Carcinogenic 'exposure circumstances' in IARC groups 1 and 2A were also covered ... agent is a group or otherwise unspecific, the definition may list the most.
Carex International Information System on Occupational Exposure to Carcinogens
OCCUPATIONAL EXPOSURE TO CARCINOGENS IN THE EUROPEAN UNION IN 1990-93 Timo Kauppinen, Jouni Toikkanen, David Pedersen, Randy Young, Manolis Kogevinas, Wolfgang Ahrens, Paolo Boffetta, Johnni Hansen, Hans Kromhout, Jeronimo Maqueda Blasco, Dario Mirabelli, Victoria de la Orden-Rivera, Nils Plato, Brian Pannett, Anja Savela, Hendrik Veulemans and Raymond Vincent
Finnish Institute of Occupational Health, Helsinki 1998
MATERIAL AND METHODS
Overview of the assessment method and data included
Agents and occupational exposure Agents covered Characterisation of agents Definition of occupational exposure Period covered
8 8 9 9 9
Industry specific estimation procedure Characterisation of industry and labour force Estimation procedure Estimates of low confidence Estimates of low level of exposure Estimates of multiple exposure
10 10 10 11 11 12
Exposure measurements and descriptions Exposure measurements included Exposure by occupation and gender
13 13 13
Estimation procedure in different countries Reference countries The countries of the European Union
14 14 16
RESULTS The European Union Austria Belgium Denmark Finland France Germany Great Britain Greece Ireland Italy Luxembourg The Netherlands Portugal Spain
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20 20 20 21 21 21 21 21 22 22 22 22 22 23 23 23
Summary • 2
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Summary • 3
CAREX is an international information system on occupational exposure to known and suspected carcinogens. The CAREX (CARcinogen EXposure) database, constructed with support from the Europe Against Cancer program of the European Union (EU), provides selected exposure data and documented estimates of the number of exposed workers by country, carcinogen, and industry. CAREX includes data on 139 agents evaluated by the International Agency for Research on Cancer (all agents in Groups 1 and 2A, and selected agents in Group 2B), displayed across the 55 industrial classes of the United Nations system (ISIC Revision 2). The 1990-93 occupational exposure to these carcinogens was estimated for the fifteen countries of the EU in two phases. First, estimates were generated automatically by the CAREX system on the basis of national workforce data and exposure prevalence estimates from two reference countries (the United States and Finland) which had the most comprehensive data available on exposures to these agents. These estimates are adjusted for the economic structure (workforce distribution) of each country individually, but do not take into account country-specific exposure patterns which may deviate from those of the reference countries. For selected countries, these estimates were then refined by national experts in view of similarity/dissimilarity to the perceived exposure patterns in their own countries. According to the results, there were about 32 million workers (23 % of the employed) in the 15 countries of the EU exposed to the IARC agents covered by CAREX in 1990-93. The estimated numbers of exposed workers by country were: Austria 800 000, Belgium 700 000, Denmark 700 000, Finland 500 000, France 4.9 million, Germany 8.2 million, Great Britain 5.0 million, Greece 900 000, Ireland 300 000, Italy 4.2 million, Luxembourg 50 000, the Netherlands 1.1 million, Portugal 1.0 million, Spain 3.1 million, and Sweden 800 000. These workers had altogether about 42 million exposures (1.3 exposures/exposed worker on average). The most common exposures were solar radiation (9.1 million workers exposed at least 75% of working time), environmental tobacco smoke (7.5 million workers exposed at least 75% of working time), crystalline silica (3.2 million exposed), diesel exhaust (3.1 million), radon (2.7 million), wood dust (2.6 million), lead and inorganic lead compounds (1.5 million), and benzene (1.4 million). The numbers of workers exposed to known or suspected carcinogens generated by the CAREX system and the network of national experts are the first estimates published for the EU and most of the member countries. These estimates should be considered preliminary, because many of them do not yet accurately account for specific national exposure patterns. Continuation of the estimation work by the CAREX network of experts would probably increase the validity of national estimates as the basic information needed to create and implement effective policies intended to control and eliminate occupational cancer in Europe.
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Summary • 4
The 'Europe Against Cancer' program of the European Union (EU) prompted a project on the estimation of the burden of occupational cancer in Europe, which includes a component on occupational exposure to carcinogens. This substudy is aimed at estimating the number of workers exposed to major known and suspected carcinogens in the EU by specific carcinogen, country and industry. The review of available literature, including the Monographs of the International Agency for Research on Cancer (IARC), indicated that direct estimates on numbers of exposed workers were usually not available. Therefore, it was obvious that most of the estimates would have to be derived indirectly by professional judgement, on the basis of available published and unpublished information on workers exposed to carcinogens. An international group of experts on carcinogen exposure was summoned to a meeting to plan the estimation procedure. After the initial meeting, a first version of exposure information system called CAREX (from Carcinogen Exposure) was constructed by the Finnish Institute of Occupational Health (FIOH) to support the estimation process. CAREX was tested and further developed in another meeting of experts. Because knowledge on national exposures is essential in the estimation process, additional experts from different countries were identified and called to participate to the project. The following scientists have contributed significantly to the planning, system design, data collection or assessment of exposure in the CAREX system:
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Dr Manolis Kogevinas
leader of the project, planning
Dr Timo Kauppinen
coordinator, planning, assessment
Mr Jouni Toikkanen
planning, system design
Dr David Pedersen
planning, US data, conversions
Mr Randy Young
US data , computing
Ms Anja Savela
Finnish data, computing
Dr Hans Kromhout
Dr Jeronimo Maqueda Blasco
Dr Victoria de la Orden-Rivera
Dr Wolfgang Ahrens
Dr Dario Mirabelli
Introduction • 5
Mr Raymond Vincent
Dr Nils Plato
Mr Brian Pannett
Dr Johnni Hansen
Dr Hendrik Veulemans
Dr Paolo Boffetta
Contact information of the participants is presented in the end of this report (Appendix 51). This report describes the adopted methodology of the assessment and presents the European results. A corresponding report will be prepared also for each member country of the EU. Only a small part of the CAREX documentation (which includes definitions, subindustrial estimates, descriptive information, results of exposure measurements, labour force data, and bibliographic references) could be included in this reports. A diskette copy of CAREX is available from FIOH upon request. It is planned to make the CAREX data available also on the Internet. This project was partially financed by the EU from the 'Europe Against Cancer' program.
