Personal Breathing Zone Air Samples Research Articles

Mixture analysis on associations between semen quality and sperm DNA integrity and occupational exposure to polycyclic aromatic hydrocarbons

The objective of this study was to assess relationships between exposure to PAHs at occupational levels and outcomes of human semen quality and sperm DNA integrity. Personal breathing zone air samples were collected to quantify exposure of 16 targeted PAHs to coke-oven workers at a steel company in southern Taiwan. Semen quality, including concentration, motility, morphology, and viability, were assessed. Sperm DNA fragmentation, 8-oxodGuo, bulky PAH adducts, and benzo[a]pyrene diol epoxide-DNA adducts served as biomarkers for assessment of sperm DNA integrity. The Bayesian Kernel Machine Regression modeling was employed to estimate mixture effects of the PAH mixture on the outcomes of semen quality and sperm DNA integrity and to identify individual compounds of PAH mixtures associated with the mixture effects. Exposure to the PAH mixture was inversely associated with sperm viability, while benzo(b)fluoranthene (B[b]F) was identified as the main predictor for sperm viability. Exposure to the PAH mixture also exhibited a positive trend with sperm DNA fragmentation. B[b]F and benzo(a)anthracene (B[a]A) were identified as individual PAH compounds associated with increased sperm DNA fragmentation.

Mixture Analyses on Polycyclic Aromatic Hydrocarbons: An Example Using Semen Quality Biomarkers and Bayesian Kernel Machine Regression

This study aimed to assess mixture effects of 16 targeted PAHs on male reproductive health by applying a novel grouping approach to the Bayesian kernel machine regression (BKMR) model. Bay region and molecular weight served as two variables to group the PAH mixture for hierarchical variable selection of BKMR. Personal breathing zone air samples were collected to quantify levels of the PAH compounds. Sperm quality was assessed using motility, viability, morphology, while DNA fragmentation served as the biomarker for assessing sperm DNA integrity. BKMR revealed joint effects of the PAH mixture on sperm quality. The bay region grouping was the important component for estimating associations between exposure to the PAH mixture and sperm DNA fragmentation. The low molecular weight grouping played a less important role for assessing the effects of the PAH mixture on sperm motility and viability. An individual PAH compound, benzo(ghi)perylene, was negatively associated with sperm morphology while benzo(b)fluoranthene and benzo(a)anthracene were positively associated with sperm DNA fragmentation. In conclusion, the BKMR model, along with the grouping approach, was suitable to determine the effects of PAH mixtures on sperm quality and DNA integrity.

Evaluation of Asbestos Exposure Associated with Research Laboratories

Asbestos containing materials (ACM) have been used for decades in research laboratory products including gloves, tong sleeves, Transite board, and other materials. These materials typically contain chrysotile asbestos with concentrations ranging up to 80%. The objective of this research was to evaluate asbestos exposure from gloves, tong sleeves, and Transite board with simulated laboratory use. An environmental chamber was used to simulate laboratory application of the products. Bulk samples of various products were tested before and after use. Personal breathing zone air samples as well as one cumulative air sample were collected during testing and followed the National Institute for Occupational Safety and Health (NIOSH) 7400/7402 methodologies. Phase contrast microscopy (PCM) and transmission electron microscopy (TEM) were used for sample analyses. Analysis of air samples using PCM, showed airborne fiber concentrations as high as 0.058 f/cc during use of tongs fitted with asbestos sleeves. Further analysis using TEM showed that the highest airborne fiber concentration was 0.0036 f/cc. Manipulation of Transite board resulted in 8-hour time-weighted-average (TWA) asbestos levels as high as 0.02 f/cc. Testing of various asbestos containing materials used in research laboratories indicate low potential for asbestos fiber exposures.

