Occupational health aspects of construction work

INDEXED World Health Organization ~-· ~ Regional Office for Europe ~ ~ Copenhagen ~ EURO Reports and Studies 86 Occupational health aspects of construction work P. Grandjean

Lfh World Health Organization a/..)\ Regional Office for Europe ~ J Copenhagen VR ~ EURO Reports and Studies 86 Occupational health aspects ot ... construction work P. Grandjean l ll Professor, Department of Environmental Medicine Odense University Denmark ICP/WKH 008 ISBN 92 890 1252 8 © World Health Organization 1983 Publications of the World Health Organization enjoy copyright protection in accordance with the provisions of Protocol 2 of the Universal Copyright Conven- tion. For rights of reproduction or translation, in part or in 1010, of publications issued by the WHO Regional Office for Europe application should be made to the Regional Office for Europe, Scherfigsvej 8, DK-2100 Copenhagen 0, Denmark. The Regional Office welcomes such applications. The designations employed and the presentation of the material in this publica- tion 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 Organiz- ation 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 . The views expressed in this publication are those of the author and do not necessarily represent the decisions or the stated policy of the World Health Organization . PRINTED IN DENMARK ISSN 0250-8710 CONTENTS Page Preface V Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii Introduction Employment turnover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 High mobility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Diversity of trades . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Variable working conditions 3 Demolition and repair work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Developmental trends . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Health hazards on building sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Physical hazards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Physiological factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Hazards to skin and mucous membranes Toxic substances Fibrogenic dusts 7 8 9 Carcinogens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Psychosocial factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I 0 Occupational diseases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Hearing loss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Disorders due to vibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Musculoskeletal diseases Dermatological diseases Intoxications 14 16 16 Pneumoconioses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Other respiratory diseases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 111 Cancer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ill Other diseases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I 9 Preventive strategies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Planning for safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Cooperation for health and safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Education . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Occupational health programmes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Conclusions and recommendations 23 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 iv PREFACE In accordance with its target of" health for all by the year 2000", the specific WHO objective for workers' health is to make available to all workers, including those employed in remote areas, preventive health care based on convenient and appropriate technology and worker participation. The WHO Regional Office for Europe has continued a 1d intensified its efforts with regard to the promotion of workers' health. In particular, the health signifi- cance of specific industrial hazards, such as in the construction industry, have been of major concern. The initiative for this publication came from the United Nations Economic Commission for Europe Committee on Housing, Building and Planning. Since 1971 the Working Party on Building has been implementing a project on environmental problems arising from construction work. At its twelfth session in 1980 the Working Party agreed to request/ram the Regional Office a report on "occupational diseases of building workers employed on sites". The report requested was prepared by the author and, after its acceptance by the Regional Office, was submitted to the ECE Working Party. The report was also circulated for review to the following experts: Dr K.P. Duncan, Director of Medical Services, Health and Safety Exec- utive, London, United Kingdom Dr Yu.I. Kundiev, Institute of Labour Hygiene and Occupational Dis- eases, Kiev, USSR Dr J. Rantanen, Director-General, Institute of Occupational Health, Helsinki, Finland Professor M. Saric, Director, Institute for Medical Research and Occu- pational Health, Zagreb, Yugoslavia. Based on the detailed comments and suggestions received, the author then undertook to prepare an extended text on the occupational health aspects of construction work. V The present publication is aimed at occupational health service personnel and government experts concerned with occupational health and the health hazards in the construction industry. In addition, construction engineers, managers, safety engineers, safety representatives and others wi,h a specific interest in the health aspects of this particular industry may find the report useful. VI ACKNOWLEDGEMENTS The author is much endebted to Dr K.P. Duncan , Dr Yu .I. Kundiev, Dr J. Rantanen and Professor M. Saric who, as mentioned in the preface, undertook to review a draft version of this report and to provide detailed comments and suggestions for improvements. In addition, the author has received considerable advice and copies of both published and unpub- lished reports from Mr B. Eisenbach, Dr A. Englund, Mr K. Hunt , Dr S.L. Nielsen, Professor V.M. Retnev, Dr Hiroyuki Sakabe, Profes- sor I.J. Selikoff, Professor K . Tsuchiya, Mr P. Voss , Dr G. Wickstrom and Dr H. Yamaguchi . The author gratefully acknowledges this invaluable help. Literature research and library services were made available by the Nordic Documentation Centre of Occupational Health, Danish Labour Inspectorate. Secretarial assistance was provided by M. Sattari, Danish National Institute of Occupational Health , and by I. B0gelund and Y. Kildeberg at the Institute of Community Health, Odense University. VII INTROL1 UCTION With 5-10% of the workforce in cuuntries of the European Region em- ployed in some aspect of the comtruction industry ( /) , the economic contribution of this industry is significant. For the nearly 20 million workers who d-!pend on the constru,. t:on industry for thei; livelihoods, the importance of a safe occupational milieu is paramount. The accidents, short-term illness and long-term adverse health effects that may result from unsafe working conditions nec-::ssitate risk identification, careful investigation, availability of medical treatment and adequate preventive measures. "Occupational health" was ciefined by the Joint ILO/WHO Committee on Occupati0nal Health in 1950° as: ... promotion and mamtence of the highest degree of physical, mental and social well-being of workers in all occupations; the prevention among workers of departures from health caused b) their working conditions; the protection of workers in their employment from risks resulting from factors adverse to hea lth: the placing and maintenance of the worker in an occupational environ- ment adapted to his physiological and psychological equipment, and, to sum- marize, the adaptation of work to man and of each man to his job. Such measures, however, may be difficult to implement in the building industry owing to the interactions ()f social, environmental and industrial factors that create a very complex Jccupational milieu. This complexity resists direct comparison with other branches of in- dustry, such as manufacturing, and complicates the application of evalu- ation and prevention measures developed for other areas of industry. While no single condition is unique to the construction industry, the combination and multiplicity of factors form a working environment that is quite different from any other (2,3). a Unpublished document WHO/ Occ.Health/2. Employment turnover Unlike those employed in many other trades, construction workers show great variability in duration of employment with given employers and sites. This variability ranges from less than one day to many months at the same site. Though the latter occurs, a much more frequent turnover is commonplace. Often a worker contracts with several employers during a short period of time. Such rapid turnover complicates the keeping of accurate records for individual workers, especially those employed for very short periods of time. In addition, the situation is further complicated by the instability of employment and, in many geographical areas, sea- sonal unemployment (4,5). Without accurate and available health and employment condition records , efforts to document exposure to dan- gerous materials and to trace the me0ical condition of a given worker through a working lifetime may be nea;·ly impossible. High mobility Workers in the construction industry tend to show high mobility within and between job sites, both nationally and internationally. Part of this high mobility is due to season and climate. ln northern Europe, for example, harsh winters preclude outside construction work and may even restrict inside jobs at si tes without adequate weather protection or heating (5). Especially during recent decades , increased international movement of migrant workers has produced a transient labour force, comprising pri- marily unskilled and semi-skilled workers, employed in the construction industry, thus adding a new perspective to occupational safety and health (6, 7). Migrant workers introduce possible language difficulties in explain- ing such things as safety precautions. In addition, differences in building techniques or materials from country to country may present compli- cations. Unfamiliarity may be serious, especially when hazardous materials are used. High