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Introduction • 6
Material and methods
Overview of the assessment method and data included The assessment procedure included several main phases which are described in more detail in the following sections: - definition of agents and occupational exposure - definition of industries and collection of labour force data - collection of exposure measurement data and descriptive exposure data - generation of default estimates of exposures by the CAREX system - generation of final estimates of exposures by national experts - estimation of multiple exposures The majority of agents were assessed according to a detailed industry-specific ('long') procedure which involves stratification by industry. The assessment of a few agents followed a country-specific ('short') procedure which provides only one figure of the exposed workers per country. For example, some medical treatments were assessed according to this procedure. Carcinogenic 'exposure circumstances' evaluated by IARC were only briefly described. For example, 'occupational exposure as a painter' was described by providing the number of painters in the country supplemented by descriptive information. No assessment was appropriate or feasible for some of the agents (betel quid, some viruses, salted fish, etc) exposure to which is not primarily occupational. They were included in the database but the number of occupationally exposed workers was assumed to be zero or unknown. Only results from the industryspecific estimations are presented in this report because data from other procedures was very incomplete. To support the estimation and to document the basis for estimates, a CAREX exposure information system was designed and constructed. It is based on the Microsoft Access 2 database which can be run on personal computers. Summarised results of published and unpublished exposure measurements and descriptions of exposure were entered in CAREX to facilitate the assessment of levels of exposure in different industries and jobs. Our preference was to use original national estimates on carcinogenic exposures, but their poor availability forced us to adopt an approach where most figures were derived indirectly on the basis of information from two reference countries with reasonably comprehensive data (Finland and the United States). The calculation of these first estimates started from direct exposure data
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Material and methods • 7
retrieved from the Finnish SUTKEA (Anttila et al 1992), FINJEM (Kauppinen et al, in press) and ASA databases (Kauppinen et al 1990), and from US NOES database (Greife et al 1995, Seta et al 1988, Sieber 1990). After conversion of the Finnish and US industrial classifications to ISIC Rev 2 of UN (1968) format, the numbers of workers exposed to agents under study were listed by industry. The absolute figures were converted to exposure frequencies (prevalences) by dividing them by the employed labour force of the industry concerned. The prevalence considered to be most valid, which was often the mean of the US and Finnish prevalences, was then multiplied by the the number of employed in the industry of the country to be assessed. The resulting estimate generated by the CAREX system was used as the first (preliminary) estimate of the numbers of the exposed workers. The first estimates were not directly valid for other countries because the industrial substructure, use pattern of agents, and temporal factors may differ significantly across countries. Therefore: 1) National experts refined the first estimates and documented in the database their changes. This resulted in 'final' estimates. 2) National data were then collected and cumulated in the CAREX information system for reporting. The degree of multiple exposure to agents covered is needed when data are summed to obtain the total number of the exposed workers in an industry or in a country. Multiple exposure to agents was estimated in Finland and calculated Finnish values were applied also to other countries unless individual national experts modified them.
Agents and occupational exposure Agents covered The selection of agents was carried out by the project group in its first meeting in March 1995. CAREX includes all agents, groups of agents and mixtures which the International Agency for Research on Cancer (IARC) had classified to group 1 (carcinogenic to humans) and group 2A (probably carcinogenic to humans) as of February 1995. Selected agents from group 2B (possibly carcinogenic to humans) were also included. In addition, ionising radiation was included because, although not evaluated by IARC, there is sufficient evidence of its carcinogenicity to humans. Appendix 3 of this report lists the agents which were assessed according to the industry-specific procedure. Some of the group 1 or 2A agents are chemically polycyclic aromatic hydrocarbons (PAHs) or their mixtures, and they were merged under that title. PAHs include coal-tar pitches, coal-tars, untreated and mildly-treated mineral oils, shale-oils, soots and creosotes, as well as benzo(a)pyrene and other probably carcinogenic PAH-compounds. The reason for this regrouping is that PAHs almost always occur in occupational setting as complex mixtures and exposure to a single PAH is impossible to distinguish. However, tobacco smoke (passive exposure at work) and diesel exhaust, while recognised also as complex mixtures containing PAHs, were assessed separately. Carcinogenic 'exposure circumstances' in IARC groups 1 and 2A were also covered but only at national levels by providing a single estimate of workers, if available.
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Material and methods • 8
Characterisation of agents The agents were described in CAREX by: - IARC name - abbreviated name - 2-4 letter code - commonly used synonyms - Chemical Abstracts System (CAS) number - IARC evaluation group: - main occurrence: - unit in which the measurement results of CAREX were provided - Occupational exposure limits (from ECDIN database) - estimation procedure used in CAREX
Definition of occupational exposure The definition of exposure provides the relevant routes of exposure (inhalatory, dermal or both of them) and the nonoccupational background level, which is used as the minimum criterion of occupational exposure. If the background level is assumed to be negligible, it is not reported numerically. If a CAREX agent is a group or otherwise unspecific, the definition may list the most common agents included. The definition may also note inclusions or exclusions of 'borderline' exposures and national deviations from the general definition.
Period covered The CAREX estimations cover the early 1990s, and available workforce statistics during the construction of CAREX. The mean workforce by industry was calculated for the years 1990-93 and the national assessors were advised to address the average exposure situation during these years.
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Material and methods • 9
Industry specific estimation procedure Characterisation of industry and labour force The numbers of exposures in CAREX were estimated mainly for industrial classes (CAREX industries) at the 3-digit level of United Nations ISIC Revision 2 (1968). For some non-manufacturing sectors, 1- or 2-digit levels were used as the assessment level. Labour force information was necessary for the estimation of exposed workers The number of employed persons used in the calculation was the mean number of employed in 1990-93. As far as possible, we tried to include all employed in the industry covering salaried workers, self-employed, working family members and part-time workers. However, labour force information in the EU countries was heterogeneous and incomplete. The major source of labour force data was Organisation for Economic Cooperation and Development (OECD) which has collected industrial structure and workforce statistics uniformly according to the ISIC Rev 2 classification since the late 1960s. The manufacturing industry and mining are divided up into 76 sectors at the 3-digit level. Selected industries data are also at the 4-digit level, if available. Non-manufacturing sectors are reported only at the 1-digit level in the OECD statistics which was not accurate enough for the CAREX purposes. Therefore, workforce data by Nomenclature Général des Activités Economiques dans les Communautés Européennes (NACE) Revision 1 (1993) of EUROSTAT, which are available at the 2-digit level (60 classes) and available national statistics were also used to derive the 1- or 2-digit level workforce figures needed for the non-industrial ISIC-sectors of CAREX. National experts surveyed, corrected, and completed data from various sources available to them. Selected information on the distribution of labour force by gender and crude occupational group (professional, administrative, clerical etc) in 1-digit industrial classes from ILO statistics was also provided for each country to help for the estimation process. The percentages of clerical/administrative workers by 3-digit industrial class were available for several countries, and Finnish and UK data were included in CAREX.
Estimation procedure CAREX includes internal routines which calculated some guiding figures on the basis of the labour force structure of the country and exposure prevalences in the reference countries. CAREX provided the national assessors several figures to choose from: 1) a figure based on exposure prevalence in Finland (FIN) 2) a figure based on exposure prevalence in the United States (USA) 3) a figure based on the mean prevalence of Finland and the United States (AVERAGE) 4) own national estimate (OWN), designated by the national assessor 5) the number of exposed is zero (ZERO) One of the values was set as DEFAULT VALUE. The logic in the selection of default value was that the AVERAGE value was preferred. If either the Finnish or the US value was flagged with a warning (indicating low validity), the other
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Material and methods • 10
was proposed as the default value. Beacause the US NOES Survey did not cover all agents included in CAREX, the Finnish value was proposed if the US value was missing. If both Finnish and US values were flagged, the AVERAGE value was used as the default value because most often the US prevalence was suspected to be too high and the Finnish value too low. The following table summarises the default values in CAREX: FINNISH VALUE no flag flagged zero US
Estimates of low confidence The confidence of many estimates in the reference countries was considered low. In Finland, the following criteria to flag estimates of low confidence were used (intuitively): 1) The order of magnitude of the estimate may be wrong. This concerns mainly low figures. 2) The absolute error may exceed 0.1% of the national workforce (about 2000 exposed workers in Finland). This concerns mainly high figures. The premises for the US low confidence flags were different. By general survey/statistical design, NOES was intended to produce 'defensible estimates' of the number of workers exposed to specific agents at the 2-digit US SIC level. According to the Standard Error Tables, any NOES estimate of less than 8000 exposed workers is associated with a standard error of 25% or more. Therefore all such subindustrial estimates were marked as 'low confidence'. This resulted in earmarking a majority of US subindustrial estimates in CAREX which included exposure information at the 4-digit SIC level.