Respirable crystalline silica exposures during asphalt pavement milling at eleven highway construction sites

ABSTRACT Asphalt pavement milling machines use a rotating cutter drum to remove the deteriorated road surface for recycling. The removal of the road surface has the potential to release respirable crystalline silica, to which workers can be exposed. This article describes an evaluation of respirable crystalline silica exposures to the operator and ground worker from two different half-lane and larger asphalt pavement milling machines that had ventilation dust controls and water-sprays designed and installed by the manufacturers. Manufacturer A completed milling for 11 days at 4 highway construction sites in Wisconsin, and Manufacturer B completed milling for 10 days at 7 highway construction sites in Indiana. To evaluate the dust controls, full-shift personal breathing zone air samples were collected from an operator and ground worker during the course of normal employee work activities of asphalt pavement milling at 11 different sites. Forty-two personal breathing zone air samples were collected over 21 days (sampling on an operator and ground worker each day). All samples were below 50 µg/m3 for respirable crystalline silica, the National Institute for Occupational Safety and Health recommended exposure limit. The geometric mean personal breathing zone air sample was 6.2 µg/m3 for the operator and 6.1 µg/m3 for the ground worker for the Manufacturer A milling machine. The geometric mean personal breathing zone air sample was 4.2 µg/m3 for the operator and 9.0 µg/m3 for the ground worker for the Manufacturer B milling machine. In addition, upper 95% confidence limits for the mean exposure for each occupation were well below 50 µg/m3 for both studies. The silica content in the bulk asphalt material being milled ranged from 7–23% silica for roads milled by Manufacturer A and from 5–12% silica for roads milled by Manufacturer B. The results indicate that engineering controls consisting of ventilation controls in combination with water-sprays are capable of controlling occupational exposures to respirable crystalline silica generated by asphalt pavement milling machines on highway construction sites.

Lead Exposure and Blood Pressure among Workers in Diverse Industrial Plants in Kenya

The study evaluated airborne exposures and blood lead (BPb) levels in 233 production workers at six diverse industrial plants in Kenya. Blood and personal breathing zone air samples were collected and analyzed for lead (Pb) using atomic absorption spectroscopy. Blood pressure (BP) levels were measured using a standard mercury sphygmomanometer. The results indicated mean airborne Pb levels ± standard deviation (SD) as follows: 183.2 ± 53.6 μg/m3 in battery recycling, 133.5 ± 39.6 μg/m3 in battery manufacturing, 126.2 ± 39.9 μg/m3 in scrap metal welding, 76.3 ± 33.2 μg/m3 in paint manufacturing, 27.3 ± 12.1 μg/m3 in a leather manufacturing, and 5.5 ± 3.6 μg/m3 in a pharmaceutical plant. The mean airborne Pb levels exceeded the U.S. Occupational Safety and Health Administration (OSHA) 8-hr time-weighted average (TWA) permissible exposure limit (PEL) for Pb of 50 μg/m3 in the battery manufacturing, battery recycling, welding, and paint manufacturing plants. Similarly, mean BPb concentrations exceeded the American Conference of Governmental Industrial Hygienists (ACGIH®) biological exposure index (BEI) for Pb of 30 μg/dl. A significant positive association was observed between BPb and breathing zone air Pb (R2 = 0.73, P < 0.001). Approximately 30% of the production workers (N = 233) were in the hypertensive range with an average systolic and diastolic blood pressure (BP) of 134.7 ± 12.7 mmHg and 86.4 ± 8.9 mmHg, respectively. In the multivariate regression analysis, age, duration of work, airborne Pb and BPb levels were significantly associated (P < 0.05) with a change in BP. We recommend improved engineering controls, work practices, and personal hygiene to reduce Pb exposures. In addition, workers should undergo comprehensive medical surveillance to include BPb and BP testing, and airborne Pb assessments in all industries with significant lead exposures.

Biomonitoring Study of Dry Cleaning Workers Using Cytogenetic Tests and the Comet Assay

