A database of exposures in the rubber manufacturing industry: design and quality control

The concerted action EXASRUB was initiated to create a database management system for information on occupational hygiene measurements that could be used to develop exposure models in the European rubber manufacturing industry. Quality of coding was assessed by calculating percentages of agreement and Cohen's kappa statistics (kappa) for an intra- and inter-centre recoding of randomly selected subsets of the measurements. In a 6-month period, 59 609 measurements from 523 surveys in 333 factories from as early as 1956 to 2003 were coded. The database consists primarily of measurements of N-nitrosamines (36%), rubber dust (23%), solvents (14%) and rubber fumes (10%). Coding of epidemiologically relevant information was done consistently with inter-centre kappa between 0.86 and 1.00. For occupational hygiene information, values of kappa were estimated to be between 0.67 and 1.00. The proposed method resulted in a large quantity of exposure measurements with auxiliary information of varying completeness and quality. Analyses showed that coding of epidemiologically relevant information in such a multi-centre, multi-country study was coded consistently. Larger errors however, occurred in coding of occupational hygiene information. This was primarily caused by lack of information in the primary records of measurements, emphasizing the importance of having a universal system in place to collect and store measurement information by occupational hygienists for future use.     

Personal sampling for inhalable aerosol exposures of carbon black manufacturing industry workers

The study was concerned with the measurement of inhalable aerosol exposures in the carbon black production industry. The primary goal of the study was to determine the extent to which inhalable aerosol exposure, as measured by the Institute of Occupational Medicine (IOM) personal inhalable sampling head, compared to "total" aerosol exposure, as measured by traditional methodology. A secondary objective was the evaluation of another inhalable aerosol sampler for carbon black aerosol measurement. In addition, an exploratory evaluation of the applicability of the National Institute for Occupational Safety and Health (NIOSH) analytical method (Method 5040) for the determination of carbon black, measured as elemental carbon, was conducted. A field study was carried out in a number of North American carbon black production plants using three samplers: the 2 Lpm IOM sampler as a reference sampler for the inhalable fraction, the 2 Lpm closed-face 37-mm plastic cassette that has been used for many years for total aerosol, and the 3.5 Lpm GSP sampler that has recently been identified by some as a possible candidate for inhalable aerosol. No such studies have previously been reported for the carbon black industry. Further, there have been no reports of the GSP performance in direct comparison to a reference instrument like the IOM sampler. The results showed that inhalable aerosol exposures for workers in carbon black production and packing areas were higher than the corresponding total aerosol exposures by a factor of nearly three, implying the presence of significantly coarser aerosol than previously thought based simply on knowledge of the carbon black production process. The fact that the aerosols collected in portions of the process comprised high proportions of non-elemental carbon particulate was thought likely to be responsible, underlining the need to consider whether gravimetric assessment for such exposure is the most appropriate metric. In addition, and somewhat surprisingly, the GSP sampler emerged clearly as a good alternative to the IOM sampler for collecting inhalable aerosol in carbon black industry workplaces like those studied (although this conclusion cannot yet be extended to other workplaces).     

Dust exposures in the Canadian grain industry

Total dust concentrations measured in 8 terminal, 9 transfer and 14 country grain elevators ranged from 0.18 to 781 mg/m3. Results indicate that elevatormen performing housekeeping and maintenance chores or working in transfer galleries are more likely to be exposed to high concentrations. Dust exposures can be related to the amount of grain handled and the extent of dust control measures in effect at a worksite. The respirable mass fraction of grain dust varies according to the type of grain handled. The quartz, inorganic material and fungal spore content and particle size of the dust from specific grains were also studied.     

Dust exposures in the wood processing industry.

