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    IPCS INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY
    Health and Safety Guide No. 104

    ACRYLIC ACID
    HEALTH AND SAFETY GUIDE






    UNITED NATIONS ENVIRONMENT PROGRAMME

    INTERNATIONAL LABOUR ORGANISATION

    WORLD HEALTH ORGANIZATION




    WORLD HEALTH ORGANIZATION, GENEVA 1997

    This is a companion volume to
    Environmental Health Criteria 191: Acrylic acid

    Published by the World Health Organization for the International
    Programme on Chemical Safety (a collaborative programme of the United
    Nations Environment Programme, the International Labour Organisation,
    and the World Health Organization) and produced within the framework
    of the Inter-Organization Programme for the Sound Management of
    Chemicals

    WORLD HEALTH ORGANIZATION, GENEVA 1997

    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

    Acrylic acid: health and safety guide.

    (Health and safety guide ; no. 104)

    1.Acrylates - adverse effects - toxicity
    2.Environmental exposure      3.Occupational exposure      I.Series

    ISBN 92 4 151104 4       (NLM Classification: QV 50)
    ISSN 0259-7268

    The World Health Organization welcomes requests for permission to
    reproduce or translate its publications, in part or in full. 
    Applications and enquiries should be addressed to the Office of
    Publications, World Health Organization, Geneva, Switzerland, which
    will be glad to provide the latest information on any changes made to
    the text, plans for new editions, and reprints and translations
    already available.

    (c) World Health Organization 1997

    Publications of the World Health Organization enjoy copyright
    protection in accordance with the provisions of Protocol 2 of the
    Universal Copyright Convention.  All rights reserved.

    The designations employed and the presentation of the material in this
    publication do not imply the expression of any opinion whatsoever on
    the part of the Secretariat of the World Health Organization
    concerning the legal status of any country, territory, city or area or
    of its authorities, or concerning the delimitation of its frontiers or
    boundaries.

    The mention of specific companies or of certain manufacturers'
    products does not imply that they are endorsed or recommended by the
    World Health Organization in preference to others of a similar nature
    that are not mentioned.  Errors and omissions excepted, the names of
    proprietary products are distinguished by initial capital letters.

    CONTENTS

    INTRODUCTION

    1. PRODUCT IDENTITY AND USES

         1.1. Identity
               1.1.1.  Primary constituent
         1.2. Physical and chemical properties
         1.3. Analytical methods
         1.4. Production and uses

    2. SUMMARY AND EVALUATION

         2.1. Human exposure
         2.2. Kinetics and metabolism
         2.3. Effects on animals
         2.4. Effects on humans
         2.5. Effects on the environment

    3. CONCLUSIONS AND RECOMMENDATIONS

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

         4.1. Main human health hazards, prevention and protection, first
               aid
               4.1.1. Advice to physicians
                       4.1.1.1   Symptoms of poisoning
                       4.1.1.2   Medical advice
               4.1.2. Health surveillance advice
         4.2. Safety in use
         4.3. Explosion and fire hazards
         4.4. Storage
         4.5. Transport
         4.6. Spillage and disposal
               4.6.1. Spillage
               4.6.2. Disposal

    5. HAZARDS FOR THE ENVIRONMENT AND THEIR PREVENTION

         5.1. Hazards
         5.2. Prevention

    6. SUMMARY OF CHEMICAL SAFETY INFORMATION

    7. CURRENT REGULATIONS, GUIDELINES AND STANDARDS

         7.1. Previous evaluations by international bodies
         7.2. Exposure limit values
         7.3. Specific restrictions
         7.4. Labelling, packaging and transport

    BIBLIOGRAPHY
    

    INTRODUCTION

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

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

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

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

    The Director
    International Programme on Chemical Safety
    World Health Organization
    1211 Geneva 27
    Switzerland

                                             

    THE INFORMATION IN THIS GUIDE
    SHOULD BE CONSIDERED AS A
    STARTING POINT TO A COMPREHENSIVE
    HEALTH AND SAFETY PROGRAMME
                                             

    1.  PRODUCT IDENTITY AND USES

    1.1.  Identity

    1.1.1  Primary constituent

    Common name:                  Acrylic acid
    CAS name:                     2-Propenoic acid
    CAS registry number:          79-10-7
    EEC No:                       607-061-00-8
    DOT UN:                       22-18-29
    RTECS Number:                 AS 4375000
    Synonyms:                     acroleic acid
                                  2-propenoic acid
                                  vinylformic acid
                                  propene acid
                                  ethylenecarboxylic acid
                                  UN 2218
                                  propenoic acid
                                  ethene carboxylic acid

    Chemical formula:             C3H4O2

    Chemical structure:

    CHEMICAL STRUCTURE 1

    Relative molecular mass:      72.06
    Conversion factors:           1 ppm = 3.0 mg/m3; 1 mg/m3 = 0.33 ppm

    1.2  Physical and Chemical Properties

         Acrylic acid is a colourless liquid with an irritating acrid
    odour at room temperature and pressure. Its odour threshold is low
    (0.20-3.14 mg/m3). It is miscible in water and most organic solvents.

