Exposure to fibres and risk of pleural mesothelioma in the Norwegian Offshore Petroleum Workers cohort.

OBJECTIVES: Pleural mesothelioma is a rare respiratory cancer, mainly caused by inhalation of asbestos fibres. Other inorganic fibres are also suggested risk factors. We aimed to investigate the association between exposure to asbestos or refractory ceramic fibres (RCFs) and pleural mesothelioma among male Norwegian offshore petroleum workers. METHODS: Among 25 347 men in the Norwegian Offshore Petroleum Workers (NOPW) cohort (1965-1998), 43 pleural mesothelioma cases were identified through the Cancer Registry of Norway (1999-2022). A case-cohort study was conducted with 2095 randomly drawn non-cases from the cohort. Asbestos and RCF exposures were assessed with expert-made job-exposure matrices (JEMs). Weighted Cox regression was used to estimate HRs and 95% CIs, adjusted for age at baseline and pre-offshore employment with likely asbestos exposure. RESULTS: An increased risk of pleural mesothelioma was indicated for the highest versus lowest tertile of average intensity of asbestos (HR=1.21, 95% CI: 0.57 to 2.54). Pre-offshore asbestos exposure (vs no such exposure) was associated with increased risk of pleural mesothelioma (HR=2.06, 95% CI: 1.11 to 3.81). For offshore workers with no pre-offshore asbestos exposure, an increased risk of pleural mesothelioma was found for the highest tertile of average intensity of asbestos (HR=4.13, 95% CI: 0.93 to 18), versus the lowest tertile. No associations were found between RCF and pleural mesothelioma. CONCLUSIONS: Associations between JEM-based offshore asbestos exposure and pleural mesothelioma were confirmed in the NOPW cohort. Pleural mesothelioma risk was also associated with asbestos exposure before work in the offshore petroleum industry.

Benzene exposure and risk of lung cancer in the Norwegian Offshore Petroleum Worker cohort: a prospective case-cohort study.

OBJECTIVE: The objective of our study was to examine whether occupational exposure to benzene is associated with lung cancer among males in the Norwegian Offshore Petroleum Workers cohort. METHODS: Among 25 347 male offshore workers employed during 1965-1998, we conducted a case-cohort study with 399 lung cancer cases diagnosed between 1999 and 2021, and 2035 non-cases sampled randomly by 5-year birth cohorts. Individual work histories were coupled to study-specific job-exposure matrices for benzene and other known lung carcinogens. Weighted Cox regression was used to estimate HRs and 95% CIs for the associations between benzene exposure and lung cancer, by major histological subtypes, adjusted for age, smoking and occupational exposure to welding fumes, asbestos and crystalline silica. Missing data were imputed. RESULTS: For lung cancer (all subtypes combined), HRs (95% CIs) for the highest quartiles of benzene exposure versus unexposed were 1.15 (0.61 to 2.35) for cumulative exposure, 1.43 (0.76 to 2.69) for duration, and 1.22 (0.68 to 2.18) for average intensity (0.280≤P-trend≤0.741). For 152 adenocarcinoma cases, a positive trend was observed for exposure duration (P-trend=0.044). CONCLUSIONS: In this cohort of offshore petroleum workers generally exposed to low average levels of benzene, we did not find an overall clear support for an association with lung cancer (all subtypes combined), although an association was suggested for duration of benzene exposure and adenocarcinoma. The limited evidence might be due to restricted statistical power.

Validation of a full-shift benzene exposure empirical model developed for work on offshore petroleum installations on the Norwegian continental shelf.

