A survey for rhinitis in an automotive ring manufacturing plant

We report findings regarding otolaryngologist-confirmed rhinitis, current exposure to MWF aerosols, fungi, and endotoxins for workers in a plant manufacturing automobile piston rings. Questionnaire data showed that 61.5% of 187 workers exhibited rhinitis-related symptoms. Rhinitis was confirmed in 99 of 115 workers whom were medically examined. Otolaryngologist-confirmed rhinitis was present in 10 of 19 grinding workers (52.6%), 67 of 142 production workers (47.2%), and 22 of 26 quality control (QC) workers (84.6%). These rates are much higher than the rates of rhinitis-related symptoms in automobile plants and other occupational settings and quite high even allowing for the common occurrence of rhinitis in the general population. We found that rhinitis could develop even in workers exposed to less than 0.5mg/m(3) MWF aerosol. The average exposure to fungi exceeded 10 x 10(3) CFU/m(3), a level higher than that reported for other automobile plants. Although we were unable to identify significant risk factors for rhinitis using only the physician-confirmed rhinitis cases, this study concludes that exposure to MWF aerosol, which would include microbes and metals, could contribute to a high occurrence of rhinitis in grinding and production workers. Forty-nine workers (63.6%) of 77 rhinitis patients in grinding and production operations were determined to handle synthetic MWF directly. For QC workers, for whom the prevalence of physician-confirmed rhinitis was highest, exposure to a low level of MWF aerosol, including specific microbe species we couldn't identify, bright light, dry air, and certain work characteristics during inspection are possible risk factors for development of rhinitis. Further studies including identification of fungi species should be conducted so a firm conclusion can be made regarding the development of rhinitis in QC manufacturing plant workers.     

Development of a job exposure matrix for the epidemiological follow-up of workers in the French nuclear industry

BACKGROUND: A pilot study was carried out in the AREVA NC Pierrelatte nuclear facility in order to investigate a possible carcinogenic effect of internal radiation exposure among nuclear workers in France. The objective of this study was to develop a method for retrospective reconstruction of the occupational exposure to internal radiation from uranium and associated chemical exposures. METHODS: A plant- and period-specific job exposure matrix (JEM) was designed. Job groups and exposure agents groups including uranium compounds and other chemical agents known as being carcinogenic, mutagenic or toxic were defined by an expert committee. Exposure was evaluated by active and retired workers included in the evaluator committee. A quantitative assignment of quantity and frequency of handling (both coded from 0 to 3) was performed for each agent groups using a method derived from the Delphi technique. RESULTS: In all, 23 experts and 353 evaluators participated to the JEM elaboration. A final JEM involved 232 "job-periods" presenting throughout the plant period 1960-2006 and 22 exposure agents groups in use at the plant. Six of them involved uranium compounds classified by their blood-transferability and toxicity characteristics. A first validation of the JEM by experts in radiological protection and industrial hygiene showed an acceptable internal consistency. CONCLUSION: In the context of missing past exposure measurement data, the plant- and period-specific job exposure matrices may be considered as a valid alternative for exposure estimation. This method may be applied to other nuclear plants and offers allowance to investigate a possible carcinogenic effect of internal radiation exposure among nuclear workers.     

Integrating workplace exposure databases for occupational medicine services and epidemiologic studies at a former nuclear weapons facility

We outline methods for integrating epidemiologic and industrial hygiene data systems for the purpose of exposure estimation, exposure surveillance, worker notification, and occupational medicine practice. We present examples of these methods from our work at the Rocky Flats Plant--a former nuclear weapons facility that fabricated plutonium triggers for nuclear weapons and is now being decontaminated and decommissioned. The weapons production processes exposed workers to plutonium, gamma photons, neutrons, beryllium, asbestos, and several hazardous chemical agents, including chlorinated hydrocarbons and heavy metals. We developed a job exposure matrix (JEM) for estimating exposures to 10 chemical agents in 20 buildings for 120 different job categories over a production history spanning 34 years. With the JEM, we estimated lifetime chemical exposures for about 12,000 of the 16,000 former production workers. We show how the JEM database is used to estimate cumulative exposures over different time periods for epidemiological studies and to provide notification and determine eligibility for a medical screening program developed for former workers. We designed an industrial hygiene data system for maintaining exposure data for current cleanup workers. We describe how this system can be used for exposure surveillance and linked with the JEM and databases on radiation doses to develop lifetime exposure histories and to determine appropriate medical monitoring tests for current cleanup workers. We also present time-line-based graphical methods for reviewing and correcting exposure estimates and reporting them to individual workers.     