Workers at four different woodworking processes--two logging sites, four sawmills, one major woodchipping operation, and five joineries situated in the state of New South Wales in Australia--were studied for personal inhalable dust exposures (N = 182). The geometric mean exposure at logging sites was 0.6 mg/m3 (N = 7), sawmills 1.6 mg/m3 (N = 93), woodchipping 1.9 mg/m3 (N = 9), and joineries 3.7 mg/m3 (N = 66). Overall, 62% of the exposures exceeded the current standards. Among joineries, 95% of the hardwood exposures and 35% of the softwood exposures were above the relevant standards. A majority of workers (approximately 90%) did not wear appropriate respirators approved for wood dust, while the ones who did wear them, used them on average less than 50% of the time. The significant determinants of personal wood dust exposures (n = 163) were found to be local exhaust ventilation, job title, use of handheld tools, cleaning method used, use of compressed air, and green or dry wood processed. Type of wood processed (softwood or hardwood) was not found to be statistically significant.     

Toluene diisocyanate exposures in the flexible polyurethane foam industry

A 3-year survey of toluene diisocyanate exposure in two flexible polyurethane foam manufacturing facilities has been conducted. The geometric mean time-weighted average exposures were 2.36 ppb, 1.10 ppb, and 1.50 ppb for the foam line workers, finishing workers, and maintenance personnel, respectively. The OSHA ceiling standard of 20 ppb was exceeded by 1.3% of the short-term (12 min) exposure measurements taken. Exposures were shown to be predominantly to the 2,6 isomer of TDI.     

Wood dust and formaldehyde exposures in the cabinet-making industry

Time-weighted average (TWA) personal total and respirable dust exposures were determined gravimetrically for 48 subjects in 4 cabinet-making plants. TWA personal formaldehyde exposures also were obtained, with the use of 3M 3750 passive monitors. Selective area sampling for formaldehyde was undertaken using two methods. The results obtained with the passive monitors were compared to the standard chromotropic acid impinger method. Considerable variation was noted in the dust exposures. Cabinet-makers exposed to softwoods were found to have a mean exposure of approximately one half of the current applicable ACGIH TWA-TLV, while hard-wood exposure was twice the applicable TWA-TLV. The highest dust exposures were recorded for those workers sanding, the mean total dust being 2.91 mg/m3 (S.E. 0.70) and respirable dust 0.63 mg/m3 (S.E. 0.20). Sanding operations also were found to produce a higher proportion of respirable dust (22%) than other woodworking operations (6%-14%). Workers in assembly areas also were found to have higher dust exposures, likely reflecting the fact that conventional dust collection devices for stationary woodworking equipment are not appropriate for hand held tools and hand sanding. The importance of making respirable dust measurements is discussed. The poor correlation between paired total and respirable dust concentrations indicates that both measurements should be made. Some potential limitations to respirable wood dust sampling using 10 mm nylon cyclones are noted, however. Area dust concentrations were found to be significantly lower than personal exposures, emphasizing the importance of personal sampling data. Formaldehyde vapor exposures were very low, with a mean of 0.06 ppm (S.E. 0.01).     

HACCP在调味紫菜生产加工中的应用

目的提高调味紫菜卫生质量,确保调味紫菜卫生安全。方法随机选择连云港市8家调味紫菜生产企业,应用HACCP的基本原理与方法,对调味紫菜的生产工艺全过程进行危害分析,确定关键控制点及关键限值,并进行相应的监控和纠偏。结果确定了4个关键控制点,关键控制点及关键限值分别为:(1)原料验收:关键限值为查验供应商的产品合格证明,保证原料来自安全海域;(2)调味料验收:关键限值为查验供应商提供的产品合格证明;(3)金属检测:关键限值为Fe:直径≤0.8mm,非Fe:直径≤1.2mm;(4)烧烤:关键限值为烧烤温度≥260℃,输送带转速≤85r/min。结论将HACCP应用于调味紫菜的生产加工过程,可显著提高调味紫菜的卫生质量。     

Pulmonary effects of exposures in silicon carbide manufacturing.