mobility, especially intf rnationally , also adds to the diffi- culties of tracing the occupational health history of given individuals. Diversity of trades The construction industry employs workers in a wide variety of trades, for example carpenters, insulators, masons, plumbers , electricians, painters, roofers and floorlayers. Within these trades , several specialized subgroups may be recognized . According to estimates by the Swedish Foundation for Occupational Safety and Health in the Construction Industry, the total number of occupations involved approaches 200. Within each occupation dozens of different materials are handled daily. Because of the range of materials used, as well as other considerations, detailed records would be necessary to document potential exposure to hazardous substances. Special 2 vigilance is needed in introducing safeguards linked to the use of new materials coming on site. The close working proximity of the various trades also carries the potential for indirect exposure or injury by hazardous materials or procedures, the so-called "bystander's exposure". Variable working conditions In addition to seasonal changes, environmental conditions such as sun- light , wind direction and speed, and daily temperature fluctuations may affect safety. Inhalation of airborne particles may vary depending on wind conditions. High temperatures may vapourize potentially dangerous ma- terials. These considerations are particularly important in the construction industry because a substantial part of the work is conducted outside and is , therefore, difficult to monitor and control. In addition, as construction work continues working conditions may also change so that a site judged safe for the use of certain materials early in construction may no longer be safe when walls restrict air movement. A growing proportion of the construction industry is becoming special- ized in underground construction , special industrial construction (such as power plants), offshore and deep-water construction, and construction in desert or arctic areas . Many workers are now employed at such projects, sometimes far from home, and under conditions that may be totally different from those otherwise typical for the industry. Demolition and repair work Construction processes have changed continuously during recent decades. In some cases , hazardous materials used in the past have been prohibited or phased out. Spray insulation with asbestos, for example, has been discouraged or forbidden, and crocidolite asbestos is probably not used at all any more . However, thef,e materials may pose renewed hazards when a building is being renovated or demolished . Ironically, some of the greatest health hazards come from such old and well established materials . The difficult decision is often whether to replace them in toto or to demolish the building in which they were used. Demolition and repair work involves risks associated with other construction work: noise, fibrogenic dust ( other than asbestos) and many ocher factors. However, the significance of the "sins of the past" should be recognized. Developmental trends During recent years, productivity in the building industry has increased, mainly due to three labour-saving methods. First, mechanization (use of 3 more power tools and heavy equipment) accompanied by more large-scale operations such as multistorey apartment and office blocks. Second, the use of prefabricated parts and elements that have reduced labour costs (8). Today walls, staircases and entire holiday homes are available as "prefab" units. Third, increased use of computers has also reduced labour hours . Computerization has facilitated a systematic approach to large-scale build- ing, calculating in advance the number of workers and the quantities of materials needed. Increased mechanization could increase the potential for accidents and other health hazards. Also, whi:e mechanization has decreased the physi- cal strains of construction work, it has also increased noise levels, exposure to whole-body vibration, and static physical work. Prefabricated elements may introduce new materials that expose the worker to potential hazards. Computerization will alter previous working patterns and may affect safety procedures. Computers may also help to analyse working con- ditions before exposure occurs. A large number of new chemical products have necessitated new work habits, thereby creating new dangers of exposure in the working environ- ment. As energy costs continue to rise, increasing emphasis will be placed on the insulation of buildings. Investigation of the various insulating materials is necessary for the health of both workers and inhabitants. Further, more string,:nt fire regulations will continue to force owners to initiate remodelling measures. Relatively small, often private dwelling jobs complicate investigation of the occupational environment because their conditions are so variable. In general , maintenance and repair work will probably comprise a larger share of the building work of the future. Such work carries the potential for continued exposure to materials such as asbestos, which are less commonly used in new construction . The cost of labour may also force property owners to attempt their own construction work. Such "do-it-yourself' efforts involve the hazards already mentioned to individuals who may not be aware of the potential danger of handling various tools and materials. The complexity of the occupational environment will not lessen . On the contrary mechanization , prefabrication, computerization and the intro- duction of new products and compounds will further complicate the situation. In the construction industry, perhaps one of the few constants is change. Investigations will have to make allowances for variable employ- ment periods, high mobility, difficulty of record-keeping, changing work- ing conditions that vary from site to site or even from day to day, and an increasing sophistication in methods and materials . 4 HEAL TH HAZARDS ON BUILDING SITES Health hazards in the construction industry are rarely regarded as a priority problem because their importance is often dwarfed by the fre- quency of occupational accidents . Machinery, heavy loads in constant movement, frequent changes of working position and necessary safety measures, and other factors create an occupational environment with a high risk of accidents. With a high turnover of employees and a large proportion of immigrants, safety rules may not always be observed. Des- pite the significance of these problems, occupational diseases comprise an important hazard that deserves attention. Previous surveys (2,3, 9-1]) have strongly emphasized physical factors such as noise and vibration, dan- gerous chemicals including allergens, fibrogenic dusts and toxic sub- stances, and ergonomic problems due to heavy burdens and difficult working positions. Today, the scope of this approach has been broadened to include the identification and evaluation of psychological and social factors of a worker's overall health. Some working conditions may involve only certain occupations, but many are common to several groups working together at the same site. Thus, indirect or "bystander's" exposure is a widespread phenomenon. Generalizations ue difficult because the combination of health hazards varies from site to site. Special problems occur, for example, at building sites on the continental shelf, at power plant construction sites, on building projects at high altitude, at underground sites, or at sites subject to extreme climatic conditions. A detailed account of such special circumstances lies outside the scope of this report, and only the general characteristics of major health hazards will be considered. Physical hazards One of the most obvious hazards at building sites is noise . Excessive levels of noise may seriously threaten the health of on-site workers and create a nuisance for nearby residents. An extensive treatise of the health effects of noise has recently been published (12). A building site can produce many sources of noise. Heavy equipment such as bulldozers, concrete mixers , compressors, dump trucks, etc. may adversely affect the hearing of workers and may substantially raise the level of background noise some distance away. Rock blasting, occasionally necessary at building sites, warrants particular concern because very high noise levels are reached. Recent research has indicated that exposure to impulse sounds, i.e. very short- lasting and high sound levels, may significantly contribute to hearing loss ( 12). The effects of impulse sounds on hearing ability have not been fully recognized because measurement of such short-lived, high sound levels has 5 not been available until recently . Many construction machines and tools emit noise levels that exceed a recommended noise standard of 85 dB(A) (3). Even 10 metres from the source, the level may be unacceptable accord- ing to this limit. Vibration dangers, which often accompany the noise hazard from machinery, are rhythmical jolts or displacement of solid bodies or objects transferred directly to the human body. Machines with rotating parts such as saws vibrate, as does equipment subject to sudden pressure changes, such as pneumatic hammers. Hand-held equipment may transmit vibra- tions to the hand and arm, causing localized effects . Many types of manual tool, such as pneumatic and hydraulic drills and hammers, carry potential risks. A construction worker is exposed to whole-body vibration when standing or sitting on a vibrating engine such as a heavy construction machine. Lateral or forward-reverse vibrations are more dangerous than vertical vibrations . The degree of vibration absorbed by a worker depends on the design, maintenance and operation of the equipment. Recommen- dations for the measurement and evaluation of vibrations have now been published (13) . Climate is often critical in the construction trades, since so much work takes place out-of-doors or at incomplete, noninsulated facilities . Intense heat in summer, extreme cold in winter, wind, rain or snow may have a significant impact on the comfort of the worker, may affect his