Use of a crop and job specific exposure matrix for retrospective assessment of long-term exposure in studies of chronic neurotoxic effects of agrichemicals

RATIONALE: Job exposure matrices (JEMs) are widely used in occupational epidemiology, particularly when biological or environmental monitoring data are scanty. However, as with most exposure estimates, JEMs may be vulnerable to misclassification. OBJECTIVES: To estimate the long term exposure of farm workers based on a JEM developed for use in a study of the neurotoxic effects of organophosphates and to evaluate the repeatability and validity of the JEM. METHODS: A JEM was constructed with secondary data from industry and expert opinion of the estimate of agrichemical exposure within every possible job activity in the JEM to weight job days for exposure to organophosphates. Cumulative lifetime and average intensity exposure of organophosphate exposure were calculated for 163 pesticide applicators and 84 controls. Repeat questionnaires were given to 29 participants three months later to test repeatability of measurements. The ability of JEM based exposure to predict a known marker of organophosphate exposure was used to validate the JEM. RESULTS: Cumulative lifetime exposure as measured in kg organophosphate exposure, was significantly associated with erythrocyte cholinesterase concentrations (partial r2 = 5%; p < 0.01), controlled for a range of confounders. Repeatability in a subsample of 29 workers of the estimates of cumulative (Pearson''s r = 0.67; 95% confidence interval (95% CI) 0.41 to 0.83), and average lifetime intensity of exposure (Pearson''s r = 0.60 95% CI 0.31 to 0.79) was adequate. CONCLUSION: The JEM seems promising for farming settings, particularly in developing countries where data on chemical application and biological monitoring are unavailable.       

Occupational and environmental exposure to extremely low frequency-magnetic fields: a personal monitoring study in a large group of workers in Italy

An inaccurate evaluation of exposure is considered a possible cause for the inadequate conclusiveness of epidemiological research on adverse effects of extremely low frequency-magnetic fields (ELF-MF). The objective of this study is to provide an evaluation of current ELF-MF exposure in workers, the specific contribution of occupational exposure to overall 24-h exposure, and the representativeness of a job exposure matrix (JEM). ELF-MF exposure was monitored in 543 workers for 2 days using personal meters. Time-weighted average (TWA) levels at work, at home and outside the home were calculated. A JEM based on the 1988 International Standard Classification of Occupations (ISCO 88) was created. Median exposure at work, at home and outside the home were 0.14, 0.03 and 0.05 μT, respectively. Occupational exposure accounted for about 60% of 24-h exposure. In the JEM, about 50% of the classified occupations included significantly different individual TWAs. Occupational exposure to ELF-MF appeared low. Median exposure levels at home and outside were 20-28% of the occupational level, giving a minor contribution to overall day-to-day exposure. The frequent occurrence of workers with different TWA included under the same job title highlights the risk of misclassification in epidemiological studies on ELF-MF effects based on JEM.     

Comparative assessing for radiological, chemical, and physical exposures at the French uranium conversion plant: Is uranium the only stressor?

This study presents the pattern of exposure to uranium and other occupational pollutants known to be potentially carcinogenic, mutagenic or toxic and used at the main uranium conversion plant in France. For different uranium compounds specified according to their solubility and purity, and 16 other categories of pollutants: chemicals, fibres, vapours, dust, and heat a time- and plant-specific job exposure matrix (JEM) was created covering the period 1960-2006. For 73 jobs and for each pollutant the amount and frequency of exposure were assessed on a four-level scale by different time periods. The JEM shows 73% sensitivity and 83% specificity. Although exposure assessment was semi-quantitative, the JEM allows computing of individual cumulative exposure score for each pollutant across time. Despite the predominant natural uranium compounds exposure, the amount of exposure to other pollutants such as TCE and other chlorinated products, asbestos, and fibres, is important at the plant. Numerous correlations detected between uranium compounds exposure and exposure to chemicals warrants improving biological monitoring of exposed workers and accounting for associated exposures in epidemiological studies. Results of this study will be used for further investigation of association between exposure and mortality among uranium conversion workers cohort.     

