Health and Safety Guide No. 62






    This is a companion volume to Environmental Health Criteria 108:

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

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

    WHO Library Cataloguing in Publication Data

    Nickel, nickel carbonyl, and some nickel compounds : health and safety

    (Health and safety guide ; no. 62)

    1.Nickel - adverse effects 2.Nickel - standards
    3.Environmental exposure
    4.Environmental pollutants I.Series

    ISBN 92 4 151062 5          (NLM Classification: QV 290)
    ISSN 0259-7268

    (c) World Health Organization 1991

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         1.1. Identity
         1.2. Physical and chemical properties
         1.3. Analytical methods
         1.4. Uses

         2.1. Sources of nickel
         2.2. Behaviour in the environment
         2.3. Human exposure
         2.4. Metabolism
         2.5. Effects on organisms in the environment
         2.6. Effects on experimental animals and  in vitro test systems
         2.7. Effects on human beings

         3.1. Conclusions
         3.2. Recommendations

         4.1. Main human health hazards, prevention and protection,
              first aid
              4.1.1. Advice to physicians
              4.1.2. Health surveillance advice
         4.2. Explosion and fire hazards
              4.2.1. Explosion hazards
              4.2.2. Fire hazards
              4.2.3. Prevention
              4.2.4. Fire extinguishing agents
         4.3. Storage
         4.4. Transport
         4.5. Spillage and disposal
              4.5.1. Spillage
              4.5.2. Disposal



         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



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

    The purpose of a Health and Safety Guide is to facilitate the
    application of these guidelines in national chemical safety
    programmes. The first three sections of a Health and Safety Guide
    highlight the relevant technical information in the corresponding EHC. 
    Section 4 includes advice on preventive and protective measures and
    emergency action; health workers should be thoroughly  familiar with
    the medical information to ensure that they can act efficiently in an
    emergency.  Within the Guide is a Summary of Chemical Safety
    Information which should be readily available, and should be clearly
    explained, to all who could come into contact with the chemical.  The
    section on regulatory information has been extracted from the legal
    file of the International Register of Potentially Toxic Chemicals
    (IRPTC) and from other United Nations sources.

    The target readership includes occupational health services, those in
    ministries, governmental agencies, industry, and trade unions who are
    involved in the safe use of chemicals and the avoidance of
    environmental health hazards, and those wanting more information on
    this topic.  An attempt has been made to use only terms that will be
    familiar to the intended user.  However, sections 1 and 2 inevitably
    contain some technical terms.  A bibliography has been included for
    readers who require further background information.

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

    The Manager
    International Programme on Chemical Safety
    Division of Environmental Health
    World Health Organization
    1211 Geneva 27



    1.1  Identity

    Common name:                  Nickel

    Chemical symbol:              Ni

    CAS registry number:          7440-02-0

    1.2  Physical and Chemical Properties

    1.2.1  Nickel

    Nickel is a naturally occurring, shiny, light-coloured metal with high
    electrical and thermal conductivities.  It is resistant to corrosion
    by air, water, and alkalis, but reacts with dilute oxidizing agents.

    1.2.2  Some nickel salts

     Nickel carbonate hydroxide tetrahydrate (2NiCO3.3Ni(OH)2.4H2O)

    The composition of basic nickel carbonate varies.  The most common
    forms range from 2NiCO33Ni(OH)2.XH2O to NiCO3Ni(OH)3.XH20. 
    Nickel carbonate hydroxide is insoluble in water, but soluble in
    ammonia and in dilute acids.

     Nickel carbonyl (Ni(CO)4)

    Nickel carbonyl is a colourless, volatile liquid that is formed when
    nickel powder is treated with carbon monoxide at about 50C.  It is
    insoluble in water, but soluble in most organic solvents.

     Nickel chloride (NiCl2)  and nickel chloride hexahydrate (NiCl2.6H2O)

    Nickel chloride and nickel chloride hexahydrate are soluble in both
    water and ethanol.

     Nickel hydroxide (Ni(OH)2)

    Nickel hydroxide is insoluble in water, but soluble in acids.  It
    forms complexes with ammonia. 

     Nickel nitrate (Ni(NO3)2)

    Nickel nitrate is readily soluble in both water and alcohol.

     Nickel oxide (NiO)

    The name "nickel oxide" covers several nickel-oxygen compounds that
    differ in stoichiometry, and chemical and physical properties.

    Nickel oxide (NiO) exists in two forms.  Black nickel oxide is
    chemically reactive and forms simple salts in the presence of acids. 
    Green nickel oxide is an inert and refractory material.  Nickel oxide
    is insoluble in water.  The solubility in acids and other properties
    depend on the method of preparation of the nickel oxide.

     Nickel sulfate (NiSO4)

    Nickel sulfate exists as a hexahydrate, initially in the alpha-form,
    which changes into the -form at 53.3C.  Nickel sulfate is soluble in
    water, ethanol, and methanol.

     Nickel sulfide (NiS)

    Nickel sulfide is insoluble in water.

     Nickel subsulfide (Ni3S2)

    At high temperatures, nickel subsulfide exists in a bronze-yellow form
    (beta-Ni3S2).  At lower temperatures, it changes to a green -form,
    which is stable at normal temperature. alpha-Nickel subsulfide occurs
    naturally as the grey mineral heazlewoodite.  Nickel subsulfide is
    insoluble in water.

    1.3  Analytical Methods

    The most commonly used analytical methods for biological and
    environmental samples are atomic absorption spectroscopy and
    voltammetry.  In order to obtain reliable results, especially in the
    ultratrace range, specific procedures have to be followed to minimize
    the risk of contamination during sample collection, storage,
    processing, and analysis.  Depending on sample pretreatment,
    extraction, and enrichment procedures, detection limits of
    1-100 ng/litre can be achieved in biological samples and water.

    For water, electrothermal atomic absorption spectroscopy (EAAS) has a
    detection limit of 10 ng nickel/litre.  Voltammetry is more sensitive
    and the use of differential pulse voltammetry (DPV) can achieve a
    detection limit of 1 ng/litre.

    DPV can also be used for the determination of the nickel contents of

    Flame atomic absorption spectroscopy (FAAS) is a commonly used method
    for measuring nickel concentrations in air.  Inductively coupled
    plasma atomic emission spectroscopy (ICP-AES) can also be used for the
    analysis of air samples.

    Atomic absorption spectroscopy is a sensitive method for nickel
    determination in blood, serum, urine, other biological samples, and

    Electron microscopy and X-ray microanalysis can be used for the
    determination of nickel levels in dust particles, such as grinding
    dust and welding fumes.

    1.4  Uses

    Nickel is mined from sulfide or oxide ores (laterites).  Production of
    nickel metal is performed by pyro- and hydrometallurgical methods. 
    Final refining can be achieved by electrolytic techniques or by
    passing carbon monoxide gas over nickel powder to form nickel
    carbonyl, which is decomposed to yield pure nickel.