Chest x rays, smoking histories, and pulmonary function tests were obtained for 171 men employed in the manufacturing of silicon carbide. A lifetime exposure to respirable particulates (organic and inorganic fractions) and sulphur dioxide was estimated for each worker. Chest x ray abnormalities were related to respirable particulates (round opacities) and to age and smoking (linear opacities). Pulmonary function was affected by respirable particulates (FVC) and by sulphur dioxide and smoking (FEV1). Pleural thickening was related to age. No exposures exceeded the relevant standards; we therefore conclude that the current standards do not provide protection against injurious pulmonary effects, at least in this industry.     

Quantification of historical dust exposures in the diatomaceous earth industry

Quantitative estimates of dust exposure in a diatomaceous earth (DE) mining and milling operation have been derived based on air sampling records for the period 1948–1988. A total of 6395 records was included in the analysis. Conversion of results obtained by particle counting, expressed as millions of particles per cubic feet (mppcf) or gravimetrically from a filter cassette and expressed as mg m⁻³ total, were converted to mg m⁻³ respirable dust using a conversion factor derived from data obtained during the same periods at the plant. Conversion factors were calculated as the average difference of means on the log scale in order to provide stable and consistent conversions and as a ratio of arithmetic means so that the results could be compared with similar studies. After converting the available data to mg m⁻³ respirable dust, geometric mean (geometric standard deviation) concentrations were 0.37 (2.43) during the 1950s and 0.17 (2.35) during later periods. Exposures were estimated using two linear models, one estimating the changes in concentration over time, and the other providing job-specific mean exposures during the more recent period. Extrapolation of the estimates to periods prior to the availability of any data was done using a subjectively-determined scaling factor. The average estimated respirable dust concentrations for 135 jobs were 3.55 (±1.25), 1.37 (±0.48), 0.47 (±0.16) and 0.29 (±0.10) mg m⁻³ prior to 1949, 1949–1953, 1954–1973 and 1974–1988, respectively. Despite the limitations of the available data, the estimation procedures used are expected to provide reasonable quantitative estimates of silica-containing dust exposure for subsequent exposure-response analyses.     

Cancer risks in the optical manufacturing industry.

A mortality odds ratio (MOR) study has been conducted to explore the cancer risks of exposures experienced in the production of optical lenses and metal spectacle frames. Male death certificates were obtained from a Massachusetts town where a large optical industry is located. Craftsmen, foremen, and operatives of non-optical industries, such as woollen textile workers and workers in the optical company with short-term or no exposure, were chosen as reference workers their incomes were similar to those of the exposed workers. Cardiovascular disease (total 714) is chosen as the reference disease to explore cancers (total 232). An excess risk of total cancers observed = 70, expected = 48) has formed among lens workers. The excess may be accounted for mainly by the excess risk of gastrointestinal cancers; the standardised MORs (sMOR) for medium and long-term exposure were 2.2 and 2.5. The excess was especially evident for colorectal cancers; the sMORs for medium and long-term exposures were 3.2 and 2.6. Excess risks of gastrointestinal cancers (sMOR = 2.9) and colorectal cancers (sMOR = 3.4) were found among metal frame workers with long-term (employed for more than 29 years) exposure, but the number of exposed cases was small (9 and 6 respectively). These results suggest that exposure to abrasives or cutting oil mists or both, possibly by ingestion, might increase the risk of gastrointestinal (especially colorectal) cancers among lens and metal spectacle frame manufacturers.     

Estimating historical exposures of workers in a beryllium manufacturing plant

BACKGROUND: Beryllium is known to be toxic to the lungs, causing beryllium lung disease and associated with increased lung cancer risk. Airborne beryllium exposures have been monitored since the 1940s. This study describes methods used to measure airborne beryllium concentrations and how historical measurements from a beryllium manufacturing plant were used to estimate workers' exposures in a lung cancer case-control study. METHODS: Airborne beryllium concentrations had been measured using all-glass impingers, high-volume air filters, and personal respirable and total dust samplers. To provide consistency in exposure estimates over time, measurements collected by the other monitoring methods were converted to approximate the most frequently used high-volume, time-weighted average measurements. Because industrial hygiene measurements were not collected in every year for all jobs throughout the duration of the case-control study, exposure estimates had to be extrapolated from the existing measurements over time and across jobs. RESULTS: Over 7,000 historical measurements were available to estimate beryllium exposures of workers over time. Average exposures between jobs varied considerably and exposures for all jobs decreased dramatically between the 1940s and 1970s due to major plant production changes. CONCLUSIONS: Although error in the exposure metrics for the cases and controls likely occurred due to limitations of the exposure assessment data, the exposure estimates for each job over time provided a reasonable, objective mechanism for categorizing workers by the relative exposures they were likely to have encountered during their tenure. Published 2001 Wiley-Liss, Inc.     