Estimates of low level of exposure If the level of exposure was considered to be close to background, the estimate was marked as such. In Finland, the nonoccupational annual dose was used as a guideline. However, the background exposure may vary quite a lot and is often subjective. Many low exposures in Finnish data involved handling of small amounts of carcinogens in laboratories, pharmacies or hospitals. Volatility, dustiness and, in some cases, skin contact were used as criteria to make the decision of existence or lack of occupational exposure. The premises for the US low level flags were different. NOES did not classify exposures by level and therefore 'low exposures' could not be systematically identified. The Finnish estimates which were judged to be close to the background level were used as one basis to mark NOES estimates. However, no NOES data were discarded on this basis which resulted in tagging of some exposures in laboratories as 'low level' in the USA when similar exposures were not considered to entail exposure (exceeding the background level) in Finland. Similarly, exposure to many impurities in polymeric materials and metal alloys were considered as 'low exposure' in the USA and as being below the minimum criterion of exposure in Finland. Another criterion to assign a 'low exposure' flag to NOES data was discrepancy with the Finnish data without an evident reason. For example, if there were over 10 000 exposed workers in a CAREX
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Material and methods • 11
industry in NOES and none in Finland, it was assumed that most of the US exposures were of low level. In addition, some very small figures were considered to reflect low exposure.
Estimates of multiple exposure If one worker is exposed to two agents, the number of exposed workers is one, but the number of exposures is two. The concept 'exposure' does not refer to the number of exposure events (eg 5 times/year) but to the qualitative occurrence of exposure of a worker. The reason for distinguishing between exposure and exposed worker relates to the calculation of exposed workers in a CAREX-industry, or in a country. If we add up all exposures within an industry, we may be counting the same workers several times (in cases of multiple exposure) and end up with an overestimate. The CAREX estimation procedure addresses exposures (number of workers exposed to a specified agent). The number of exposures and that of the exposed workers is the same if there is only one carcinogenic exposure/worker within the CAREX-industry. The estimation of exposed workers in multiple exposure situation required the development of industry-specific factors (multipliers), which convert the numbers of exposures to those of the exposed workers. These 'multiple exposure factor' were derived in CAREX for the Finnish data only. They are based on the assessment of additivity of exposed subgroups. The US NOES data did not us allow to derive multiple exposure factors by CAREX industry. The approach where primarily exposures are estimated can also be defended by arguing that under the assumption of independent effect of the agents, the number of cases of cancers caused by them depends on the number of exposures, not on the number of exposed workers. However, because of 'multiple exposure factors' CAREX is able to provide estimates to both exposures and exposed workers. The numbers of exposures and those of the exposed workers are equal (except the sum of all agents) in tables where data are shown by agent (eg, Appendix 3).
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Material and methods • 12
Exposure measurements and descriptions Exposure measurements included In order to identify worker groups at high risk, information on the level of exposure is important. A valid estimation of the level would require that the levels (eg, high and low) are accurately defined and enough knowledge on exposure circumstances from different countries are available. Industrial hygienic data are available for many agents but their representativeness and generalisation across countries are debatable. It was considered too laborious and uncertain to estimate exposures by level in each of the countries. However, CAREX includes agent- and industry-specific measurement data to enable the user of the database to make his/her own estimations and conclusions on the levels. The descriptions of measurements also show illustrative examples of work tasks and operations where exposure may occur. The industrial hygienic measurement sets are characterised by: - country where measurements were carried out - year(s) of measurements - range of concentrations in standard units - mean concentrations in standard units - number of measurements on which the mean is based - bibliographic reference - brief description of the measurement site, process, representativeness etc The measurement data was limited to data easily available from published or unpublished sources. In Finland, over 1 000 measurement sets were entered. Data were available for arsenic, asbestos, benzene, cadmium, chromium VI, diesel engine exhaust (measured as nitrogen dioxide), formaldehyde, glasswool, methylenechloride, nickel compounds, PAHs, lead, perchloroethylene, silica, styrene and wood dust. Most of the measurements are from Finland but also the IARC Monographs were used as sources of information.
Exposure by occupation and gender CAREX includes some information about carcinogenic exposures by occupation and gender at the national level. The countries of the European Union have adopted the ISCO 88 (COM) classification of occupations. The workforce data are available at the 3-digit level, but EUROSTAT has emphasised that comparability of figures across countries is poor because of non uniform definitions and data collection practises. Therefore, occupation was not used as a basic variable in CAREX. Instead, descriptive information of the distribution of exposures by occupation was provided for the reference countries (Finland and the United States). These data do not allow systematic calculation of exposure prevalences by occupation, but help to identify the occupations at potential risk. Detailed workforce statistics of OECD were not separately available for men and women (except for some countries). Gender could therefore not be used as a basic variable in CAREX. The reference countries had some exposure information available for men and women separately and descriptive information was included in CAREX.
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Material and methods • 13
Estimation procedure in different countries Reference countries Finland Finnish estimates were generated and documented as accurately as possible at subindustrial level. The major source of Finnish data were the reports of a comprehensive estimation survey (SUTKEA project) carried out by industrial hygienists of the Finnish Institute of Occupational Health (FIOH) in the late 1980s and early 1990s. SUTKEA summarised the exposure data and experience of FIOH on the situation in Finland. It was not a systematic field survey but was based on industrial hygienic data collected for separate research projects, or for compliance testing. Much of the exposure data collected for SUTKEA is included in CAREX as background data to indicate crudely the level of exposure in different work tasks. Because the measurements were partially carried out for compliance testing purposes, they can not be generalised directly to all exposed workers in addressed industries. The numbers of exposed workers are estimates generated by individual Finnish experts responsible for the SUTKEA reports. Another basic source of information was the national register of workers exposed to carcinogens (ASA Register) kept by FIOH since 1979. ASA data are based on empoyers' annual notifications on exposed workers and use of carcinogens. The ASA notifications are obligatory and they cover all salaried workers in Finland. However, the coverage of ASA is incomplete for many carcinogenic exposures, because occasional low level exposures are often not reported, and there are also employers who are not aware of exposures or who neglect the notification duty. ASA estimates, subjectively adjusted for incompleteness, were used in CAREX when SUTKEA did not provide an estimate of exposed workers. If neither SUTKEA nor ASA provided estimates, other available sources were used as the basis of estimation. CONCEPT OF EXPOSURE: The basic criterion for assigning occupational exposure in Finland was that the annual exposure dose at work exceeded the nonoccupational dose. This was also the proposed criterion used to assess exposure in other countries in CAREX. If the dose due to occupational exposure was close to the background level and it was unclear if exposure was compatible with the definition of exposure, decisions on inclusion and exclusion were made. These decisions were documented in the CAREX system. WARNING FLAGS: One weakness of Finnish estimation procedure was that it was not based on a systematic survey and it may have discarded many small groups of exposed workers, especially when exposure was infrequent or at a low level. If omission of small groups was suspected, a warning flag (red question mark in the CAREX application) was attached to all estimates proposed by CAREX for other countries. On the other hand, this estimation procedure is able to pick up some exposures which may have been missed by a sample-based field survey. A warning flag was used also to indicate that exposure may occur in other countries although it does not exist in Finland because there is no such industry (eg, coal mining, oil drilling) or activity (manufacture of carcinogen X) at all in Finland. The person reponsible for the Finnish data and estimates was Dr Timo Kauppinen (FIOH, Helsinki) who collaborated with many Finnish industrial hygienists and other experts.