    A major use of nickel is as an alloying element for steel and cast
    iron, yielding alloys and steels with increased strength and
    resistance to corrosion and temperature.  Nickel compounds are used in
    nickel-cadmium batteries, in electronic and computer equipment, and as
    constituents of pigments in the glass and ceramics industries.  Other
    important applications include the use of nickel sulfate and nickel
    chloride in electroplating, and of nickel compounds as catalysts in
    the manufacture of organic chemicals, petroleum refining, and edible
    oil hardening.  Nickel carbonyl is used in nickel refining.


    2.1  Sources of Nickel

    Nickel is a ubiquitous trace metal and occurs in soils, water, air,
    and in the biosphere.  The average content of the earth's crust is
    about 0.008%.  Farm soils contain between 3 and 1000 mg nickel/kg. 
    Levels in natural waters have been found to range from 2 to
    10 g/litre (fresh water) and from 0.2 to 0.7 g/litre (marine). 
    Atmospheric nickel concentrations in remote areas range from <0.1 to
    3 ng/m3.

    Nickel ore deposits are accumulations of nickel sulfide minerals
    (mostly pentlandite) and laterites.  Nickel is extracted from the
    mined ore by pyro- and hydro-metallurgical refining processes.  Global
    mining production of nickel was approximately 67 million kg in 1985.

    Most of the nickel is used for the production of stainless steel and
    other nickel alloys with high corrosion and temperature resistance. 
    Nickel alloys and nickel plating are used in vehicles, processing
    machinery, armaments, tools, electrical equipment, household
    appliances, and coinage.  Nickel compounds are also used as catalysts,
    pigments, and in batteries.  The primary sources of nickel emissions
    into the ambient air are the combustion of coal and oil for heat or
    power generation, the incineration of waste and sewage sludge, nickel
    mining and primary production, steel manufacture, electroplating, and
    miscellaneous sources, such as cement manufacturing.  In polluted air,
    the predominant nickel compounds appear to be nickel sulfate, oxides,
    and sulfides, and, to a lesser extent, metallic nickel.

    Nickel from various industrial processes and other sources finally
    reaches waste water.  Residues from waste-water treatment are disposed
    of by deep well injection, ocean dumping, land treatment, and
    incineration.  Effluents from waste-water treatment plants have been
    reported to contain up to 0.2 mg nickel/litre.

    2.2  Behaviour in the Environment

    Nickel is introduced into the environment from both natural and
    man-made sources and is circulated throughout all environmental
    compartments by means of chemical and physical processes, as well as
    by being biologically transported by living organisms.

    Atmospheric nickel is considered to exist mainly in the form of
    particulate aerosols containing different concentrations of nickel,
    depending on the source.  The highest nickel concentrations in ambient
    air are usually found in the smallest particles.  Nickel carbonyl is
    unstable in air and decomposes to form nickel oxide.

    The transport and distribution of nickel particles to, or between,
    different environmental compartments is strongly influenced by
    particle size and meteorological conditions.  Particle size
    distribution is primarily a function of the emitting sources.  In
    general, particles from man-made sources are smaller than natural dust

    Nickel is introduced into the hydrosphere by removal from the
    atmosphere, by surface runoff, by discharge of industrial and
    municipal waste, and also following natural erosion of soils and
    rocks.  In rivers, nickel is mainly transported in the form of a
    precipitated coating on particles, and in association with organic
    matter;  in lakes, it is transported in the ionic form, predominantly
    in association with organic matter.  Nickel may also be absorbed on
    clay particles and via uptake by biota.  Absorption processes can be
    reversed leading to the release of nickel from the sediment.  Part of
    the nickel is transported via rivers and streams to the ocean. 
    Riverine suspended particulate input is estimated to be
    135  107 kg/year.

    Depending on the soil type, nickel may exhibit a high mobility within
    the soil profile, finally reaching ground water and, thus, rivers and
    lakes.  Acid rain has a pronounced tendency to mobilize nickel from
    the soil.  Terrestrial plants take up nickel from soil, primarily via
    the roots.  The amount of nickel uptake from soil depends on various
    geochemical and physical parameters including the type of soil, soil
    pH, humidity, the organic matter content of the soil, and the
    concentration of extractable nickel.  The best known example of nickel
    accumulation is the increased nickel levels, in excess of 1 mg/kg dry
    weight, found in a number of plant species ("hyperaccumulators")
    growing on relatively infertile serpentine soils.  Nickel levels
    exceeding 50 mg/kg dry weight are toxic for most plants.  Accumulation
    and toxic effects have been observed in vegetables grown on sewage
    sludge-treated soils and in vegetation near nickel-emitting sources. 
    High concentration factors have been observed in aquatic plants. 
    Laboratory studies showed that nickel had little capacity for
    accumulation in all the fish studied. In uncontaminated waters, the
    concentrations reported in whole fish, on a wet-weight basis, ranged
    from 0.02 to 2 mg/kg.  These values could be up to 10 times higher in
    fish from contaminated waters.  However, there is no evidence for the
    biomagnification of nickel in the food chain.

    In wildlife, nickel is found in many organs and tissues, due to
    dietary uptake by herbivorous animals and their carnivorous predators.

    2.3  Human Exposure

    Typical atmospheric nickel levels for human exposure range from about
    5 to 35 ng/m3 at rural and urban sites, leading to a nickel uptake
    via inhalation of 0.1-0.7 g/day.  Drinking-water generally contains
    less than 10 g nickel/litre, but, occasionally, nickel may be
    released from the plumbing fittings resulting in concentrations of up
    to 500 g nickel/litre.

    Nickel concentrations in food are usually below 0.5 mg/kg fresh
    weight.  Cocoa, soybeans, some dried legumes, various nuts, and
    oatmeal contain high concentrations of nickel.  Daily intake of nickel
    from food varies widely, according to different dietary habits, and
    can range from 100 to 800 g/day;  the mean dietary nickel intake in
    most countries is 100-300 g/day.  Release of nickel from kitchen
    utensils may contribute significantly to oral intake.  Pulmonary
    intake of 2-23 g nickel/day can result from smoking 40 cigarettes a

    Daily skin contact with nickel-plated objects or nickel-containing
    alloys (e.g., jewellery, coins, clips) is an important factor in the
    induction and maintenance of contact hypersensitivity.

    Iatrogenic exposure to nickel results from implants and prostheses
    made from nickel-containing alloys, from intravenous or dialysis
    fluids, and from radiographic contrast media.  An estimated average
    intravenous nickel uptake from dialysis fluids is 100 g per

    In the working environment, airborne nickel concentrations can vary
    from a few g/m3 to, occasionally, a few mg/m3, depending on the
    process involved and the nickel content of the material being handled.

    Globally, millions of workers are exposed to nickel-containing dusts
    and fumes during welding, plating, grinding, mining, nickel refining,
    and in steel plants, foundries, and other metal industries.

