Exposure to inhalable dust and its cyclohexane soluble fraction since the 1970s in the rubber manufacturing industry in the European Union.

OBJECTIVES: As exposures to airborne particulates in the European rubber industry might still be causing genotoxic risks, it is important to assess trends in levels of inhalable dust and its cyclohexane soluble fraction (CSF) between the 1970s and 2003. METHODS: 13 380 inhalable and 816 respirable dust and 5657 CSF measurements, collected within the framework of the European Union Concerted Action EXASRUB, were analysed. Hierarchical mixed effects models were applied to assess exposure trends, taking into account between-factory, between-worker/location and day-to-day variances. RESULTS: Geometric mean levels of inhalable dust and CSF exposure changed by -4% (range -5.8 to +2.9%) and -3% (range -8.6 to 0%) per year, respectively. Significant reductions in inhalable dust concentrations were found in all countries for handling of crude materials and mixing and milling (-7% to -4% per year), as well as for miscellaneous workers (-11% to -5% per year), while significant CSF exposure reductions were found in curing (-8.6% per year) and maintenance and engineering departments (-5.4% per year). CONCLUSION: These analyses suggest that on average exposure levels of inhalable dust and its CSF in the European rubber manufacturing industry have steadily declined. Most likely genotoxic risks have also lessened over time since exposure levels have decreased and the most toxic chemicals have been replaced. In addition to differences in exposure reductions and levels among various stages of the production process, large differences across countries were noted. These patterns should be taken into account in retrospective assessment of exposure for epidemiological studies assessing cancer risk in the rubber industry.

Hazard prevention and control in the work environment. Report of a WHO meeting.

On the 19-21 September 1994 an international meeting of experts was convened at the World Health Organization office in Geneva. The result of this meeting was the formation of the PACE working group. PACE stands for 'Prevention And Control Exchange'. It is a programme designed to stimulate the sharing of solutions and control measures in order to reduce occupational hazards. Internationally there is wide agreement on the need for sharing of knowledge and a realisation that a collaborate effort is required.

[Pleural mesothelioma in women is associated with environmental exposure to asbestos]. / Pleuramesothelioom bij vrouwen in verband gebracht met milieublootstelling aan asbest.

OBJECTIVE: To determine whether local environmental exposure to asbestos in the community of Hof van Twente, The Netherlands (which houses a large asbestos cement facility and has a serious environmental asbestos pollution problem), is accompanied by an increased mortality due to pleural mesothelioma among women. DESIGN: A descriptive, ecologic-epidemiological study. METHOD: Twenty-nine women with a verified diagnosis of pleural mesothelioma were selected from 810 requests for compensation submitted to a specialised lawyers' office in the period 1990-2002. Information on asbestos exposure from occupational, household, environmental or unknown sources was obtained. The place of residence was compared to information on sources of asbestos in the immediate environment derived from the settlement 'Asbestos removal in the environment'. The expected number of cases of pleural mesothelioma among women was estimated on the basis of the observed mortality in The Netherlands in the period 1996-2002. A standardised mortality ratio (SMR) was calculated as the ratio of observed cases divided by the number of expected cases of pleural mesothelioma x 100. RESULTS: In total, 5 cases of pleural mesothelioma were identified among women without occupational or household exposure to asbestos. The age at diagnosis varied from 38 to 81 years. Each case was exposed to asbestos in the direct vicinity of the residence through walking and cycling over local roads metalled with asbestos cement scrap material. The expected number of cases of mortality due to pleural mesothelioma in the town of Hof van Twente for the period 1996-2002 was about 0.46. The SMR was 1090 (95% CI: 465-2551), indicating a 10-fold increase in risk. CONCLUSION: The increased mortality of pleural mesothelioma was most probably due to environmental exposure to asbestos. This finding agrees with comparable studies in other countries.

[Future increase of the incidence of mesothelioma due to occupational exposure to asbestos in the past]. / Toenemende incidentie van mesothelioom in de toekomst door beroepsmatige blootstelling aan asbest in het verleden.