safety, and may even cause increased morbidity. Clothing should be geared to balance the climatic conditions to the individual body heat produced during work (14). Severe heat may be a particular problem for roofing workers handling melted asphalt on hot days. Certain countries have defined standards for the microclimate in workrooms with limits for acceptable temperature, draught and humidity at different workloads (J J). Excessive exposure to solar radiation is an additional consideration (J 5), particularly in individuals with little skin pigmentation working at low latitudes. Ultraviolet radiation from welding processes may be a particular risk to "bystanders" whose eyes are not protected adequately, and new problems have been created by the development of artificial radiation sources. The increasing use of lasers by surveyors and engineers may pose a risk both for the operators themselves and for "bystanders" (16). Other sources of radiation may occur at special construction sites such as nuclear power plants. Physiological factors Heavy burdens and uncomfortable positions pose serious problems. Most concern centres on static work that requires positioning of the arms above shoulder height , standing with the body bent, or in a backward inclined or 6 similar uncomfortable position (17) . Dynamic work is generally less ex- hausting because of increased blood flow to the muscles . Also, much dynamic work has been mechanized. Joints, too, are less susceptible to ill effects from dynamic work. Standing positions are deleterious to the blood flow in the legs unless a frequent change of position is possible. In many cases a sitting position is possible and preferable. Working on the knees may cause trouble from the prepatellar bursa. Recommendations for safe working positions, including instructions for proper lifting and carrying of heavy burdens, have been worked out (2). Many countries enforce weight limits; in Romania, for example, various limits have been defined for men and women of different age groups (11). Nevertheless , ergonomic prob- lems on building sites are common, since many occupations involve carry- ing and holding heavy burdens such as cement, sand, bricks, wood and equipment. Concrete reinforcement workers probably have the heaviest physical workload (18) . Finishing of concrete floors, working in confined spaces, painting of ceilings and roofing work are processes that may involve chronic hazards to muscles, bones and joints. Hazards to skin and mucous membranes A number of occupational hazards in the construction industry involve dermatological disease (19) . A major skin problem results from the use of cement, i.e. mixing concrete, mounting concrete sections, bricklaying, plastering, floor and foundation laying, etc. Cement is hygroscopic, which tends to cause drying and fissuring of the skin, has a caustic action, and contains grains of quartz which cause mechanical irritation. More seriously, cement contains water-soluble chromates which may cause allergic derma- titis (type IV allergy). Nickel and cobalt salts may also contribute to this condition . Exposure to chemicals in rubber is probably widespread in the building trades but appears to be less serious than cement contact. Constituents and additives in rubber, such as tetramethylthiouram monosulfide or disulfide, may be involved in contact dermatitis among electricians, glaziers, car- penters or cement workers. The fixatives of epoxy and polyurethane paints and binders contain very strong allergens to which painters , carpenters or floor layers may be exposed. Other allergens in construction include formaldehyde, acrylates, chloracetamide and hydrazin. Degreasing chemicals such as solvents, or frequent hand washing with soap, may remove natural fat from the skin, thereby providing easier access for allergens or irritants. This problem particularly affects painters who may have to clean their hands with thinners or cleansers several times every day. Man-made mineral fibres or plastic particles may cause mech- anical skin irritation, and irritants such as formaldehyde may affect the mucous membranes. 7 Eye irritation is particularly serious if it interferes with visual acuity in a high-risk environment. Irritation or frank conjunctivitis (arc eye) can result from direct or indirect exposure to welding radiation. Ultraviolet light from solar radiation may cause skin cancer. Exposure to sunlight in com- bination with coal tar pitch or other phototoxic agents may cause photo- sensitization of the skin, particularly in roofing workers and plumbers. Some allergens may be associated with pulmonary diseases if inhaled (type I or III allergy or nonspecific) (20). Thus, spraying of polyurethane materials may involve hazardous exposure to isocyanate vapours. Other chemicals that may provoke allergic attacks include formaldehyde, epoxy resins , phthalic acid and isomellitinic acid an hydrides . Exotic woods may also cause pulmonary symptoms if the dusts are inhaled, and the list of substances causing pulmonary allergy in the workplace is steadily growing. Toxic substances Much research has focused on exposure to solvents (21). The most exposed groups are painters and floor layers, but some studies have documented very significant indirect exposure, since evaporation of solvents may con- tinue for many hours after the painter has finished the job. Solvents are used in coatings, lacquers , varnishes, glues and impregnating materials. Solvent exposure also occurs when concrete workers spray oil during the lathing process. Respiratory intake is usually most prominent, but solvents may be absorbed through the skin because of their lipid solubility. The various kinds of white spirit and other thinners may contain several different solvents - aromatic or aliphatic, chlorinated compounds, alco- hols, ketones, etc. The hazardous chemicals include toluene, xylene, ben- zene, methylene chloride, ethylacetate, trichloroethylene and methylethyl- ketone. Because of serious toxic effects, benzene is now only rarely used. Also, water-based paints are increasingly taking over. The potential for a classic disease, lead poisoning, still exists in the building industry (3). Minium, a long-used anticorrosive agent on steel, often requires about 500 g of lead to protect one square metre of steel surface. Continued spray-painting with lead pigments would be a potential hazard but seems to be exceptional. The burning off of lead paint with a soldering lamp might create hazardous lead fumes . More serious exposure has been found when lead-treated steel is welded or cut (22). Other welding operations, such as those associated with the use of reinforced concrete, may result in high levels of welding fumes (zinc, chromates, nickel, nitro- gen oxides and ozone). Weldable plastic flooring has become increasingly popular, especially for "wet" floors in hospitals, laboratories, kitchens, etc. The material is installed by hot-air welding. The decomposition fumes may contain car- bon monoxide, phthalates and hydrochloric acid. 8 Carbon monoxide exposure may also be caused by faulty heating installations, gas pipes, or by the operation of motorized appliances in enclosed spaces . Nitrogen oxides and methane are occasional hazards in underground work and other confined spaces. Pyrolysis of chlorinated organic compounds can lead to the formation of the very toxic gas phos- gene (carbonyl chloride). This can happen if solvents are decomposed in a welding flame. The range of chemical exposure is wide, and only a small number of compounds have been mentioned. The chemical hazards are probably the most complex part of the exposure situation on building sites. Fibrogenic dusts The use of asbestos in construction is being phased out in some European countries, and exposure is being limited in others. Since asbestos-associated diseases occur after an appreciable latency period, today's cases may be considered a reflection of past exposure (20,23,24). Asbestos has been widely used in spackling and filling materials and was previously used for almost all insulation purposes (boilers, tubes, fire protection, etc.) . As- bestos may be added to concrete for acid resistance and other purposes, and asbestos cement shingles and pipes are still widely used . Some uses have now been prohibited, but current standards of exposure may be exceeded when cutting or sawing asbestos cement (22). Asbestos textiles have been used for personal protection, e.g. by welders, and these products may also emit fibres. Particularly in the past, asbestos posed a major occupational hazard in the construction industry. The problem may still exist to some degree since many tonnes of asbestos products have been used in buildings in all countries. Unexpected or unusual exposure could occur during the maintenance, repair or demolition of such buildings. Thus, while the use of asbestos is now severely restricted, the hazard remains. Other natural mineral fibres will probably be more widely used in the future, in part as alternatives to asbestos, but they may not be without risk (24). In Turkey, zeolite (erionite) has been extensively used as a building material in a local area, and high frequencies of cancer now seem to be related to this mineral. Other natural fibres, such as wollastonite, have not been extensively studied but should be used with caution as asbestos substitutes since adverse health effects cannot be ruled out. Man-made mineral fibres are now used for many insulation purposes. With improved production technology, decreased use of asbestos, and increased emphasis on energy conservation, the use of man-made fibres has accelerated during the last two decades . During insulation work using man-made fibres, up to several respirable fibres per millilitre have been measured in the air. Work practice can, to some degree, reduce the possible 9 inhalation hazard. Fortunately, there is little evidence of any long-term health effects of such fibres (25). However, prudence would suggest that exposure be limited to the standards laid down for natural mineral fibres . New techniques have sharply increased exposure to silica dusts. Rock blasters and masons have well documented levels of