Workers on offshore petroleum installations might be exposed to benzene, a carcinogenic agent. Recently, a full-shift benzene exposure model was developed based on personal measurements. This study aimed to validate this exposure model by using datasets not included in the model. The exposure model was validated against an internal dataset of measurements from offshore installations owned by the same company that provided data for the model, and an external dataset from installations owned by another company. We used Tobit regression to estimate GM (geometric mean) benzene exposure overall and for individual job groups. Bias, relative bias, precision, and correlation were estimated to evaluate the agreement between measured exposures and the levels predicted by the model. Overall, the model overestimated exposure when compared to the predicted exposure level to the internal dataset with a factor of 1.7, a relative bias of 73%, a precision of 0.6, a correlation coefficient of 0.72 (p = 0.019), while the Lin's Concordance Correlation Coefficient (CCC) was 0.53. The model underestimated exposure when compared to the external dataset with a factor of about 2, with a relative bias of -45%, a precision of 1.2, a correlation coefficient of 0.31 (p = 0.544), and a Lin's CCC of 0.25. The exposure model overestimated benzene exposure in the internal validation dataset, while the precision and the correlation between the measured and predicted exposure levels were high. Differences in measurement strategies could be one of the reasons for the discrepancy. The exposure model agreed less with the external dataset.

Exposure to benzene and other hydrocarbons and risk of bladder cancer among male offshore petroleum workers.

BACKGROUND: Occupational exposures constitute the second leading cause of urinary bladder cancer after tobacco smoking. Increased risks have been found in the petroleum industry, but high-quality exposure data are needed to explain these observations. METHODS: Using a prospective case-cohort design, we analysed 189 bladder cancer cases (1999-2017) and 2065 randomly drawn non-cases from the Norwegian Offshore Petroleum Workers cohort. Cases were identified in the Cancer Registry of Norway, while work histories (1965-1998) and lifestyle factors were recorded by questionnaire at baseline (1998). Occupational petroleum-related hydrocarbon exposures were assessed by expert-developed job-exposure matrices. Hazard ratios were estimated by weighted Cox-regressions, adjusted for age, tobacco smoking, education, and year of first employment, and with lagged exposures. RESULTS: Increased risks were found in benzene-exposed workers, either long-term exposure (≥18.8 years, HR = 1.89, 95% CI: 1.14-3.13; p-trend = 0.044) or high-level cumulative benzene exposure (HR = 1.60, 95% CI: 0.97-2.63; p-trend = 0.065), compared with the unexposed. Associations persisted with 20-year exposure lag. No associations were found with skin or inhalation exposure to crude oil, mineral oil (lubrication, hydraulics, turbines, drilling), or diesel exhaust. CONCLUSIONS: The results suggest that exposures in the benzene fraction of the petroleum stream may be associated with increased bladder cancer risk.

Esophageal and Head and Neck Cancer Patients Attending Ocean Road Cancer Institute in Tanzania from 2019 to 2021: An Observational Study.

BACKGROUND: Cancer in Africa is an emerging public health problem that needs urgent preventive measures, particularly in workplaces where exposure to carcinogens may occur. In Tanzania, the incidence rate of cancer and mortality rates due to cancers are increasing, with approximately 50,000 new cases each year. This is estimated to double by 2030. METHODS: Our hospital-based cross-sectional study describes the characteristics of newly diagnosed patients with head and neck or esophageal cancer from the Ocean Road Cancer Institute (ORCI), Tanzania. We used an ORCI electronic system to extract secondary data for these patients. RESULTS: According to the cancer registration, there were 611 head and neck and 975 esophageal cancers recorded in 2019-2021. Two-thirds of these cancer patients were male. About 25% of the cancer patients used tobacco and alcohol, and over 50% were involved in agriculture. CONCLUSION: Descriptions of 1586 head and neck cancer patients and esophageal cancer patients enrolled in a cancer hospital in Tanzania are given. The information may be important for designing future studies of these cancers and may be of value in the development of cancer prevention measures.

Benzene Exposure From Selected Work Tasks on Offshore Petroleum Installations on the Norwegian Continental Shelf, 2002-2018.