         Acrylic acid is commercially available in two grades: technical
    grade (94%) for esterification, and glacial grade (98-99.5% by weight
    and a maximum of 0.3% water by weight) for production of water-soluble
    resins. Acrylic acid polymerizes easily when exposed to heat, light or
    metals, and so a polymerization inhibitor is added to commercial
    acrylic acid to prevent the strong exothermic polymerization. The
    inhibitors that are usually used in acrylic acid preparations are the
    monomethyl ether of hydroquinone (methoxyphenol) at 200  20 ppm,
    phenothiazine at 0.1% and hydroquinone at 0.1%. Methylene blue at 0.5
    to 1.0% and N,N'-diphenyl- p-phenylenediamine at 0.05% can also be
    used.

         Acrylic acid preparations containing polymerization inhibitors
    are reasonably stable when stored at 15-25C and handled according
    to the supplier's recommendations. Heat can cause vigorous
    polymerization in some circumstances. Acrylic acid reacts readily with
    free radicals and electrophilic or nucleophilic agents. It may
    polymerize in the presence of acids (sulfuric acid, chlorosulfonic
    acid), alkalis (ammonium hydroxide), amines (ethylenediamine,
    ethyleneimine, 2-aminoethanol), iron salts, elevated temperature,
    light, peroxides, and other compounds that form peroxides or free
    radicals. In the absence of inhibitor,  peroxides are formed when
    oxygen is sparged into acrylic acid. This mixture can undergo violent
    polymerization if heated to 60C.

         The presence of oxygen is required for the stabilizer to function
    effectively. A head space containing sufficient air should always be
    maintained above the monomer to ensure inhibitor effectiveness.
    Dissolved oxygen takes part in the inhibition reaction and therefore
    is gradually consumed. The level of dissolved oxygen should
    periodically be replenished. This can be accomplished by thoroughly
    aerating the liquid phase, i.e. recirculation of the inventory in
    tanks or agitating drums (rotating).

         Acrylic acid must never be handled under an inert atmosphere.

         Freezing of acrylic acid occurs at 13C. Rethawing under
    inappropriate temperature conditions is another frequent reason for
    acrylic acid polymerization. During the crystallization process the
    inhibitor and oxygen concentrate in the mother liquor. Therefore no
    mother liquor should be withdrawn from a partially frozen container.
    This may result in a severe deficiency of the inhibitor system in the
    crystalline matrix. If direct heat is applied, polymerization will
    start immediately, often with great violence. Under no  circumstances
    must steam be used to thaw frozen acrylic acid, nor must thawing be
    carried out at temperatures above 35C.

         Acrylic acid is a strong corrosive agent to many metals, such as
    unalloyed steel, copper and brass. Frequently the hydrolysis of such
    metalic materials generates a deep discoloration in acrylic acid.
    Polyvalent metal salts formed during hydrolytic reactions could also
    induce polymerization. Therefore, under no circumstances should
    acrylic acid be stored or transported with equipment which contains
    the above-mentioned metals. Acrylic acid does not affect stainless
    steel.

    1.3  Analytical Methods

         Acrylic acid residues in air and other media can be quantified by
    means of gas chromatographic, high performance liquid chromatographic
    and polarographic techniques. The detection limits of these methods
    was found to be 14 mg/m3 (14 ppm) in air and down to 1 mg/kg or
    1 mg/litre (1 ppm) in other media.

    1.4  Production and Uses

         The worldwide  production of acrylic acid in 1994 was estimated
    to be approximately 2 million tonnes. Acrylic acid is used primarily
    as a starting material in the production of acrylic esters; as a
    monomer for polyacrylic acid and salts, as a co-monomer with
    acrylamide for polymers used as flocculants, with ethylene for ion
    exchange resin polymers, with methyl ester for polymers, and with
    itatonic acid for other copolymers.