    Dermal exposure to nickel may occur in a wide range of jobs, either by
    direct exposure to dissolved nickel, e.g., in the refining,
    electroplating, and electroforming industries, or by handling
    nickel-containing tools.  Wet cleaning work may involve exposure to
    nickel, because of the nickel that becomes dissolved in the washing

    2.4  Metabolism

    Nickel can be absorbed by humans and animals via inhalation,
    ingestion, or percutaneously.  Respiratory absorption with secondary
    gastrointestinal absorption of nickel (insoluble and soluble) is the
    major route of entry during occupational exposure.  A significant
    quantity of inhaled material is swallowed following mucociliary
    clearance from the respiratory tract.  Thus, poor personal hygiene and
    work practices can  contribute to gastrointestinal exposure. 
    Percutaneous absorption is negligible, quantitatively, but is
    important in the pathogenesis of contact hypersensitivity.  Absorption
    is related to the solubility of the compound, following the general
    relationships nickel carbonyl >soluble nickel compounds >insoluble
    nickel compounds.  Nickel carbonyl is the most rapidly and completely
    absorbed nickel compound in both animals and man.  Studies in which
    nickel was administered via inhalation are limited.  Studies on
    hamsters and rats, exposed to insoluble nickel oxide, showed poor
    absorption with retention of much of the material in the lung after
    several weeks.  In contrast, absorption of soluble nickel chloride or
    amorphous nickel sulfide was rapid.  Nickel is transported in the
    blood principally bound to albumin.

    Gastrointestinal absorption of nickel is variable and depends on the
    composition of the diet.  In a recent study on human volunteers,
    absorption of nickel was 27% from water versus less than 1% from food. 
    All body secretions are potential routes of excretion including urine,
    bile, sweat, tears, milk, and mucociliary fluid.  Non-absorbed nickel
    is eliminated in the faeces.

    Transplacental transfer has been demonstrated in rodents.

    Following parenteral administration of nickel salts, the highest
    nickel accumulation occurs in the kidney, endocrine glands, lung, and
    liver:  high concentrations are also observed in the brain following
    administration of nickel carbonyl.  Data on nickel excretion suggest a
    two-compartment model.  Nickel concentrations in the serum and urine
    of healthy non-occupationally exposed adults are 0.2 g/litre (range: 
    <0.05-1.1g/litre) and 2 g/litre (range: 0.5-6.0 g/litre)
    equivalent to 2 g/g creatinine (range: 0.4-6.0 g/g creatinine),
    respectively.  Increased concentrations of nickel are noted in both of
    these fluids following occupational exposure.  The body burden of
    nickel in a non-exposed, 70 kg adult is 0.5 mg.

    2.5  Effects on Organisms in the Environment

    In microorganisms, growth was generally inhibited at nickel
    concentrations in the medium of 1-5 mg/litre in the case of
    actinomycetes, yeast, and marine and non-marine eubacteria, and at
    concentrations of 5-1000 mg/litre in the case of filamentous fungi. 
    In algae, no growth was observed at approximately 0.05-5 mg
    nickel/litre.  Abiotic factors, such as the pH, hardness, temperature,
    and salinity of the medium, and the presence of organic and inorganic
    particles, influence the toxicity of nickel.

    Nickel toxicity in aquatic invertebrates varies considerably,
    according to species and abiotic factors.  A 96-h LC50 of 0.5 mg
    nickel/litre was found for  Daphnia spp. while, in molluscs, 96-h
    LC50 values of around 0.2 mg/litre were found for two freshwater
    snail species and of 1100 mg/litre for a bivalve.

    In fish, the 96-h LC50 values generally fall within the range
    4-20 mg nickel/litre, but they can be higher in some species. 
    Long-term studies on fish and fish development demonstrated some
    effects on rainbow trout in soft water at levels as low as
    0.05 mg nickel/litre.  In terrestrial plants, nickel levels exceeding
    50 mg/kg dry weight are usually toxic.  Copper was found to act
    toxicologically in a synergistic way, whereas calcium reduced the
    toxicity of nickel.  Data on the effects of nickel on terrestrial
    animals are limited.  Earthworms seem to be relatively insensitive to
    nickel, when the medium is rich in microorganisms and organic matter,
    thus making nickel less available to earthworms.  Nickel has not been
    considered as a wide-scale global contaminant; however, ecological
    changes, such as decreases in the number and diversity of species,
    have been observed near nickel-emitting sources.  Microecosystem
    studies have shown that the addition of nickel to soil disturbs the
    nitrogen cycle.

    2.6  Effects on Experimental Animals and In vitro Test Systems

    Nickel is essential for the catalytic activity of some plant and
    bacterial enzymes.  Slow weight gain, anaemia, and decreased viability
    of offspring have been described in some animal species, after dietary
    deprivation of nickel.

    The most acutely toxic nickel compound is nickel carbonyl, the lung
    being the target organ;  pulmonary oedema may occur within 4 h
    following exposure.  The acute toxicity of other nickel species is

    Though contact allergy to nickel is very common in humans,
    experimental sensitization in animals is only successful under special
    conditions.  Long-term inhalation exposure to metallic nickel, nickel
    oxide, or nickel subsulfide caused mucosal damage and an inflammatory
    reaction in the respiratory tract in rats, mice, and guinea-pigs. 
    Epithelial hyperplasia was observed in rats after inhalation exposure
    to nickel chloride or nickel oxide aerosols.

    High-level, long-term exposure to nickel oxide led to gradually
    progressive pneumoconiosis in rats.  Inflammatory reaction, sometimes
    accompanied by slight fibrosis, was observed in rabbits after
    high-level exposure to nickel-graphite dust.  Pulmonary fibrosis was
    seen in rats exposed to nickel subsulfide.

    Nickel salts induced a rapid transistory hyperglycaemia in rats,
    rabbits, and chickens, after parenteral administration.  These changes
    may be associated with effects on alpha and beta cells in the islets
    of Langerhans.  Nickel also decreased the release of prolactin. 
    Nickel chloride, given orally or by inhalation, has been reported to
    decrease iodine uptake by the thyroid.

    Nickel salts, given intravenously, decreased blood flow in the
    coronary arteries in the dog;  high concentrations of nickel decreased
    the contractility of the dog myocardium  in vitro.

    Nickel chloride affects the T-cell system and suppresses the activity
    of natural killer cells.  Parenteral administration of nickel chloride
    and nickel subsulfide has been reported to cause intrauterine
    mortality and decreased weight gain in rats and mice.  Inhalation
    exposure to nickel carbonyl caused fetal death and decreased weight
    gain, and was teratogenic in rats and hamsters. No information on
    maternal toxicity was given in these studies.  Nickel carbonyl has
    been reported to cause dominant lethal mutations in rats.

    Several inorganic nickel compounds were tested for mutagenicity in
    various test systems.  Nickel compounds were generally inactive in
    bacterial mutagenesis assays, except where fluctuation tests were
    used.  Mutations were observed in several cultured mammalian cell
    types.  Nickel compounds inhibited DNA synthesis in a wide variety of
    organisms.  In addition, nickel compounds induced chromosomal
    aberrations and sister chromatid exchange (SCE) in both mammalian and
    human cultured cells.  Chromosomal aberrations, but not SCE (except in
    one study on electrolysis workers), were observed in humans
    occupationally exposed to either insoluble or soluble nickel
    compounds.  Nickel induced cell transformation  in vitro.