OBJECTIVES: Work on offshore petroleum installations may cause exposure to benzene. Benzene is a carcinogenic agent, and exposure among workers should be as low as reasonably practicable. We aimed to assess short-term (less than 60 min) benzene exposure from the most frequent work tasks on offshore installations on the Norwegian continental shelf and identify determinants of exposure. In addition, we aimed to assess the time trend in task-based benzene measurements from 2002 to 2018. METHODS: The study included 763 task-based measurements with a sampling duration of less than 60 min, collected on 28 offshore installations from 2002 to 2018. The measurements were categorized into 10 different tasks. Multilevel mixed-effect Tobit regression models were developed for two tasks: sampling and disassembling/assembling equipment. Benzene source, season, indoors or outdoors, design of process area, year of production start, sampling method, and work operation were considered as potential determinants for benzene exposure in the models. RESULTS: The overall geometric mean (GM) benzene exposure was 0.02 ppm (95% confidence intervals 95%(CI: 0.01-0.04). The pipeline inspection gauge (PIG) operation task was associated with the highest exposure, with a GM of 0.33 ppm, followed by work on flotation cells, disassembling/assembling, and sampling, with GMs of 0.16, 0.04, and 0.01 ppm, respectively. Significant determinants for the disassembling/assembling task were work operation (changing or recertifying valves, changing or cleaning filters, and breaking pipes) and benzene source. For sampling, the benzene source was a significant determinant. Overall, the task-based benzene exposure declined annually by 10.2% (CI 95%: -17.4 to -2.4%) from 2002 to 2018. CONCLUSIONS: The PIG operation task was associated with the highest exposure out of the ten tasks, followed by work on flotation cells and when performing disassembling/assembling of equipment. The exposure was associated with the type of benzene source that was worked on. Despite the decline in task-based exposure in 2002-2018, technical measures should still be considered in order to reduce the exposure.

Occupational Benzene Exposure in the Norwegian Offshore Petroleum Industry, 2002-2018.

PURPOSE: Workers on offshore petroleum installations are at risk of being exposed to benzene which is carcinogenic to humans. The present study aimed to assess the time trend of full-shift benzene exposure from 2002 to 2018 in order to characterize benzene exposure among laboratory technicians, mechanics, process operators, and industrial cleaners, and to examine the possible determinants of benzene exposure. METHODS: A total of 924 measurements of benzene exposure from the Norwegian petroleum offshore industry were included. The median sampling duration was 680 min, ranging from 60 to 940 min. The overall geometric mean (GM) and 95% confidence interval, time trends, and determinants of exposure were estimated using multilevel mixed-effects tobit regression analyses. Time trends were estimated for sampling duration below and above 8 h, both overall and for job groups. The variability of exposure between installation and workers was investigated in a subset of data containing worker identification. RESULTS: The overall GM of benzene exposure was 0.004 ppm. When adjusting for job group, design of process area, season, wind speed, and sampling duration, industrial cleaners had the highest exposure (GM = 0.012). Laboratory technicians, mechanics, and process operators had a GM exposure of 0.004, 0.003, and 0.004 ppm, respectively. Overall, the measured benzene exposure increased by 7.6% per year from 2002 to 2018. Mechanics had an annual increase of 8.6% and laboratory technicians had an annual decrease of 12.6% when including all measurements. When including only measurements above 8 h, mechanics had an increase of 16.8%. No statistically significant time trend was found for process operators. Open process area, high wind speed, and wintertime were associated with reduced exposure level. CONCLUSIONS: An overall increase in measured exposure was observed from 2002 to 2018. The increase may reflect changes in measurement strategy from mainly measuring on random days to days with expected exposure. However, the time trend varied between job groups and was different for sampling duration above or below 8 h. Industrial cleaners had the highest exposure of the four job groups while no differences in exposure were observed between laboratory technicians, mechanics, and process operators. The design of the process area, job group, wind speed, and season were all significant determinants of benzene exposure.

Occupational exposure to air pollutants emitted from in situ burning of offshore oil spills: a large-scale field study.