    2.  SUMMARY AND EVALUATION

    2.1  Human Exposure

         No data on general population exposure are available. However,
    consumers may be exposed to unreacted acrylic acid in household goods
    such as polishes, paints and coatings, adhesives, rug backing,
    plastics, textiles and paper finishes. A potential source of internal
    exposure to acrylic acid may result from metabolism of absorbed
    acrylic acid esters. Acrylic acid also occurs in wastewater effluent
    from its production. It is estimated that thousands of workers could
    be exposed to acrylic acid, but exact figures are not available.

    2.2  Kinetics and Metabolism

         Inhalation and contact with skin are important routes of
    occupational exposure.

         Regardless of the route of exposure, acrylic acid is rapidly
    absorbed and metabolized. It is extensively metabolized, mainly to
    3-hydroxypropionic acid, CO2 and mercapturic acid, which are
    eliminated in the expired air and urine. Owing to its rapid metabolism
    and elimination, the half-life of acrylic acid is short (minutes) and
    therefore it has no potential for bioaccumulation.

    2.3  Effects on Animals

         Although a wide range of LD50 values has been reported, most
    data indicate that acrylic acid is of low to moderate acute toxicity
    by the oral route, and of moderate acute toxicity by the inhalation
    and dermal routes.

         Acrylic acid is corrosive or irritant to skin and eyes. It is
    unclear what concentration is non-irritant. It is also a strong
    irritant to the respiratory tract.

         Positive and negative skin sensitization results have been
    reported with acrylic acid, but it appears that the positive results
    may be due to an impurity.

         In drinking-water studies on rats the no-observed-adverse-effect
    level (NOAEL) was 140 mg/kg body weight per day for decreased body
    weight gain in a  12-month study  and 240 mg/kg bw per day for
    histopathological changes in the stomach. A chronic drinking-water
    study on rats showed no effect at the highest dose tested (78 mg/kg
    body weight per day). For inhalation studies a lowest-observed-
    adverse-effect level (LOAEL) of 15 mg/m3 (5 ppm) was observed in mice
    exposed to acrylic acid for 90 days, based on very mild nasal lesions
    in females at this level. Nasal effects in rats were observed at
    225 mg/m3 (75 ppm), but not at 15 or 75 mg/m3 (5 or 25 ppm).

         Available reproduction studies indicate that acrylic acid is not
    teratogenic and has no effect on reproduction.

         Both positive and negative results have been obtained in  in 
     vitro genotoxicity tests. An  in vivo bone marrow chromosome
    aberration assay was negative, and no firm conclusions can be drawn
    from an  in vivo DNA binding study or from a dominant lethal assay.

         Available data do not provide evidence for an indication of
    carcinogenicity of acrylic acid, but the data are inadequate to
    conclude that no carcinogenic hazard exist.

    2.4  Effects on Humans

         There have been no reports of poisoning incidents in the general
    population. No occupational epidemiological studies have been
    reported.

         Because acrylic acid toxicity occurs at the site of contact,
    separate guidance values are recommended for oral and inhalation
    exposure. Guidance values of 9.9 mg/litre for drinking-water and
    54 g/m3 for ambient air for the general population are proposed.

    2.5  Effects of the Environment

         No quantitative data on environmental levels of acrylic acid in
    ambient air, drinking-water or soil have been reported.

         Acrylic acid is miscible with water and, therefore, would not be
    expected to adsorb significantly to soil or sediment. Under soil
    conditions, chemicals with low Henry's Law constants are essentially
    non-volatile. However, the vapour pressure of acrylic acid would
    suggest that it may volatilize from surfaces and dry soil. Acrylic
    acid may be formed by hydrolysis of acrylamide monomer from industrial
    waste in soil, especially under aerobic conditions.

         The toxicity of acrylic acid to bacteria and soil microorganisms
    is low.

         Acrylic acid emitted into the atmosphere will react with
    photochemically produced hydroxyl radicals and ozone, resulting in
    rapid degradation. There is no potential for long-range atmospheric
    transport of acrylic acid because it has an atmospheric lifetime of
    less than one month.

         When released into water, acrylic acid readily biodegrades. The
    fate of acrylic acid in water depends on chemical and microbial
    degradation. When added to water acrylic acid is rapidly oxidized, and
    so it can potentially deplete oxygen if discharged in large quantities
    into a body of water. Acrylic acid has been shown to be degraded under
    both aerobic and anaerobic conditions.

         On the basis of the low octanol-water partition coefficient of
    acrylic acid, bioconcentration in aquatic organisms is unlikely. There
    have been no reports of biomagnification of acrylic acid in food
    chains.