exposure to silicogenic dusts. Moreover, grinding, finishing and resurfacing of cement surfaces, granite, marble or other stones containing quartz may cause high dust levels (22). Boring, cutting, sandblasting or demolition involving these materials may be other significant sources of fibrogenic dust. Again, work practices have been regulated in several countries where cases of silicosis seen today are a result of past exposure. Carcinogens The current list of established human carcinogens is rather short (26) . However, it includes several health hazards to which construction workers are exposed. A major carcinogen already mentioned is asbestos . Welding fumes and paint may contain chromates and nickel which are considered carcinogenic. Ultraviolet radiation , another carcinogenic factor, may be significant for workers with long outside exposures. Coal tar used for roofing contains carcinogenic chemicals. Exposure to other polyaromatic hydrocarbons may result from exhaust gases or from burning or heating of organic compounds. Several other factors could be potentially dangerous under building conditions. Experimental work to screen chemicals for carcinogenicity has resulted in a much longer list of chemicals that cause cancer in animals (27) . Although the possible carcinogenic potential for man has not yet been evaluated, caution should be exercised in using such compounds as synthetic resins, lacquers, paints, plastics, rubber and wood treatment chemicals. Psychosocial factors Psychosocial factors may also figure prominently in the overall wellbeing of a construction worker. Such factors are often referred to as causing "stress". The significance of these factors at the construction site remains to be evaluated, but will undoubtedly include pace of work, interest in specific tasks, fitness of individual abilities for job requirements, known or suspected risk of accidents or health impairment, and relations with man- agement and co-workers. The relevance of such factors has been substan- tiated (28). Psychosocial factors may also aggravate pre-existing minor health problems into conditions that impair performance. Migrant employees, who are mainly unskilled and semiskilled workers, may face additional psychosocial difficulties such as international and language problems (6). Lack of specific education and deficient instruction 10 may subject foreigners to excessive occupational st ress . Such workers may also fail to benefit from national health and social security services. Similar concerns may apply to construction workers employed at building sites in remote areas, in the arctic, in deserts , or on the continental shelf. Fre- quently away from their families and living in isolated areas, they are exposed to social and psychological risks that have not yet been evaluated in detail. OCCUPATIONAL DISEASES In the case of an occupational accident, such as traumatic injury, a cause- effect relationship is often readily apparent. With occupational diseases, such connections are often more difficult to trace (29,30). Many diseases are not specific for a certain occupation or exposure and may be confused with changes due to aging, smoking, alcohol abuse or hereditary factors. Chronic bronchitis, for example, is often caused by smoking, but occupational exposure may contribute to the overall preval- ence, even in non-smokers . Also, since many disorders have a multifac- torial cause, the occupational environment on building sites may possibly contribute to the development of such conditions or their aggravation. A construction worker with a known allergy to house dust may suffer asth- matic attacks through exposure during repair work. Some chemical com- pounds are believed to aggravate heart and liver diseases. Arthritis and varicose veins could be worsened by heavy physical work on building sites. Thus, although such diseases are nonspecific, occupational factors can play a significant role. An illness may take years to develop and, when diagnosed, the expo- sure to hazardous factors may have ceased or changed, making document- ation difficult. The existence of a latency period seems to characterize many occupational disorders of construction workers . Degenerative disc disease or contact dermatitis , for example, may develop after years of employment, but a thorough appreciation of the responsible work patterns may be hampered by a deficient work history. The situation may be worse in the case of diseases such as pneumoconiosis or occupationally-related cancer. Thus, the development of lung fibrosis is slow when exposure to fibrogenic dusts is irregular and at a relatively low level. The dust is deposited in the lungs, and the fibrotic process often continues after the discontinuation of exposure. Silicosis and asbestosis may be diagnosed 20, 30 or even 40 years after the onset of exposure, at a time when the patient is no longer occupationally exposed. After 40 years, difficulties in proving that occupational exposure was the cause may be insurmountable. II The best illustration of the problem is probably offered by the occu- pational cancers (26). Several known and many suspected carcinogens exist on building sites. Exposure could cause occupationally-related can- cers several years later. However, the histological type and the site of the cancer are rarely specific for a particular exposure, and this effect usually hits only a small percentage of an exposed group. An increased cancer incidence or mortality in a particular occupation may be difficult to relate to any one factor or group of factors at the place of work. If the cancer incidence is doubled, no way exists of deciding which half was due to occupational factors and which one was not. From an insurance or compensation point of view, cause-specific dis- orders are easy to deal with , while multifactorial illnesses are quite another case. The goal of preventive medicine in this area is, however, not restricted to diseases with a recognized single cause, such as poisonings; occupa- tional disease patterns in a broad sense should be taken into consideration. The scope of occupational health includes a variety of diseases that are not caused by occupational factors but may be promoted or aggravated by working conditions. In particular, cardiovascular diseases , certain dis- orders of the locomotor system and some nervous system diseases belong to this category. These diseases are not commonly regarded as "occu- pational" , but they comprise an important part of occupational health practice . Additionally, questions of fitness and safety include medical evaluation but these are not covered in this report. Hearing loss Noise-induced hearing loss may be either temporary or permanent (12). The temporary threshold shift is a reversible indication that exposure has taken place, but may be a warning sign that permanent changes can occur if excessive noise exposure continues. The permanent threshold shift is audiometrically similar to presbycusis, i.e. hearing loss attributed to the natural aging process. The loss usually starts at 2000 Hz and above . Early changes may not be apparent to the individual worker because speech frequencies between 500 and 2000 Hz are not affected. Later , however, these frequencies are also affected, and hearing loss becomes socia lly detrimental. Noise also produces different effects on the autonomic nervous system, but the associated long-term health risks are poorly understood . Noise can reduce the alertness of a construction worker and impair performance (psychological fatigue). Interference with communication at a building site can lead to accidents due to inability to hear warning shouts, etc. Thus, noise has both short-term and long-term deleterious effects (12) . The frequency of occupational deafness increases with age, i.e. years of exposure to noise. A cross-sectional study of almost 125 000 construction 12 workers in Sweden showed that about 7% suffered from serious hearing loss probably induced by noise (31). Particularly high prevalences were found in rock blasters, sheet metal workers and carpenters . Groups of tool repair workers, heavy equipment operators and concrete workers also exhibited a high rate of hearing loss . In the Federal Republic of Germany, noise-induced hearing loss has been found most frequently in drivers of heavy construction equipment and in crane and bulldozer operators (32). Hearing loss may comprise up to a half of all occupational diseases in construction workers claiming compensation (/ 1). This occupational hazard is therefore very widespread. Hearing aids are of some help to patients with noise-induced hearing loss. However, the disease may be so serious as to impair work capacity and socia l life. Disorders due to vibration The effect of vibrations depends on their frequency , intensity and length of exposure. Thus, slow vibrations oflarge construction equipment will cause osteoarticular and muscular lesions, especially in the back. High frequency vibrations give rise to more localized angioneurotic and osteoarticular effects , typically in the hand and arm operating the vibrating tool. Drivers of heavy construction machines are expost:d to whole-body vibration. Characteristically, these workers may develop back pain, some- times located in a specific area of the lower vertebral column. Radiography may show some arthrosis of the small vertebral joints. Increased morbidity in construction workers exposed to whole-body vibration seems to involve musculoskeletal diseases and ischaemic heart disease (33). Selection pro- cesses seem to be partly responsible for the fact that no clearcut patterns were found (34) . Thus, occupational diseases caused by whole-body vibra- tion are nonspecific, and thorough occupational history and exposure documentation may be necessary to reach a definite diagnosis . A well documented result of long-term use of hand-held pneumatic equipment is "dead (or white) fingers", or Raynaud's phenomenon (35). This disorder causes attacks of local ischaemia with loss of sensitivity, later followed by increased blood now in the fingers and tingling pain. The whole attack lasts for several hours and most often concerns the third and fourth fingers