Acute high dose exposure to benzene in shipyard workers (original) (raw)
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Biological monitoring of benzene exposure during maintenance work in crude oil cargo tanks
Chemico-Biological Interactions, 2006
We investigated the association between the individual concentrations of benzene in the breathing zone and the concentrations of benzene in the blood and urine among workers maintaining crude oil cargo tanks. Benzene exposure was measured during three consecutive 12 h work days among 13 tank workers and 9 unexposed referents (catering section). Blood and urine samples were collected pre-shift on the first day, post-shift on the third day, and pre-next shift on the following morning. The workers used halfmask air-purifying respirators, but not all workers used these systematically. The individual geometric mean benzene exposure in the breathing zone of tank workers over 3 days was 0.15 ppm (range 0.01-0.62 ppm). The tank workers' post-shift geometric mean benzene concentrations were 12.3 nmol/l in blood and 27.0 nmol/l in urine versus 0.7 nmol/l for both blood and urine among the referents. Benzene in the work atmosphere was highly correlated with the internal concentration of benzene both in post-shift blood (r = 0.87, P < 0.001) and post-shift urine (r = 0.90, P < 0.001), indicating that the varying use of respirators did not explain much of the variability in absorbed benzene. The results showed that, despite low benzene exposure in this work atmosphere and the use of personal protective equipment to a varying degree, the tank workers had a significant uptake of benzene that correlated highly with benzene exposure. The internal concentration of benzene was higher than expected considering the measured individual benzene exposure, probably due to an extended work schedule of 12 h and physical strain during tank work. Control measures should be improved for processes, which impose a potential for increased absorption of benzene upon the workers.
Scandinavian Journal of Work, Environment & Health, 2010
Objective Benzene is a natural constituent of crude oil and natural gas (0.1-3.0% by volume). Materials that are refined from crude oil and natural gas may contain some residual benzene. Few datasets have appeared in the peer-reviewed literature characterizing exposures to benzene at specific refineries or during specific tasks. In this study, historical samples of airborne benzene collected from 1977-2005 at the ExxonMobil Baton Rouge, Louisiana, USA, docks were evaluated. Methods Workers were categorized into 11 job titles, and both non-task (≤180 minutes sample duration) and task-related (<180 minutes) benzene concentrations were assessed. Approximately 800 personal air samples (406 non-task and 397 task-related) were analyzed. Results Non-task samples showed that concentrations varied significantly across job titles and generally resulted from exposures during short-duration tasks such as tank sampling. The contractor-tankerman job title had the highest average concentration [N=38, mean 1.4 parts per million (ppm), standard deviation (SD) 2.6]. Task-related samples indicated that the highest exposures were associated with the disconnection of cargo loading hoses (N=134, mean 11 ppm, SD 32). Non-task samples for specific job categories showed that concentrations have decreased over the past 30 years. Recognizing the potential for benzene exposure, this facility has required workers to use respiratory protective equipment during selected tasks and activities; thus, the concentrations measured were likely greater than those that the employee actually experienced. Conclusions This study provides a job title-and task-focused analysis of occupational exposure to benzene during dock facility operations that is insightful for understanding the Baton Rouge facility and others similar to it over the past 30 years.
Low level occupational benzene exposure and hematological parameters
Chemico-Biological Interactions, 2010
At high and prolonged exposure levels (e.g. >30 ppm), benzene can cause hematological effects. However, there is conflicting evidence on potential hematological effects at lower concentrations. We conducted a study to examine hematological effects at low benzene exposure levels in an occupational setting. Extensive exposure data and data from routine hematology examinations were available for Dow employees at the Terneuzen site in the Netherlands. We compared 8532 blood samples of Dow employees with low benzene exposure to 12,173 samples of employees with no benzene exposure that were available for the period between 1981 and 2007. Based on 21,584 benzene air measurements, a Job Exposure Matrix (JEM) was constructed for all employees with exposure. The JEM was used to estimate benzene exposure in the year in which each blood sample was collected. The average lymphocyte counts for the exposed and non-exposed group were similar. By means of mixed model regression adjustments were made for smoking, age and month of blood sample. These adjustments did not change the results and there was no indication for an adverse effect on any of the hematological parameters under investigation. A further stratification of the exposed population into three subgroups (<0.5 ppm, 0.5-1 ppm and >1 ppm) showed no significant differences for any of the hematological parameters between the three exposure categories or compared with the non-exposed group. The analysis modeling the continuous exposure effect relationship showed similar findings. This study does not indicate that workers exposed to low benzene concentrations are at an increased risk for hematological effects.
Early hematological and immunological alterations in gasoline station attendants exposed to benzene
Environmental Research, 2015
Introduction: Elucidation of effective biomarkers may provide tools for the early detection of biological alterations caused by benzene exposure and may contribute to the reduction of occupational diseases. This study aimed to assess early alterations on hematological and immunological systems of workers exposed to benzene. Methods: Sixty gasoline station attendants (GSA group) and 28 control subjects were evaluated. Environmental and biological monitoring of benzene exposure was performed in blood and urine. The potential effect biomarkers evaluated were δ-aminolevulinate dehydratase (ALA-D) activity, CD80 and CD86 expression in lymphocytes and monocytes, and serum interleukin-8 (IL-8). The influence of confounding factors and toluene co-exposure were considered. Results: Although exposures were below ACGIH (American Conference of Governmental Industrial Hygienists) limits, reduced ALA-D activity, decreased CD80 and CD86 expression in monocytes and increased IL-8 levels were found in the GSA group compared to the control subjects. Furthermore, according to multiple linear regression analysis, benzene exposure was associated to a decrease in CD80 and CD86 expression in monocytes. Conclusions: These findings suggest, for the first time, a potential effect of benzene exposure on ALA-D activity, CD80 and CD86 expression, IL-8 levels, which could be suggested as potential markers for the early detection of benzene-induced alterations.
