinary concentrations of
    approximately 0.01 mg/litre for the general population.

    Automated processes and the use of closed systems have greatly reduced
    worker exposure in large-scale manufacturing and modern wood-treatment
    factories and sawmills. Other improvements in industrial hygiene can
    significantly reduce exposure, as measured by lower urinary-PCP
    concentrations.

    2.3.1.2  Toxic effects

    Past use of PCP has affected workers producing or using this chemical.
    Chloracne, skin irritation and rashes, respiratory disorders,
    neurological changes, headaches, nausea, weakness, irritability, and
    drowsiness have been documented in exposed workers. Work-place
    exposures are to technical PCP, which usually contains mg/kg
    quantities of microcontaminants, particularly H6CDD. Subacute
    effects, such as chloracne, and potential subchronic and chronic
    effects, such as hepatotoxicity, fetotoxicity, and immunotoxicity (as

    reported in animal studies), are probably mainly caused by
    microcontaminants. However, the PCP molecule itself appears to play a
    role in the pathology of the last three effects and is likely to be
    wholly responsible for the reports of skin and mucous membrane
    irritation, hyperpyrexia and, in severe cases, coma and death. The
    toxicity of pure or purified PCP has not been evaluated for human
    beings, because human exposure has usually been to technical PCP.

    Investigations of biochemical changes in woodworkers with long-term
    exposure to PCP have failed to detect consistently significant effects
    on major organs, nerves, blood, reproduction, or the immune system.
    However, the statistical power of these studies has been limited as a
    result of the small sample sizes used. Overall, the body of research
    suggests that long-term exposure to levels of PCP encountered in the
    work-place is likely to cause borderline effects on some organ systems
    and biochemical processes.

    Some epidemiological studies from Sweden and the USA have revealed an
    association between exposure to mixtures of chlorophenols, especially
    2,4,5-T3CP, and the incidences of soft-tissue sarcomas, lymphomas,
    and nasal and nasopharyngeal cancers. Other studies have failed to
    detect such a relationship. It was not possible to address the effects
    of exposure to PCP itself in any of these studies.

    The results of animal studies, designed to assess the carcinogenicity
    of PCP and reported to date, have been negative. Carcinogenicity
    bioassays with one other chlorophenol (2,4,6-T3CP) and a mixture of
    two H6CDD congeners found in PCP have been positive. Hence, the
    carcinogenic effects of long-term exposure of animals to technical PCP
    are not clear.

    2.3.1.3  Risk evaluation

    It is clear that the levels of PCP found in work-places have adversely
    affected some aspects of the health of exposed workers. Potentially
    the most deleterious effect of technical PCP is on the fetus, and
    pregnant women should avoid exposure, whenever possible. There is
    limited evidence that PCP may cause hepatotoxic effects, neurological
    disorders, and effects on the immune system. No convincing data for or
    against a carcinogenic link exist.

    The US National Academy of Sciences (1977) calculated an acceptable
    daily intake (ADI) for PCP of 3 µg/kg body weight per day. This ADI is
    based on data from a feeding study on rats and a 1000-fold safety
    factor. The results of long-term studies indicate that the
    no-observed-adverse-effect level for rats is below 3 mg/kg body weight
    per day. A recent human study has shown that the steady-state body
    burden is 10-20 times higher than the value extrapolated from rat

    pharmacokinetic data, suggesting that caution should be applied when
    extrapolating directly from the rat model to man. Furthermore, the ADI
    in the USA was not based on an inhalation study, and does not account
    for the possibly greater toxicity of PCP via inhalation, as indicated
    by animal studies. Hence, the safety factor of 1000 used to derive
    this ADI value is by no means too conservative. The intake for a 60-kg
    adult exposed to concentrations of PCP at the ADI level would be
    180 µg/person per day.

    A rough estimate of occupational exposure alone can be calculated,
    assuming a moderate breathing rate of 1.8 m3/h for a 60-kg worker,
    100% uptake of all inhaled PCP (which takes some account of the often
    significant dermal uptake), and an 8-h working shift per day, 5 days
    per week. Hence, an exposure to 500 µg PCP/m3 per shift would result
    in an average daily PCP intake of approximately 5000 µg/person per
    day, averaged over the entire week. Under these circumstances, the ADI
    level proposed by the National Academy of Sciences is significantly
    exceeded, even when consideration is given to the effects of
    intermittent exposures during the working week and the high health
    status assumed for workers.

