Objectives-To investigate possible relations between respiratory health and past airborne exposure to refractory ceramic fibres (RCFs) and respirable dust in workers at six European factories, studied previously in 1987. Methods-The target population comprised all current workers associated with RCF production, plus others who had participated in 1987 "leavers". Information was collected on personal characteristics, chest radiographs, lung function, respiratory symptoms, smoking, and full occupational history. Regression analysis was used to study relations between indices of health of individual workers and of cumulative exposure to airborne dust and fibres, and likely past exposure to asbestos. Results and discussion-774 workers participated (90% of current workers, 37% of leavers). Profusion of small opacities in exposed workers (51% 0/1+; 8% 1/0+) was similar to that among an unexposed control group but higher than in new readings of the 1987 study films (11% 0/1+, 2% 1/0+). The large diVerence between 1987 and recent films may be, at least in part, a reading artefact associated with film appearance. Small opacities of International Labour Organisation (ILO) category 1/0+ were not associated with exposure. An association of borderline significance overall between 0/1+ opacities and exposure to respirable fibres was found for some exposure periods only, the time related pattern being biologically implausible. Pleural changes were related to age and exposure to asbestos, and findings were consistent with an eVect of time since first exposure to RCFs. Among men, forced expired volume in 1 second (FEV 1 ) and forced vital capacity (FVC) were inversely related to exposure to fibres, in current smokers only. FEV 1 / FVC ratio and transfer factor (TL CO ) were not related to exposures. The estimated restrictive eVect was on average mild. Prevalence of respiratory symptoms was low. Chronic bronchitis and its associated symptoms (cough, phlegm) showed some association with recent exposure to respirable fibres. This could be due to an irritant eVect of RCFs. (Occup Environ Med 2001;58:800-810)

Objectives-Little information is available on the quantitative risks of respiratory disease from quartz in airborne dust in the heavy clay industry. Available evidence suggested that these risks might be low, possibly because of the presence in the dust of other minerals, such as illite and kaolinite, which may reduce the harmful eVects of quartz. The aims of the present cross sectional study were to determine among workers in the industry (a) their current and cumulative exposures to respirable mixed dust and quartz; (b) the frequencies of chest radiographic abnormalities and respiratory symptoms; (c) the relations between cumulative exposure to respirable dust and quartz, and risks of radiographic abnormality and respiratory symptoms. Methods-Factories were chosen where the type of process had changed as little as possible during recent decades. 18 were selected in England and Scotland, ranging in size from 35 to 582 employees, representing all the main types of raw material, end product, kilns, and processes in the manufacture of bricks, pipes, and tiles but excluding refractory products. Weights of respirable dust and quartz in more than 1400 personal dust samples, and site histories, were used to derive occupational groups characterised by their levels of exposure to dust and quartz. Full size chest radiographs, respiratory symptoms, smoking, and occupational history questionnaires were administered to current workers at each factory. Exposureresponse relations were examined for radiographic abnormalities (dust and quartz) and respiratory symptoms (dust only). Results-Respirable dust and quartz concentrations ranged from means of 0.4 and 0.04 mg.m -3 for non-process workers to 10.0 and 0.62 mg.m -3 for kiln demolition workers respectively. Although 97% of all quartz concentrations were below the maximum exposure limit of 0.4 mg.m -3 , 10% were greater than this among the groups of workers exposed to most dust. Cumulative exposure calculations for dust and quartz took account of changes of occupational group, factory, and kiln type at study and non-study sites. Because of the importance of changes of kiln type additional weighting factors were applied to concentrations of dust and quartz during previous employment at factories that used certain types of kiln. 85% (1934 employees) of the identified workforce attended the medical surveys. The frequency of small opacities in the chest radiograph, category >1/0, was 1.4% (median reading) and seven of these 25 men had category >2/1. Chronic bronchitis was reported by 14.2% of the workforce and breathlessness, when walking with someone of their own age, by 4.4%. Risks of having category >0/1 small opacities differed by site and were also influenced by age, smoking, and lifetime cumulative exposure to respirable dust and quartz. Although exposures to dust and to quartz were highly correlated, the evidence suggested that radiological abnormality was associated with quartz rather than dust. A doubling of cumulative quartz exposure increased the risk of having...