    Nickel subsulfide induced benign and malignant pulmonary tumours in
    rats in an inhalation study.  A few pulmonary tumours were seen in
    rats in a series of inhalation studies with nickel carbonyl.  There
    was no significant increase in lung tumours in rats in an adequate
    inhalation study with metallic nickel.  Inhalation exposure to black
    nickel oxide did not induce lung tumours in Syrian golden hamsters (a
    species resistant to lung carcinogenesis).  Adequate carcinogenicity
    studies using inhalation exposure were not available for other nickel
    compounds.  However, nickel subsulfide, metallic nickel powder, and an
    unspecified nickel oxide induced benign and malignant lung tumours in
    rats after repeated intratracheal instillations.

    Nickel carbonyl, nickelocene, and a large number of slightly soluble
    or non-soluble nickel compounds, including nickel subsulfide,
    carbonate, chromate, hydroxide, sulfides, selenides, arsenides,
    telluride, antimonide, various unidentified oxide preparations, two
    nickel-copper oxides, metallic nickel, and various nickel alloys,
    induced local mesenchymal tumours in a variety of experimental animals
    after intramuscular, subcutaneous, intraperitoneal, intrapleural,
    intraocular, intraosseous, intrarenal, intra-articular,
    intratesticular, or intra-adipose administration.  No local
    carcinogenic response was seen in single-dose studies with some nickel
    alloys, colloidal nickel hydroxide, or with two specimens of nickel
    oxide, especially prepared for carcinogenicity testing by calcining at
    735C or 1045C.

    Nickel sulfate and nickel acetate, but not nickel chloride, induced
    tumours of the peritoneal cavity in rats after repeated
    intraperitoneal administration.

    Metallic nickel and a very large number of nickel compounds have been
    tested for carcinogenicity by the parenteral route of administration; 
    with few exceptions, they caused local tumours.

    Only nickel subsulfide has been shown convincingly to cause cancer
    after inhalation exposure.  However, the number of adequate inhalation
    studies is very small.

    In studies using repeated intratracheal instillation, nickel powder,
    nickel oxide, and nickel subsulfide caused pulmonary tumours.

    When three different soluble nickel salts, which had not induced local
    tumours in earlier studies, were tested using repeated intraperitoneal
    administration, two of the salts elicited a carcinogenic response.

    The International Agency for Research on Cancer concluded, in 1989,
    that there was:

         a)  sufficient evidence in experimental animals for the
         carcinogenicity of metallic nickel, nickel monoxides, nickel
         hydroxides, and crystalline nickel sulfides;

         b)  limited evidence in experimental animals for the
         carcinogenicity of nickel alloys, nickelocene, nickel carbonyl,
         nickel salts, nickel arsenides, nickel antimonide, nickel
         selenides, and nickel telluride;

         c)  inadequate evidence in experimental animals for the
         carcinogenicity of nickel trioxide, amorphous nickel sulfide, and
         nickel titanate.

    2.7  Effects on Human Beings

    In terms of human health effects, nickel carbonyl is the most acutely
    toxic nickel compound.  The effects of acute nickel carbonyl poisoning
    include frontal headache, vertigo, nausea, vomiting, insomnia, and
    irritability, followed by pulmonary symptoms similar to those of a
    viral pneumonia.  Pathological pulmonary lesions include haemorrhage,
    oedema, and cellular derangement.  Liver, kidneys, adrenal glands,
    spleen, and brain are also affected.  Cases of nickel poisoning have
    also been reported in patients dialysed with nickel-contaminated
    dialysate and in electroplaters who accidentally ingested water
    contaminated with nickel sulfate and nickel chloride.

    Chronic effects, such as rhinitis, sinusitis, nasal septal
    perforations, and asthma, have been reported in nickel refinery and
    nickel plating workers.  Some authors have reported pulmonary changes
    with fibrosis in workers inhaling nickel dust.  In addition, nasal
    dysplasia has been reported in nickel refinery workers.  Nickel
    contact hypersensitivity has been documented extensively in both the
    general population and in a number of occupations, including those in
    which workers were exposed to soluble nickel compounds.  In several
    countries, it has been reported that 10% of the female population and
    1% of the male population are sensitive to nickel; 40-50% of these
    have vesicular hand eczema, which, in some cases, may be very severe
    and lead to loss of working ability.  Oral nickel intake may aggravate
    vesicular hand eczema and possibly eczema arising on other parts of
    the body where there has been no skin contact with nickel.

    Prostheses or other surgical implants made from nickel-containing
    alloys have been reported to cause nickel sensitization or to
    aggravate existing dermatitis.

    Nephrotoxic effects, such as renal oedema with hyperaemia and
    parenchymatous degeneration, have been reported in cases of accidental
    industrial exposure to nickel carbonyl.  Transient nephrotoxic effects
    have been recorded after accidental ingestion of nickel salts.

    Very high lung and nasal cancer risks have occurred in nickel refinery
    workers employed in the high-temperature roasting of sulfide ores,
    involving substantial exposure to nickel subsulfide, nickel oxide, and
    perhaps nickel sulfate.  Similar risks have been reported in processes
    involving exposure to soluble nickel (electrolysis, copper sulfate
    extraction, hydrometallurgy), often combined with some nickel oxide
    exposure, but with low nickel subsulfide exposure.  The risk to miners
    and other refinery workers has been much lower.  Cancer rates have
    generally been close to normal in workers in stainless steel welding
    and in the nickel-using industries, except where exposure to chromium
    has been involved, particularly electroplating.  However, the risk of
    lung cancer may have been slightly increased in nickel/cadmium battery
    workers exposed to high levels of both nickel and cadmium.  Excesses
    of various cancers, other than lung and nasal cancers (e.g.,renal,
    gastric, or prostatic cancers), have occasionally been reported in
    nickel workers, but none has been found consistently.

    There is evidence of a cancer risk in workers who had been exposed to
    soluble nickel concentrations of the order of 1-2 mg/m3, both in
    electrolysis and in the preparation of soluble salts.  These workers
    were also exposed to other nickel compounds, but often at lower levels
    than in other high-risk processes.  In the absence of historical
    exposure measurements, it is impossible to draw unequivocal
    conclusions, but the evidence that soluble nickel is carcinogenic is
    certainly strong.  Refinery dust sometimes contains a substantial
    proportion of nickel sulfate, in addition to nickel subsulfide.  This
    raises the possibility that the very high cancer risk observed in
    workers employed in the high-temperature oxidation of nickel
    subsulfide may partly be due to soluble nickel.

    In refinery areas where cancer risks were high, exposure to nickel
    subsulfide almost always occurred together with exposure to the oxide
    and perhaps the sulfate (see above).  Therefore, it is difficult to
    demonstrate that nickel subsulfide is carcinogenic on the basis of
    epidemiological data alone, though this seems likely.

    Nickel oxide was present in almost all circumstances in which cancer
    risks were elevated, together with one or more other forms of nickel
    (nickel subsulfide, soluble nickel, metallic nickel).  As for nickel
    subsulfide, it is difficult either to demonstrate or to disprove its
    suspected carcinogenicity from epidemiological data alone.