    There is a clear need for a reduction in occupational exposure to PCP.
    Emphasis must be placed on reducing airborne concentrations at
    production and wood-treatment facilities, as well as dermal contact
    with solutions containing PCP. In addition, reductions in the
    concentrations of microcontaminants in technical PCP, particularly
    PCDDs and PCDFs, would reduce the potential for expression of several
    effects and would better protect the health of workers in these
    industries.

    2.3.2  Non-occupational exposure

    2.3.2.1  Exposure levels and routes

    Domestic use of products containing technical PCP, especially the
    indoor application of wood preservatives and paints based on PCP, has
    led to elevated concentrations of PCP in indoor air. Indoor exposures
    have been well documented in houses constructed with PCP-treated wood,
    or in which interior wood panels or boards have been treated with PCP.
    PCP concentrations in indoor air can be expected to reach 30 µg/m3
    during the first month after treatment. Considerably higher levels, up
    to 160 µg/m3, have been reported in houses with concomitant poor
    indoor ventilation. Even higher concentrations can be encountered
    immediately after do-it-yourself applications of PCP-containing wood
    preservatives.

    In the long term, values of between 1 and 10 µg/m3 are typical,
    though higher levels, up to 25 µg/m3, have been found in rooms
    treated one to several years earlier. Indoor air concentrations are
    influenced by a variety of factors, e.g., intensity of treatment,
    solvents and additives involved, species of wood treated,
    environmental conditions, and time elapsed since treatment.

    In many cases, levels of PCP in the serum and urine of people exposed
    in the home overlap those for occupationally exposed persons; but, on
    average, urine-PCP levels are approximately 0.04 mg/litre for
    non-occupationally exposed persons.

    Exposure to PCP in treated buildings continuously decreases with time,
    owing to the high volatility of PCP. Because of their lower vapour
    pressure, the volatilization of PCDDs and PCDFs from the wood surface
    is much slower than that of PCP. Hence, these microcontaminants are
    emitted at a low rate, but over a longer period of time. Long-term
    exposure to these lipophilic contaminants is likely to lead to
    accumulation of PCDDs and PCDFs in fatty body tissues.

    As a result of regulations restricting the use of PCP, and also
    changing use patterns, indoor exposure to PCP is probably declining in
    most developed countries.

    2.3.2.2  Risk evaluation

    Assuming a daily respiratory volume of 20 m3/adult and 100% uptake
    of all inhaled PCP (a worst case that takes some account of dermal
    uptake), the exposure of persons living in PCP-treated buildings,
    shortly after treatment, or, in some cases, after a long period of
    time, could be expected to range between 600 and 3200 µg/person per
    day. Long-term exposure to concentrations of 1-25 µg PCP/m could
    result in a daily PCP intake of 20-500 µg/person per day. The median
    value of 5 µg/m reported from a survey of 104 homes corresponds to a
    daily PCP uptake of 100 µg/person per day. Other potential sources of
    exposure to PCP including food, drinking-water, and consumer products
    contribute further to PCP uptake.

    The indoor air data suggest that, at least during the first weeks
    following indoor treatment, and occasionally for quite prolonged
    periods of time, the ADI level of 180 µg/person per day is
    significantly exceeded. Under these circumstances, there is a
    potential health risk. This conclusion is supported, in part, by
    reports of signs and symptoms similar to those in persons
    occupationally exposed to PCP (dermatosis, nausea, headache,

    dizziness, fatigue). These signs and symptoms are most likely to be
    associated with the effects of the PCP molecule and, in some cases,
    the solvents associated with the wood treatment chemicals used. The
    long-term significance of exposure to low levels of PCDDs and PCDFs
    and their accumulation in human tissues is not entirely clear;
    however, at least two isomeric groups of the PCDDs family are
    carcinogenic for animals.

    Animal data indicate that low concentrations of PCP in biological
    tissues or body fluids do not signify an absence of biologically
    active PCDDs and PCDFs.

    It is worth noting that exposure in the home is frequently for longer
    periods of time than exposures in the work-place and can affect
    subpopulations potentially at greater risk than workers, for example,
    children, the elderly, pregnant women, or those with an existing
    adverse health condition.

    2.3.3  General population exposure

    2.3.3.1  Exposure levels and routes

    Exposure of the general population to low levels of PCP is common. PCP
    has been found in air, food, water, and other consumer products.
    Biotransformation of some chlorinated hydrocarbons (e.g., lindane,
    hexachlorobenzene) to PCP also contributes to the human body burden.

    The ambient air in urban areas typically contains several ng/m3,
    while concentrations in less developed areas are roughly an order of
    magnitude lower.