Lead exposure and blood lead level of workers in a battery manufacturing plant in Thailand

This study was conducted in a battery manufacturing plant where lead was used in the processes of production, to survey the working conditions and safety behaviors, and to measure the airborne lead level contaminated in the workplace and the blood lead level of workers. The survey of working conditions showed that the workers were directly exposed to lead in sections e.g. grid casting, spreading, forming and polishing, assembly and special battery production sections. Some workers in these sections used a cotton mask to protect dust exposure, but most workers did not use any masks. High airborne lead level more than 0.2 mg/m3 was frequently measured in these sections. Geometric average of blood lead level slightly increased from 17.9 microg/dl to 22.3 microg/dl during 1998 and 2001. However, the geometric average of blood lead level dropped to 17.4 microg/dl in 2002. No workers had blood lead level above 60 microg/dl. Workers with different age groups had no significantly different average blood lead level. Workers whose duration of work was between 20-29 years had average blood lead level of 21.5 microg/dl. This group of workers had slightly higher blood lead level than those whose duration of work was 19 years or less, but with no significant difference. 21 subjects underwent annual health examination and exposure monitoring in 2002. There was no significant relation between airborne lead level and blood lead level.     

Study on allergic rhinitis in workers exposed to methyltetrahydrophthalic anhydride

Methylterahydrophthalic anhydride (MTHPA) is used as a hardening agent in an epoxy resin system. Because work-related nasal symptoms were observed in some workers exposed toMTHPA at two condenser plants, a cross-sectional survey was performed to improve their work environment. MeanMTHPA levels in the manufacturing processes to which the workers were routinely assigned were extremely low (1.09-22.4 μg/m3). However, specific IgE antibody (S-IgE) was detected in 9 (32%) of 28 workers. Of these, 8 (89%) had nasal symptoms. An IgE-mediated mechanism seems to be associated with at least some of the cases of work-related nasal symptoms. This indicates that the occupational health administration ofMTHPA cannot be controlled simply by limiting exposure in the work environment. Total IgE (T-IgE) levels were significantly higher in S-IgE-positive workers than in S-IgE-negative workers (geometric mean, 200.5 and 51.3 IU/ml, respectively; p<0.002, unpaired t test). These findings demonstrate that workers in whom S-IgE is less likely to be produced, i.e., those in whom the T-IgE level is 80 IU/ml or less, should be assigned to work in these manufacturing processes.     

Development of a job exposure matrix (JEM) for the textile industry in Shanghai, China

We developed a job exposure matrix (JEM) for the Shanghai textile industry constructed along three axes: industry sector, textile process, and hazardous agent. We assessed 35 different categories of dust, chemical, and physical agents for 149 textile processes within nine industry sectors: cotton, cotton/synthetic, cotton/other (nonsynthetic), wool, silk, synthetic, mineral, other mixed (e.g., wool and synthetic), and nonproduction. The JEM was constructed from two components: a priori assessment of the textile process by a team of U.S. industrial hygienists, and the prevalence of exposures reported by Chinese industrial hygienists in specific textile processes within the factory. The JEM was applied to an ongoing case-cohort study of cancer in women textile workers. The JEM assessed only dichotomous exposure (ever/never), and could be coupled with cumulative exposure by years of employment. The most common exposures in cotton mills were cotton dust and solvent exposures. Dyeing processes had the highest frequency of exposures, including solvents, acids, bases and caustics, bleaching agents, dyes, dye chemicals and intermediates, and formaldehyde. Only two processes were identified with formaldehyde exposure, beck dyeing and resin finishing. The most prevalent exposures among the subcohort, occurring in more than 60% of the women, were electromagnetic fields, lubricants, and cotton dust. More than one-third of subcohort subjects were also exposed to synthetic fiber dust, and slightly less than one-third of women were exposed to endotoxin. This JEM could be applicable for epidemiologic research in other textile industries.     