    No increased cancer risk has been demonstrated in workers exposed
    exclusively to metallic nickel.  The combined data on nickel alloy
    workers and gaseous diffusion workers, who were exposed to average
    concentrations of the order of 0.5 mg nickel/m3, show no excess
    risk, though the total number of lung cancers in these cohorts is too
    small to exclude a small increase in risk at this level.

    The International Agency for Research on Cancer concluded, in 1989,
    that nickel compounds are carcinogenic to humans (Group 1) and
    metallic nickel is possibly carcinogenic to humans (Group 2B).


    3.1  Conclusions

    (a)  Exposure

    Nickel is an ubiquitous element and has been detected in different
    media in all parts of the biosphere.

    Nickel is introduced into the environment from both natural and
    man-made sources and is circulated throughout all environmental
    compartments by means of chemical and physical processes, as well as
    by the biological transport mechanisms of living organisms.

    Acid rain may leach nickel as well as other metals from plants and

    Atmospheric nickel is considered to exist mainly in the form of
    particulate aerosols.

    Nickel is introduced into the hydrosphere by removal from the
    atmosphere, by surface run-off, by the discharge of industrial and
    municipal wastes, and also following natural erosion of soils and

    A major source of nickel in the environment is the combustion of
    fossil fuels, particularly coal.

    Uncontrolled emissions and disposal of wastes may impact the
    environment and have adverse effects.

    The chemical and physical forms of nickel and its salts strongly
    influence their bioavailability and toxicity.

    Nickel from soil and water is absorbed and metabolized by plants and
    microorganisms and these small quantities of nickel are widely present
    in all foods and water.

    Some foods, such as pulses and cocoa products, contain relatively high
    amounts of nickel, but these quantities have not been correlated with
    adverse health effects.

    (b)  Human health effects

    Nickel is normally present in human tissues and, under conditions of
    high exposure, these levels may increase significantly.

    The general population is exposed to nickel via the diet and objects
    containing nickel, especially jewellery and coins.

    Occupational exposure to nickel is important.

    Inhalation is an important route of exposure to nickel and its salts
    with regard to health risks.  The gastrointestinal route is of lesser

    Nickel absorption from the gastrointestinal tract is poor, though, in
    an empty stomach, nickel in drinking-water is absorbed to a greater
    extent.  This may be a risk for sensitized persons.

    Smoking tobacco may contribute to nickel intake, but there is no
    agreement on the chemical nature of nickel or on its health
    significance in tobacco smoke.

    Target organs are the respiratory system, especially the nasal
    cavities and sinuses, and the immune system.

    The percutaneous absorption of nickel is minor, but important in

    Nickel and its salts are potent skin sensitizers and possible
    respiratory sensitizers in man.  Nickel dermatitis is a common result
    of nickel exposure, especially in women.

    Primary skin and eye irritation reactions to high concentrations of
    soluble nickel salts have also been reported.

    Acute nickel toxicity is a minor risk, except in the case of nickel

    There is no convincing evidence that nickel salts produce point
    mutations in bacterial systems.  However, some nickel salts are
    clastogenic  in vitro, producing chromosome aberrations
    (transformation), and sister chromatid exchanges, in mammalian cells.

    Evidence for a carcinogenic risk from oral nickel exposure is lacking,
    but the possibility that nickel acts as a promoter has been raised.

    There is evidence of a carcinogenic risk in association with the
    inhalation of nickel metal dusts and some nickel compounds.

    Only very high concentrations of nickel induce teratogenic or
    genotoxic effects.

    The effects of nickel on the immune system are not clear.

    (c)  Environmental effects

    Nickel is accumulated by plants.  Growth retardation has been reported
    in some species exposed to high nickel concentrations.

    There is no evidence that nickel undergoes biotransformation, though
    it does undergo complexation.

    Nickel has been shown to be essential for the nutrition of many
    microorganisms, a variety of plants, and for some vertebrate animals.

    3.2  Recommendations

    The use of nickel in consumer products that may release nickel in
    contact with skin should be regulated.  The specification and testing
    requirements should be standardized.

    Priority should be given to improving industrial hygiene in
    occupations where exposure to high levels of soluble nickel compounds
    may occur.


    4.1  Main Human Hazards, Prevention and Protection, First Aid

    The human health hazards associated with exposure to nickel and nickel
    compounds, preventive and protective measures, and first aid are
    listed in the Summary of Chemical Safety Information in section 6.

    4.1.1  Advice to physicians

    In cases of suspected poisoning by inhalation, attention should be
    paid to the lungs and upper respiratory tract for irritant effects. 
    Acute poisoning can be associated with heart failure.  Admit to
    hospital as soon as possible.  Obtain detailed advice on diagnosis and
    treatment from the nearest Poisons Information Centre.

    Nickel carbonyl is the only nickel compound that causes acute
    poisoning by inhalation.  If breathing stops, apply artificial
    respiration and administer oxygen.  Measurement of urinary nickel will
    assist in assessing the severity of poisoning.  Inhaled steroids will
    help to prevent lung damage and oedema.  When poisoning is the result
    of ingestion, gastric lavage can be performed, providing precautions
    are taken to prevent accidental aspiration into the respiratory tract.

    4.1.2  Health surveillance advice

    Workers occupationally exposed to nickel and its compounds should
    undergo periodic health checks, with emphasis on the condition of the
    skin, lungs, and upper respiratory tract.  Cases of dermatitis should
    be patch tested (usually with 0.5% nickel sulfate) by a qualified
    dermatologist; in case of positive results they should be given
    alternative employment, where available.  Since nickel exposure can
    interfere with immune defence mechanisms, careful attention should be
    given to persistent infective diseases.

    The physician should be aware of the carcinogenic potential of nickel
    and nickel compounds.

    4.2  Explosion and Fire Hazards

    4.2.1  Explosion hazards

    The vapour of nickel carbonyl is heavier than air.  It can react
    violently with atmospheric oxygen, with risk of explosion at about

    4.2.2  Fire hazards

    With the exception of nickel carbonyl, most nickel compounds of
    commercial interest do not normally constitute a fire hazard.  Liquid
    nickel carbonyl is extremely flammable and autoignition is possible at
    its boiling point (42.2C).  Nickel carbonyl vapour can ignite
    spontaneously at room temperature.

    4.2.3  Prevention

    For nickel carbonyl, use closed systems, suitable ventilation,
    non-sparking tools, explosion-protected electrical equipment and
    lighting.  Do not use nickel carbonyl near sources of ignition.  Do
    not use compressed air for filling, discharging, or handling nickel
    carbonyl.  In case of fire, keep containers with nickel carbonyl cool
    by spraying with water.  Fire fighters should use self-contained
    breathing apparatus.

    4.2.4  Fire extinguishing agents

    Suitable agents include: carbon dioxide, powder, or water.

    4.3  Storage

    Nickel compounds should be stored in tightly closed and correctly
    labelled containers.  In the case of nickel carbonyl, these should be
    kept in a cool, ventilated area away from heat and oxidizing agents,
    such as nitric acid and chlorine.