on the hand, or hands, holding the equipment. The attacks may completely cease upon early withdrawal from exposure. Disturbed sensitivity may last between attacks which, after long-term exposure, may become more frequent and resemble classical Raynaud's disease. Another effect (though rarer) is osteoarticular lesions, such as osteolysis, or osteo- necrosis, occasionally located at the semilunar bone (Kienbock's disease). In a Swedish cross-sectional questionnaire involving 2300 construction workers, vibration-related symptoms in hands and fingers occurred in 13 more than half of the 252 workers exposed to vibrations from hand-held tools (36) . Subjective impairment seems, therefore, to be quite common. A recent study has suggested that vibrations from hand-held equipment may induce a hyper-responsiveness to cold in the exposed arteries , even in individuals (as yet) without symptoms (37). The potentially wide occur- rence of such a subclinical stage of vibration-induced Raynaud's phen- omenon would further emphasize the need for preventive measures and special protection of individuals suffering early stages of this disease. Very high frequency vibration may cause local muscle and nerve changes in the hands, leading to tingling and painful sensations, numb- ness or cramps. These disorders are reversible when exposure ceases. Another relatively rare disorder caused by pneumatic tools is osteoarticular lesions of the elbow. Bony formations, such as exostoses and osteophytes, may be seen on an X-ray of the elbow joint. Decreased and painful movement is the clinical appearance. Some individuals seem to be very susceptible to vibration disorders, and both work habits and design of the equipment may influence the amplitude of the vibrations. In addition climatic conditions, especially cold, may aggravate the symptoms or, perhaps, accelerate the disease process. Also, "dead fingers" seem to be more frequent in smokers than in non-smokers . Most severe ill effects occur after some years of exposure, and early changes may be fully reversible . Musculoskeletal diseases Hard physical labour in construction work promotes the development of degenerative disease and low back pain. Severe lumbar disc degeneration has been found in 30-40% of workers in jobs with exposure to back loads, whereas the prevalence of this disorder in reference groups was usually below 20% (18) . The spinal degeneration may include osteoarthrosis with osteophyte formation and ankylosing spondylitis. The symptoms may be of both "lumbago" and "sciatica" types, with stiffness, aches and radi- ating pains. In a cross-sectional study of concrete reinforcement workers, Wickstrom et al. (38) found that 38% had restricted lumbar flexion, half as many had pain during forward bending, and three out of four men with moderately or severely restricted lumbar flexion had radiological signs of disc degeneration . Thus, this very common disorder in exposed trades is of major concern. Occasionally, long-term overstraining of the spine at the muscular insertions may cause fracture of the spinous processes. The lesion usually occurs in the upper part of the vertebral column. Shovelling work seems to be hazardous in this regard ("digger's fracture") . A radiograph is essential for the diagnosis. Fortunately, recovery is usually complete and fairly 14 rapid . Such fatigue fractures were accepted in 257 cases during 1958-1978 as occupational diseases in the German Democratic Republic (39) . This effect is therefore not just a matter of history. Tenosynovitis is a common musculoskeletal disease, an inflammatory reaction of the tendons due to excessive muscular work. The patient suffers swelling and pain in the tendon affected. A high radial form at the elbow is most frequent in construction workers and is provoked by excessive lifting, carrying, etc. Other locations may sometimes be seen. The mus- cular overstrain may also give rise to lesions at the insertion point of the tendon on the bone , i.e. periostitis . In this case, the pain is located at this very point. Most frequently, this disorder in building workers is seen in the form of epicondylitis ("tennis elbow") when located at one characteristic insertion site. These disorders are very frequently reported in construction workers (11.32). The kneeling position of floor workers , tile layers and masons may lead to occupational diseases of the knee. In particular, the prepatellar bursa may be the site of a degenerative transformation, bur- sitis, caused by the prolonged pressure and irritation of the area. About 10% of a ll occupational diseases reported during 1971-1976 in construc- tion workers in the Federal Republic of Germany were cases of bursitis, most frequently in floor layers and roofing workers (32). Fortunately, this disease usually ca uses only few days of sick leave. The repeated bending of the knees may cause excessive wear of the meniscuses of the knees. The meniscus degeneration may involve loosening of fragments that can block articular movement. Surgery may be necessary to correct the problem. Prolonged local pressures caused by awkward work positions or re- peated strain against a particular area may cause nerve paralysis. Pneu- matic tools may damage the cubital or median nerves. The carrying of timber , steel rods, etc. on the shoulder may paralyse nerves of several shoulder muscles. Sitting in a crouching or kneeling position may cause pressure on the external or internal popliteal and other nerves . The symp- toms in the beginning relate to dullness and odd sensations; paralysis may follow . During 1958-1978, over 150 cases of pressure neuritis were ac- cepted as occupational disease in construction workers in the German Democratic Republic (39). Muscular tension and muscle knots are , in general, frequent in con- struction workers ( 40). Although such symptoms may not be regarded as an occupational disease, they may cause increased morbidity and de- creased work performance. Many concrete reinforcement workers retire early due to musculoskeletal diseases (/8), and the same may be true of other construction workers. The seriousness of this problem should there- fore not be underrated. 15 Dermatological diseases Skin disease, especially contact dermatitis , is one of the commonest occu- pational diseases in construction workers . In the Federal Republic of Germany, for example, some 50% of the 6000 occupational diseases in building workers reported per year during 1971-1976 were skin diseases (32). Similar results have been found in other countries (11,41). Contact dermatitis occurs in two forms (19) . Toxic eczema is usually caused by degreasing or cleaning agents and by irritating or otherwise injurious chemicals. This irritant type of dermatitis may predispose the patient to subsequent development of an allergic eczema caused by delayed allergy (type IV reaction) to a specific substance. Later, the allergic patient may react both to the original allergen and to some related or unrelated com- pounds . In construction workers , the most common skin disease is "ce- ment dermatitis" . Cement causes toxic eczema in many workers , and some develop the allergic form later on. Usually the allergen is soluble chromate, but cobalt and nickel may also be involved (19). Painters, too, suffer a high frequency of contact dermatitis, probably due to the irritant and allergenic effects of many solvents and epoxy products ( 42). Other experience sug- gests that skin diseases occur particularly often in concrete workers and painters (32) . Other occupations are probably less subject to these dis- orders. A definite diagnosis always rests , in part, on a careful occupational history and epicutaneous (patch) allergen tests . Although allergy is acquired for life , a change of occupation is not always necessary, provided suitable precautions are taken ( 43). Other dermatoses occur much less frequently. Industrial acne may be caused by oils and tar . Granulomas may develop because of penetration of mineral fibres into the skin, but simple skin irritation from the fibres is very common. Lichen plan us may also be occupationally related ( 44). Excess exposure to ultraviolet radiation may cau~e solar erythema, phototoxicity and malignant skin tumours (15). Intoxications Solvents are lipid soluble and may. when inhaled, cause acute toxicity of the central nervous system. Patients suffer from acute or subacute symp- toms of intoxication and fatigue. More importantly, recent studies in Scandinavia have shown that painters with long-term exposure to solvents exhibit neuropsychiatric symptoms suggesting a chronic toxic encephalo- pathy (21) . This "painter's syndrome" causes complaints such as memory impairment, fatigue and sleep disturbances, difficulty in concentrating, and other nonspecific symptoms. The combination of these complaints, and their high prevalence in solvent-exposed workers, is typical ( 45). Neuropsychological and neurophysiological testing in cross-sectional 16 studies have, to a large extent, confirmed the impression that solvent exposure may cause a chronic toxic encephalopathy ( 46). Reversibility of the chronic changes is questionable. During recent years, some national social insurance boards have accepted an increasing number of cases of "painter's syndrome" as occupationally induced, and water-based paints are gaining an increased market share due to stricter regulation of solvent- based paints. However, relatively strong differences of opinion remain in certain European countries regarding the interpretation of "non-objective" test results ( 47). Thus, the long-term health significance of solvent ex- posure is not uniformly recognized and accepted. The habit of protecting steel structures from corrosion with a layer of red lead paint may cause serious lead exposure conditions many years later when the structures are demolished. Lead fumes are created by the acetylene flame used to cut the steel and may cause lead poisoning ( 48). Long-term lead exposure may have chronic effects, including neurotoxicity ( 49). Other poisonings, except perhaps carbon monoxide intoxication, seem to be quite rare in the construction industry, unless caused by an accident. Anecdotal