Occupational and Environmental Medicine, 1997
Objective-To provide quantitative estimates of exposure to benzene for cases and controls in an epidemiology study to investigate the risk of leukaemia in petroleum distribution workers. Methods-Work histories were obtained for cases and controls together with detailed information on the distribution sites. For each job in the work history, an estimate of exposure (parts per million (ppm)) was obtained by multiplying a measure derived from exposure data by modifying factors to reflect the differences between the conditions that existed at the time of measurement and those at the time of interest. The modifying factors used related to job activity, the number of road tankers loaded, the benzene content of the gasoline, the mixture of products handled, temperature, and loading technology. Cumulative exposures for each case and control were obtained by multiplying the exposure estimates for each job by the duration of time in the respective jobs, and summing these over all jobs in the work history. Peak exposure and exposure through dermal contact were quantitatively classified for each job. Results-Measured exposures were obtained for 30 job categories, and ranged from 0-003 to 8-20 ppm. 40% of work histories were assigned background exposures, with a further 34% assigned the exposure estimate for a driver carrying out top submerged loading of motor fuel into road tankers. Cumulative exposures ranged from < 1 to > 200 ppm-years, although 81% were < 5 ppm-years. Comparison of the exposure estimates for selected jobs with data from sources not used in the study showed similar results. Conclusion-The estimates of exposure to benzene in this study provide a sound basis for the epidemiological analyses.
Risk Assessment on Benzene Exposure among Gasoline Station Workers
International Journal of Environmental Research and Public Health, 2019
Benzene is a human carcinogen presented in gasoline (1% by volume). It is also found in vehicle exhaust. The aim of this study was to assess the health risk of inhalation exposure to benzene among gasoline station workers. The ambient benzene concentration was measured by personal sampling from 150 gasoline station workers (137 fueling workers and 13 cashiers). Additional data of working characteristics were collected by interviews and on-site observations. All workers were non-smokers and passive smoking was limited. Risk assessment of inhalation exposure was determined using the United State Environmental Protection Agency (USEPA), and showed a high risk of adverse health effect (Hazard Quotients (HQ) >1) in 51.33% of workers. The cancer risk was increased from 1.35 × 10-8 to 1.52 × 10-4, and 70.67% of the workers had a lifetime cancer risk (>Inhalation Unit Risk (IUR): 2.2 × 10-6). A significantly higher risk was found in fueling workers compared to cashiers, and in workers...
Hematotoxicity in workers exposed to low levels of benzene
Science, 2004
1 Division of Cancer Epidemiology and Genetics, National Cancer Institute (NCI), National Institutes of Health (NIH), Department of Health and Human Services (DHHS), Bethesda, MD 20892, USA. ... 2 School of Public Health, University of California, Berkeley, CA 94720, USA.
Occupational exposure to benzene at the ExxonMobil Refinery in Baytown, TX (1978–2006)
Journal of Exposure Science and Environmental Epidemiology, 2009
Although occupational benzene exposure of refinery workers has been studied for decades, no extensive analysis of historical industrial hygiene data has been performed focusing on airborne concentrations at specific refineries and tasks. This study characterizes benzene exposures at the ExxonMobil Baytown, TX, refinery from 1978 to 2006 to understand the variability in workers' exposures over time and during different job tasks. Exposures were grouped by operational status, job title, and tasks. More than 9000 industrial hygiene air samples were evaluated; approximately 4000 non-task (43 h) and 1000 task-related (o3 h) personal samples were considered. Each sample was assigned to one of 27 job titles, 29 work areas, and 16 task bins (when applicable). Process technicians were sampled most frequently, resulting in the following mean benzene concentrations by area: hydrofiner (n ¼ 245, mean ¼ 1.3 p.p.m.), oil movements (n ¼ 286, mean ¼ 0.23 p.p.m.), reformer (n ¼ 575, mean ¼ 0.10 p.p.m.), tank farm (n ¼ 9, mean ¼ 0.65 p.p.m.), waste treatment (n ¼ 446, mean ¼ 0.13 p.p.m.), and other areas (n ¼ 460, mean ¼ 0.062 p.p.m.). The most frequently sampled task was sample collection (n ¼ 218, mean ¼ 0.40 p.p.m.). Job title and area did not significantly impact task-related exposures. Airborne concentrations were significantly lower after 1990 than before 1990. Results of this task-focused study may be useful when analyzing benzene exposures at other refineries.
International Archives of Occupational and Environmental Health, 2012
Purpose Characterize ethylbenzene and xylene air concentrations, and explore the biological exposure markers (urinary t,t-muconic acid (t,t-MA) and unmetabolized toluene) among petroleum workers offshore. Offshore workers have increased health risks due to simultaneous exposures to several hydrocarbons present in crude oil. We discuss the pooled benzene exposure results from our previous and current studies and possible co-exposure interactions.