Perchloroethylene (PCE) is the main solvent used in the dry cleaning industry worldwide. The aim of the present work was to evaluate the genotoxic potential of occupational exposure to PCE in dry cleaning workers. The study was carried out in 59 volunteers (30 workers, 29 controls). The genotoxic effect was evaluated by analyzing chromosome aberrations (CAs), and micronuclei (MN) and DNA damage (assessed by the comet assay) in peripheral blood lymphocytes. Environmental monitoring of exposure was carried out on personal breathing zone air samples collected during two consecutive working days by measuring the concentration of PCE air levels. The mean PCE concentration in workplace air of dry cleaning workers was 31.40 mg/m3. There were no significant differences in CA frequency between dry cleaning workers and the controls, but analysis showed a significant association of CA frequency with employment duration and frequency of exposure to PCE. The MN frequency and DNA damage detected by alkaline comet assay were significantly increased in dry cleaning workers compared to the controls. The results suggest that (a) chronic occupational exposure to dry cleaning solvents below permissible occupational exposure limit of 70 mg/m3 (i.e., ∼10.3 ppm) may lead to an increased risk of genetic damage among dry cleaning workers, and (b) CA, MN tests, and comet assay are useful to monitor populations exposed to low doses of PCE.

Assessing Formaldehyde Exposure in Your Gross Lab: Occupational Exposure Limits and Best Practices

Anatomists’ formaldehyde exposures often exceed Occupational Exposure Limits (OELs) set to minimize risks of cancer, allergy and irritation. OELs vary worldwide. The U.S. OSHA regulatory 8‐hour OEL is 0.75 ppm with an Action Level of 0.5 ppm. The 15‐minute Short Term Exposure Limit is 2 ppm. The American Conference of Governmental Industrial Hygienists (ACGIH) recommends a lower Ceiling Limit of 0.3 ppm, which is in use by many countries and is designed to prevent eye and upper respiratory tract irritation. Personal breathing zone air samples are preferred and are typically &gt;2 times higher than area samples. Short‐term sampling captures worst case exposures such as initial dissection of the cranium, abdomen and thoracic cavity. Passive, active and real‐time techniques each have benefit and will be discussed along with the value of using credentialed industrial/occupational hygienists, validated sampling methods and accredited laboratories where available. In the U.S., formaldehyde levels at or above the OSHA Action Level of 0.5 ppm trigger required signage, training, medical monitoring, and personal protective equipment. The challenges of formaldehyde respirator use in gross anatomy labs will be reviewed via a case study. Risk management of sensitive individuals due to pregnancy, asthma or formaldehyde allergy and unregulated individuals such as students and volunteers will also be addressed.

An engineering intervention resulting in improvement in lung function and change in urinary 8-hydroxydeoxyguanosine among foundry workers in Taiwan

To assess changes in oxidative DNA damage and lung function amongst a group of foundry workers resulting from an engineering intervention to reduce air respirable dust in their working environment. We studied all 22 workers recruited from a typical small Taiwanese iron foundry plant before and 3 months after improvements to air exhaust control. The effectiveness of the air exhaust intervention in reducing respirable dust and SiO₂ was determined by personal breathing-zone air sampling. Initial baseline biomarker measurements were taken of lung function and urinary 8-hydroxy-deoxyguanosine (8-OHdG) in all of the workers, with follow-up measurements taken 3 months after the engineering control was put in place. Generalized estimating equations were used to assess the effect of the intervention on lung function and oxidative DNA damage. Following the intervention, respirable dust density decreased from 2.87 ± 1.38 mg/m³ to 1.60 ± 0.70 mg/m³ (p = 0.07), and SiO₂ concentration decreased from 0.43 ± 0.25 mg/m³ to 0.18 ± 0.11 mg/m³ (p < 0.05). Compared to initial baseline, significant improvements were found in lung function (FVC, FEV1, FVC%pred and FEV1%pred) amongst the workers after the engineering intervention. A significant increase in concentration of urinary 8-OHdG was observed after the engineering intervention in smokers, but not in non-smokers. These findings indicate that reductions in workplace respirable dust and SiO₂ concentration can result in improved lung function amongst foundry workers.