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Material and methods • 14
The United States The National Occupational Exposure Survey (NOES) conducted by the US National Institute for Occupational Safety and Health (NIOSH) was a nationwide observational survey conducted in a sample of 4,490 establishments from 1981-83. The goal of the NOES was to compile data on the kinds of exposure agents found in the workplace, and the kinds of safety and health programs which had been implemented at the plant level. The sample of establishments included in the survey was designed to represent those segments of industry covered under the Occupational Safety and Health Act of 1970. The target population was defined as employees working in establishments or job sites in the US employing eight or more workers in a defined list of Standard Industrial Classifications. Generally, these classifications emphasized coverage of construction (USSIC1972 classes 15-17), manufacturing (20-39), transportation (40-47), private and business service (72-76), and hospital industries (80). The NOES had little or no sampling activity in agriculture, mining, wholesale/retail trade, finance/real estate, or government operations. The NOES sample was designed to maximize the reliability of estimates of the number of workers with defined characteristics, and utilized a two-stage sampling strategy which considered industrial activity, facility employment size, and geographical location. National estimates of the numbers of workers were obtained through the use of weighting factors assigned to sampled establishments, based on the probability of their selection from the national universe. The inverse of the sampling probability was then used as a weighting factor for facility-level observations, the results were subjected to ratio estimation to improve estimate precision, and then summed across sampled facilities nationally and by industry classification for final estimates. The computerized NOES data file of approximately 10,000 chemical, physical, and biological agents was searched for the CAREX agents. Where the designated agent was not a single unique agent (eg, cadmium compounds) the appropriate IARC Monograph was searched for listings of individual agents by CAS number, and these CAS numbers were used to identify agents in the NOES data base for an 'aggregate estimate'. In the case of unique agents, an estimate of the number of US workers potentially exposed to the agent in question was produced for the US as a whole, and for all industry classifications at the 2-, 3-, and 4-digit US Standard Industrial Classification (SIC) levels in the NOES sample frame. In the case of an aggregate estimate, special computer processing allowed the production of estimates of the number of workers estimated to be potentially exposed to one or more of the agents in a nonunique or 'aggregated' list, again for the US as a whole, and for those industries at the 2-, 3-, and 4-digit SIC levels in the NOES sample frame. NOES potential exposure data displayed in the CAREX system is limited to those industries which were sampled and surveyed in the NOES. The NOES did not provide for a sample in facilities employing less than 8 workers, or for activity in agriculture, mining, lerge portions of wholesale/retail trade, finance/real estate, or government operations. In order to utilize the NOES data in the CAREX system, it was necessary to convert the US 1987 SIC codes to the ISIC Rev2 system common outside the US. To accomplish this, a conversion table was established and used to convert from one coding system to the other so that data on the number of workers by industry estimated to be potentially exposed to carcinogens could be expressed in US SIC 1987, ISIC Rev2 notation, or ISIC Rev3 code, as desired. NOES data did not include environmental level measurements, with the exception of noise level readings. MISSING NOES DATA: Because the NOES Survey did not cover all agents and industries in CAREX, first estimates based on NOES data could not be
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Material and methods • 15
generated for uncovered CAREX agents or for uncovered or incompletely covered industries. If NOES covered a CAREX industry only partially, the number of exposed persons in the covered part of that industry was presented in the database (in Subgroup Exposure fields) but prevalence was not calculated because it was potentially invalid. CONCEPT OF EXPOSURE: NOES addressed recordable potential exposure. A potential exposure had to meet two criteria to be recorded: (1) A chemical, physical or biological agent or a tradename product had to be observed in sufficient proximity to an employee such that one or more physical phases of that agent or product were likely to enter or contact the body of the employee, and (2) The duration of the potential exposure had to meet the minimum duration guidelines (at least 30 minutes/week on an annual average, or at least once per week for 90% of the weeks of the work year). The following types of potential exposure were encountered: (1) Observed potential exposure: any potential exposure to chemical, physical, or biological agents observed directly by the surveyor. (2) Inferred potential exposure: If there is an observable dust accumulation or other physical evidence in the workplace which indicates that an agent is present in the workplace and if there are persons working in the immediate area of the agent and the minimum duration guidelines were met, or secondly, if the process is not functioning at the time of the surveyor's observation, the surveyor must, through questioning, identify and record any potential exposures which in his/her judgement, are associated with the functioning process. For tradename products, the potential exposure was assigned to all components of the product. Approximately 80% of the exposures in NOES are due to the presence of agents in the tradename formulations, and about 80% of all NOES exposures are part-time in duration. WARNING FLAGS: Because NOES data addressed potential (including very small) exposures, from 1981 to 1983, and did not cover all industries and agents in CAREX, it was considered reasonable to warn the users about applying US prevalence figures too directly to other countries. These flags are readable under the red question marks in the CAREX application. Selected Finnish estimates were also flagged with similar warnings. The NOES survey included data about part-time (or occasional) exposures and small groups of potentially exposed workers which were often discarded in Finnish estimates (resulting in a warning flag to some Finnish estimates). The NOES estimates were provided for the CAREX system by Dr David Pedersen and Mr Randy Young (NIOSH, Cincinnati, OH).
The countries of the European Union Austria The Austrian estimates are default (preliminary) estimates generated by the CAREX system and not modified by a national expert. These estimates are adjusted for the economic structure/workforce distribution of Austria, but they do not take into account country-specific exposure patterns, which may deviate in Austria from those in the reference countries. Belgium The Belgian estimates are default (preliminary) estimates generated by the CAREX system. The Belgian contact person in the CAREX network was Dr Hendrik Veulemans (University of Louvain, Leuven). Denmark The Danish estimates were provided by Dr Johnni Hansen (Danish Cancer Society, Copenhagen). The Danish estimates are based on 1) nationawide
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surveys on industrial use of carcinogens and potential carcinogens in 1983-85 (Hansen 1992) and 1992 (Bjersing et al 1992), 2) a sample-based survey on the use of organic solvents in 1000 companies in 1984 (Seedorf and Olsen 1990, Olsen, Seedorf and Laursen 1988), 3) a survey in 10% of all companies in the wood and furniture industry in 1988 (Borglum, Damgaard and Nielsen 1989), and 4) a sample-based survey including 1500 companies in 1989 (Brandorf et al 1994, Brandorf et al 1995). The default estimates generated by the CAREX system were replaced by estimates based on Danish surveys (mainly the survey in 1989), if available. However, since a Danish classification of industries was used in the 1989 survey, supporting results from other surveys using the same classification as CAREX were used to complement information on the numbers of exposed workers. The figures were usually as rounded to one or two integers. It was also checked if agents not reported to occur in specific industries of the reference countries were actually used in Denmark. If no appropriate estimates were available from the Danish surveys, the default estimates of the CAREX system were used, unless they were considered invalid for Denmark on the basis of subjective judgement. The Danish surveys did not include all CAREX agents, e.g. solar radiation, radon, diesel exhaust, wood dust outside the wood and furniture industries, and sulphuric acid mists. France The French estimates were provided by Mr Raymond Vincent (INRS, Nancy) with the contribution from many of his collegues. Several data sources were used: -the SUMER survey (Heran Le Roy and Sandret 1996) conducted in1994 by the French ministry of labour, -the INRS COLCHIC national occupational exposure measurements database , -employment and economic statistics issued from the Ministry of trade and industry or INSEE ( national statistical institute). The SUMER study was conducted in 1994 by the French Ministry of labour. It concerned 48190 workers who were asked by 1205 occupational physicians about their working conditions and chemical hazards at their workplaces. A large part of chemical substances included in CAREX was assessed during this survey. After obtaining these results, estimations were made by industry and company size. The results of the SUMER study were used for industry-specific estimates of CAREX. They are documented in the CAREX database with the following remarks: -'results of the SUMER study' means that SUMER results were directly used in the estimation resulting in good confidence of estimates -'assessor's estimate based on results of the SUMER study' means that estimates were based on results having low confidence, or on results having good confidence but requiring some corrections. For example, the SUMER survey provided a good estimate for a group of agents (eg, halogenated solvents) but not for the CAREX substance itself. In this case, estimates were obtained by using economic statistics or substance-specific production rates. -'assessor's estimate' means that SUMER results of low confidence were used. In some situations, this remark means that no data were available from the SUMER study. In these cases, the estimates are based on knowledge of different INRS experts, or on crude estimates issued from the reference countries. If the estimate had to be based on the prevalence of exposure in the reference countries, the estimate (Finnish, US or their average) judged to be most valid for France was selected.