    Drinking-water concentrations of PCP rarely exceed several µg/litre,
    even in highly industrialized regions, and most are less than
    1 µg/litre.

    Fruits, vegetables, and other produce usually contain much less than
    10 µg/kg, but may on occasion exceed this level. Most meats contain
    similar concentrations of PCP (10 µg/kg) but, a few samples,
    particularly liver, can contain over 100 µg/kg. Fish skeletal muscle
    typically contains PCP levels of 4 µg/kg or less. Overall estimates of
    PCP intake from all foods, based on total diet samples in the USA and
    the Federal Republic of Germany, are remarkably similar, i.e., up to
    6 µg/person per day.

    PCP is also present in a wide variety of consumer products, including
    veterinary supplies, disinfectants, photographic solutions, fabrics,
    home-care products, and pharmaceutical products. No calculated
    estimates of the contribution made by consumer products to overall
    exposure to PCP are available.

    2.3.3.2  Risk evaluation

    On the basis of the PCP levels in the various compartments, the
    overall exposure of an average person without known specific exposure
    can be estimated to be approximately 6 µg/person per day from food,
    2 µg/person per day from drinking-water, and 2 µg/person per day from
    the ambient air. Thus, the total exposure of the general population
    could be approximately 10 µg/person per day (exclusive of exposure to
    consumer products), which is far below the intake based on the ADI
    proposed by the US National Academy of Science of 180 µg/person per
    day. On the basis of available data, this exposure is not likely to
    constitute a health hazard.

    However, the diffuse contamination of the environment with technical
    PCP must be considered as an important source of environmental PCDDs
    and PCDFs.

    2.4  Evaluation of Effects on the Environment

    The widespread use of technical PCP and its physical and chemical
    properties (water solubility,  n-octanol/water partition coefficient,
    volatility) lead to ubiquitous contamination of air, soil, water,
    sediments, and organisms in the environment.

    Depending on the soil type, PCP can be very mobile, potentially
    leading to contamination of ground water and hence, of drinking-water.
    Because applications in agriculture have been reduced, soil
    contamination will, for the most part, be confined to treatment areas.

    Photodecomposition and biodegradation processes may not be adequate to
    eliminate PCP from the different compartments. Unfavourable
    temperature, pH, and other environmental conditions may retard
    degradation of PCP allowing it to persist in the environment.
    Biological decomposition may also be limited in waste-treatment
    factories resulting in high concentrations in the final effluents. PCP
    has also been used in aquatic environments as a molluscicide and an
    algicide.

    PCP concentrations in surface waters are usually in the range of
    0.1-1 µg/litre, though much higher levels can be found near point
    sources or after accidental spills.

    PCP is highly toxic for aquatic organisms. Apart from very sensitive
    or resistant species, there is apparently no difference in the
    sensitivity to PCP of the different taxonomic groups. Invertebrates
    (annelids, molluscs, crustaceans) and fish are adversely affected by
    PCP concentrations below 1 mg/litre in acute toxicity tests. Sublethal
    concentrations are in the low µg/litre range.

    As little as 1 µg PCP/litre can have adverse effects on very sensitive
    algal species. Moreover, low concentrations (µg/litre) may lead to
    substantial alterations in community structures, as seen in model
    ecosystem studies.

    3.  CONCLUSIONS AND RECOMMENDATIONS

    3.1  Conclusions

    In this section, PCP and Na-PCP are referred to as PCP.

    ( a) Human exposure to PCP is usually from technical products that
    contain several toxic microcontaminants, including PCDDs and PCDFs.

    ( b) The acute health effects of exposure to high concentrations of
    technical PCP are generally the result of the biological action of the
    PCP molecule itself. Sub-chronic effects and the effects of long-term
    exposure to technical PCP are most probably largely related to the
    biological action of the PCDDs and PCDFs.

    ( c) A dose-effect relationship for the acute or chronic toxicity of
    technical PCP for human beings cannot be derived from available data.
    Derivation of this relationship is confounded by variations in
    individual susceptibility, social and environmental influences,
    concomitant exposure to other chemical substances, a lack of accurate
    exposure estimates, and inadequate toxicity data.

    ( d) Occupational exposure to technical PCP can lead to adverse
    health effects.

    ( e) Non-occupationally exposed persons (users of products containing
    technical PCP and/or those living in buildings treated with wood
    preservatives or paints containing PCP) may be exposed to
    concentrations of PCP in air that can have adverse health effects.