    4.4  Transport

    In case of accident during the road transport of nickel carbonyl, stop
    the engine.  Remove all sources of ignition.  Evacuate the danger
    area.  Keep bystanders at a distance, put warning signs on the road,
    and keep upwind.  Notify the police and fire brigade immediately.  If
    self-contained breathing apparatus is available, use it.  In case of
    spillage or fire, follow the advice given in sections 4.7 and 4.4,
    respectively.  In case of poisoning, follow the advice in the Summary
    of Chemical Safety Information (section 6).

    4.5  Spillage and Disposal

    4.5.1  Spillage

    In case of spillage of nickel carbonyl, remove all ignition sources
    and evacuate the danger area.  Wear full protective clothing and a
    self-contained breathing apparatus.  Collect and put leaking liquid in

    sealable containers.  Cover smaller quantities of spilled liquid with
    water and slowly add nitric acid to convert nickel carbonyl into
    nickel nitrate.  In case of larger spillage, absorb the spilled liquid
    in a absorbent and remove in a sealable container to a safe place.  Do
    not allow nickel carbonyl to runoff into sewers and ditches.  To avoid
    water contamination, do not allow spilled nickel compounds (especially
    soluble nickel salts) to run into soil and ground water.

    4.5.2  Disposal

    Large quantities of nickel carbonyl should be collected and atomized
    in a suitable combustion chamber equipped with an efficient effluent
    gas-cleaning device.  Other nickel compounds should also be treated as
    hazardous wastes.


    Nickel circulates throughout all environmental compartments (air,
    soil, and water), and can be accumulated by microorganisms and higher
    aquatic and terrestrial organisms.  Nickel is toxic for many
    organisms, but problems arise only when it is present in high
    concentrations as a result of man-made contamination.

    Contamination of soil, water, and air can be minimized by proper
    methods of storage, transport, handling, and waste disposal.  In case
    of spillage, apply methods recommended in section 4.7.1.


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

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


    Ni(C0)4,:   CAS Registry No. 13463-39-3


    PHYSICAL PROPERTIES                                                   OTHER CHARACTERISTICS

    Melting point (C)                       -19.3                        Nickel carbonyl is a colourless liquid that
    Boiling point (C)                       43                           autoignites at its boiling point (42.2C);
    Water solubility                         insoluble                    its vapour can ignite spontaneously
    Specific density (g/cm3) (25C)          1.318                        at room temperature.
    Relative vapour density (25C)           1.2983
    Vapour pressure (kPa) (20C)             4.28
    Flash-point (C)                         -20


    HAZARDS/SYMPTOMS                        PREVENTION AND PROTECTION                    FIRST AID

    SKIN: nickel carbonyl may enter         Wear effective, impervious                   Wash skin immediately with plenty of water;
    body through skin                       clothing, gloves and                         remove contaminated clothing
                                            boots; change clothing
                                            daily, maintain high standard
                                            of personal hygiene

    EYES: nickel carbonyl may enter         Wear safety goggles or                       Rinse eyes with plenty of water for at least
    body through mucous membranes           face-shield                                  15 minutes; obtain medical advice

    INHALATION: fatigue, nausea,            Use closed systems with                      Fresh air, rest; keep victim warm, conscious
    vomiting, headache, dyspnoea; after     automatic devices and                        victim may inhale steroid spray;  if breathing
    a latency period of 12-36 h:            alarm systems;  apply                        has stopped, apply artificial respiration; obtain
    chest pain, difficulty in breathing,    exhaust ventilation;                         medical attention and hospital admission
    coughing, elevated temperature,         wear self-contained                          urgently
    lung oedema, cyanosis, death in         breathing apparatus for
    severe cases                            non-routine operations

    INGESTION: effects on                   Do not drink, eat, or                        Give plenty of water to drink;  administer
    gastro-intestinal and respiratory       smoke when working                           activated charcoal if available; obtain medical
    system; in severe cases: death          with nickel carbonyl                         attention and hospital admission


    INHALATION: excitement,                 Avoid exposure
    sleeplessness, headache, dizziness,
    weakness, poor memory, tightness
    in chest, polyidrosis, loss of hair, 
    sexual frigidity, increased risk of 
    nasal and lung cancer


    SPILLAGE                                STORAGE                                      FIRE AND EXPLOSION

    Remove ignition sources;                Store in tightly closed                      Nickel carbonyl is extremely flammable; no open 
    evacuate area; collect                  containers; store                            fires, no sparks; extinguish with carbon-dioxide,
    leaking liquid in sealable              containers with nickel                       powder, fluorocarbons, or water; nickel carbonyl
    containers                              carbonyl in a cool,                          vapour can react violently with air
                                            ventilated area away
                                            from oxidizers

    Atomization in a combustion
    chamber with appropriate
    effluent gas-cleaning device



    Ni: CAS Registry No. 7440-02-0


    PHYSICAL PROPERTIES                                                   OTHER CHARACTERISTICS

    Melting point (C)                          1555                      Nickel is a naturally occurring, lustrous, 
    Boiling point (C)                          2837                      light-coloured metal, very resistant to
    Water solubility                            insoluble                 corrosion by air, water, and non-oxidizing 
    Specific density (g/cm3) (25C)             8.90                      acids; most nickel compounds do not constitute
    Relative vapour density (25C)              -                         a fire or explosion hazard
    Vapour pressure (kPa) (20C)                -
    Flash-point (C)                            -


    HAZARDS/SYMPTOMS                        PREVENTION AND PROTECTION                    FIRST AID

    (Nickel is a possible human carcinogen: nickel compounds are carcinogenic)

    SKIN: irritation, dermatitis            Wear effective, impervious                   Wash skin immediately with plenty of water;
    (eczema)                                clothing, gloves and                         remove contaminated clothing; obtain medical
                                            boots; change clothing                       advice
                                            daily; maintain high
                                            standard of personal hygiene

    EYES: irritation by dust and            Wear safety goggles or                       Rinse eyes with plenty of water for at least
    aerosols                                face shield                                  15 minutes; obtain medical advice

    INHALATION (powders, dusts,             Use closed system with automatic             Remove victim to fresh air; keep 
    aerosols): irritation of respiratory    monitoring devices and alarm                 victim warm and quiet; obtain medical
    tract; carcinogenicity                  systems; apply exhaust ventilation;          advice
                                            use self-contained breathing
                                            apparatus for non-routine operations

    INGESTION (solids, solutions):          Do not drink, eat, or                        Keep victim warm and quiet; give 
    vomiting, diarrhoea, tremor,            smoke when working                           plenty of water to drink; administer
    respiratory problems, death; and in     with nickel compounds                        activated charcoal, if available;
    case of nickel salts solutions:                                                      obtain medical attention and hospital
    nausea, headache, giddiness,
    lassitude                                                                            admission


    SKIN: Dermatitis (eczema)               Wear clean impervious clothing, 
                                            gloves, and boots; change clothing
                                            daily and maintain high standard
                                            of personal hygiene


    HAZARDS/SYMPTOMS                        PREVENTION AND PROTECTION                    FIRST AID

    INHALATION:  Chronic irritation         Avoid exposure or keep exposure
    of upper respiratory tract, loss of     as low as possible
    sense of smell, bronchial asthma,
    pulmonary fibrosis, pneumoconiosis;
    increased risk of nasal and lung 


    SPILLAGE                                STORAGE                                      FIRE AND EXPLOSION

    Remove larger spillages of              Store in tightly closed                      Not flammable  
    dusts or solutions containing           containers
    nickel by special vacuum 
    cleaners or with water


    Recycle, if possible; otherwise use
    hazardous waste disposal site; highly
    toxic nickel salts, e.g., arsenide, 
    antimonide, selenide, should be
    encapsulated before disposal


    The information given in this section has been extracted from the
    International Register of Potentially Toxic Chemicals (IRPTC) legal
    file and other United Nations sources.  Its intention is to give the
    reader a representative, but not an exhaustive, overview of current
    regulations, guidelines, and standards.  When no effective date
    appears in the IRPTC legal file, the year of the reference from which
    the data are taken is indicated by (r).