OBJECTIVE: To estimate the future course of mesothelioma mortality as a result of occupational exposure to asbestos in the past. DESIGN: Cohort age model. SETTING: Department of Public Health, Erasmus University Rotterdam, the Netherlands. METHODS: A cohort age model was developed, based upon age-specific rates of pleural mesothelioma mortality during 1969-1994. This model was linked to the future trend in mortality among Dutch men as projected by the Central Bureau for Statistics in order to predict the future course of mesothelioma mortality in the period 1995-2030. RESULTS: In the next 35 years about 20,000 cases of pleural mesothelioma among men are expected. The projection results in a peak of annual male mesothelioma deaths of approximately 700 in about the year 2018. After 2020 the annual mortality will rapidly decline to about 450 cases in 2030. It is expected that this rapid decline will continue after 2030. In the 1943-1947 birth cohort pleural mesothelioma may account for 0.87% of all deaths. Exposure to asbestos at work largely explains this particular mortality pattern. CONCLUSION: Exposure to asbestos at work has created an important public health problem among Dutch men.

[Prevention of risk and its control in the work environment. Report from the World Health Organization, 19 October 1994]. / Zapobieganie ryzyku I kontrola w srodowisku pracy. Raport z Posiedzenia Swiatowej Organizacji Zdrowia, 19 Pazdziernika 1994.

On the 19-21 September 1994 an international meeting of experts was convened at the World Health Organization office in Geneva. The result of this meeting was the formation of the PACE working group. PACE stands for "Prevention And Control Exchange". It is programme designed to stimulate the sharing of solutions and control measures in order to reduce occupational hazards. Internationally there is wide agreement on the need for sharing of knowledge and a realisation that a collaborate effort is required.

An expert system for the evaluation of historical asbestos exposure as diagnostic criterion in asbestos-related diseases.

Compensation schemes for asbestos-related diseases have developed different strategies for attributing a specific disease to occupational exposure to asbestos in the past. In the absence of quantitative exposure information that allows a valid estimate of an individual's historical exposure, general guidelines are required to retrospectively evaluate asbestos exposure. A risk matrix has been developed that contains qualitative information on the proportion of workers exposed and the level of exposure in particular industries over time. Based on this risk matrix, stepwise decision trees were formulated for decisions regarding the decisive role of historical asbestos exposure in case ascertainment of asbestosis and mesothelioma. Application of decision schemes will serve to speed up the process of verifying compensation claims and also contribute to a uniform decision-making process in legal procedures.

The effect of seat suspension on exposure to whole-body vibration of professional drivers.

In this study the effectiveness of the seat suspension on the transmission of whole-body vibration through the driver's seat has been determined. Eleven types of seat frequently used in lorries, agricultural tractors and fork-lift trucks were selected. The transmissibility coefficient of each seat was measured by the ratio of the acceleration (weighted root-mean-square in the vertical axis) at the interface between the seat surface and the human body to the vibration at the attachment points of the seat on the vehicle floor. Measurements in the laboratory, using standardized representative vehicle vibration spectra and two volunteers of different weights, showed transmissibility coefficients of 0.34-1.28. Attenuation of the vibration input spectrum was obtained in 20 out of 24 (83%) measurements. Measurements in the field, conducted in vehicles under representative working conditions, showed transmissibility coefficients of 0.60-1.45. Attenuation of the vibration spectrum was obtained in 17 out of 24 (71%) vehicle-seat combinations. No significant differences were observed between seats with conventional suspension and those with air suspension. Laboratory measurements of the dynamic response of the seat suspension did not provide an adequate basis for predicting its performance in the field. In most work situations the magnitude and duration of vibration-exceeded the 8 h fatigue-decreased proficiency boundary of 0.32 m s-2 in the vertical axis, which indicates that in many working situations with a daily exposure of 8 h or more suspended seats will not protect professional drivers from harmful exposure to whole-body vibration.

Prevention and control of chemical exposures in the rubber manufacturing industry in The Netherlands.