    ( f) The exposure of the general population to diffuse sources of PCP
    (via food, drinking-water, ambient air, consumer products, chlorinated
    compounds that can be metabolized to PCP) is very low and, on the
    basis of available data, it is not likely to constitute a health
    hazard.

    ( g) Epidemiological investigations and animal studies, conducted to
    date, are insufficient for an evaluation of the carcinogenicity of
    technical PCP. Uncertainties also exist over the genotoxic and
    fetotoxic effects of technical PCP.

    ( h) PCP is rather persistent, quite mobile, and found in all
    environmental compartments. At the higher concentrations found in the
    surface water near point sources or discharges (mg/litre), aquatic
    life is adversely affected. Ambient concentrations of PCP commonly
    found in surface waters (0.1-1 µg/litre) may adversely affect very
    sensitive organisms and may lead to alterations in the ecosystem.

    ( i) The use of technical PCP and its improper disposal (landfill and
    low-temperature combustion) can contribute significantly to the
    contamination of the environment with PCP, PCDDs, and PCDFs.

    3.2  Recommendations

    In this section, PCP and Na-PCP are referred to as PCP.

    ( a) Concentrations of microcontaminants in technical PCP, especially
    PCDDs and PCDFs, must be reduced by improving the quality in
    production processes.

    ( b) There is a need for specification of a technical PCP.

    ( c) The disposal of technical PCP and associated waste should
    preferably involve high-temperature combustion or, where this is not
    possible, the use of secure landfill sites.

    ( d) In order to reduce contamination of surface waters and the
    hazards for the aquatic ecosystem, manufacturers and users of
    technical PCP should prevent releases into the environment.

    ( e) Protective measures should be provided for non-target aquatic
    organisms in cases where PCP is used as a molluscicide or algicide.

    ( f) Occupational exposure to technical PCP must be reduced to a
    minimum. Reduction in exposure can be achieved by:

    - explicit product labelling;

    - employee instruction on product handling;

    - lowering airborne concentrations; and

    - use of effective protective equipment.

    ( g) Industries handling technical PCP should ensure adequate routine
    monitoring and health surveillance of all potentially exposed
    employees.

    ( h) The indoor application of PCP-based wood preservatives and wood
    stains and the use of PCP-treated wood products in the interior of
    buildings should cease.

    ( i) The availability and use of consumer products containing PCP
    should be reduced and controlled.

    ( j) The following commercial uses of PCP-based products should be
    eliminated, in order to reduce contamination of food and the
    environment:

         (i) application as wood preservatives on wooden food containers,
         horticultural lumber, wood and tools in mushroom houses, and
         above-ground interior wood of farm buildings;

         (ii) application during the curing of hides;

         (iii) application as a herbicide or soil sterilant;

         (iv) application as a slimicide in wood pulp and paper
         operations; and

         (v) application as a molluscicide in surface water, if another
         control chemical or measure is available that is less toxic for
         man and the aquatic ecosystem.

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

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

    PCP is highly toxic and it is irritant to the skin, eyes and mucous
    membrane. It can be highly hazardous to human beings if incorrectly
    handled. For details, see the International Chemical Safety Card.

    4.1.1  Advice to physicians

    4.1.1.1  Clinical features

    PCP uncouples oxidative phosphorylation processes thus increasing the
    metabolic rate and causing hyperpyrexia. Early signs and symptoms are:
    nausea, fatigue, unusual and excessive sweating, and thirst. Insomnia,
    oliguria, and loss of body weight (dehydration) may occur in more
    protracted cases. Anxiety and restlessness, increased rate and depth
    of respiration, palpitations, tachycardia, fever, and eventually
    convulsion and coma may occur in more severe cases. Laboratory
    examination may reveal a rise in white blood cells and hypoglycaemia.
    Pentachlorophenol can be detected in the urine.

    4.1.1.2  Medical advice

    Absolute rest is essential. Gastric lavage may be necessary in cases
    of ingestion, followed by administration of activated charcoal. No
    specific antidote or treatment is known. Poisoning cases should be
    treated by continuous administration of oxygen, and fever should be
    controlled by physical means, such as sponging with alcohol solutions.
    Fluid losses should be replaced and urine should be kept alkaline by
    the administration of sodium bicarbonate.

    In very severe cases, intravenous infusion of chlorpromazine to reduce
    the rate of metabolism and the body temperature may be helpful.
    However, this should be done very cautiously.

    Atropine and barbiturates are strictly contraindicated.

    The symptoms of lung oedema often do not become manifest until after a
    few hours and they are aggravated by physical effort. Rest and
    hospitalization are therefore essential. As a preventive measure,
    administration of a corticosteroid-containing spray should be
    considered.