         Algae are the most sensitive group of aquatic organisms studied,
    with EC50 values, based on growth, ranging from 0.04 to 63 mg/litre,
    and a no-observed-effect concentration (NOEC) for the most sensitive
    species of 0.008 mg/litre. EC50 values (based on immobilization)
    for  Daphnia magna were 54 mg/litre (24 h) and 95 mg/litre (48 h).
    Acute toxicity studies with fish have yielded results ranging from
    27 mg/litre (96-h LC50) for the rainbow trout to 315 mg/litre
    (72-h LC50) for the golden orfe. The 96-h NOEC for acrylic acid
    toxicity to rainbow trout was found to be 6.3 mg/litre based on a lack
    of sublethal/behavioural responses.

         No data on the effects of acrylic acid on terrestrial organisms
    have been reported.

    3.  CONCLUSIONS AND RECOMMENDATIONS

         The risks associated with occupational exposure to acrylic acid
    are low, as long as good industrial practice is followed. There is a
    lack of quantitative data on the levels of exposure to acrylic acid.
    However, no obvious adverse effects in the general population have
    been identified.

         Acrylic acid poses minimal risk for the general environment,
    except in the case of uncontrolled discharge.

         It is recommended that exposure of the general public to acrylic
    acid in the ambient air and drinking-water does not exceed the
    guidance values given in the Environmental Health Criteria No. 19
    Acrylic Acid (IPCS, 1997). These are as follows:

         *    Inhalation exposure:  54 g/m3

         *    Oral exposure via drinking-water: 9.9 mg/litre.

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

    4.1.  Main human health hazards, prevention and protection, first aid.

         Additional details are given in the Summary on Chemical Safety
    Information (section 6)

    4.1.1  Advice to physicians

    4.1.1.1  Symptoms of poisoning

         The principal hazard of acrylic acid is its corrosive effect on
    tissues. Both vapour and liquid can be irritating or corrosive to the
    mucous membranes, skin and eyes. The severity of these effects is
    dependent on the duration of contact, which, if prolonged, may result
    in blisters and burns. Blister formation can appear as late as 24 h
    after exposure. Severe corneal burns could occur to the eyes.
    Permanent tissue damage may result if prompt and appropriate emergency
    response is not provided. First aid recommendations are given in
    section 6.

         Inhalation of concentrated vapours and mist could produce
    moderate to severe irritation of the respiratory tract. High
    concentrations could result in pulmonary oedema while lower
    concentrations could produce nasal and throat irritation. Lacrymation
    may also result from inhalation exposure.

         Although ingestion is not an expected route of human exposure,
    swallowing of acrylic acid may cause severe irritation or burning of
    the mouth, throat, oesophagus or stomach.

         No serious health effects have been reported to result from
    single exposure or repeated exposure at low concentrations of acrylic
    acid.

    4.1.1.2  Medical advice

         In order to minimize possible consequences of accidents, all
    personnel assigned to handle acrylic acid must be aware that prompt
    and appropriate response (see following sections) is essential. First
    aid must be rendered immediately. The installation of a sufficient
    number of emergency showers and eye washes is a prerequisite for the
    proper management of incidents.

         If even minute quantities of acrylic acid enter the eyes, they
    must be irrigated by means of an eye wash with copious amounts of
    lukewarm water for at least 15 min. In order to secure the complete
    removal of the acid, the assistance of a helper is strongly advised.
    The eyelids should be held wide open and away from the eye balls.
    Immediate help of an eye specialist should be sought. Oil or oily
    ointments should not be applied unless recommended by a physician.

         In the event that skin contact with acrylic acid has occurred,
    all clothing should be completely removed under an emergency shower.
    Washing with water should be continued until all odour has
    disappeared, in any case not less than 15 min. The advice of a
    physican should be sought. Contaminated clothing must never be reused
    unless properly laundered. Leather wear must be disposed off.

         A person who has suffered from inhalation of acid fumes should be
    removed at once from the contaminated area and made to lie down in
    fresh air without moving. If the patient is unconscious, he should be
    placed on his side in a stable position. A physician and ambulance
    should be summoned immediately. If available, pure oxygen should be
    administered by means of a respirator, but only by a person who is
    authorised for such duty by a physican.

         If acrylic acid is ingested, the patient should be made to drink
    large amounts of water. Vomiting should not be induced. A physican and
    ambulance should be summoned immediately.

    4.1.2  Health surveillance advice

         Pre-employment and annual general medical examinations are
    advised for regularly exposed workers.

    4.2  Safety in Use

         Acrylic acid should only be handled in well-aerated and well-
    ventilated places. If exposure to concentrated vapour can not be
    excluded (as in the case of an accident), self-contained breathing
    apparatus or air supply masks must be worn. Care must be taken when
    using filter-type masks to ensure that the filter capacity is not
    exceeded for the intended time of use and expected concentration.