BACKGROUND: In-situ burning (ISB) could be an effective cleanup method during spills. This study aims to study occupational exposure to pollutants emitted from offshore, large-scale ISB-experiments among personnel on vessels involved in ISB. MATERIALS AND METHODS: Six experimental ISBs after release of 4.2-6 m3 crude or refined oils were performed. Air measurements on three vessels were taken of particulate matter (PM) of different size fractions, polycyclic aromatic hydrocarbons (PAH) and volatile organic compounds (VOC). RESULTS: One vessel was located upwind (about 80-140 m) from the burning oil while two work boats were positioned 200-400 m downwind. One of the work boats moved back and forth transverse to the smoke plume while the other followed the edge of the smoke plume downwind. During the burn period (28-63 min) the range of mean concentrations of PM2.5 particles in the closest work boat downwind from the burn (0.068-0.616 mg/m3) was considerably higher than in the upwind vessel (0.0198-0.029 mg/m3) and in the work boat moving downwind at the edge of the visible smoke (0.007-0.078 mg/m3). The particles were mainly in the PM<1 fraction. In the work boat closest to the burn the mean concentration of particulate PAH and VOC was 0.046-0.070 ng/m3 and < limit of detection -17.1 ppm, respectively. CONCLUSIONS: The mean PM2.5 levels in the closest vessel varied between 4 and 41 times higher than the 24-hour Norwegian Air Quality Criteria for the general population, indicating that the particulate exposure may impose a health risk for personnel up to 400 m downwind from an ISB. Exposure to VOC and PAH among crew on board vessels both upwind and downwind from the burning was low during these conditions. However, it is recommended that crew on vessels close to and downwind of smoke plumes from oil fires should use half-masks with P3 filters.

Night shift work, chemical coexposures and risk of female breast cancer in the Norwegian Offshore Petroleum Workers (NOPW) cohort: a prospectively recruited case-cohort study.

OBJECTIVES: This study examined the association between night shift work and risk of breast cancer, overall and by hormone receptor subtype, among females in the Norwegian Offshore Petroleum Workers (NOPW) cohort. We also examined the association of coexposure (chlorinated degreasers and benzene) and breast cancer risk, and possible interaction with work schedule. DESIGN: Prospectively recruited case-cohort study within the NOPW cohort. SETTING: Female offshore petroleum workers active on the Norwegian continental shelf. PARTICIPANTS: 600 female workers (86 cases and 514 non-cases) were included in the study. We excluded workers that died or emigrated before start of follow-up, had missing work history, were diagnosed with breast cancer or other prior malignancy (except non-melanoma skin cancer) before start of follow-up. RESULTS: No overall association was found between breast cancer risk and work schedule (HR 0.87, 95% CI 0.52 to 1.46 for work schedule involving night shift vs day shift only). There was no significant association between work schedule and risk of any breast cancer subtype. No significant interactions were found between work schedule and chemical coexposures (breast cancer overall Pinteraction chlorinated degreasers=0.725 and Pinteraction benzene=0.175). CONCLUSIONS: Our results did not provide supporting evidence that work schedule involving night shift affects breast cancer risk in female offshore petroleum workers, but should be considered cautiously due to few cases. Further studies with larger sample sizes are warranted.

Offshore field experiments with in-situ burning of oil: Emissions and burn efficiency.

In situ burning (ISB) is an oil spill response technique including ignition and burning to remove oil on the water surface. The technique rapidly and effectively removes large portions of the oil. However, the combustion process causes a large smoke plume and leaves a viscous residue in the water. During six large-scale experimental burns in the North Sea in 2018 and 2019, the smoke plume, released oil and contained residues were analysed. The objectives were to document the content of particles and gases in the smoke plume, properties of both the released oils and residues, and the effectiveness of the burns. Oseberg crude oil, Ultra Low Sulphur Fuel Oil (ULSFO), Intermediate Fuel Oil (IFO180) and Marine Gas Oil (MGO) were released into a fire-boom and ignited. Particles and gases in the smoke plume were monitored using drones with several sensors. Soot particle monitoring indicated that more than 90% of the particles produced during the burns were <1 µm. Soot fallout was mainly limited to visible smoke, and the particle concentration was highest directly under the smoke plume and declined with distance from the burn. Gas monitoring in the smoke indicated low concentrations of SO2 and NOX (<2 ppm), and the concentrations of CO2 and CO were within air quality standards. Black Carbon produced relative to the amount of oil burned was 10-18%. The burn efficiency varied and were estimated to 80-91% for Oseberg, >90% for MGO, and <60% for both ULSFO and IFO180. The present paper addresses the results of the smoke plume monitoring, properties of the ISB residues and the burn efficiency.