Beyond the job exposure matrix (JEM): the task exposure matrix (TEM)

The job exposure matrix (JEM) has been employed to assign cumulative exposure to workers in many epidemiological studies. In these studies, where quantitative data are available, all workers with the same job title and duration are usually assigned similar cumulative exposures, expressed in mgm(-3)xyears. However, if the job is composed of multiple tasks, each with its own specific exposure profile, then assigning all workers within a job the same mean exposure can lead to misclassification of exposure. This variability of exposure within job titles is one of the major weaknesses of JEMs. A method is presented for reducing the variability in the JEM methodology, which has been called the task exposure matrix (TEM). By summing the cumulative exposures of a worker over all the tasks worked within a job title, it is possible to address the variability of exposure within the job title, and reduce possible exposure misclassification. The construction of a TEM is outlined and its application in the context of a study in the primary aluminium industry is described. The TEM was found to assign significantly different cumulative exposures to the majority of workers in the study, compared with the JEM and the degree of difference in cumulative exposure between the JEM and the TEM varied greatly between contaminants.     

Characterisation of protracted low-level exposure to uranium in the workplace: A comparison of two approaches

Retrospective estimates of internal doses received by workers in the nuclear industry following intake of radionuclides, based on bioassay data, are a benchmark method in epidemiological studies. Nonetheless, full information relative to thousands of people included in an epidemiological cohort is rarely available, thus implying difficulties to estimate exposure precisely. To evaluate the cumulative exposure to uranium in a cohort of the AREVA NC Pierrelatte plant workers, we compared the epidemiological Job Exposure Matrix (JEM) method with the dosimetric method based on biological monitoring of exposure for 30 workers randomly selected within the cohort. A moderate to strong correlation was observed between the estimators resulting from the two approaches, thereby validating the JEM as a tool that can be used to characterise cumulative exposure to uranium in the cohort. In addition, this study showed that the JEM is a valuable complement to the interpretation of bioassy, (1) in providing information on exposure periods as well as on physical and chemical form of the radionuclides and (2) in compensating for the lack of exposure data regarding the very earliest periods. Combining the two methods may improve the precision in reconstructing cumulative exposure for epidemiological studies.     

Comparability of different methods of retrospective exposure assessment of metals in manufacturing industries

Many occupational case-control studies have relied on either self-report or exposure assessment based on job titles linked to a job exposure matrix (JEM) as opposed to the generally considered more accurate, but labor intensive, method of expert review of job histories. Our study examined the comparability of these different methods in assessing occupational exposure to the metals copper (Cu), lead (Pb), and iron (Fe) in manufacturing industries. Subjects were older people from a case-control study of a neurologic disease, and consisted of 188 individuals (72% male, 85% white) who had worked an average of 22.4 years in the manufacturing industry. An industrial hygienist review (IHR) of occupational history data from a comprehensive questionnaire was used as the reference method. The percent agreement (%A), sensitivity (SE), and specificity (SP) for direct self-report of metal exposures were: Cu, %A = 94.6, SE = 83.6, SP = 96.1; Pb, %A = 91.9, SE = 72.5, SP = 93.5; and Fe, %A = 82.7, SE = 64.5, SP = 88.1. Using the National Institute for Occupational Safety and Health (NIOSH) JEM, we analyzed the jobs of 115 of the 188 study subjects who had all their jobs listed in the JEM. Exposure assessment based on the NIOSH JEM compared with the IHR resulted in greater misclassification relative to direct self-report: Cu, %A = 81.5, SE = 21.2, SP = 89.2; Pb, %A = 86.0, SE = 0.0, SP = 92.6; and Fe, %A = 69.2, SE = 15.5, SP = 86.4. For all three study metals, combining the information from both direct self-report and the JEM did not improve upon the results compared with direct self-report alone. Due to the complex nature of metal exposure assessment, we suggest using an expert review of job histories whenever possible to minimize potential misclassification. Am. J. Ind. Med. 31:36–43 © 1997 Wiley-Liss, Inc.     