    4.1.2  Health surveillance advice

    A complete medical history and physical examination should be made, on
    an annual basis, in workers regularly exposed to PCP. Special
    attention should be paid to the cardiovascular system, upper
    respiratory tract, liver, kidneys, and skin. Regular measurement of
    PCP exposure should be undertaken, preferably in the breathing zone.

    4.2  Explosion and Fire Hazards

    4.2.1  Explosion hazards

    The explosion hazard will depend on the solvent used in the
    formulation, or on the characteristics of the dust.

    4.2.2  Fire hazards

    Technical PCP will not burn. Formulated products and oil solutions are
    likely to be highly flammable. All products will decompose and produce
    harmful fumes, if involved in a fire, and the fire service must be
    advised accordingly.

    Fires should be controlled with alcohol-resistant foam, dry powder, or
    carbon dioxide. The use of water should be confined to the cooling of
    unaffected stock, thus avoiding the accumulation of polluted run-off.

    4.3  Storage

    Technical PCP is a solid. The formulated product is usually a solution
    in oil or organic solvent, or an emulsifiable concentrate.

    All PCP products should be stored in secure, well ventilated buildings
    under cool and dry conditions, and out of reach of children and
    unauthorized persons. Keep away from food, drink, and animal feed.

    If any containers in the store are leaking, take precautions and use
    personal protective equipment as required (see International Chemical
    Safety Card). Empty any product remaining in damaged/leaking
    containers into a clean, empty drum, which should then be suitably
    labelled.

    Sweep up spillage with sawdust, sand, or earth and dispose of safely.

    Wash contaminated areas with detergent and a small amount of water,
    absorbing as much as possible with sawdust, sand, or earth.

    When emptied, decontaminate leaking containers several times with at
    least 1 litre of water per 20-litre drum. Swirl round to rinse walls,
    empty and add rinsings to the contaminated sawdust, sand, or earth.
    Puncture the container to prevent re-use.

    4.4  Transport

    Comply with any local requirements regarding movement of hazardous
    goods. Do not load with feed or foodstuffs. Check that containers are
    sound and correctly labelled before despatch.

    4.5  Spillage and Disposal

    4.5.1  Spillage

    Before dealing with any spillage, precautions should be taken as
    required and appropriate personal protective equipment should be used
    (see International Chemical Safety Card).

    Absorb spilt liquids with sawdust, lime, sand, or earth. Prevent
    liquids from spreading or contaminating other cargo, vegetation, or
    waterways by building a barrier of the most readily available
    material, e.g., earth or sand.

    Sweep up spilt technical material and place this together with any
    contaminated absorbents in a closeable container for later transfer to
    a safe place for disposal.

    4.5.2  Disposal

    Surplus product, contaminated absorbents and containers should be
    burned at a high temperature in an appropriate incinerator with
    effluent gas scrubbing. When no incinerator is available, bury in an
    approved dump, in an area where there is no risk of contamination of
    surface or ground water. Comply with any local legislation.

    5.  HAZARDS FOR THE ENVIRONMENT AND THEIR PREVENTION

    Because of its action as an uncoupler of oxidative phosphorylation,
    pentachlorophenol is highly hazardous for most forms of terrestrial
    and aquatic life, depending on the exposure level. It is a rather
    persistent and mobile pesticide and as a result it can occur in all
    environmental compartments.

    It is therefore essential that PCP levels in the environment be kept
    as low as possible. Containers should not be emptied or washed into
    ditches or waterways. Any effluent containing PCP should be properly
    treated. Any PCP spillage should be prevented from contaminating
    vegetation and waterways.

    6.  INTERNATIONAL CHEMICAL SAFETY CARD

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

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

        INTERNATIONAL CHEMICAL SAFETY CARD

    PENTACHLOROPHENOL CAS No. 87-86-5; C6Cl5OH

    PHYSICAL PROPERTIES                             OTHER CHARACTERISTICS

    Boiling point, decomposition                    310°C                             Colourless to light brown flakes or crystals, with
    Melting point                                   191°C                             characteristic phenolic odour; decomposes on
    Relative density      (water = 1)               2.0                               heating in the presence of water, forming corrosive
                          (air = 1)                 9.2                               fumes (hydrochloric acid); substance may be absorbed
    Vapour pressure (20°C)                          2 mPa                             into body by inhalation, or ingestion or through skin;
    Relative molecular mass                         266.3                             corrosive to the respiratory tract; affects the nervous
    Octanol/water part. coeff. (pH 6.5)             3.56                              system; not flammable and non-corrosive in unmixed
                                                                                      state; dissolved in oil, it causes deterioration
    Solubility in water (20°C, pH 7)                   2 g/litre                      of rubber
    Solubility in organic solvents (25°C)
        acetone                                      500 g/litre
        benzene                                      150 g/litre
        ethanol                                     1200 g/litre
        methanol                                    1800 g/litre

    INTERNATIONAL CHEMICAL SAFETY CARD (cont'd).