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

    7.1  Previous Evaluations by International Bodies

    No information available.

    7.2  Exposure Limit Values

    Some exposure limit values are given in the table on pages 38-44.

    7.3  Specific Restrictions

    In the Federal Republic of Germany, the concentration of respirable
    dusts and aerosols of nickel metal, nickel sulfide and sulfidic ores,
    nickel oxide, nickel carbonate, and nickel carbonyl in air emissions,
    may not exceed 1 mg nickel/m3 at a mass flow (= mass of emitted
    compound related to time) of 5 g/h or more.  In the European Economic
    Community (EEC), nickel emissions in waste gas, resulting from the
    combustion of waste oils, may not exceed 1.0 mg/m3 (plants with
    thermal input of 3 MW or more).  The USSR has set daily, average,
    maximum allowable concentrations in ambient air of 0.0002 mg/m3 for
    water-soluble nickel salts and 0.001 mg/m3 for metallic nickel.

    The EEC, Sweden, and the USA regulate nickel waste.  In the EEC,
    member states must limit the introduction of nickel and its compounds
    into ground and marine waters by controlling direct and indirect
    discharges.  Nickel in titanium dioxide waste discharged on to soil
    can result in the migration of nickel to surface and ground waters. 
    The use of sludge as an agricultural fertilizer is prohibited, if the
    concentration of nickel exceeds 400 mg/kg (dry matter) and the limit
    for the amount of nickel that can be added annually to agricultural
    land is 3 kg/ha per year (10-year average).  Sweden requires reporting

    of the composition of nickel wastes, and authorization for transport,
    handling, and export.  The United Kingdom treats waste consisting of
    nickel and nickel compounds as "special waste", with specified
    disposal procedures.  In the USA, nickel and its compounds are
    classified as toxic pollutants and permits are required for discharges
    into water.

    7.4  Labelling, Packaging, and Transport

    The United Nations classifies dry nickel catalyst as:

         Hazard Class 4.2  -  Substance liable to spontaneous combustion; 

         Packing Group 1  -  Very dangerous substance.

    Czechoslovakia classifies nickel in nickel ore processing and nickel
    production and refining as a carcinogenic substance; requirements are
    listed for handling, labelling, packing, storing, and transport.

    7.5  Waste Disposal

    The International Registry of Potentially Toxic Chemicals advises
    "Recycling; Precipitation, Solidification, Landfill.  Sort, classify
    and put in a box properly labelled.  Salvage profitably for reuse by
    local shop or sell as scrap metal.  Nickel antimonide, nickel
    arsenide, nickel selenide  -  encapsulation followed by disposal in a
    chemical waste landfill.  However, nickel from various industrial
    wastes may also be recovered and recycled.  Insoluble nickel compounds
    may be landfilled.  Soluble nickel compounds should be treated to
    precipitate an insoluble nickel compound, solidified and landfilled".



    Medium      Specification       Country/            Exposure limit descriptiona                  Value              Effective
                                    organization                                                                          date

    AIR         Occupational        Australia           Threshold limit value (TLV)                                       1985 (r)
                                                        - Time-weighted average (TWA)
                                                          Metallic nickel                            1.0 mg/m3
                                                        - Time-weighted average (TWA)
                                                          Soluble nickel compounds                   0.1 mg/m3 (as Ni)
                                                        - Short-term exposure limit (STEL)
                                                          Soluble nickel compounds                   0.3 mg/m3 (as Ni)

                                    Belgium             Threshold limit value (TLV)                                       1989 (r)
                                                        - Time-weighted average (TWA) (metal)        1 mg/m3
                                                        - Time-weighted average (TWA)                0.1 mg/m3 (as Ni)
                                                          (soluble compounds)

                                    Bulgaria            Maximum permissible concentration (MPC)      0.5 mg/m3            1985 (r)

                                    Canada              Threshold limit value (TLV)                                       1980
                                                        - Time-weighted average (TWA)                1 mg/m3
                                                        - Time-weighted average (TWA)                0.1 mg/m3
                                                          (soluble compounds as Ni)

                                    Czechoslovakia      Maximum allowable concentration (MAC)                             1985
                                                        - Time-weighted average (TWA)                0.05  mg/m3
                                                        - Ceiling value (CLV) (calculated as Ni)     0.25  mg/m3
                                                          (applies to nickel and its compounds)


    Medium      Specification       Country/            Exposure limit description                   Value                Effective
                                    organization                                                                          date

    AIR         Occupational        Germany, Federal    No maximum allowable concentration (MAK)     carcinogenic         1989 (r)
                                    Republic of         value established (applies to dusts/aerosols working
                                                        from nickel metal, nickel sulfide and sulfidic                    material
                                                        ores, nickel oxide and nickel carbonate 
                                                        arising in production and processing)

                                                        Technical reference concentration (TRK)
                                                        (nickel and compounds except nickel carbonyl)
                                                        - Time-weighted average (TWA)                0.5 mg/m3 (as Ni)
                                                                                                     respirable dusts and
                                                                                                     fumers, except dusts
                                                                                                     from nickel alloys 
                                                                                                     (calculated as nickel in
                                                                                                     total inhalable dust) 
                                                                                                     0.05 mg/m3 (as Ni) 
                                                                                                     respirable droplets  
                                                                                                     (calculated as Ni sensi-
                                                                                                     tization in entire
                                                                                                     respirable portion)

                                    Japan               Maximum allowable concentration (MAC)                             1988 (r)
                                                        - Time-weighted average (TWA)                1 mg/m3
                                                          working material)                          (carcinogenic)

                                    Netherlands         Maximum limit (MXL)                                               1987 (r)
                                                        - Time-weighted average (TWA), metal         1 mg/m3
                                                        - Time-weighted average (TWA),               0.1 mg/m3 (as Ni)
                                                          (water soluble nickel compounds)

                                    Romania             Maximum permissible concentration (MPC)      Nickel salts as      1985 (r)
                                                        - Time-weighted average (TWA) (as Ni)        0.5 mg/m3
                                                        - Ceiling value (CLV) (as Ni)                1.5 mg/m3


    Medium      Specification       Country/            Exposure limit description                   Value                Effective
                                    organization                                                                          date