Exposure to polycyclic aromatic hydrocarbons in petrochemical industries by measurement of urinary 1-hydroxypyrene.

Biological monitoring of exposure of workers to polycyclic aromatic hydrocarbons (PAHs) in petrochemical industries was performed by the measurement of urinary excretion of 1-hydroxypyrene. In 121 of the 462 workers studied (both smokers and non-smokers) who had had no recent occupational exposure to PAHs a median 1-hydroxypyrene concentration of 0.21 micrograms/g creatinine was found. The upper limit of the 95% confidence interval in these workers of 0.99 micrograms/g creatinine was used as the upper normal value for industrial workers. Urinary 1-hydroxypyrene concentrations were measured in workers involved in manufacture and maintenance operations in oil refineries (13 studies in eight different settings), in workers manufacturing or handling products containing PAHs in chemical plants (five studies in three settings) and laboratories (four studies), and in workers digging soil contaminated with PAHs (three studies). In most studies in oil refineries 1-hydroxypyrene concentrations were only marginally greater than the values measured in the 121 workers with no recent occupational exposure to PAHs. This was also the case in maintenance operations with higher potential exposure to PAHs, indicating that personal protection equipment was generally adequate to prevent excessive exposure. The studies in chemical plants also showed that exposure to PAHs is low. An exception was the workers engaged in the production of needle coke from ethylene cracker residue, where increased urinary 1-hydroxypyrene concentrations were measured. The excretion of 1-hydroxypyrene by the operators and maintenance workers of this plant was investigated in relation to potential methods of exposure to PAHs. Dermal and inhalatory exposure were both significant determinants of exposure to PAHs.     

Solvent-associated decrements in olfactory function in paint manufacturing workers

To assess the effects of low-level organic solvent exposure on olfactory function, a cross-sectional study in paint manufacturing workers was undertaken. Workers in two paint manufacturing facilities (N = 187) were tested using the University of Pennsylvania Smell Identification Test (UPSIT), a standardized, quantitative test of olfactory function. Industrial hygiene air samples over the past 13-15 years revealed that average solvent exposures in these plants were 2-40% of the existing threshold limit values for the three chemicals measured. Stratification by smoking status revealed evidence of dose-related decrements in olfactory function (p = .01) only in non-smokers. Furthermore, those nonsmoking workers in the highest exposure category had UPSIT scores below the fifth percentile for their age. These results suggest that solvents may cause nervous system dysfunction at lower levels than previously suspected, and that the olfactory system may be a critical target organ for the neurotoxic effects of solvents and other chemicals.     

Air and blood lead levels in lead acid battery recycling and manufacturing plants in Kenya

The concentration of airborne and blood lead (Pb) was assessed in a Pb acid battery recycling plant and in a Pb acid battery manufacturing plant in Kenya. In the recycling plant, full-shift area samples taken across 5 days in several production sections showed a mean value ± standard deviation (SD) of 427 ± 124 μg/m(3), while area samples in the office area had a mean ± SD of 59.2 ± 22.7 μg/m(3). In the battery manufacturing plant, full-shift area samples taken across 5 days in several production areas showed a mean value ± SD of 349 ± 107 μg/m(3), while area samples in the office area had a mean ± SD of 55.2 ± 33.2 μg/m(3). All these mean values exceed the U.S. Occupational Safety and Health Administration's permissible exposure limit of 50 μg/m(3) as an 8-hr time-weighted average. In the battery recycling plant, production workers had a mean blood Pb level ± SD of 62.2 ± 12.7 μg/dL, and office workers had a mean blood Pb level ± SD of 43.4 ± 6.6 μg/dL. In the battery manufacturing plant, production workers had a mean blood Pb level ± SD of 59.5 ± 10.1 μg/dL, and office workers had a mean blood Pb level ± SD of 41.6 ± 7.4 μg/dL. All the measured blood Pb levels exceeded 30 μg/dL, which is the maximum blood Pb level recommended by the ACGIH(?). Observations made in these facilities revealed numerous sources of Pb exposure due to inadequacies in engineering controls, work practices, respirator use, and personal hygiene.     