Objectives-To identify whether there is evidence of pneumoconiosis and other respiratory health effects associated with exposure to respirable mixed dust and quartz in United Kingdom opencast coalmines. Methods-A cross sectional study of current workers (1224 men, 25 women) was carried out at nine large and medium sized opencast sites in England, Scotland, and Wales. To characterise a range of occupational groups within the industry, full shift measurements of personal exposures to respirable dust and quartz were taken. Up to three surveys were carried out at each site, covering all four seasons. For the purposes of comparisons with health indices these groups were further condensed into five broad combined occupational groups. Full sized chest radiographs, respiratory symptoms, occupational history questionnaires, and simple spirometry were used to characterise the respiratory health ofthe workforce. Logistic or multiple regression techniques were used to examine relations between indices of exposure and respiratory health. Results-None of the group geometric mean dust concentrations, based on 626 valid dust samples, exceeded 1 mg.m'3, and 99% of all quartz concentrations were below 0.4 mg.m5, the current maximum exposure limit. The highest quartz concentrations were experienced by the rock drilling team and drivers of bulldozers (used to move earth and stone from layers of coal). There were clear differences in mean respirable dust and quartz concentrations between occupational groups. These were consistent across the different sites, but depended in part on the day of measurement. The variations between sites were not much greater than between days, suggesting that differences between sites were at least partly explained by differences in conditions at the time of the measurements. The prevalence of radiographic small opacities profusion category > 1/0, based on the median of three readings, was 4.4%. Five men had category 2 pneumoconiosis and two men (including one of these five) had progressive massive fibrosis category A. From regression analyses, the relative risk of attaining a profusion ofcategory e 0/1 was estimated to be doubled for every 10 years worked in the dustiest, preproduction opencast jobs, after allowing for age, smoking, and site effects. Risk was not associated with time worked in any other occupation within the industry, nor with previous employment in underground mining or other dusty jobs. Symptoms of chronic bronchitis were present in 13% of the men. Frequency of chronic bronchitis was influenced by years worked in dusty jobs outside opencast mining, but not by time spent in occupations within the industry. Asthmatic symptoms were reported by 5% ofthe workforce, close to the mean frequency found in adult men. No positive associations were found between asthma and occupational exposures. Lung function on average was close to predicted values and showed no relation to time worked in opencast occupations. Conclusions-Frequency of (mostly mild) chest radiographic abnormalities is a...

Although personal respiratory protection is widely recognized as having a lower priority than reduction of any risk at source, respiratory protective equipment (RPE) is a major part of risk management for many employers. We have identified the key elements of what constitutes an effective risk control programme involving RPE, through a 3-fold approach involving (i) a review of the published scientific literature, (ii) exploring the issue through >40 years of research publications from the Institute of Occupational Medicine (IOM) (in which the ergonomics of personal protection equipment has been a significant thread), and (iii) a series of interviews and discussions with IOM and Health and Safety Executive staff with experience in the testing, prescription, or use of RPE. We have used the findings to formulate a series of recommendations for the constituents of an effective RPE programme. The role of management is paramount in recognizing the need for and providing appropriate RPE, which is both technically and ergonomically effective. Only then does any focus on the role of the employee, in wearing the RPE correctly at the appropriate times, becomes viable.

As part of a wider epidemiological research programme, an occupational hygiene study was carried out during 1995-1996 to assess workers' current exposures to airborne materials in six European refractory ceramic fibre (RCF) plants. These plants had also participated in a cross-sectional occupational hygiene survey in 1987. The sampling strategy focussed principally on personal shift-average exposures of workers, by occupation, to respirable fibres. Monitoring was undertaken in two integrated phases: a 1-week cross-sectional survey followed by a prospective, and ongoing, programme by the RCF industry. Statistical (analysis of variance) analyses to identify patterns of variability by plant, occupational group (OG) and occupations within group were based on 464 individual shift samples, the greatest amount of data being available for production occupations. Concentrations of respirable fibres showed marked differences between plants and between OGs. Average respirable fibre concentrations among Primary and Secondary Production and Ancillary workers ranged from <0.1 f ml(-1) to up to 0.4 f ml(-1), depending on OG and plant. Individual shift-average measurements were almost invariably <1 f ml(-1). Within Secondary Conversion and Finishing, plant-specific averages ranged from 0.3 f ml(-1) to 1.25 f ml(-1). Respirable fibre concentrations were, in some plants, less than half those found in 1987. In other plants, mainly those where concentrations had been relatively low in 1987, the dust exposure had remained essentially unchanged or increased slightly. An ongoing programme of sampling is being carried out by the participating companies, generating additional information that could assist research in the long term and in improving control.