Registered health problems and demographic profile of integrated textile factory workers in Ethiopia: a cross-sectional study.

BACKGROUND: Textile and garment factories are growing in low and middle-income countries as worldwide demand for inexpensive clothing increases each year. These integrated textile and garment production factories are often built-in areas with few workplaces and environmental regulations, and employees can be regularly exposed to workplace hazards with little regulatory oversight. Consequently, workers' health may be significantly affected due to long term exposure to hazards. This study describes registered health problems and their association to work-related and personal factors among workers in integrated textile factories in Ethiopia. METHODS: Institution-based cross-sectional study design was employed for this analysis. A one-year recording of worker's clinical diagnoses (between March 2016 and February 2017) was gathered from the factory clinics of three integrated textile factories. Clinical diagnosis data was obtained as factory workers visited the clinics if feeling unwell. Sociodemographic characteristics and work-related information were obtained from the factory's human resource departments. The sociodemographic and clinical diagnosis statuses of 7992 workers were analyzed. The association between the registered diagnoses and workplace factors (work in textile production, garment production and support process) and personal factors (age, sex and educational status) were studied using logistic regression analysis. RESULTS: The average employee age and years of service were 40 years and 11 years respectively. 60% of workers were females, comprising of 4778 women. 66% of all workers (5276) had 27,320 clinical diagnoses. In total, this caused 16,993 absent working days due to sick leave. Respiratory diseases (34%) and musculoskeletal disorders (29%) were the most prevalent diagnoses, while bodily injuries were the cause of most work absences. Work department, sex and educational status are variables that were most significantly associated with higher prevalence of disease groups. CONCLUSIONS: About two-thirds of the integrated textile factory workers were diagnosed with different types of disease. The textile and garment production department workers were affected at a greater rate than the support process workers, indicating that some diseases may be related to workplace exposure. Further study should investigate rare chronic diseases such as cancer, heart diseases, renal diseases and diabetes.

Temporary Threshold Shifts among Iron and Steel Factory Workers in Tanzania: A Pre-Interventional Study.

Background: Workers in iron and steel factories in Tanzania are exposed to noise levels above recommended limit values, without using hearing protection devices. Exposure to noise levels above 85 dB(A) is associated with temporary threshold shifts (TTS) of human hearing. Nevertheless, there are few studies of noise and hearing from African countries. Objective: To determine whether the normal hearing workers in Tanzania experiences TTS after full-shift occupational noise exposure of 85 dB(A) and above. Methods: A total of 55 workers were included. Full-shift personal noise measurements were conducted. Pre- and post-shifts pure-tone audiometry were conducted for each worker. TTS was defined as a 10 dB or greater change at 1000, 2000, 3000 or 4000 Hz in either ear. Results: We found that 85.5% of the workers developed TTS across the work shift. There was significant increase in mean hearing thresholds across shift at 1000, 2000, 3000 and 4000 Hz among the workers exposed to an average personal noise exposure (LAeq,8h) of 90.4 dB(A) (SD = 2.7). The difference in mean hearing thresholds was higher at 4000 Hz [Arithmetic Mean (AM) = 10 dB SD = 4 dB] compared to that of 1000 Hz (AM = 4 dB SD = 3 dB), 2000 Hz (AM = 4 dB SD = 4 dB), and 3000 Hz (AM = 9 dB SD = 6 dB), respectively. Conclusions: Interventions to reduce occupational personal noise exposure are warranted to reduce the high risk of developing a permanent threshold shift with persistent high noise exposure. An intervention study is planned for this group of workers.

Occupational noise exposure and hearing loss: A study of knowledge, attitude and practice among Tanzanian iron and steel workers.