    SODIUM PENTACHLOROPHENATE CAS No. 131-52-2; C6Cl5ONa

    PHYSICAL PROPERTIES                                                               OTHER CHARACTERISTICS

    Boiling point                                   decomposition                     Tan powder, pellets, or briquettes with phenolic
    Melting point                                   decomposition                     odour; decomposes on heating, forming toxic
    Relative density (water = 1)                    2.0                               fumes (chlorides and sodium oxide); substance may
    Relative molecular mass                         288.3                             be absorbed into body by inhalation, ingestion, and
    Solubility in water (25°C)                      330 g/litre                       through skin; corrosive to the respiratory tract
    Solubility in organic solvents (25°C)
        acetone                                     350 g/litre
        benzene                                     insoluble
        ethanol                                     650 g/litre
        methanol                                    250 g/litre

    INTERNATIONAL CHEMICAL SAFETY CARD (cont'd).

                                                    BOTH COMPOUNDS

    HAZARDS/SYMPTOMS                           PREVENTION AND PROTECTION                 FIRST AID

    GENERAL:                                   Strict hygiene; prevent dispersion
    Highly toxic chemical                      of dust; if you feel unwell seek
                                               medical advice (show the label where
                                               possible); keep out of reach of
                                               children

    SKIN: toxic in contact with                Avoid contact; wear PVC or neoprene       Remove contaminated clothes, wash
    skin; may cause white spots,               gloves, neoprene apron, and rubber        contaminated skin immediately with
    sometimes wounds                           boots                                     plenty of water and soap, and obtain
                                                                                         medical attention

    EYES: may cause redness, pain              Avoid contamination with dust or mist;    First rinse with plenty of water for
                                               use face shield or goggles                15 minutes, then transport to a doctor,
                                                                                         if necessary

    INHALATION: toxic by inhalation;           Avoid inhalation of vapour, dust, or      Fresh air, rest, half-upright position, cool
    may cause headache, fatigue,               mist; use local exhaust ventilation       down, and transport to hospital; symptoms
    perspiration, thirst, faintness,           or breathing protection; closed           of lung oedema often do not become manifest
    increased body temperature; in severe      system; not recommended for               until a few hours have passed, and are
    cases lung oedema may occur                interior use on large surface areas       aggravated by physical effort; hospitalization
                                                                                         is therefore essential

    INGESTION: toxic if swallowed;             Do not eat, drink, or smoke during        Do not induce vomiting; otherwise
    may cause nausea, vomiting,                work; keep away from food, drink,         as above
    abdominal spasm, diarrhoea;                and animal feed
    liver and kidney injury may
    occur; severe cases may be fatal

    INTERNATIONAL CHEMICAL SAFETY CARD (cont'd).

                                                    BOTH COMPOUNDS

    HAZARDS/SYMPTOMS                           PREVENTION AND PROTECTION                 FIRST AID

    REPEATED EXPOSURE --                       Take bath or shower after work and        As above
    SKIN, EYES, INHALATION,                    change clothing; otherwise as above
    INGESTION: May cause
    acneiform dermatitis

    ENVIRONMENT: highly                        Avoid spillage into the
    hazardous to most aquatic                  environment
    and terrestrial organisms

    SPILLAGE                                   STORAGE                                   FIRE AND EXPLOSION

    Sweep up spilled substances,               Store in secure well ventilated,          Not combustible, formulated products may
    and remove to safe place;                  cool and dry place; do not store          be flammable; may give rise to harmful
    carefully collect remainder                near foodstuffs or animal feed            decomposition products such as polychlorinated
    (extra personal protection,                                                          dibenzo-p-dioxines; control fares with
    particle-filter respirator);                                                         alcohol resistant foam, dry powder, or carbon
    adsorb spilled liquids with                                                          dioxide
    sawdust, lime, sand, or earth;
    prevent liquids from spreading
    or contaminating other cargo,
    vegetation or waterways

    INTERNATIONAL CHEMICAL SAFETY CARD (cont'd).