Engineering Control Technologies to Reduce Occupational Silica Exposures in Masonry Cutting and Tuckpointing

A number of tasks in construction generate worker overexposures to respirable crystalline silica dust, which is a significant contributor to occupational mortality and morbidity. This study evaluated the performance of commercially available engineering controls used in dusty construction tasks commonly performed by bricklayers. Local exhaust ventilation (LEV) controls for a portable abrasive cutter and for tuckpointing grinders were examined at a bricklayers' training center, as were two stationary wet saws. Personal breathing zone air samples were collected with and without the use of LEV or water suppression during simulated concrete block cutting, brick cutting, and tuckpointing. Compared with the use of no exposure control during block and brick cutting, the portable LEV unit significantly reduced mean respirable quartz exposures by 96% for block cutting and 91% for brick cutting (p < 0.01). The use of stationary wet saws was also associated with 91% reductions in exposure (p < 0.01). For tuckpointing, the reductions in mean respirable quartz concentrations were between 91% and 93% with the LEV controls (p < 0.05). Reductions of up to 96% in mean respirable quartz concentration were observed between control and no-control scenarios. These reductions with commercially available off-the-shelf tools demonstrate the effectiveness of engineering control interventions to reduce crystalline silica exposures in construction. Strategies to further improve control performance and approaches for increasing control interventions in construction are needed.

Environmental Tobacco Smoke: Incomplete Research or Author Bias?

Environmental Tobacco Smoke: Incomplete Research or Author Bias?

Predictors of occupational exposure to styrene and styrene-7,8-oxide in the reinforced plastics industry

Objective: To identify demographic and work related factors that predict blood levels of styrene and styrene-7,8-oxide (SO) in the fibreglass reinforced plastics (FRP) industry. Methods: Personal breathing-zone air samples and...

A control technology evaluation of state-of-the-art, perchloroethylene dry-cleaning machines.

NIOSH researchers evaluated the ability of fifth-generation dry-cleaning machines to control occupational exposure to perchloroethylene (PERC). Use of these machines is mandated in some countries; however, less than 1 percent of all U.S. shops have them. A study was conducted at a U.S. dry-cleaning shop where two fifth-generation machines were used. Both machines had a refrigerated condenser as a primary control and a carbon adsorber as a secondary control to recover PERC vapors during the dry cycle. These machines were designed to lower the PERC concentration in the cylinder at the end of the dry cycle to below 290 ppm. A single-beam infrared photometer continuously monitors the PERC concentration in the machine cylinder, and a door interlock prevents opening until the concentration is below 290 ppm. Personal breathing zone air samples were measured for the machine operator and presser. The operator had time-weighted average (TWA) PERC exposures that were less than 2 ppm. Highest exposures occurred during loading and unloading the machine and when performing routine machine maintenance. All presser samples were below the limit of detection. Real-time video exposure monitoring showed that the operator had peak exposures near 160 ppm during loading and unloading the machine (below the OSHA maximum of 300 ppm). This exposure (160 ppm) is an order of magnitude lower than exposures with more traditional machines that are widely used in the United States. The evaluated machines were very effective at reducing TWA PERC exposures as well as peak exposures that occur during machine loading and unloading. State-of-the-art dry-cleaning machines equipped with refrigerated condensers, carbon adsorbers, drum monitors, and door interlocks can provide substantially better protection than more traditional machines that are widely used in the United States.

Doses and lung burdens of environmental tobacco smoke constituents in nonsmoking workplaces.