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Material and methods • 17
The exposure measurements in the COLCHIC database of the INRS indicated in some situations exposure in certain industries even though there were no estimates available from the SUMER survey. In those cases the estimate is based on crude professional judgement. Selected exposure measurements from COLCHIC database are included in CAREX. Germany The German estimates are default (preliminary) estimates generated by the CAREX system. The German contact person in the CAREX network was Dr Wolfgang Ahrens (Institute of Medical Information, Essen). Great Britain The UK estimates are default (preliminary) estimates generated by the CAREX system. The British contact person in the CAREX network was Mr Brian Pannett (Medical Research Council, Environmental Epidemiology Unit, Southampton). Greece The Greek estimates are default (preliminary) estimates generated by the CAREX system. The contact person for Greece in the CAREX network was Dr Manolis Kogevinas (IMIM, Barcelona, Spain). Ireland The Irish estimates are default (preliminary) estimates generated by the CAREX system. Italy The Italian estimates were first generated by the CAREX system and then modified by a national expert (Dr Dario Mirabelli, Agenzia per la Protezione Ambientale del Piemonte, Grucliasco). They take into account exposure patterns in Italy to the extent the expert was able to identify them. In the absence of a general reporting system on occupational exposure to carcinogens in Italy, and due to lack of countrywide as well as regional surveys, the assessor based his judgements either on the evaluations received from a group of Italian industrial hygienists who revised the occupational exposure patterns of the CAREX agents during the development of an industrial activity/exposure matrix within the framework of the PRiOR programme (an occupational hazards surveillance programme in 1996-97 in Piedmont region), or on his own experiance in the surveillance of occupational exposures as a member of an Occupational Health and Safety Unit in an industrialised area close to Turin. Luxembourg The Luxembourgian estimates are default (preliminary) estimates generated by the CAREX system. The Netherlands The Dutch estimates were first generated by the CAREX system and then checked by a national expert (Dr Hans Kronhout, Wageningen Agricultural University, Wageningen). They take into account exposure patterns in the Netherlands to the extent the expert was able to identify them. As a data source the WAUNC database with approximately 20,000 chemical exposure measurements was used. Input from collegues was used to some extent. Unpublished data from the Ministry of Social Affairs and Employment on the occurrence of exposure to carcinogens by industry and process was also taken into account. Portugal
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Material and methods • 18
The Portugese estimates are default (preliminary) estimates generated by the CAREX system. Spain The Spanish estimates are default (preliminary) estimates generated by the CAREX system. The Spanish contact persons in the CAREX network were Dr Jeronimo Maqueda Blasco and Dr Victoria de la Orden-Rivera (Instituto Nacional de Seguridad e Higiene en el Trabajo, Madrid). Sweden The Swedish estimates are default (preliminary) estimates generated by the CAREX system and not checked by a national expert. Alternative estimates were produced on the basis of the Swedish national report on exposure to carcinogens (Plato, Nise, Lundberg 1995). Because the definitions and estimation procedures were different from the CAREX system, the alternative Swedish estimates are reported separately. The Swedish contact person in the CAREX network was Dr Nils Plato (Karolinska Institute, Stockholm). The alternative Swedish figures were estimated on the basis of occupational labour force figures, whereas CAREX used industrial labour force as the starting point. The differences of these procedures are illustrated in the following example on exposure to chromium (VI) in welding of stainless steel: Total number of welders in Sweden was 27 145 males and 1 003 females. The Swedish welding association estimated that 7% of welders work regularly with stainless steel which equals with 1 970 welders exposed to chromium VI. When industry code 381 (metal products) is linked with occupational code 756.12 (welders), there would be 9 356 welders in that industry and 655 welders exposed to chromium VI. The comparative CAREX estimates extrapolated to Sweden are 7 397 welders exposed to chromium VI, out of which 2 751 are employed in the metal product industry. The Swedish alternative figures are only 27% and 24% of the respective CAREX estimates. One important reason for the discrepancy is that CAREX estimates 20% of welders as regularly or temporarily exposed, and that also an equivalent number bystanders are considered exposed.
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Material and methods • 19
The detailed main results are presented in appendices of this report. The results for the EU are presented first, followed by figures for the individual EU countries in alphabetical order.
The European Union According to the results (Appendix 1), there were about 32 million workers (23 % of the employed) in the 15 countries of the EU exposed to the agents covered by CAREX in 1990-93. These workers had altogether about 42 million exposures (1.3 exposures/exposed worker on average). These figures are rounded from calculatory estimates presented in Appendix 1. Because of uncertainty of the estimates, it is reasonable to round all figures in the following appendices to a precision of one or two integers only. The numbers of exposed workers by country (Appendix 2) were: Austria 800 000, Belgium 700 000, Denmark 700 000, Finland 500 000, France 4.9 million, Germany 8.2 million, Great Britain 5.0 million, Greece 900 000, Ireland 300 000, Italy 4.2 million, Luxembourg 50 000, the Netherlands 1.1 million, Portugal 1.0 million, Spain 3.1 million, and Sweden 800 000. The total numbers of exposed workers by agent are presented in Appendix 3. The most common exposures in the EU countries (Appendix 4) were solar radiation (9.1 million workers exposed at least 75% of working time), environmental tobacco smoke (7.5 million workers exposed at least 75% of working time), crystalline silica (3.2 million exposed), diesel exhaust (3.1 million), radon (2.7 million), wood dust (2.6 million), lead and inorganic lead compounds (1.5 million), and benzene (1.4 million).
Austria According to the preliminary estimates, there were ca. 800 000 workers (25% of the employed) exposed to the agents covered by CAREX (Appendix 5). The most common exposures (Appendices 6-7) were solar radiation (240 000 workers exposed at least 75% of working time), environmental tobacco smoke (180 000 workers exposed at least 75% of working time), crystalline silica (100 000 exposed), wood dust (80 000), diesel engine exhaust (80 000), radon and its decay products (70 000), benzene (50 000), ethylene dibromide (50 000), lead and inorganic lead compounds (40 000) and glasswool (20 000).
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Results • 20
Belgium According to the preliminary estimates, there were ca. 700 000 workers (21% of the employed) exposed to the agents covered by CAREX (Appendix 8). The most common exposures (Appendices 9-10) were solar radiation (200 000 workers exposed at least 75% of working time), environmental tobacco smoke (190 000 workers exposed at least 75% of working time), radon and its decay products (90 000), crystalline silica (70 000 exposed), diesel engine exhaust (70 000), wood dust (55 000), lead and inorganic lead compounds (30 000), benzene (20 000), chromium VI compounds (19 000), and glasswool (19 000).
Denmark According to the results, there were ca. 700 000 workers (24% of the employed) exposed to the agents covered by CAREX (Appendix 11). The most common exposures (Appendices 12-13) were solar radiation (180 000 workers exposed at least 75% of working time), environmental tobacco smoke (100 000 workers exposed at least 75% of working time), formaldehyde (90 000 exposed), diesel engine exhaust (70 000), crystalline silica (60 000), wood dust (50 000), benzene (50 000), styrene (36 000), ethylene dibromide (26 000), and chromium VI compounds (25 000).