                                                    BOTH COMPOUNDS

    HAZARDS/SYMPTOMS                           PREVENTION AND PROTECTION                 FIRST AID

    WASTE DISPOSAL

    Burn at high temperature in                National occupational exposure            UN: 2761, 2762, 2995, 2996
    incinerator with effluent gas              limit:
    scrubbing; if not available,
    bury in an approved dump;                  National poison control centre:
    comply with local regulations
                                               Local trade names:

                                                                                                                                                
        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 and other UN sources. The intention is to give the reader a
    representative but non-exhaustive overview of current regulations,
    guidelines, and standards.

    The reader should be aware that regulatory decisions about chemicals
    taken in a certain country can only be fully understood in the
    framework of the legislation of that country.a

    7.1  Previous Evaluations by International Bodies

    "The WHO Recommended Classification of Pesticides by Hazard" (WHO,
    1986) distinguishes between the four hazard classes Ia, Ib, II, and
    III, on the basis of the toxicity of technical products. In this
    report, PCP is classified in Class Ib, being highly hazardous.

    The WHO manual "Prevention, diagnosis and treatment of insecticide
    poisoning" (Plestina, 1984) provides practical advice that generally
    applies to nitro- and chlorophenols. In the WHO  Guidelines for
     drinking-water quality, a guideline value of 10 µg/litre is
    recommended for PCP.

    No evaluation of the carcinogenicity of PCP has been made by the
    International Agency for Research on Cancer, because the available
    data on the carcinogenic and mutagenic effects of PCP were considered
    inadequate for a sound evaluation.

    IRPTC (1984) issued a review on pentachlorophenol in its series
    "Scientific reviews of Soviet literature on toxicity and hazard of
    chemicals".

    7.2  Exposure Limit Values

    Some examples of exposure limit values are shown in the following
    table. 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).

    a  The regulations and guidelines of all countries are subject to
       change and should always be verified with the appropriate
       regulatory authorities before application.

        EXPOSURE LIMIT VALUES

    Medium     Specification     Country/           Exposure limit description                       Value                Effective
                                 organization                                                                             date

    AIR        Workplace         Japan              Maximum allowable concentration (MAC)            0.5 mg/m3
                                                    - time-weighted average (TWA)
                                                    - short-term exposure limit (STEL)

                                 Sweden             Hygienic limit value (8-h TWA)                   0.5 mg/m3
                                                    - short-term exposure limit                      1.5 mg/m3

                                 United Kingdom     Recommended limit (RECL) (8-h TWA)               0.5 mg/m3
                                                    - short-term exposure limit (10-min TWA)         1.5 mg/m3

                                 Germany,           Maximum work-site concentration
                                 Federal            - time-weighted average (8 hours)                0.5 mg/m3
                                 Republic of        - 30-min STEL, 4 ×/shift                         1 mg/m3

                                 USSR               Maximum allowable concentration (MAC)
                                                    - Ceiling value                                  0.1 mg/m3            1977

                                 USA                Permissible exposure limit (PEL-TWA)             0.5 mg/m3
                                                    - STEL                                           1.5 mg/m3

    AIR        Workplace         Italy              Threshold limit value (TLV)                      0.5 mg/m3

    AIR        Ambient           USSR               Maximum allowable concentration (1 × per day)    0.005 mg/m3
                                                    (average per day)                                0.001 mg/m3
                                                    Preliminary safety limits (PSL) (1 × per day)    0.02 µg/m3

    EXPOSURE LIMIT VALUES

    Medium     Specification     Country/           Exposure limit description                       Value                Effective
                                 organization                                                                             date

    FOOD                         USA                Acceptable daily intake (ADI)                    3 µg/kg              1977
                                                    body weight
                                                    per day

    FOOD       Plant             Germany,           Maximum residue limits                           0.01-0.03 mg/kg      1978
                                 Federal
                                 Republic of

    WATER      Surface           USSR               Maximum allowable concentration                  0.01 mg/litre        1983

    WATER      Drinking          WHO                Maximum allowable concentration
                                                    (guideline value)                                10 µg/litre          1984

        7.3  Specific Restrictions

    The use of pentachorophenol has been more and more restricted during
    the last few years as a result of the increasing concern about the
    potential health and environmental hazards of PCP and its impurities.

    To mention a few:

    -    Sweden banned all use of PCP in 1977 and the Federal Republic of
         Germany banned all use in 1987;

    -    the USA cancelled its registration for herbicidal and
         anti-microbial use and for the preservation of wood in contact
         with food, feed, domestic animals, and livestock. The sale and
         use of PCP is restricted to certified applicators;

    -    the agricultural use of PCP has been suspended or restricted in,
         among others, Canada, Denmark, German Democratic Republic, and
         Japan;

    -    Canada and the Netherlands have suspended its use for indoor wood
         treatment.