evidence suggests that toxic substances that interfere with the nervous system may be of particular relevance in an occupational environment with high accident risks. A slight effect on vestibular function, a decreased attention or vigilance level, or related effects may seriously reduce the safety of an individual worker. This aspect deserves proper study in the future. Pneumoconioses Dust is a major health hazard in the construction industry. Some respirable dust may be fibrogenic and cause scarring of the lungs . Free si lica ( quartz) and asbestos are of special concern at building sites. Asbestosis usually develops several years after the onset of exposure. With the irregular exposure conditions typical of construction work, the latency may stretch into decades. Present-day cases of asbestosis are, therefore, the result of using filling materials , asbestos textiles, asbestos cement, insulation materials, etc. 20, 30 or more years ago (20,23). Pleural diseases such as pleural thickening or placques, and even parenchymal asbestosis, are seen particularly in insulation workers and plumbers, but both masons and painters occasionally develop signs of this pneumoconi- osis, possibly due to indirect asbestos exposure in the past (50). The radiographic appearance of the pleura and the scarred lung tissue are characteristic of this disease, and detailed diagnostic criteria have been developed (20). This pneumoconiosis often causes dyspnoea, dry cough and chest pain. A more serious effect is the development of pleural and peritoneal mesothelioma and certain carcinomas, particularly in the lungs 17 (20.23). Such cancers may occur in up to 50% of insulation workers exposed to asbestos. Exposure-response relationships suggest that even limited exposure may be hazardous (24). Silicosis generally appears after rather long exposure. Development is usually slow and may continue after the cessation of exposure (20). Workers running a specific silicosis risk include rock blasters and stone masons (51) . Concrete grinding, drilling and chiselling, and marble finishing entail a definite risk (52,53). There were about 400 reported cases of silicosis per year during 1971-1976 among construction workers in the Federal Repub- lic of Germany (34). The diagnosis is usually established on the basis of a chest X-ray and an occupational history including free silica exposure (20) . The main symptom is dyspnoea, sometimes coupled with cough and some expectoration. Silicosis is sometimes associated with an increased risk of tuberculosis . Other respiratory diseases Bronchial asthma (type I allergy) related to occupational exposure may be seen in construction workers . Individuals who are allergic to house dust or certain fungal spores may experience acute attacks when exposed, for example during repair work . Particularly carpenters, but also other build- ing workers, could be exposed to dusts from exotic woods, which are a documented source of respiratory allergens. After sensitization, an im- mediate type of allergy may develop following subsequent contact. Delayed allergic reactions (type III allergy) may also be caused by the inhalation of chemicals and organic dusts present on building sites (20). In some cases, pulmonary allergy seems to be worsened by nonspecific irritants. Many dusts and vapours have irritant effects. Long-term exposure, such as to welding or asphalt fumes , can lead to respiratory impairment. Thus, while smoking is the most important cause of chronic nonspecific lung disease, some occupational exposures may be contributing factors (54). Zinc fever may occur in welders as a result of inhalation of freshly formed metal oxide aerosols. This disease results in influenza-like symptoms and lasts for only 1-2 days . The most serious acute respiratory disorder, however, is the pulmonary oedema induced by phosgene or nitrogen dioxide (20) . This rare , but potentially fatal, condition occurs after a latency period of several hours following exposure. In a few instances, chemical pneumonitis has been caused by cadmium fumes. Cancer Numerous human and animal carcinogens occur in the construction en- vironment and carcinogenic risk is therefore a reality. Due to the variability 18 of exposure at building sites and the difficulty in evaluating employment records, investigations of cancer rates related to the building trades meet with special problems. The validity of epidemiological studies in this field is therefore difficult to assess. Excess cancer rates have been found in members of certain trade unions. For example, painters appear to suffer excess oesophagus and liver cancer, and high rates of stomach, lung and laryngeal cancer have been seen in plumbers (55). A possible relationship between employment as an operating engineer ( operation and maintenance of power-driven machinery) and excess rates of cancer, particularly of lung cancer, has been found (56). The possible causes of such occupationally related cancer remain in doubt. In insulation workers, a strong association between asbestos exposure and cancer rates has been documented (23). Other diseases In questionnaire studies, a frequent complaint among construction workers is stress associated with the pace of work, and problems due to changes in the nature of building work (57). Many occupations within the building trades are physically demanding and entail a high degree of psychological stress. Theorell et al. (58) found an increased incidence of myocardial infarction in concrete workers and related this finding to the al:-nve- mentioned factors. However, the significance of these findings needs to be further explored. Migrant workers constitute a special high-risk group (6), and some health related problems may be associated with conditions at work. PREVENTIVE STRATEGIES In principle, all occupational diseases are preventable, as are occupational accidents. Perhaps th,_ preventive efforts with regard to accidents have, to some degree, drawn attention away from possibilities of preventing occu- pational diseases. These diseases are not an unavoidable result of the occupation, as such, within the building trade. The cause is generally a specific preventable hazard or a combination of such factors. These par- ticular hazards should be identified and brought under control. As outlined above , however, some occupational disorders cannot yet be referred to a specific cause, and the complexity of the occupational environment and the changing work sites, etc. make investigation difficult. Such studies should nonetheless be encouraged in order to obtain even better information on which to base preventive measures. Safety and health are a necessary consideration in all stages of the work. Prevention can be instituted at several different levels . 19 Planning for safety Primary prevention is, whenever feasible, to be preferred, and health hazards should be controlled by substitution of less hazardous products and processes or by installation of adequate safeguards. These preventive efforts should be dealt with as early as the planning phase of a construction project. A complete ban on a particular compound or work process is rarely deemed necessary; usually limitation of the hazard or exposure is sufficient. Also, the design of many machines and tools should be further improved to reduce potential danger. For example, air exhaust outlets on drills should be muffled, and noisy machines should be enclosed in a hood to reduce the noise level. Vibration of pneumatic tools should be con- trolled by better designs, perhaps by the use of the so-called pons cylinder which reduces the vibration transferred to the hand and arm (3) . Main- tenance, including frequent lubrication and change of damaged parts, generally helps to reduce noise and vibration levels. Further, the chromate content of cement , a major cause of contact dermatitis , could be in- activated by the addition of0.1-0.2% ferrous sulfate. During recent years , less dangerous water-based paints have been substituted for paints with high organic solvent contents. In general , pretesting of chemicals and construction equipment should be encouraged and instituted wherever possible. Cooperation for health and safety The promotion of health and safety at work is by no means a separate issue but forms a necessary part of ordinary operations. In some countries, safety organizations have been formed voluntarily by employers, as a result of agreements between employers' and workers' organizations, or because of a legal obligation. The duties of such organizations (committees or groups) comprise watching, verifying and advising on safety. As a rule there is no direct influence, the major function being to achieve successful cooperation on safety matters and to draw the attention of management to shortcomings and defects. Experience shows that good safety organ- izations often do more for safety at work than do regulations (3). If such an organization is unavailable, for example with small enterprises or subcontractors, informal cooperation should be encouraged, perhaps covering several small enterprises within the same branch of the construc- tion industry. Education Improved information on health concerns in the building trades might encourage planners, designers and managers to seriously consider how to 20 improve working conditions. Education of the workers themselves is also necessary (59). In some countries safety committee members (safety stewards, safety officers) receive basic education in occupational safety and health . Special attention should be paid to migrant or foreign workers so that they receive appropriate information in a language they understand . Products containing hazardous substances should be labelled accord- ingly, and instructions concerning the safe handling of the product should be made easily available . A full declaration of the contents is useful, especially to prevent accidents. This information should always be given in a language that is understood by the construction workers who are hand- Lng the product (even though the product is imported). In Finland, for example, the employer is responsible for providing safety data sheets for all chemicals used and