         In areas where a release of acrylic acid is possible, eye
    protection devices, face shields, neoprene gloves and rubber boots
    should be worn. A chemical suit with a self-contained breathing
    apparatus is strongly recommended if larger spills or emissions have
    to be cleared. Appropriate protective clothing should be worn for work
    involving breaking or entering into a closed acrylic acid system.
    Owing to its vapour pressure, the concentration of acrylic acid in
    closed rooms can reach high values.

         If clothing or shoes have accidentally been contaminated with
    acrylic acid, they must be removed immediately. Contaminated leather
    shoes or other leather goods must be discarded.

         For timely and appropriate emergency response, it is advisable to
    provide complete sets of safety protection equipment near places where
    accidents with acrylic acid are possible.

    4.3  Explosion and Fire Hazards

         Acrylic acid has a flash point of 54-68C and does not form
    explosible vapour mixtures at ordinary ambient temperatures. However,
    ignition may occur if excessive amounts of mist or aerosols have
    formed in air. Ignition sources can include spark discharges from
    static electricity, and this can occur when acrylic acid is flowing
    through or being discharged from a line. During transfer from one
    container into another, the containers should be electrically
    interconnected and properly grounded. Splashing into a tank should be
    avoided by using a dip tube.

         Since acrylic acid and water are miscible in any proportion,
    water can be used to extingish fires. Small fires can be fought with
    carbon dioxide or dry chemical extinguishers, whereas for larger fires
    foam (alcohol or universal type) can be used.

         If a fire occurs in or close to a tank farm containing acrylic
    acid, tanks and pipes should be cooled by spraying with water in order
    to prevent the acid from polymerizing.

    4.4.  Storage

         Acrylic acid should be stored in a detached, cool, well-
    ventilated, non-combustible place and its containers should be
    protected against physical damage. Acrylic acid can be stored only in
    vessels lined with glass, stainless steel, aluminum or polyethylene.
    In order to inhibit polymerization during transport and storage,
    200 ppm MeHQ (the monomethyl ether of hydroquinone) is commonly added
    to acrylic acid by the manufacturer. The presence of oxygen is
    required for the inhibitor to be effective. A major concern during the
    storage of acrylic acid is the avoidance of elevated temperatures as
    well as freezing, since both can lead to a failure of the inhibitor
    system. Ideally acrylic acid should be stored within a temperature
    range of 15 to 25C.

         Acrylic acid and its solutions should be kept out of reach of
    children and unauthorized persons as well as away from food, drink and
    animal feed. If any container in the store is leaking, appropriate 
    precautions should be taken (see section 6) and  personal protective
    equipment used.

    4.5.  Transport

         Acrylic acid is shipped in containers in compliance with
    regulations according to ADR/RID/GGVS/GGVE, Class 8 Packing Group B
    specifications. Acrylic acid is commonly shipped in steel drums with

    polyethylene inserts or in self-supporting high-density polyethylene
    drums impermeable to ultraviolet light. White polyethylene container
    are translucent to ultraviolet light and therefore may promote
    polymerization. Stainless steel ISO containers are recommended for the
    transport of quantities of acrylic acid up to 1 tonne.

    4.6.  Spillage and disposal

    4.6.1.  Spillage

         Before dealing with any spillage, appropriate personal protective
    equipment should be used (see section 6).

         Small spills of up to 5 litres can be absorbed in commercially
    available clean-up kits (using sand or clay). If a wastewater sewer is
    close by, the spill can also be washed down with water provided that
    it is not a storm-sewer or ditch that is routed to surface water.

         Large spills should be contained, if possible, within a diked
    area. A temporary dike can be arranged by stacking sand bags or
    similar devices. Avoid run-off into storm sewers routed to public
    surface water. If possible, the material should be recovered in
    appropriate containers for reuse or disposal. If a wastewater sewer is
    available, the acid or remainders can also be sparingly washed down
    after dilution and neutralization prior to being discharged to a
    water-treatment plant. During all handling operations of large spills
    a chemical suit with a self-contained or air-supplied breathing device
    must be worn.

         In the event of accidental spillage of acrylic acid to surface
    water or to a municipal sewer system, the pollution control agencies
    must be notified promptly.