Development of solvent exposure index for construction painters

This article describes methodological approaches for reconstructing long-term occupational exposure to organic solvents among construction painters. A detailed exposure questionnaire was administered to 125 painters to develop a job exposure matrix (JEM). The questionnaire inquired about painting activities with solvent-based paints and use of protection equipment for the previous 25 years in 5-year intervals. Current and historical distributions of solvent air concentrations were assessed for the same time period based on the following information: industrial hygiene measurements, paint composition changes, and VOC emission rate changes from architectural and industrial maintenance coatings. Changes in protection factors of respirators were also assessed. A cumulative solvent exposure index was calculated for each painter through Monte Carlo simulations by combining appropriate input distributions of solvent air concentrations and protection factors of respirators with JEM. Sensitivity simulations revealed that the historical variations in solvent air concentrations had a higher impact on the cumulative solvent exposure index than changes in protection factors for respirators. Fifty-eight percent of painters were classified with a different exposure quartile when the solvent exposure index was used vs. an exposure based only on years using solvent-based paints, suggesting the need for more detailed exposure analysis than just years working when conducting epidemiologic studies for this worker population.     

Mortality of workers employed in two asbestos cement manufacturing plants.

In a study of the mortality experience of 6931 employees of two New Orleans asbestos cement products manufacturing plants over 95% were traced. Chrysotile was the primary fibre used in both plants. Plant 1 also used small amounts of amosite and, later, crocidolite irregularly whereas plant 2 used crocidolite steadily in pipe production. Previously reported exposure concentration estimates were revised, based on additional air sampling data and re-evaluation of these data. Workers in the two plants had similar duration of employment (overall, a mean of 3.8 years) and estimated exposure concentration (a mean of 7.6 million particles per cubic foot (mppcf)). Mortality was similar for these plants and comparable with Louisiana rates for all causes combined, nonmalignant causes, and primary cancers of specified sites other than lung. Short term workers from both plants showed raised and similar risk of lung cancer, but risk among longer term workers differed--for example, for workers employed over one year there was no excess in plant 1 (16 observed, 17.2 expected) but a significant excess in plant 2 (52 observed, 28.9 expected, p less than 0.001). After excluding short term workers, risk of lung cancer in plant 2 showed a significant trend with estimated cumulative asbestos exposure; using a conversion of 1.4 fibres/ml = 1 mppcf, the slope of the line was 0.0076. The slope for plant 1 was 0.0003. Among all workers (the 6931, plus 167 early employees) ten mesotheliomas had occurred up to 1984: two from plant 1, eight from plant 2. In plant 2 a case-control analysis found a relation between risk of mesothelioma and duration of employment (p less than 0.01) and proportion of time spent in the pipe area (p less than 0.01), thus adding to the evidence of a greater risk of mesothelioma from crocidolite than chrysotile asbestos. A review of the mortality findings of eight cohorts of asbestos cement workers is presented.     

Mortality from heart disease among workers exposed to solvents

Several rubber industry jobs that are associated with cardiovascular disease (CVD) mortality involve the use of solvents and, since the only known occupational cause of atherosclerosis is a solvent (carbon disulfide), solvent exposures may contribute to the CVD excess observed among rubber industry workers. Detailed exposure estimates for 25 solvents were available for a cohort of 1,282 white male production workers in a large rubber- and tire-manufacturing plant, and a survivorship analysis compared the CVD mortality experience of exposed and nonexposed workers during a 15-year follow-up period. The known association between carbon disulfide exposure and ischemic heart disease (IHD) was apparent among these workers, and two other solvents, ethanol and phenol, were also found to be significant predictors of IHD. These exploratory findings suggest that solvents other than carbon disulfide may cause atherosclerotic disease.