    AIR         Occupational        Sweden              Threshold limit value (TLV)
                                                        - Time-weighted average (TWA), 1 day                              1988
                                                          metallic nickel                            0.5 mg/m3
                                                        - Time-weighted average (TWA), 1 day
                                                          (soluble nickel compounds,                 0.1 mg/m3 (as Ni)
                                                          nickel oxide and nickel carbonate)         carcinogenic

                                    Switzerland         Maximum work-site concentration (MAK)                             1985 (r)
                                                        - Time-weighted average (TWA)                0.5 mg/m3 (as Ni)
                                                          metal dust, sulfide, oxide and carbonate

                                    Switzerland         - Time-weighted average (TWA)                0.05 mg/m3 (as Ni)
                                                          dust of water soluble nickel               sensitizer
                                                          compounds                                  carcinogenic

                                    United Kingdom      Recommended limit (RECL)                                          1987 (r)
                                                        - Time-weighted average (TWA)
                                                          elemental nickel                           1 mg/m3
                                                        - Time-weighted average (TWA)
                                                          soluble nickel compounds                   0.1 mg/m3 (as Ni)
                                                          insoluble nickel compounds                 1.0 mg/m3 (as Ni)
                                                        - Short-term exposure limit (STEL),
                                                          (10-min time-weighted average)             
                                                          soluble nickel compounds                   3 mg/m3 (as Ni)
                                                          insoluble nickel compounds                 0.3 mg/m3 (as Ni)

                                    USA (ACGIH)         Threshold limit value (TLV)                                       1987
                                                        - Time-weighted average (TWA), metal         1 mg/m3 (as Ni)
                                                        - Time-weighted average (TWA),               0.1 mg/m3
                                                          soluble compounds                          (as Ni)


    Medium      Specification       Country/            Exposure limit description                   Value                Effective
                                    organization                                                                          date

    AIR         Occupational        USA (OSHA)          Permissible exposure limit (PEL)                                  1987 (r)
                                                        - Time-weighted average (TWA), metal         1 mg/m3
                                                          and soluble compounds                      (as Ni)

                                    USSR                Maximum allowable concentration (MAC)                             1989
                                                        - Ceiling value (CLV), metal, oxides,        0.05 mg/m3 
                                                          sulfide and mixtures of these compounds    (as Ni)
                                                        - Ceiling value (CLV), nickel salts,         0.005 mg/m3
                                                          aerosols                                   (as Ni)

    AIR         Ambient             USSR                Maximum allowable concentration (MAC)                             1984
                                                          Metallic nickel (daily average)            0.001 mg/m3 (as Ni)
                                                          Water soluble nickel salts,                0.0002 mg/m3
                                                          (daily average)                            (as Ni)

    WATER       Surface             Czechoslovakia      Maximum allowable concentration (MAC)                             1975
                                                        Nickel and its compounds                     0.1 mg/litre

                                    USSR                Maximum allowable concentration (MAC)                             1983
                                                        Nickel and its inorganic compounds           0.1 mg/litre (as Ni)
                                                        - Surface water for fishing                  0.01 mg/litre        1982 (r)
                                                          Nickel and its compounds                   (as Ni)

    WATER       Drinking            European            Maximum allowable concentration (MAC)        0.05 mg/litre        1982

                                    United Kingdom      Maximum residue limit (MRL)                  0.05 mg/litre        1985

    Water       Drinking            USA (EPA)           10-day health advisory (HA) - child          1.0 mg/litre         1985
                                                        10-day health advisory (HA) - adult          3.5 mg/litre
                                                        Acceptable daily intake (ADI)                0.35 mg/litre


    Medium      Specification       Country/            Exposure limit description                   Value                Effective
                                    organization                                                                          date

    SOIL        Agricultural        European            Maximum limit (MXL)                          30-75 mg/kg          1989 (r)
                                    Economic            dry matter in soil sample with pH=6

    SOIL        General             USSR                Maximum allowable concentration (MAC)        4 mg/kg              1985
                                                        mobile forms of nickel extractable by
                                                        ammonium acetate buffer solution pH=4.6

    SEWAGE      Agriculture         European            Maximum limit (MXL)                          300-400 mg/kg        1989
    SLUDGE                          Economic            dry matter
                                    Community           Annual limit value                           3 kg/ha/yr
                                                        (10 year average)                            

    FOOD                            CMEA                Maximum permissible concentration (MPC)                           1983
                                                        Nickel and its compounds (as Ni)
                                                        - Milk products                              0.1 mg/kg
                                                        - Meat products                              0.5 mg/kg
                                                        - Fish products (as Ni)                      0.5 mg/kg
                                                        - Cereals                                    3.0 mg/kg
                                                        - Vegetables, fruits                         0.5 mg/kg
                                                        - Other products                             0.2-8.0 mg/kg
                                                        - Beverages                                  0.3 mg/kg

                                    Czechoslovakia      Maximum permissible concentration (MPC)                           1986
                                                        Nickel and its compounds
                                                        (due to production, packing, transport and 
                                                        storage of food products)
                                                        - Specified food products                    0.1-8.0 mg/kg
                                                        - Beverages, general                         0.3 mg/kg


    Medium      Specification       Country/            Exposure limit description                   Value                Effective
                                    organization                                                                          date

    FOOD                            USSR                Maximum permissible concentration (MPC)                           1981
                                                        Nickel and its compounds (as Ni)
                                                        - Fish products                              0.5 mg/kg
                                                        - Meat products                              0.5 mg/kg
                                                        - Milk products (as Ni)                      0.1 mg/kg
                                                        - Cereals                                    0.5 mg/kg
                                                        - Vegetables, fruits                         0.5 mg/kg
                                                        - Beverages                                  0.3 mg/kg


    a TWA = time-weighted average over one working day (usually 8 h).


    ACGIH (1986)  Documentation of the threshold limit values and
     biological exposure indices. Cincinnati, American Conference of
    Governmental Industrial Hygienists.

    ACGIH (1989)  Threshold limit values and biological exposure indices
     for 1989-1990. Cincinnati, American Conference of Governmental
    Industrial Hygienists.

    CLAYTON, G.D. & CLAYTON, F.E. (1981)  Patty's Industrial Hygiene and
     Toxicology, Vol. 2C.  New York, Wiley-Interscience, John Wiley &

    GOSSELIN, R.E., HODGE, H.C., SMITH R.P., & GLEASON, M.N. (1984)
     Clinical toxicology of commercial products, 5th ed. Baltimore,
    Maryland, The Williams and Wilkins Company.

    DUTCH SAFETY INSTITUTE (1989)   Handling chemicals safely, 2nd ed.,
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    IARC (1990)  Chromium, nickel and welding. International Agency for
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    IRPTC (1988)  Data profile (legal file).  Geneva, International
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    SAX, N.I. (1984)  Dangerous properties of industrial materials.  New
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    US NIOSH (1976)  A guide to industrial respiratory protection. 
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    US NIOSH/OSHA (1985)  Pocket guide to chemical hazards.  Washington,
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    US NIOSH/OSHA (1981)  Occupational health guidelines for chemical
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    WHO (1991)  Environmental Health Criteria: 108. Nickel. Geneva, World
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    See Also:
       Toxicological Abbreviations