In a survey in the rubber manufacturing industry in The Netherlands both the chemical and physical exposure of operators as well as company policies on working conditions were assessed. Defining the effectiveness of control measures was a part of this study and is the subject of this article. A method of solution-directed workplace analysis was applied to compare and evaluate the control measures within this branch of industry. Elimination of sources appears to be a strategy for prevention which has been adopted on only a limited scale. Control of exposure to particulates is more frequently applied, with local exhaust ventilation as the most important control measure. Both qualitative and quantitative analysis confirmed that local exhaust ventilation has a limited effect. Dust-free forms of chemicals, especially those with health risks, are used on only a moderate scale. In addition to hazard identification and evaluation based on exposure levels, the foreseeable risks associated with the design and requirements of production processes were established. The forthcoming industrial agreement for the rubber manufacturing industry in The Netherlands will, amongst other measures, stimulate use of source related strategies.

Trends in exposure to inhalable particulate and dermal contamination in the rubber manufacturing industry: effectiveness of control measures implemented over a nine-year period.

Exposure to inhalable particulates and dermal exposure to cyclohexane soluble matter (CSM) were evaluated in seven rubber manufacturing companies in 1988 and 1997. The identified exposure trends were used to study the effectiveness of control measures implemented over a nine-year period. Sampling and analytical methodologies were identical in both surveys. Inhalable particulate exposure was measured with a PAS6 sampling head. Dermal exposure was assessed by means of a dermal pad sampler worn at the lower wrist of the hand of preference. Changes in working organization and control measures taken after 1988 were identified based on discussions with management representatives and two walk-through surveys performed in 1994 and 1997. Exposure data were aggregated for comparison between years both at company and production function level. The mixed effect statistical procedure was used to evaluate the influence of control measures and seniority on current exposure levels. Comparison of the exposure levels between 1988 and 1997 revealed a reduction rate of 5.7 and 6.7% per year for inhalable particulate and dermal exposure, respectively. Companies and production functions with the highest exposure levels in 1988 and workers with seniority (more experience) showed a steeper decline in exposure levels. Fifty-seven control measures, mostly designed to control the levels of inhalable exposure were identified. Elimination of sources significantly reduced the inhalable particulate and dermal exposure by two-thirds of the level of 1988. Reduction of emission did not show a significant overall decrease in exposure concentrations. Control measures designed to control the levels of contaminants showed a significant reduction for both inhalable and dermal exposure, respectively 34 and 49% of the exposure level of 1988. These results indicate that efforts taken to improve work conditions in the rubber manufacturing industry in The Netherlands over this decade have been successful in reducing both inhalable particulate and dermal contamination.

Empirical modelling of chemical exposure in the rubber-manufacturing industry.

As part of a study of working conditions chemical exposure was assessed in 10 rubber-manufacturing plants in The Netherlands. Personal exposures to airborne particulates, rubber fumes and solvents, and also dermal contamination, were measured. To identify factors affecting exposure the personal exposure levels and information on tasks performed, ventilation characteristics and production variables were used in multiple linear regression models. The exposure was generally very variable. The specific circumstances in each department of each plant determined the actual levels of exposure to a large extent. The factors affecting exposure turned out to be different for each of the types of exposure considered. The model for exposure to airborne particulates explained 40% of the total variability and incorporating the actual time spent on a task only slightly improved the model (R2 = 0.42). The handling of chemicals in powder form was the main factor affecting exposure, forced ventilation having a negligible effect. The model for exposure to curing fumes (measured as the cyclohexane-soluble fraction of the particulate matter) explained 50% of the variability. Both curing temperature and pressure determined the level of rubber fumes. Local exhaust ventilation showed a significant exposure reducing effect. The effect of curing different elastomers was not statistically significant. Dermal exposure to cyclohexane-soluble matter could only be explained to a limited extent (R2 = 0.22). Tasks with frequent contact with (warm) compound and maintenance tasks in the engineering services departments resulted in high dermal exposure. Tasks in which solvents were directly used explained 56% of the variation in solvent exposures. Exposure data, together with information on tasks, methods of work, ventilation and production throughout a branch of industry, can be used to derive empirical statistical models which occupational hygienists can apply to study factors affecting exposure. These determining factors are of crucial importance, whenever hazard control or epidemiological research is the ultimate goal.