Finland The Finnish estimates are adjusted for the economic structure/workforce distribution of Finland, and they take also into account country-specific exposure patterns to the extent the experts were able to identify them. According to the estimates, there were in 1990-93 ca. 500 000 workers (24 % of the employed) exposed to the agents covered by CAREX (Appendix 14). The most common exposures (Appendices 15-16) were solar radiation (180 000 workers exposed at least 75% of working time), environmental tobacco smoke (110 000 workers exposed at least 75% of working time), crystalline silica (80 000 exposed), wood dust (65 000), radon (50 000), diesel engine exhaust (40 000), benzene (14 000), lead and inorganic lead compounds (13 000), ethylene dibromide (12 000), and glasswool (12 000).
France There were ca. 5 million workers (23 % of the employed) exposed to the agents covered by CAREX (Appendix 17). The most common exposures (Appendices 18-19) were solar radiation (1.5 million workers exposed at least 75% of working time), environmental tobacco smoke (1.2 million workers exposed at least 75% of working time), radon (500 000), diesel exhaust (400 000), sulphuric acid mist (400 000), formaldehyde (300 000), wood dust (180 000), tetrachloroethylene (140 000), asbestos (140 000), and lead and inorganic lead compounds (140 000).
Germany According to the preliminary estimates, there were ca. 8 million workers (24% of the employed) exposed to the agents covered by CAREX (Appendix 20). The most common exposures (Appendices 21-22) were solar radiation (2.4 million workers exposed at least 75% of working time), environmental tobacco smoke (2.0 million workers exposed at least 75% of working time), crystalline silica (1.0 million exposed), radon and its decay products (800 000), diesel engine exhaust (740 000), wood dust (670 000), benzene (470 000), lead and inorganic
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Results • 21
lead compounds (460 000), ethylene dibromide (450 000), chromium VI compounds (250 000), and glasswool (240 000).
Great Britain According to the preliminary estimates, there were ca. 5 million workers (22% of the employed) exposed to the agents covered by CAREX (Appendix 23). The most common exposures (Appendices 24-25) were environmental tobacco smoke (1.3 million workers exposed at least 75% of working time), solar radiation (1.3 million workers exposed at least 75% of working time), crystalline silica (600 000), radon and its decay products (600 000), diesel engine exhaust (470 000), wood dust (430 000), benzene (300 000), ethylene dibromide (280 000), lead and inorganic lead compounds (250 000), glasswool (140 000), and chromium VI compounds (130 000).
Greece According to the preliminary estimates, there were ca. 900 000 workers (27% of the employed) exposed to the agents covered by CAREX (Appendix 26). The most common exposures (Appendices 27-28) were solar radiation (460 000 workers exposed at least 75% of working time), environmental tobacco smoke (170 000 workers exposed at least 75% of working time), crystalline silica (90 000), diesel engine exhaust (80 000), radon and its decay products (70 000), wood dust (50 000), benzene (35 000), ethylene dibromide (33 000), lead and inorganic lead compounds (24 000), glasswool (17 000), and asbestos (15 000).
Ireland According to the preliminary estimates, there were ca. 260 000 workers (24% of the employed) exposed to the agents covered by CAREX (Appendix 29). The most common exposures (Appendices 30-31) were solar radiation (110 000 workers exposed at least 75% of working time), environmental tobacco smoke (58 000 workers exposed at least 75% of working time), crystalline silica (29 000), radon and its decay products (24 000), diesel engine exhaust (21 000), wood dust (18 000), benzene (11 000), ethylene dibromide (10 000), lead and inorganic lead compounds (9 000), glasswool (6 000), and asbestos (6 000).
Italy There were ca. 4.2 million workers (25 % of the employed) exposed to the agents covered by CAREX (Appendix 32). The most common exposures (Appendices 33-34) were environmental tobacco smoke (800 000 workers exposed at least 75% of working time), solar radiation (600 000 workers exposed at least 75% of working time), asbestos (700 000), diesel engine exhaust (600 000), PAHs (400 000), crystalline silica (300 000 exposed), wood dust (300 000), lead and inorganic lead compounds (300 000), benzene (200 000), formaldehyde (170 000) and tetrachloroethylene (180 000).
Luxembourg According to the preliminary estimates, there were ca. 50 000 workers (25% of the employed) exposed to the agents covered by CAREX (Appendix 35). The most common exposures (Appendices 36-37) were solar radiation (14 000 workers exposed at least 75% of working time), environmental tobacco smoke (11 000 workers exposed at least 75% of working time), crystalline silica
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Results • 22
(7 000), diesel engine exhaust (4 000), radon and its decay products (4 000), wood dust (4 000), lead and inorganic lead compounds (2 600), benzene (2 000), PAHs (1 700) and ethylene dibromide (1 700).
The Netherlands According to the results corrected by a national expert, there were ca. 1.1 million workers (17% of the employed) exposed to the agents covered by CAREX (Appendix 38). The most common exposures (Appendices 39-40) were environmental tobacco smoke (350 000 workers exposed at least 75% of working time), solar radiation (290 000 workers exposed at least 75% of working time), crystalline silica (170 000), diesel engine exhaust (110 000), wood dust (95 000), lead and inorganic lead compounds (48 000), benzene (43 000), glasswool (34 000), and chromium VI compounds (29 000).
Portugal According to the preliminary estimates, there were ca. one million workers (24% of the employed) exposed to the IARC agents covered by CAREX (Appendix 41). The most common exposures (Appendices 42-43) were solar radiation (370 000 workers exposed at least 75% of working time), environmental tobacco smoke (210 000 workers exposed at least 75% of working time), radon and its decay products (92 000), wood dust (85 000), crystalline silica (83 000), diesel engine exhaust (73 000), benzene (43 000), ethylene dibromide (40 000), formaldehyde (36 000), lead and inorganic lead compounds (33 000), PAHs (21 000) and tetrachloroethylene (21 000).
Spain According to the preliminary estimates, there were ca. 3.1 million workers (25% of the employed) exposed to the IARC agents covered by CAREX (Appendix 44). The most common exposures (Appendices 45-46) were solar radiation (1 100 000 workers exposed at least 75% of working time), environmental tobacco smoke (700 000 workers exposed at least 75% of working time), crystalline silica (400 000 exposed), wood dust (400 000), radon and its decay products (280 000), diesel engine exhaust (270 000), lead and inorganic lead compounds (100 000), glasswool (90 000), benzene (90 000), and ethylene dibromide (80 000).
Sweden According to the preliminary estimates, there were ca. 800 000 workers (20% of the employed) exposed to the IARC agents covered by CAREX (Appendix 47). The most common exposures (Appendices 48-49) were solar radiation (240 000 workers exposed at least 75% of working time), environmental tobacco smoke (210 000 workers exposed at least 75% of working time), radon and its decay products (100 000), crystalline silica (86 000), wood dust (84 000), diesel engine exhaust (81 000), lead and inorganic lead compounds (35 000), benzene (34 000), ethylene dibromide (31 000), chromium VI compounds (21 000), glasswool (20 000) and PAHs (18 000). The alternative estimates produced on the basis of the Swedish national report on exposure to carcinogens (Plato, Nise, Lundberg 1995) are presented in Appendix 50.