We assessed Knowledge Attitude and Practice (KAP) regarding occupational noise exposure, Noise-induced hearing loss, audiometry and use of hearing protection devices among iron and steel factory workers exposed to high noise level. A modified, validated, structured questionnaire was used to collect information from 253 male workers randomly selected from the four factories. The sum scores for each domain of KAP were computed. Scores above 75% were defined as good knowledge and positive attitude. For practice, scores of >50% were defined as good. Independent samples t-test and Chi-squared test were used to analyze association between KAP and continuous/categorical variables respectively. Majority of workers displayed poor knowledge and poor practice (94%), but 76% displayed a positive attitude. Most of the workers (86%) had never been provided with hearing protection devices. The mean scores for attitude and practice differed significantly between the four factories (one-way ANOVA, p < 0.001). Implementation of hearing conservation program with provision of hearing protection devices are suggested.

Prevalence of Noise-Induced Hearing Loss Among Tanzanian Iron and Steel Workers: A Cross-Sectional Study.

Iron and steel factory workers in Tanzania are likely to develop noise-induced hearing loss (NIHL) due to exposure to high sound levels. Studies on hearing status in this population are lacking. The aims of this study were to determine prevalence of NIHL among iron and steel workers and compare hearing thresholds at different frequencies with a control group. We conducted a cross-sectional study among 221 iron and steel workers exposed to average noise level of 92 dB(A), compared with 107 primary school teachers recruited as controls and exposed to average noise level of 79.7 dB(A). We used a questionnaire-based interview to collect information on socio demographic characteristics and other confounding variables. Hearing loss was defined as hearing threshold levels ≥25 dB hearing loss in either ear at 3000, 4000 or 6000 Hz. The prevalence of hearing loss was significantly higher among the exposed group than among the controls, i.e. 48% and 31%, respectively. There were significant differences in hearing thresholds between the exposed and control groups at 3000, 4000, 6000, and 8000 Hz. Hearing loss was more frequent among workers exposed to higher noise levels than among the controls suggesting that iron and steel workers run a higher risk of developing hearing loss.

Determinants of airborne benzene evaporating from fresh crude oils released into seawater.

Benzene, toluene, ethylbenzene, xylenes, naphthalene and n-hexane evaporating from a thin oil film was measured for 30 min in a small-scale test system at 2 and 13 °C and the impact of physicochemical properties on airborne benzene with time after bulk oil release was studied. Linear mixed-effects models for airborne benzene in three time periods; first 5, first 15 and last 15 min of sampling, indicated that benzene content in fresh oil, oil group (condensate/light crude oil) and pour point were significant determinants explaining 63-73% of the total variance in the outcome variables. Oils with a high pour point evaporated considerably slower than oils with a low pour point. The mean air concentration of total volatile organic compounds was significatly higher at 13 °C (735 ppm) compared to 2 °C (386 ppm) immediately after release of oil, but at both temperatures the concentration rapidly declined.

Maternal exposure to gasoline and exhaust increases the risk of childhood leukaemia in offspring - a prospective study in the Norwegian Mother and Child Cohort Study.

BACKGROUND: In the prospective population-based Norwegian Mother and Child Cohort Study (MoBa), comprising 113 754 offspring, we investigated the association between parental exposure to "gasoline or exhaust", as a proxy for benzene exposure, and childhood leukaemia. METHODS: Around gestational week 17, mothers and fathers responded to a questionnaire on exposure to various agents during the last 6 months and 6 months  pre-conception, respectively. Benzene exposure was assessed through self-reported exposure to "gasoline or exhaust". Cases of childhood leukaemia (n = 70) were identified through linkage with the Cancer Registry of Norway. Risk was estimated by hazard ratios (HRs) with 95% confidence intervals (95%CI), comparing offspring from exposed and unexposed parents using a Cox regression model. RESULTS: Maternal exposure to "gasoline or exhaust" was associated with an increased risk of childhood leukaemia (HR = 2.59; 95%CI: 1.03, 6.48) and acute lymphatic leukaemia (HR = 2.71; 95%CI: 0.97, 7.58). There was an increasing risk for higher exposure (p value for trend = 0.032 and 0.027). The association did not change after adjustment for maternal smoking. CONCLUSION: In spite of rather few cases, the findings in this prospective study, with the exposure metric defined a priori, support previous observations relating maternal exposure to benzene from gasoline and other petroleum-derived sources and the subsequent development of childhood leukaemia in the offspring.