Chemical exposures in the synthetic rubber industry and lymphohematopoietic cancer mortality

OBJECTIVE: This study evaluated the association between exposure to several chemicals and mortality from lymphohematopoietic cancer (LHC) among 16,579 synthetic rubber industry workers who were followed up from 1943 to 1998. METHODS: Poisson regression analyses examined LHC rates in relation to butadiene, styrene, and DMDTC exposure. Models provided maximum likelihood estimates of the relative rate for the contrast between categories of one agent, adjusting for other agents and for additional potential confounders. RESULTS: Cumulative exposure to 1,3-butadiene was associated positively with all leukemia (relative rates of 1.0, 1.4, 1.2, 2.9, and 3.7, respectively, for exposures of 0, >0 to <33.7, 33.7 to <184.7, 184.7 to <425.0, and 425.0+ ppm-years), chronic myelogenous leukemia and to a lesser extent with chronic lymphocytic leukemia. Adjusting for styrene and DMDTC attenuated these associations. After controlling for butadiene, neither styrene nor DMDTC displayed a consistent exposure-response trend with all leukemia, chronic myelogenous leukemia, or chronic lymphocytic leukemia. CONCLUSIONS: This study found a positive association between butadiene and leukemia that was not explained by exposure to other agents examined.     

Occupational injury and illness in the semiconductor manufacturing industry

Two thousand nine hundred and ninety-four reports of OSHA-reportable occupational injury or illness cases in 1984 from member companies of a national trade association of semiconductor manufacturing firms were analyzed. The 37 participating manufacturing facilities represented 16 companies employing over 95,000 persons, or approximately one-third of the U.S. work force for this industry in 1984. The annual incidence rate for all reportable injuries and illnesses was 2.7 per 100 full-time employees (FTE) for men and 3.7 per 100 FTE for women. Strains, sprains, or dislocations were the most frequently reported incidents (N = 956 [31.9%]), followed by cuts, lacerations, punctures, scratches, and abrasions (N = 445 [14.9%]), and chemical burns (N = 401 [13.4%]). Increased work-loss days per case were associated with manufacturing sites that did not have an employee health clinic on the premises, with custodial occupations, and with female gender.     

Hierarchical cluster analysis applied to workers' exposures in fiberglass insulation manufacturing

The objectives of this study were to explore the application of cluster analysis to the characterization of multiple exposures in industrial hygiene practice and to compare exposure groupings based on the result from cluster analysis with that based on non-measurement-based approaches commonly used in epidemiology. Cluster analysis was performed for 37 workers simultaneously exposed to three agents (endotoxin, phenolic compounds and formaldehyde) in fiberglass insulation manufacturing. Different clustering algorithms, including complete-linkage (or farthest-neighbor), single-linkage (or nearest-neighbor), group-average and model-based clustering approaches, were used to construct the tree structures from which clusters can be formed. Differences were observed between the exposure clusters constructed by these different clustering algorithms. When contrasting the exposure classification based on tree structures with that based on non-measurement-based information, the results indicate that the exposure clusters identified from the tree structures had little in common with the classification results from either the traditional exposure zone or the work group classification approach. In terms of the defining homogeneous exposure groups or from the standpoint of health risk, some toxicological normalization in the components of the exposure vector appears to be required in order to form meaningful exposure groupings from cluster analysis. Finally, it remains important to see if the lack of correspondence between exposure groups based on epidemiological classification and measurement data is a peculiarity of the data or a more general problem in multivariate exposure analysis.