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Results • 23
The numbers of workers exposed to known or suspected carcinogens generated by the CAREX system and the network of national experts are the first estimates published for the EU and most of the member countries. In that respect this new approach turned out to be feasible and successful. The results suggest that the number of workers exposed to carcinogenic substances and factors was very large in 1990-93, and amounted to about 32 million workers, or about 23% of the total number of workers employed in the EU. The absolute figures varied strongly by country and the proportion of exposed workers varied between 17% and 27%, as estimated by the CAREX procedure. Substantial part of all exposures originated from natural sources (ultraviolet radiation from the sun, radon from the ground) or from activities not related to work as such (environmental tobacco smoke at work). The contribution of these environmental factors was 19-20 million exposures out of 42 million exposures. The strengths of the CAREX system are its systematic nature, good coverage and ease of use. CAREX applies basically the same definitions and procedures to each country, which improves comparability and consistency of the results across countries. It covers all industries in an international classification of industries and is able to provide national figures in addition to industry-specific estimates. Major known and suspected carcinogens occurring at work, as evaluated by IARC, are included. CAREX is easy to use in personal computers. It allows the addition of new countries, provided that reasonably accurate labour force statistics are available. CAREX automatically calculates preliminary estimates for a new country and produces a rather wide variety of standard reports. Validity of the estimates was extensively discussed during the planning and construction of CAREX, and several solutions to improve validity and facilitate the estimation process were adopted. First, all estimates were standardised by the labour force structure of the country. For manufacturing industries where exposure depends strongly on the type of industry, standardisation took place at the 3-digit level of the classification. Second, uniform definitions of agents and of occupational exposure, with inclusions and exclusions, were used to improve consistency. Third, preliminary estimates were in many countries checked and modified by national experts familiar with the exposure situation in their own country. Fourth, exposures in the reference countries were made at 'subindustrial' level where different subgroups of exposed workers could be defined, assessed and described. The same procedure was possible for each country assessed. Fifth, industrial hygiene data, description of industries and proportions of 'white-collar' and 'blue-collar' workers by industry were included to support estimation. The premises of the estimates were documented to facilitate their modification and quality assessment. Sixth, estimates of low confidence could be earmarked to identify them. Seventh, estimates entailing low level of exposure were earmarked to allow their inclusion or exclusion since
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Discussion • 24
low exposures may have a strong effect on the estimated numbers of exposed. Eight, 'warning flags' were build into CAREX to avoid the use of possibly invalid prevalence figures from the reference countries. The prevalence figures used by the CAREX system in the generation of preliminary estimates for other countries were selected to be the most valid ones on the basis of information from the reference countries. In spite of these precautions and aids included in the CAREX system, there are many validity issues which are of concern and require further discussion. The inspection of data from the reference countries revealed several differences between exposure estimates from Finnish and US sources. These differences include: (1) National industrial processes and related use patterns for carcinogens (2) national survey protocols (3) time frame, and (4) national industrial coding systems and conversion difficulties. These points are discussed separately below since they concern not only Finnish and US figures but also have consequences for estimates of other countries. (1) Country-specific exposure patterns Omission of country-specific exposure patterns may bias results seriously. One example is exposure to radon. Exposure to radon from the ground in Finland is higher than in most other EU countries. The ground emits significantly less radon, e.g., in Denmark and The Netherlands, and therefore regular indoor workers are hardly ever exposed to levels exceeding the Finnish average background level in dwellings. If Finnish prevalence values are used for other countries, the result may be an overestimate. Similar bias may concern crystalline silica, because Finnish stone and construction materials contain frequently silica from granite. A further example would be solar radiation. Direct use of Finnish prevalence figures (prevalence of regular outdoor workers) is likely to result in underestimation for countries in Southern Europe because there also many part-time outdoor workers will be exposed to similar doses due to more intense solar radiation. The industrial substructure may also differ significantly by country depending on the type of products or processes used. This concerns exposures especially in the chemical industry. Different legislation may lead to large variations between countries. For example, the use of asbestos in 1990-93 was legally prohibited or restricted in many countries, but not in all. The same applies to passive smoking at work. Sometimes the use pattern is regulated strongly by price policy. For example, exposure to ethylene dibromide (scavenger agent in leaded gasoline) decreased drastically in Finland in 1990-93 when unleaded gasoline substituted for more expensive leaded gasoline. Because the average prevalence of the USA and Finland (when not identified to be unreliable) was preferred in the CAREX procedure, the preliminary estimates inherently assume that the exposure pattern of the country is typically between that of a big country (such as the USA) and that of a smaller country (such as Finland). This assumption may be rather valid for big European countries (such as the UK, France, Germany, Italy and Spain) where a wide range of processes and exposures occur. However, the CAREX procedure probably provides many rare exposures which do not occur in small countries with less varying economic structure (such as Luxembourg). (2) Definition of occupational exposure It is notable that the concept of exposure used in the reference countries differ. The Finnish protocol required in most cases that the nonoccupational exposure measured as annual dose had to be exceeded whereas the US protocol addressed potential exposure. The Finnish approach sets the minimum limit generally higher than the US approach and results in lower estimates of exposed workers. The CAREX system compromises between these two concepts and usually
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Discussion • 25
applies the average of the US and Finnish prevalences to calculate preliminary estimates for other countries. This means that the concept of exposure in CAREX becomes unclear and is between potential exposure (as in the USA) and exposure exceeding nonoccupational background (as in Finland). In practise CAREX thus partially addresses exposures which are lower than the background. The national experts face the same problem while making their own estimates or choosing among estimates based on US, Finnish or their average figures. (3) Estimation procedures Another significant difference is that the US data is based on an observational field survey and the Finnish data on professional judgement. Both methods have their advantages and disadvantages. A field survey is sensitive in identifying typical and untypical exposures whereas professional judgement may neglect small exposed groups and atypical exposures. However, sometimes professional judgement may identify exposures which are missed in a comprehensive field survey. For example, the NOES sample did not include any nickel refineries and did not therefore identify nickel exposure in ISIC 372 (manufacture of other metals). The Finnish professional judgement identified nickel refineries and provided a more reliable estimate in this case. The US procedure provided empirical values for many rare agents but was unable to address all CAREX agents. Professional judgement in Finland was extented to cover all CAREX agents. The NOES procedure was based on direct observations and inferences at work places. The effect of subjective opinions on the results was probably rather small. However, inclusion or exclusion of very low or infrequent exposures may depend on the observer. The Finnish procedure based more on experience of the experts on occurrence and level of exposure in different industries, although industrial hygiene data and labour force data were also used to the extent possible. Another kind of procedural difference arose when the CAREX estimates were compared with alternative estimates from a Swedish national report. The alternative estimates differed significantly from those generated by the CAREX system. Major source of difference was the definition of agent-specific exposure, and the estimation of low levels of exposure. Generally, the alternative exposure prevalences were lower than those in the CAREX. For example, CAREX was able to take crudely into account exposures of bystanders employed in workshops where stainless steel was welded. This is an appropriate and feasible approach when one bases the calculations on industry codes (as in CAREX) but very difficult when assessment is carried out by occupations (as in the Swedish method). Therefore bystander exposures were neglected in the estimation of alternative Swedish figures. (4) Time frame The reference data from the United States comes from 1981-83. Exposure patterns may have changed after that in the United States and elsewhere. For example, the production or use of some agents may have been forbidden or strongly restricted since then. Although CAREX does not use clearly outdated US figures as default values, there probably are a number of them which could not be identified as outdated during the CAREX project. Therefore some of the resulting CAREX estimates may be biased by the US situation in the early 1980s when occupational exposure to carcinogens may have been more frequent than in 1990-93. The Finnish estimates are for the same period (1990-93) as those of other EU countries. (5) National industrial coding systems and conversion difficulties Conversions between different industrial coding systems were used in the processing of labour force statistics and US (NOES) exposure data. Major part
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of labour force statistics came from OECD directly in the UN ISIC Revision 2 coding system. However, the OECD data are not coded originally according to UN ISIC but according to national classifications which are then converted to UN ISIC. Conversions, different definitions of the employed populations included, and estimations of missing values caused some inaccuracy and incomparability to the labour force statistics used in CAREX. Also the US workforce figures and exposure data were converted from US SIC 1987 through UN ISIC Rev 3 to UN ISIC Rev 2. The concersion was carried out at maximal level of specificity to minimise conversion errors. In spite of conversion problems, the order of magnitude of the labour force figures is probably correct and not a major source of error. (6) Estimation of multiple exposures The CAREX system applied Finnish values to other EU countries in the estimation of the degree of multiple exposure. This resulted sometimes in estimates of exposed workers which exceeded the total labour force of the industrial class. In those cases applying the Finnish figure based on Finnish multiple exposure patterns was clearly inappropriate. National modifications of multiple exposure multipliers are therefore necessary, especially if the exposure pattern within the industrial class is likely to differ significantly from the Finnish one.