Variability and Determinants of Occupational Noise Exposure Among Iron and Steel Factory Workers in Tanzania.

Background: Machines, processes, and tasks in the iron and steel factories may produce noise levels that are harmful to hearing if not properly controlled. Studies documenting noise exposure levels and related determinants in sub-Saharan Africa, including Tanzania are lacking. The aim of this study was to document noise exposure and to identify determinants of noise exposure with a view to establishing an effective hearing conservation programme. Methods: A walk-through survey was conducted to describe the working environment in terms of noise sources in four metal factories (A-D) in Tanzania. Noise measurements were conducted by both personal, full-shift noise measurements (8 h) using dosimeters and area measurements (10-s measurements) using a sound level meter. A total of 163 participants had repeated personal noise measurements (Factory A: 46 participants, B: 43, C: 34, and D: 40). Workers were randomly selected and categorized into 13 exposure groups according to their job. Linear mixed effects models were used to identify significant determinants of noise exposure in the furnace section and the rolling mill section. Results: The average personal noise exposure in the four factories was 92.0 dB(A) (range of job group means; 85.4-96.2 dB(A)) (n = 326). Personal exposure was significantly higher in the rolling mill section (93.0 dB(A)) than in the furnace section (89.6 dB(A)). Among the job groups, the cutters located in the rolling mill section had the highest noise exposure (96.2 dB(A)). In the furnace section, furnace installation (below the ground floor), manual handling of raw materials/billets/crowbars, and billet weighing/transfer were significant determinants explaining 40% of the total variance in personal noise exposure. In the rolling mill section, the size of the cutting machine, steel billet weight and feeding re-heating furnace explained 46% of the total variance in personal noise exposure. The mean noise level of the area measurements was 90.5 dB(A) (n = 376). Conclusion: Workers in the four iron and steel factories in Tanzania were exposed to average noise of 92.0 dB(A), without using hearing protection, implying a high risk of developing hearing loss. Task and factory level determinants were identified in the furnace and the rolling mill sections of the plant, which can inform noise control in factories with similar characteristics.

Biomonitoring of Benzene and Effect of Wearing Respirators during an Oil Spill Field Trial at Sea.

Objectives: The main aim of this study was to assess the biological uptake of benzene and polycyclic aromatic hydrocarbons (PAHs) for subjects exposed to fresh crude oil released at sea. Methods: The study included 22 subjects participating in an 'oil-on-water' field trial in the North Sea. Over 2 consecutive days, there were six releases with two different types of fresh crude oils. Exposed subjects (n = 17) were either located in small, open-air boats downwind and close to the released oil (<50 m) or on the main deck of two large vessels further from the released oil (100-200 m). Subjects assumed to be unexposed (n = 5) were located indoors on the command bridge of either vessel. Full-shift personal benzene exposure was monitored with passive thermal desorption tubes (ATD-tubes) packed with Tenax TA and subsequent gas chromatographic analysis. Urine samples were collected before and after work-shift on both days and analyzed for urinary markers of benzene [(S-phenylmercapturic acid (SPMA)] and PAHs [1-hydroxypyrene (1-OH)]. Information about the use of personal protective equipment, smoking habits, location, work tasks, and length of work-shift were recorded by a questionnaire. Results: Subjects located in the small boats downwind and close to the released oil were exposed to relatively high concentrations of benzene (arithmetic mean = 0.2 ppm, range 0.002-1.5 ppm) compared to the occupational exposure limits (OELs) for 8 h (1 ppm) and 12 h (0.6 ppm). Although respirators were available to all exposed subjects, SPMA was detected in post-shift urine (0.5-3.3 µmol mol-1) of five exposed subjects reporting not wearing respirators, all located in the small boats downwind and close to the released oil. For exposed subjects wearing respirators (n = 12), the post-shift urinary SPMA was below the detection limit (0.8 µmol mol-1) even when the benzene exposure exceeded the OELs. Urinary levels of PAH were within the reference range of what is considered as background levels (<0.4 µmol mol-1). Conclusions: During the initial stages of a bulk oil spill at sea, when the evaporation of benzene is at its highest, it is important to use appropriate respirators to prevent biological uptake of benzene.