         Spills of the monomer may be diluted and washed into a biological
    treatment plant after notification of the person in charge. The
    biodegradability of the material in diluted form is good (> 70% Zahn-
    Wellens static test OECD 302 B). However, acrylic acid may be toxic to
    the system if the bacteria have not been conditioned properly to this
    material. Accordingly, the initial feed rate should be low with a
    stepwise increase if a significant amount is to be fed into the
    biological treatment plant. The maximum concentration should not
    exceed 1000 mg per litre. It should be kept in mind, however, that
    large quantities may affect the optimal acidity of the milieu and may
    therefore need to be neutralized by the simultaneous addition of
    sodium hydroxide.

    4.6.2.  Disposal

         State laws and local regulations governing waste disposal make it
    essential for producers, suppliers, hauliers and users of acrylic acid
    to be fully aware of viable options for the ultimate disposal of
    materials containing acrylic acid. Materials to be disposed of may be
    residues from production or cleaning operations as well as waste
    material from spills.

         Acrylic acid is a highly corrosive material. Accordingly it
    should always be handled with appropriate safety equipment.

         Solid materials containing acrylic acid, such as absorbents or
    polymeric material, can be disposed of by incineration. Disposal in
    landfills must be thoroughly checked with the authorities and should
    be practiced only as a last resort.

         For the disposal of waste materials originating from laboratory
    samples, great care must be taken to keep the monomer separated from
    incompatible material, such as peroxides, which may initiate
    polymerization.

    5.  HAZARDS FOR THE ENVIRONMENT AND THEIR PREVENTION

    5.1.  Hazards

         Most of the available data indicate that acrylic acid has low
    toxicity for mammals and aquatic organisms. Algae are the most
    sensitive group of aquatic organisms. Acrylic acid is miscible with
    water and therefore would not be expected to adsorb significantly to
    soil or sediment. If released on land or into water, acrylic acid
    should readily biodegrade although no rate data are available. Acrylic
    acid is unlikely to  pose a problem in the general environment.

    5.2.  Prevention

         Because of its action as a strong irritant to mucous membranes
    and explosive properties of its mixtures with air, it is essential
    that concentrations of acrylic acid in the ambient air be kept as low
    as possible. Care should be taken during any manipulations with any
    acrylic acid containers. Any effluent containing acrylic acid should
    be properly treated, and any acrylic acid spillage should be protected
    from all possible ignition sources.

    6.  SUMMARY OF CHEMICAL SAFETY INFORMATION

                                                                        

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

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


        SUMMARY OF CHEMICAL SAFETY INFORMATION

                                                                      ACRYLIC ACID
                                                                    CAS no. 79-10-7;
                                                                Chemical formula:  C3H4O2
                                                                                                                                              

    PHYSICAL PROPERTIES                                                                       OTHER CHARACTERISTICS
                                                                                                                                              

    Relative molecular mass                 72.06                                             Watery, colourless liquid with an irritating acrid
    Melting point (C)                      12.3-14                                           odour; polymerizes on heating or in the presence
    Boiling point (C)                      141.3-141.6                                       of oxygen, acids, alkalis, amines, iron salts,
    Flash point, open cup (C)              54.4-68.3                                         light or other compounds forming peroxides or free
    Autoignition temperature (C)           390-446                                           radicals; during polymerization a large amount of
    Flammable limits                                                                          heat may be released; owing to photochemical
      lower                                 2.0%                                              attack, decomposes in the atmosphere; when heated,
      upper                                 8.0%                                              toxic gases are generated, which can form an
    Specific gravity (20C)                 1.0497-1.0511 g/ml                                explosive mixture; miscible with water and soluble
    Relative vapour density                                                                   in many organic solvents; corrosive to many metals
      (air = 1 at 20C )                    2.5
    Vapour pressure (39C)                  10 mm Hg
    Octanol/water partition coefficient
     (log Kow at 20-25C)                   0.161-0.46
    Henry's law constant                    3.210-7 atm  m3/mol
    Solubility in water                     miscible
    Solubility in organic solvents
      alcohol                               miscible
      chloroform                            miscible
      benzene                               miscible
      acetone                               soluble (> 10 %)
                                                                                                                                              

    SUMMARY OF CHEMICAL SAFETY INFORMATION (Con't)

                                                                                                                                              

    HAZARD/EFFECTS                          PREVENTION AND PROTECTION                         FIRST AID
                                                                                                                                              

    GENERAL:  Strong irritative liquid      Prevent any spill; avoid inhalation of vapour;
    and vapours                             if you feel unwell seek medical advice; keep
                                            out of reach of children.