    7.4  Labelling, Packaging, and Transport

    The United Nations Committee of Experts on the Transportation of
    Dangerous Goods classifies pentachlorophenol in:

    -    Hazard Class 6.1: poisonous substance;

    -    Packing Group II: a substance presenting a serious risk of
         poisoning in transport.

    The label should be as follows:

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

    The label must read:

     Toxic by inhalation, in contact with skin and if swallowed, after
     contact with skill, wash immediately with plenty of ........
     (to be specified by the manufacturer); wear suitable protective
     clothing and eye/face protection; if you feel unwell, seek medical
     advice(show the label where possible).

    The European Community legislation on the labelling of paints,
    varnishes, printing inks, adhesives, and similar products requires the
    following labelling.

    ( a) When the concentration of pentachlorophenol in these
    preparations exceeds 5%, the symbol used should be:

    ( b) When the concentration is between 0.5 and 5%, the symbol should
    be:

    The European Community legislation on the labelling of pesticide
    preparations classifies pentachlorophenols in Class 1/a for the
    purpose of determining the label for pesticide preparations containing
    this substance.

    7.5  Waste Disposal

    In the USA, pentachlorophenol is regarded as hazardous and restricted
    for the purpose of discharge into waters. Detailed instructions are
    given.

    BIBLIOGRAPHY

    FAO (1985a)  Guidelines for the packaging and storage of pesticides.
    Rome, Food and Agriculture Organization of the United Nations.

    FAO (1985b)  Guidelines for the disposal of waste pesticides and
     pesticide containers on the farm. Rome, Food and Agriculture
    Organization of the United Nations.

    FAO (1985c)  Guidelines on good labelling practice for pesticides.
    Rome, Food and Agriculture Organization of the United Nations.

    GIFAP (1982)  Guidelines for the safe handling of pesticides during
     their formulation, packing storage and transport. Brussels, Groupement
    International des Associations Nationales des Fabricants de Produits
    Agrochimiques.

    GIFAP (1983)  Guidelines for the safe and effective use of pesticides.
    Brussels, Groupement International des Associations Nationales des
    Fabricants de Produits Agrochimiques.

    GIFAP (1984)  Guidelines for emergency measures in cases of pesticide
     poisoning. Brussels, Groupement International des Associations
    Nationales des Fabricants de Produits Agrochimiques.

    IARC (1972-present)  IARC monographs on the evaluation of carcinogenic
     risk of chemicals to man. Lyons, International Agency for Research on
    Cancer.

    IRPTC (1983)  IRPTC legal file 1983. Geneva, International Register
    of Potentially Toxic Chemicals, United Nations Environment Programme.

    IRPTC (1985)  IRPTC file on treatment and disposal methods for waste
     chemicals. Geneva, International Register for Potentially Toxic
    Chemicals, United Nations Environment Programme.

    PLESTINA, R. (1984)  Prevention, diagnosis, and treatment of
     insecticide poisoning, Geneva, World Health Organization
    (Unpublished WHO document VBC/84.889).

    SAX, N.I. (1984)  Dangerous properties of industrial materials, New
    York, Van Nostrand Reinhold Company, Inc.

    UNITED NATIONS (1986)  Recommendations on the transport of dangerous
     goods. 4th ed. New York, United Nations.

    US NIOSH/OSHA (1981)  Occupational health guidelines for chemical
     hazards, 3 Vols, Washington DC, US Department of Health and Human
    Services, US Department of Labor (Publication No. DHSS(NIOSH) 01-123).

    WHO (1986)  The WHO recommended classification of pesticides by hazard
     and guidelines to classification 1986-87. Geneva, World Health
    Organization (Unpublished WHO document VBC/86.1).

    WHO (1987)  EHC No. 71: Pentachlorophenol. Geneva, World Health
    Organization, 236pp.

    WORTHING, C.R. & WALKER, S.B. (1983)  The pesticide manual. 7th ed.
    Lavenham, Lavenham Press Limited, British Crop Protection Council.
    
    See Also:
       Toxicological Abbreviations
       Pentachlorophenol (EHC 71, 1987)
       Pentachlorophenol (ICSC)
       Pentachlorophenol (PIM 405)
       Pentachlorophenol (IARC Summary & Evaluation, Volume 53, 1991)