for ensuring that the information on risks and safe handling is understood by the employees. Similar rules apply in other countries. Apart from the customary training that workers , including apprentices, receive for jobs on building sites, they may also need special instruction for particular jobs at special sites or when new processes or products are introduced. In addition, physical fitness and good health should be encouraged as part of a general approach towards the preven- tion of work related diseases. A code of work practices published by the International Labour Office (2,3) describes in general terms how to avoid hazardous working con- ditions . Maximum weights for lifting have been recommended, and a large number of rules have been developed with a view to ensuring safety. However, safe work practices need to be developed in more detail based on the knowledge of properties of equipment, chemical compounds, etc. used on building sites. Sophisticated ventilation facilities are rarely available, and the work codes need to take this fact into consideration . Thus, in some circumstances, paints containing volatile solvents may not be used unless exposed workers wear respirators. Also, particularly during repair and demolition work, instruction should make allowance for the possible presence of asbestos and other hazards that may not occur in new con- struction. The stress of arduous work , uncomfortable positions and ex- hausting speed may not be completely eliminated but could be reduced by regular breaks. Personal protective equipment is necessary on building sites, the most important being hard hats, work clothes, safety boots, etc.; goggles and e:ir protection may also be needed. Gloves or ointments (barrier creams) may be useful for the prevention of contact dermatitis. More specific equipment, such as water-resistant knee protection or respirators, may be of help. Detailed instructions for the proper use of such equipment should be available on the site. Recommendations to this effect have been pub- lished (3). 21 As recently discussed by the Joint ILO/WHO Committee on Occu- pational Health (60), training and education must focus on three different areas: knowledge, motivation and skills. This needs to be properly reflected in all teaching programmes in this field . Educational efforts should also cover occupational health service personnel and government employees in labour inspectorates and other agencies. The Joint Committee has sug- gested general principles for such teaching programmes. With regard to occupational health and safety, however, the construction industry differs from other occupations. The particular problems and needs of this industry should be incorporated in the curriculum of the professionals concerned. Occupational health programmes On building sites, occupational health programmes should be instituted to " ... promote and maintain the highest possible level of health among the gainfully employed ... To meet those objectives, it is necessary ... to identify and bring under control at the workplace all chemical, physical , mechanical, biological, and psychosocial agents that are known to bt: or suspected of being hazardous ... [and] to discover and improve work situations that may contribute to the overall ill health of workers in order to ensure that the burden of general illness in different occupational groups is not increased over the community level ... " (61). The occupational health programme should therefore incorporate both environmental m~ni- toring (industrial hygiene) and health surveillance. The main purpose of environmental monitoring is to identify risks and to assess the magnitude of potentially hazardous factors. A traditional industrial hygiene programme, however, would not be efficient in the construction industry because the occupational environment is constantly changing. Direct-reading instruments may be very useful, but slow sam- pling techniques followed by detailed laboratory determination are mean- ingless in this situation. Measurements should be instituteci when a char- acteristic work process is initiated, so that the monitoring conclusions, when they become available, can still be applied. However, owing to the limitations of such monitoring, the definition and enforcement of safe working conditions should be a main aim of the occupational health programme. Medical monitoring is carried out by occupational health services in many European countries . An examination may be needed to evaluate the fitness of a worker for a certain job or to judge whether wearing of respiratory protection is advisable for a particular worker. Also, a pre- employment examination may be necessary to identify individuals with certain impairments who, because of this impairment, in certain jobs may pose a risk to themselves or to their fellow workers. Periodic examinations of workers exposed to occupational hazards are undertaken on a considerable 22 scale by occupational health services in several countries in the European Region (62). Such examinations are, unfortunately, almost useless as a control of workplace safety. If baseline data are available, some long-term follow-up of building workers might provide an indication of possible health hazards. In this industry, however, with constant changes of em- ployers and exposures, such studies may not be easy to evaluate. The fact is sometimes overlooked that the examination of a worker does nothing to eliminate the hazard. Such programmes should thus be restricted to in- clude on:y examinations of proven relevance and validity. The organization of occupational health services in Europe differs con- siderabl:r according to local conditions and national traditions. Such pro- grammes may be mandatory or voluntary. Among the countries with well develored services for the construction industry , Sweden and the German Democn.tic Republic have instituted special occupational health services that are branch related , i.e . directed to the particular needs of the construc- tion industry. Finland and Denmark, on the other hand, cover this branch of industry along with others through occupational health service centres. Countries without such specialized services rely on an efficient primary care system and support from labour inspectorates and other authorities. Obviously, the needs of the construction industry may be satisfied in a number of ways , and no single solution seems applicable in all countries. CONCLUSIONS AND RECOMMENDATIONS Occupational diseases among construction workers vary from very minor spells of aches and pains to severe and occasionally potentially fatal disorders. The major groups of work related diseases are: hearing loss, vibratio,1 induced disorders, musculoskeletal diseases, contact dermatitis and intl-xication . Owing to unstable employment patterns, proper infor- mation on incidence rates for these diseases is as yet unavailable. However, during his lifetime a worker in the building trades runs a very high risk of suffering one or more of the major occupational diseases mentioned . In addition , pneumoconioses occur in some building occupations, and some workeri: may run an increased risk of developing cancer. All occupational diseases in building workers are, in principle, prevent- able. Primary prevention is, whenever feasible , to be preferred. Pretesting of equipment, products and processes should be carried out to minimize hazards. Exposure monitoring and risk identification are a necessary part of occupational health programmes , but monitoring plav.s a less important role in the construction industry than elsewhere because working conditions 23 and exposures are changeable. Instead, a particular need is the prior definition of safe working practices under various conditions. Safety data sheets for all products used should be available to the t:.sers at the building sites, and basic information on first aid, chronic toxicity , pyro- lytic decomposition, etc. should be understood by all workers concerned. Owing to the significant hazards occurring at building sites, the change- ability of the working environment, and the difficulties associated with a transient workforce, the occupational health problems need solutions that may differ from those in other industries. Occupational health programmes should be part of a general health service approach. The occup.!tional health service should incorporate both technical and medical functions. Medical surveillance is necessary to ensure the fitness of worker~ and job suitability, and to detect early health effects when preventive measures have failed or when a worker suffers a particular susceptibility to a particu- lar hazard. However, health examinations as such will not rid buildir.g sites of health hazards. The establishment of a national centre for research, training and de- velopment in occupational health in the construction industry WC'uld be justified in many countries . This centre should be closely affiliated with other institutions covering other areas of occupational health. Branch orientated surveys of specific risks and health hazards should be carried out to evaluate the prevalence of priority factors in the construc- tion industry. Such surveys will be useful in identifying hazardous work processes or products. National policies on education and training in occupational health should give due consideration to the specific hazards anc:I problems in the construction industry. Such policies should deal with the education and training of workers, employers , planners, occupational health service per- sonnel, and other groups concerned with health at construction sites. Within a limited number of subsections of the construction industry, long-term prospective studies should be undertaken to examine potential health effects following chronic exposures or long latency periods. A personal health and safety card for each individual worker should be developed , and its practical use should be assessed. Thes~ cards may focus additional attention on the importance of a sound working enviroriment. In addition , the cards may be of great value for the collection of exposure and health data in these transient workers in case of epidemioiogical follow-up studies. Guidance and mechanisms for education and training in occupational health in the construction industry should be developed for all groups of people concerned. In particular, detailed descriptions of safe work practices under different conditions should be developed on an international basis as a guideline for national requirements and performance standards. Similar guidelines on the identification, assessment and control of health hazards in 24 the construction industry should be developed to strengthen the preventive efforts of safety organizations and occupational health services. REFERENCES I. Year book of labour statistics. Geneva, International Labour Of- fice , I 979. 