    SKIN:  liquid is a primary irritant,    Avoid contact: wear neoprene gloves, acid         Remove contaminated clothes and wash exposed
    may cause burns by splash contact       goggles or face shield; safety footwear of        area thoroughly with plenty of water and soap;
                                            chemical resistant material should be worn        a physician should be consulted if irritation
                                            over leather safety shoes; safety shower may      or pain persists
                                            be required

    EYES:  splashes may cause burns,        Avoid contamination with liquid or exposure to    If even minute quantities of acrylic acid enter
    corneal damage and blindness;           vapour; use acid goggles or face shield; safety   the eyes, rinse them with copious amounts of
    vapour may cause lacrimation and        fountain may be required                          lukewarm water for at least 15 min; immediate
    strong irritancy                                                                          help of an eye specialist should be sought

    INHALATION:  mild inhalation            Avoid exposure to vapour; wear chemical           Move victim to fresh air, provide all emergency
    effects may occur from acute            respirator at ambient temperature to avoid        medical care; if the victim is not breathing, give
    exposure                                inhalation of noxious fumes; suitable             artificial respiration; if breathing is difficult,
                                            protective clothing and self-contained            give humidified oxygen; call a physician and
                                            respiratory protective apparatus should be        ambulance immediately
                                            available for those who may have to rescue
                                            people overcome by fumes

    INGESTION:  strong irritant to          Do not eat, drink or smoke during work            If victim is conscious, give large amounts of
    mucous membranes of alimentary                                                            water to drink; do not induce emesis as acrylic
    tract                                                                                     acid is a corrosive material; obtain medical
                                                                                              advice immediately

    ENVIRONMENT:  High concentrations       Avoid spillage into the environment
    in surface waters may be toxic to
    aquatic organisms; algae are the most
    sensitive group of aquatic organisms
                                                                                                                                              

    SUMMARY OF CHEMICAL SAFETY INFORMATION (Con't)

                                                                                                                                              

    SPILLAGE                                STORAGE                                           FIRE AND EXPLOSION
                                                                                                                                              

    Absorb spilled liquid with sand, clay   Store in detached, well-ventilated cool and       Acrylic acid is flammable and may be ignited
    or other non-combustible material;      dry place; substance should be stored only in     by heat, sparks or flames; when heated, toxic
    alternatively dilute the spillage       glass, stainless steel, aluminum or               vapours are generated; use water spray,
    with water and neutralize with sodium   polyethylene-lined equipment; care should be      alcohol foam, dry chemicals or carbon dioxide
    hydrogen carbonate, crushed             taken that uninhibited acrylic acid vapour        to extinguish fires
    limestone or lime; use appropriate      does not polymerize in the vents of flame
    personal protective equipment           arresters of storage tanks, resulting in
    (goggles, gloves, boots etc.)           stoppage of vents
                                                                                                                                              

    WASTE DISPOSAL                          NATIONAL INFORMATION
                                                                                                                                              

    Burn at high temperature (up to         National occupational exposure limit:
    1600C) in liquid injection             National Poisons Control Centre:
    incinerator, rotary kiln incinerator    Local trade names
    or fluidized bed incinerator
                                                                                                                                              
        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.
    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

         The carcinogenicity of acrylic acid has been evaluated by the
    International Agency for Research on Cancer. Data on the
    carcinogenicity of the compound for humans were considered inadequate.
    There was inadequate evidence for carcinogenicity in animals.
    Therefore, acrylic acid is not classifiable as to its carcinogenicity
    to humans.

    7.2  Exposure Limit Values

         Regulatory standards established by national bodies in different
    countries and the European Union are summarized in the legal file of
    the International Register of Potentially Toxic Chemicals. Exposure
    limit values in some countries are shown in the table.

    7.3  Specific Restrictions

         In the USA acrylic acid as a commercial chemical product is
    classified as a toxic waste subject to regulation and notification
    requirements.

         In the European Economic Community preparations that contain
    acrylic acid at concentrations greater than 25% should be considered
    as corrosive and at concentrations of 2-25% as irritant. Member States
    should ensure that dangerous preparations containing acrylic acid are
    not placed on the market unless their packages, fastenings and labels
    comply with requirements laid down (section 7.4).

         In Canada, the maximum amount of acrylic acid that may be
    transported on a passenger aircraft, train or road vehicle is one
    litre. The maximum amount that may be transported on a cargo aircraft
    is 30 litres.