Aromatic hydrocarbons and risk of skin cancer by anatomical site in 25 000 male offshore petroleum workers.

BACKGROUND: We prospectively examined skin cancer risk according to occupational exposure to aromatic hydrocarbons with adjustment for ultraviolet radiation exposure, in a cohort of 24 917 male offshore petroleum workers. METHODS: Hazard ratios (HRs) and 95% confidence intervals were estimated with Cox regression adapted to a stratified case-cohort design. RESULTS: During 13.5 years of follow-up, 112 cutaneous melanomas (CMs) and 70 non-melanoma skin cancers were identified. Increased risks of CM and of squamous cell carcinoma on the forearm and hand were seen among those ever exposed to crude oil or benzene. For skin cancers of the forearm and hand combined, cumulative and duration metrics of benzene exposure showed Ptrends of 0.031 and 0.003, respectively. CONCLUSIONS: Our results support an association between exposure to crude oil or benzene and skin cancer risk on hands and forearms among offshore petroleum workers. Dermal uptake of polycyclic aromatic hydrocarbons or benzene may explain this association.

Oil Spill Field Trial at Sea: Measurements of Benzene Exposure.

OBJECTIVES: Characterize personal exposure to airborne hydrocarbons, particularly carcinogenic benzene, during spill of two different fresh crude oils at sea. METHODS: The study included 22 participants taking part in an «oil on water¼ field trial in the North Sea. Two types of fresh crude oils (light and heavy) were released six times over two consecutive days followed by different oil spill response methods. The participants were distributed on five boats; three open sampling boats (A, B, and C), one release ship (RS), and one oil recovery (OR) vessel. Assumed personal exposure was assessed a priori, assuming high exposure downwind and close to the oil slick (sampling boats), low exposure further downwind (100-200 m) and upwind from the oil slick (main deck of RS and OR vessel), and background exposure indoors (bridge of RS/OR vessel). Continuous measurements of total volatile organic compounds in isobutylene equivalents were performed with photoionization detectors placed in all five boats. Full-shift personal exposure to benzene, toluene, ethylbenzene, xylenes, naphthalene, and n-hexane was measured with passive thermal desorption tubes. RESULTS: Personal measurements of benzene, averaged over the respective sample duration, on Day 1 showed that participants in the sampling boats (A, B, and C) located downwind and close to the oil slick were highest exposed (0.14-0.59 ppm), followed by participants on the RS main deck (0.02-0.10 ppm) and on the bridge (0.004-0.03 ppm). On Day 2, participants in sampling boat A had high benzene exposure (0.87-1.52 ppm) compared to participants in sampling boat B (0.01-0.02 ppm), on the ships (0.06-0.10 ppm), and on the bridge (0.004-0.01 ppm). Overall, the participants in the sampling boats had the highest exposure to all of the compounds measured. The light crude oil yielded a five times higher concentration of total volatile organic compounds in air in the sampling boats (max 510 ppm) than the heavy crude oil (max 100 ppm) but rapidly declined to <20 ppm within 24 min after release of oil, indicating short periods of exposure. CONCLUSIONS: The personal exposure to benzene downwind and close to the oil slick during spills of light crude oil was relatively high, with concentration levels approaching the occupational exposure limits for several participants. For bulk spill scenarios like in this study, cleanup should not be initiated the first 30-60 min to allow for evaporation, while appropriate personal protective equipment should be used in continuous spills when working downwind and close to the oil slick.