The validity of the CAREX results is so far unknown. Validity testing would require well-defined and comprehensive field surveys and mesurements because validity may vary quite a lot by agent, industry, and country. Such surveys would be very labourious and expensive. However, we believe that the CAREX procedure, especially when supplemented by assessment of national experts, has produced interesting estimates of at least moderate confidence. All estimates do not yet take accurately into account specific features of national exposure patterns. Continuation of the estimation work by the CAREX network of experts would probably increase the validity of national estimates as the basic information needed to create and implement effective policies intended to control and eliminate occupational cancer in Europe.
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Anttila A, Jaakkola J, Tossavainen A, Vainio H. Occupational exposure to chemical agents in Finland (In Finnish), Altisteet työssä 34, Työterveyslaitos ja työsuojelurahasto, Helsinki1992 Bjersing M, Hansen J, Schöller C, ThomsenP. Kraeftfremkaldende stoffer I Danmark. Forekomst, anvendelse og regulering af 240 stoffer, 1989. Kobenhavn: Arbejdsmiljoinsituttet 1992. Borglum B, Damgaard K, Nielsen S. Trae- og mobelindustrien. Tvaersnitsundersogelse - Kemiske stoffer og materialer. Kobenhavn: At-rapport 1989:1-31. Brandorf NP, Flyvholm MA, Beck ID, Skov T, Bach E. National survey on the use of chemicals in the working environment: estimated exposure events. Occup Environ Med 1995;52:454-63. Brandorf NP, Beck ID, Skov T, Flyvholm MA. Kemikalieforbruk og eksponering I danske virksomhedet 1989. Kemikalieforbruksundersogelsen. Kobenhavn: Arbejdsmiljoinstituttet 1994. Greife A, Young R, Carroll M, Sieber W, Pedersen D, Sundin D, Seta J. National Institute for Occupational Safety and Health general industry occupational exposure databases: their structure, capabilities, and limitations. Appl Occup Environ Hyg 1995;10:264-9. Hansen J. Industriel anvendelse af utvalgde kemiske stoffer og risiko for kraeft, 1979-84. Delrapport II. Udarbejdelse af en eksponeringsmatrice. Kobenhavn: Arbejdsmiljoinstituttet 1992:1-116. Heran Le Roy O, Sandret N. Enquête nationale SUMER 94, premiers résultats (National survey SUMER 94, preliminary results). Ministère du Travail et des Affaires Sociales, Paris 1996 Kauppinen T, Savela A, Vuorela R. ASA 1990 - employees exposed to carcinogens in Finland in 1990, reviews 18, Finnish Institute of Occupational Health, Helsinki 1992 Kauppinen T, Toikkanen J, Pukkala E. From cross-tabulations to multipurpose exposure information systems: a new job-exposure matrix. Am J Ind Med , in press Olsen E, Seedorf L, Laursen B. Organiske oplosningsmidler-kartlaegning af anvendelsen og forekomsten af dampe. Kobenhavn: Arbejdstilsynet 1988:1-101. Seedorf L, Olsen E. Exposure to organic solvents I. A survey on the use of solvents. Ann Occup Hyg 1990;34: 371-8.
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Seta J, Sundin D, Pedersen D. National Occupational Exposure Survey. Volume I. Survey manual. U.S. Department of Health and Human Services, National Institute for Occupational Safety and Health, Cincinnati 1988. Sieber W. National Occupational Exposure Survey. Volume II. Sampling methodology. U.S. Department of Health and Human Services, National Institute for Occupational Safety and Health, Cincinnati 1990.
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References • 29
1. Employment, exposed workers and exposures in the EU in 1990-1993 2. Exposed workers by country in the EU in 1990-93 3. Exposed workers (exposures) by agent in the EU in 1990-93 4. Most common exposures to IARC agents in the EU in 1990-1993 5. Employment, exposed workers and exposures in Austria in 1990-1993 6. Exposed workers (exposures) by agent in Austria in 1990-93 7. Most common exposures to IARC agents in Austria in 1990-1993 8. Employment, exposed workers and exposures in Belgium in 1990-1993 9. Exposed workers (exposures) by agent in Belgium in 1990-93 10. Most common exposures to IARC agents in Belgium in 1990-1993 11. Employment, exposed workers and exposures in Denmark in 1990-1993 12. Exposed workers (exposures) by agent in Denmark in 1990-93 13. Most common exposures to IARC agents in Denmark in 1990-1993 14. Employment, exposed workers and exposures in Finland in 1990-1993 15. Exposed workers (exposures) by agent in Finland in 1990-93 16. Most common exposures to IARC agents in Finland in 1990-1993 17. Employment, exposed workers and exposures in France in 1990-1993 18. Exposed workers (exposures) by agent in France in 1990-93 19. Most common exposures to IARC agents in France in 1990-1993 20. Employment, exposed workers and exposures in Germany in 1990-1993 21. Exposed workers (exposures) by agent in Germany in 1990-93 22. Most common exposures to IARC agents in Germany in 1990-1993 23. Employment, exposed workers and exposures in Great Britain in 1990-1993 24. Exposed workers (exposures) by agent in Great Britain in 1990-93 25. Most common exposures to IARC agents in Great Britain in 1990-1993 26. Employment, exposed workers and exposures in Greece in 1990-1993 27. Exposed workers (exposures) by agent in Greece in 1990-93 28. Most common exposures to IARC agents in Greece in 1990-1993 29. Employment, exposed workers and exposures in Ireland in 1990-1993 30. Exposed workers (exposures) by agent in Ireland in 1990-93 31. Most common exposures to IARC agents in Ireland in 1990-1993 32. Employment, exposed workers and exposures in Italy in 1990-1993
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33. Exposed workers (exposures) by agent in Italy in 1990-93 34. Most common exposures to IARC agents in Italy in 1990-1993 35. Employment, exposed workers and exposures in Luxembourg in 1990-1993 36. Exposed workers (exposures) by agent in Luxembourg in 1990-93 37. Most common exposures to IARC agents in Luxembourg in 1990-1993 38. Employment, exposed workers and exposures in the Netherlands in 1990-93 39. Exposed workers (exposures) by agent in the Netherlands in 1990-93 40. Most common exposures to IARC agents in the Netherlands in 1990-93 41. Employment, exposed workers and exposures in Portugal in 1990-1993 42. Exposed workers (exposures) by agent in Portugal in 1990-93 43. Most common exposures to IARC agents in Portugal in 1990-1993 44. Employment, exposed workers and exposures in Spain in 1990-1993 45. Exposed workers (exposures) by agent in Spain in 1990-93 46. Most common exposures to IARC agents in Spain in 1990-1993 47. Employment, exposed workers and exposures in Sweden in 1990-1993 48. Exposed workers (exposures) by agent in Sweden in 1990-93 49. Most common exposures to IARC agents in Sweden in 1990-1993 50. Alternative Swedish estimates 51. List of participants
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Appendices • 31