    7.4  Labelling, Packaging and Transport

         Acrylic acid has been classified in the European Community under
    Council Directive 67/548/EEC (as amended for the seventh time in
    Council Directive 92/32/EEC) and appears in Annex 1 under EEC No
    607-061-00-8. Acrylic acid is classified as both flammable with risk
    phrase RIC (flammable) and corrosive with symbol C and risk phrase R34
    (causes burns). It is also labelled with the following safety phrases: 
    S26 (in case of contact with eyes, rinse immediately with plenty of
    water and seek medical advice), S36 (wear suitable protective
    clothing) and S45 (in case of accident or if you feel unwell seek
    medical advice immediately, show the label where possible). The
    following phrases also apply if the substance is sold to the general
    public or is likely to be used in places where the public has access: 
    S1 (keep locked up) and S2 (keep out of reach of children).


        CURRENT REGULATIONS, GUIDELINES AND STANDARDS

                                                                                                   

    EXPOSURE LIMIT VALUES
                                                                                                   

    Medium    Specification   Country/organization    Exposure limit description           Value
                                                                                           (mg/m3)
                                                                                                   

    AIR       Occupational    Australia               Threshold limit value (TLV)
                                                      Time-weighted average (8-h TWA)         30

                              Belgium                 Time-weighted average (TWA)             5.9

                              Denmark                 Time-weighted average (TWA)             30

                              France                  Threshold limit value (TLV)             5.9

                              Italy                   Time-weighted average (TWA)             5.9

                              Netherlands             Time-weighted average (TWA)             5.9

                              Poland                  Maximum allowable concentration
                                                      - TWA                                   20
                                                      - Ceiling value                         50

                              Sweden                  Hygienic limit value (HLV)
                                                      - Time-weighted average (8-h TWA)       30
                                                      - Short-term exposure limit (STEL)      45

                              Switzerland             TWA                                     30

                              United Kingdom          Time-weighted average (8-h TWA)         60
                                                      Short-term exposure limit (STEL)
                                                      (10-min TWA)
                                                                                                   

    CURRENT REGULATIONS, GUIDELINES AND STANDARDS (Con't)

                                                                                                   

    EXPOSURE LIMIT VALUES
                                                                                                   

    Medium    Specification   Country/organization    Exposure limit description           Value
                                                                                           (mg/m3)
                                                                                                   

                              USA (OSHA)              Permissible exposure limit (PEL)        30
                                                      - Time-weighted average (TWA)           (skin)

                              USA (ACGIH)             Threshold limit value (TLV)             59
                                                      - Time-weighted average (TWA)           (skin)

                              Former USSR             Maximum allowable concentration (MAC)
                                                      - Ceiling value (short-term)            5
                                                                                                   
    
    BIBLIOGRAPHY

    ACGIH (1990) 1990-1991 Threshold limit values for chemical substances
    and physical agents and biological exposure indices. Cincinnati,
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    CEC/IPCS (1993) International Chemical Safety Card 688 Acrylic acid.
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    CHRIS (1989) CHRIS Hazardous Chemical Data, US Department of
    Transportation, US Coast Guard, Washington, DC (CD-ROM Version).
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    Clayton G.D. and Clayton F.E. (Eds) (1982) Patty's industrial hygiene
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    Finkel A.J. (1983) Hamilton and Hardy's Industrial Toxicology, 4th
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    Fire Protection Guide on Hazardous Materials, 7th ed. (1978) Boston,
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    Hamilton A. & Hardy H.L. (1974) Industrial Toxicology, 3rd ed.
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    HSDB (1989) Hazardous substances data bank. National Library of
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    Micromedex, Inc.

    IPCS (1997) Environmental Health Criteria 191: Acrylic acid. Geneva,
    World Health Organization.

    ITI (1985) Toxic and Hazardous Industrial Chemicals Safety Manual.
    Tokyo, Japan, International Technical Information Institute.

    Kirk-Othmer Encyclopedia of Chemical Technology (1978-1984) 3rd ed.
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    NIOSH (1985) Pocket Guide to Chemical Hazards. Cincinnati, Ohio,
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    OHM/TADS (1989) Oil and Hazardous Materials/Technical Assistance Data
    System. US Environmental Protection Agency, Washington, DC (CD-ROM
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    OSHA (1989) Department of Labour, Occupational Safety and Health
    Administration: 29 CFR Part 1910; Air Contaminants; Final Rule.
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    RTECS (1988) Registry of toxic effects of chemical substances.
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    Sax N.I. and Lewis R.J. (1987) Hawley's Condensed Chemical Dictionary,
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    Sax N.I. and Lewis R.J. (1989) Dangerous properties of industrial
    chemicals, 7th ed. New York, Van Nostrand Reinhold, pp 71-72.
    



    See Also:
       Toxicological Abbreviations
       Acrylic acid (EHC 191, 1997)
       Acrylic acid (ICSC)
       Acrylic acid  (IARC Summary & Evaluation, Volume 71, 1999)