This paper models nicotine dose and ultraviolet-absorbing particulate matter (UVPM) alveolar lung burden resulting from exposure to environmental tobacco smoke (ETS) for nonsmokers in workplaces where smoking was reported not to occur. Data were obtained from personal monitoring of ETS in 16 U.S. cities [Jenkins R.A., Guerin M.R., Palausky A., Counts R.W., Bayne C.K., and Dindal A.B. Determination of human exposure to environmental tobacco smoke (ETS): a study conducted in 16 U.S. cities. Draft final report by Oak Ridge National Laboratory for Center for Indoor Air Research, Linthicum, MD, 1996a; Jenkins R.A., Palausky A., Counts R.W., Bayne C.K., Dindal A.B., and Guerin M.R. Exposure to environmental tobacco smoke in sixteen cities in the United States as determined by personal breathing zone air sampling. J. Expos. Anal. Environ. Epidemiol. 1996b: 6(4): 473-502.]. This is a continuation of earlier analyses focusing on nonsmokers in smoking workplaces (SWs) [LaKind J.S., Graves C.G., Ginevan M.E., Jenkins R.A., Naiman D.Q., and Tardiff R.G. Exposure to environmental tobacco smoke in the workplace and the impact of away - from - work exposure. Risk Anal. 1999a: 19(3): 349-358; LaKind J.S., Jenkins R.A., Naiman D.Q., Ginevan M.E., Graves C.G., and Tardiff R.G. Use of environmental tobacco smoke constituents as markers for exposure. Risk Anal. 1999b: 19 (3): 359-373; LaKind J.S., Ginevan M.E., Naiman D.Q., James A.C., Jenkins R.A., Dourson M.L., Felter S.P., Graves C.G., and Tardiff R.G. Distribution of exposure concentrations and doses for constituents of environmental tobacco smoke. RiskAnal. 1999c: 19 (3): 375-390.]. Even though study participants characterized their workplaces as nonsmoking, some individuals reported observing cigarettes in the workplace. Individuals observing six or more cigarettes were excluded from the analysis on the grounds that they were in defacto SWs. Exposure to ETS was lower in nonsmoking than SWs, but even with this exclusion, exposure was not zero. Distributions were selected for each model input, and at least 2000 iterations of the model were made for each dose or lung burden characterization (e.g., for females, for males). In these nonsmoking workplaces (NSWs), neither nicotine nor UVPM concentrations were lognormally distributed. Hence, observed concentrations were used directly via bootstrap sampling (nicotine) or a constant number of times (UVPM) as input to the models. As in SWs, individuals from smoking homes (SHs) experienced greater exposure in NSWs to both nicotine and UVPM than did individuals from nonsmoking homes (NSH; P<0.001 ). The distributions of modeled nicotine dose and UVPM lung burden were highly skewed, with most individuals receiving relatively low exposure to ETS in the workplace. Comparing doses from NSWs modeled here to doses from SWs modeled previously, less difference between smoking and NSWs was apparent in UVPM levels than in nicotine levels. For average exposure, UVPM alveolar lung burdens were approximately 10-fold higher in smoking than NSWs, while average nicotine doses were 20-25 times higher in smoking than NSWs. These findings are in the range observed by other investigators and are partly explained by very low denominators in the ratios (i.e., very low levels experienced in NSWs). For upper bound exposure, the nonsmoking-to-smoking ratios remained about the same for UVPM. For nicotine, the upper bound ratios remained the same for people from NSHs but were halved for people from SHs.

Manganese dioxide exposures and respirator performance at an alkaline battery plant.

Two industrial hygiene studies were conducted at an alkaline battery plant to evaluate worker exposures to manganese dioxide particulate and the effectiveness of filtering facepiece respirators. The work areas studied included the plant's powder-processing tower and press rooms where manganese was blended, compacted with graphite, and inserted into battery cans. Full-shift personal breathing zone monitoring was conducted to estimate manganese dust exposures of press operators, mechanics, and material handlers. In-facepiece and personal breathing zone air sampling pairs were also collected using a program protection factor protocol to estimate the protection provided by the respirators. Particle size evaluations were made using nylon cyclones and Marple personal multi-stage impactors. All samples were analyzed for manganese by inductively coupled argon plasma, atomic emission spectroscopy via NIOSH analytical method 7300 utilizing a modified acid digestion procedure. Fifty-four, full-shift, time-weighted average (TWA) exposures to total manganese ranged from 0.1 to 5.4 milligrams per cubic meter (mg/m3); worker exposures were substantially lower during a follow-up study due to engineering control improvements. Concurrent area sample comparisons of total and respirable manganese revealed that the respirable particulate mass fractions ranged from 6 to 32 percent, and mass median aerodynamic diameters determined from personal breathing zone air samples were mostly greater than 10 micrometers. Fifteen respirator performance evaluations were conducted using Moldex 2200 respirators fitted with 25 millimeter cassettes and light weight sampling probes. Protection factors ranged from 5 to 220, with a geometric mean and standard deviation of 31 and 2.97, respectively. The 5th percentile protection factor estimate was 5, as calculated from the protection factor distribution for this sample set. In 1995, the American Conference of Governmental Industrial Hygienists (ACGIH) lowered the elemental and inorganic manganese dust Threshold Limit Value (TLV) from 5 mg/m3 to 0.2 mg/m3 to address adverse pulmonary and central nervous system effects and male infertility. Although most personal breathing zone concentrations were above 0.2 mg/m3, none of the in-facepiece concentrations exceeded this concentration. Parkinson's-like symptoms have been reported in the literature for high manganese dust and fume exposures, but the importance of low dust exposures for producing neurological effects is uncertain.