2. Safety and health in building and civil engineering work. Geneva, Inter- national Labour Office, 1972. 3. Building work. A compendium of occupational safety and health prac- tice. Geneva, International Labour Office, I 979 (Occupational Safety and Health Series, No. 42). 4. Instability of employment in the construction industries. Building, Civil Engineering and Public Works Committee, second session, report II. Geneva, International Labour Office, 1948. 5. Seasonal unemployment in the construction industry. Building, Civil Engineering and Public Works Committee, third session, report Ill. Geneva, International Labour Office, 195 I. 6 .. Blaizot, M., ed. Medecine du travail et travailleurs migrants. Revue de medecine du travail, 4: 1-172 ( 1976). 7. International migration of labour in the construction industry. Building, Civil Engineering and Public Works Committee, sixth session, re- port I I. Geneva, International Labour Office, 1959. 8. Social aspects of prefabtication in the construction industry. Building, Civil Engineering and Public Works Committee, eighth session, re- port II. Geneva, International Labour Office, 1968. 9. Magnuson, H.J. Health hazards in the construction industry. Journal of occupational medicine, 3: 321-325 (I 961 ). I 0. Ahonen, K. et al. [ Chemical and physical hazards in house construction]. Helsinki , Institute of Occupational Health, 1977 (Finnish, with Eng- lish summary). 11. Haublein, H.-G. & Heuchert, G. Gesundheitliche Berufsrisiken durch physikalische Noxen und korperliche Schwerarbeit im Bauwesen. Zeitschrifr fur die gesamte Hygiene und ihre Grenzgebiete, 25: 725-737 (1979). 12. Noise. Geneva, World Health Organization, 1980 (Environmental Health Criteria No. 12). 13 . Principles for the measurement and the evaluation of human exposure to vibration Transmitted to rhe hand. Geneva , International Organ- ization for Standardization, 1979 (Draft International Standard ISO/DIS 5349). 25 14. Fanger, P.O. Thermal comfort. Copenhagen, Danish Technical Press, 1970. 15. Ultraviolet radiation. Geneva, World Health Organization, 1979 (En- vironmental Health Criteria No. 14). 16. Goldman, L. et al. Optical radiation, with particular reference to lasers. In: Suess, M.J., ed. Nonionizing radiation protection. Copen- hagen , WHO Regional Office for Europe, 1982 (WHO Regional Pub- lications, European Series, No. 10). 17. Grandjean, E. Physiologische Arbeitsgestaltung, 2. Auflage. Thun & Munich, Otto Verlag, 1967. I 8. Wickstrom, G. Effect of work on degenerative back disease: a review. Scandinavian journal of work, environment & health, 4(Suppl. I): 1-12 (1978). 19. Fisher, A.A. Contact dermatitis. 2nd ed. Philadelphia, Lea & Fibiger, 1975. 20. Parkes, W.R. Occupational lung disorders. 2nd ed. London, Butter- worth, 1982. 21. International Symposium Control of Air Pollution in the Working En- vironment, Stockholm, 6-8 September 1977. Part II: Solvents, welding. Stockholm, Arbetarskyddsfondet, I 977. 22. Schiitz, A. & Heidermanns, G. Gesundheitsgefahrliche Staube im Hoch- und Tiefbau. Staub, Reinhaltung der Luft, 37: 273-277 ( I 977). 23. Selikoff, I.J. & Lee, D.H.K., ed. Asbestos and disease. New York, Academic Press, 1978. 24. Nicholson, W.J. Criteria document for Swedish occupational stan- dards: asbestos and inorganic fibres . Arbete och hiilsa, 17: 1-103 ( 1981 ). 25 . Biological effects of man-made mineral fibres: report on a WHO meet- ing. Copenhagen, WHO Regional Office for Europe, 1983 (EURO Reports and Studies, No . 8 I). 26. Doll, R. & Peto, R. The causes of cancer. Journal of the National Cancer Institute, 66: 1191-1308 (1981). 27. Tomatis, L. et al. Evaluation of the carcinogenicity of chemicals. Cancer research, 38: 877-885 ( 1978). 28 . Levi, L. Stress and distress in response to psychosocial stimuli. Oxford, Pergamon Press, 1972. 29. Hernberg, S. Evaluation of epidemiologic studies in assessing long- term effects of occupational noxious agents. Scandinavian journal of work, environment & health, 6: 163-169 ( 1980). 30. Kusnetz, S. & Hutchison, M.K., ed. A guide to the work-relatedness of disease. Washington, DC, US Department of Health, Education, and Welfare, 1979 (Publication (NIOSH) 79-116). 31. Voigt, P. et al. [Noise-induced hearing loss in the building trades]. Stock- holm, Swedish Foundation for Occupational Safety and Health in the Construction Industry, 1976 (Publication No. BHF 1976:5) (Swedish). 26 32. Eggeling, F. Berufskrankheitenrisiken der 196 am hiiufigsten betroffenen Berufe. Dortmund, Bundesanstalt fi.ir Arbeitsschutz und Unfallfor- schung, 1980. 33. Spear, R.C. et al. Morbidity studies of workers exposed to whole body vibration . Archives of environmental health, 31: 141-145 (1976). 34. Spear, R.C. et al. Morbidity patterns among heavy equipment operators exposed to whole-body vibration. Washington , DC, US Department of Health, Education and Welfare, 1977 (Publication (NIOSH) 77-120). 35 . Fawer, R. Pathologie professionelle provoquee par Jes vibrations des marteaux-piqueurs et des perforatrices. Archives des maladies profes- sionelles, 37: 739- 760 ( I 976). 36. Wintzell, K.-A. [ Vibration-induced lesions in the upper extremities of construction workers]. Stockholm, Swedish Foundation for Occupa- tional Safety and Health in the Construction Industry, 1979 (Pub- lication No. BH F I 979: I) (Swedish, with English summary). 37 . Olsen, N. et al. Cold response of digital arteries in chain saw operators. British journal of industrial medicine. 39: 82-88 ( 1982). 38 . Wickstrom, G. et al. Restriction and pain during forward bending in concrete reinforcement workers . Scandinavian journal of work, en- vironment & health, 4(Suppl. I): 29-38 ( 1978). 39. Hiiublein, H.-G. Ober berufsbedingte Verschleisskrankheiten am Be- wegungsapparat. Zeitschriftfilr die gesamte Hygiene und ihre Grenzge- biete, 26: 443-446 ( 1980). 40. Wickstrom, G. et al. [Concrete reinforcement workers. Part 2: clinical investigation]. Helsinki, Institute of Occupational Health, 1975 (Pub- lication No. 98) (Finnish , with English summary). 41. Vaaranen, V. & Vasama, M. Occupational diseases in Finland in 1978- 1979. Helsinki , Institute of Occupational Health, 1980. 42. Hogberg, M. & Wahlberg, J.E. Health screening for occupational dermatoses in house painters . Contact dermatitis, 6: I 00-106 ( I 980). 43 . Kiihl, M. Zur Aufgabe der beruflichen Beschaftigung von Ekzem- kranken. Berufsdermatosen, 21 : 159-168 (1973). 44. Hellgren, L. Lichen ruber planus in occupational groups in total populations. Berufsdermatosen, 24: 71-78 ( 1976). 45 . Hane, M. & Hogstedt, C. [Subjective symptoms among occupational groups exposed to organic solvents). Liikartidningen, 77: 435-439 ( I 980) (Swedish, with English summary). 46. Elofsson, S.-A. et al. Exposure to organic solvents. Scandinavian jour- nal of work, environment & health, 6: 239-273 ( 1980). 47 . Cherry, N. & Waldron, H.A. Behavioural tests in human toxicology. In: McDonald, J .C., ed. Recent advances in occupational health. Edin- burgh, Churchill Livingstone, 1981 , pp. 141-147. 48. Fischbein, A. et al. Lead hazard among ironworkers . New York State journal of medicine, 78: 1250-1259 ( 1978). 27 49. WHO Technical Report Series, No. 647, 1980 (Recommended health- based limits in occupational exposure to heavy metals). 50. Frostrom, K. Results from an examination of 410 building workers exposed to asbestos dust. In: Abstracts, XIXth International Congress on Occupational Health, 1978, p. 563 . 51. Askergren, A. & Tollqvist, J. [Incidence of silicosis in the building and construction industry]. Liikartidningen, 77: 4781-4783 ( 1980) (Swedish, with English summary). 52. Sors, C. et al. Silicose pulmonaire chez des ouvriers du biitiment et des travaux publics . Archives des maladies professionelles, 33: 301-305 ( 1972). 53. Hodel, T. et al. Backstein- und Betonbohrersilikose. Schweizerische medizinische Wochenschrift, 107: 1896-1899 (1977). 54. Early detection of chronic lung diseases: report on a WHO Meeting. Copenhagen, WHO Regional Office for Europe, 1980 (EURO Reports and Studies, No. 24). 55. Engholm, G. et al. [Mortality and cancer incidence among painters. plumbers and insulators in the Swedish building trades]. Stockholm, Swedish Foundation for Occupational Safety and Health in the Con- struction Industry, 1977 (Publication No . BHF 1977:3) (Swedish). 56. Decooufle, P. et al. Causes of death among construction machinery operators. Journal of occupational medicine, 19: 123-128 ( 1977). 57. Wickstrom, G. & Kauppinen-Toropainen, K. [ Working conditions and health of building workers, questionnaire study]. Helsinki, Institute of Occupational Health, 1974 (Publication No. 91) (Finnish, with Eng- lish summary). 58 . Theorell, T. et al. Concrete work and myocardial infarction . Scan- dinavian journal of work, environment & health, 3: 144-153 (1977). 59. The training of managers and workers in the construction industry. Building, Civil Engineering and Public Works Committee, ninth ses- sion, report III. Geneva, International Labour Office, 1977. 60. WHO Technical Report Series, No. 663, 1981 (Education and training in occupational health, safety and ergonomics). 61. WHO Technical Report Series, No. 535, 1973 (Environmental and health monitoring in occupational health) . 62. Study on periodic health examination of workers exposed to industrial hazards. Copenhagen, WHO Regional Office for Europe, 1979 ( docu- ment ICP/ WKH 002). 28 1111111 11111 11111 11111 1111111111 11111 111!11111111 .. 0 0 0 0 0 5 0 0 ,.