Personal exposure to environmental tobacco smoke: salivary cotinine, airborne nicotine, and nonsmoker misclassification.

A large study was conducted to assess exposure to environmental tobacco smoke (ETS) in a geographically dispersed study population using personal breathing zone air sampling and salivary cotinine levels. Approximately 100 self-reported nonsmoking subjects in each of 16 metropolitan areas were recruited for this investigation. Cumulative distributions of salivary cotinine levels for subjects in smoking and nonsmoking homes and workplaces exhibited a general trend of decreasing salivary cotinine levels with decreasing time spent in smoking environments. Median salivary cotinine levels for the four experimental cells in the study (product of smoking and nonsmoking home and workplaces) were comparable to those reported for a large national study of serum levels of cotinine (Third National Health and Nutrition Examination Survey, NHANES III), when the latter was corrected for expected differences between serum and saliva concentrations. However, the most highly exposed group in this study had a median salivary cotinine concentration approximately a factor of 2 greater than that of the comparable group in the NHANES III study. Misclassification rates, both simple (for self-reported nonsmokers) and complex (self-reported lifetime never smokers), were near the median of those reported for other studies. Estimated misclassification rates for self-reported lifetime never-smoking females are sufficiently high (2.95% using a discrimination level of 106 ng/ml) that, if used in the Environmental Protection Agency (EPA) risk assessment related to ETS and lung cancer, would place the lower 90% confidence interval (CI) for relative risk at nearly 1.00, i.e., no statistically significant increased risk. For the 263 most highly exposed subjects in the study whose self-reported nonsmoking status was accurate, the correlation between airborne exposure to nicotine and average salivary cotinine is so small, on an individual basis, that it makes the relationship useless for estimating exposure on a quantitative basis. When subjects are grouped according to likely categories of nicotine exposure, correlation between group median airborne nicotine exposure and salivary cotinine level increases dramatically. The comparison improves for the most highly exposed subjects, suggesting that such quantitative comparisons are useful for only those subjects who are exposed to the higher levels of ETS. However, airborne nicotine exposure for most of the subjects does not account for estimated systemic levels of nicotine, based on salivary cotinine levels.

Immunochemical quantification and particle size distribution of airborne papain in a meat portioning facility.

The use of enzymes in industry continues to expand. With this increased use comes a concerted need to better understand potential respiratory health hazards to exposed workers and to quantify exposure levels that cause impaired health. To this end, projects were undertaken by the National Institute for Occupational Safety and Health (NIOSH) Health Hazard Evaluations Program and Cole Associates whereby this information was collected. Data concerning medical evaluation and aspects of industrial hygiene are the subjects of two separate reports from these respective groups. This method/results report includes a description of (1) a sensitive immunoradiometric assay for the quantification of airborne papain and its particle size distribution, (2) measurement of papain from both general area and personal breathing zone air samples obtained from a meat processing plant that used this immunochemical analysis, (3) a sampling strategy, and (4) an improved air sample processing technique. Airborne papain was measured at levels ranging from low nanogram to microgram per cubic meter concentrations. Approximately half of the papain activity was associated with particles having an aerodynamic diameter of less than 9.4 microns. These data point to a need for containment and controls in the manufacture and use of such compounds. This approach can be considered by the hygienist as an effective tool to be used in conjunction with epidemiologic studies to help set standards that are practical, safe, and maintained.

Overexposures to Lead at a Covered Outdoor Firing Range

Significant overexposures to airborne lead were found in a covered, outdoor firing range among seven cadets during firing of conventional, nonjacketed, lead bullets. The mean lead concentrations in general area air samples and personal-breathing-zone air samples were 68.36 μg/m3 and 128.46 μg/m3, respectively, calculated as an 8h, time-weighted average (TWA). Eight (44%) of 18 area air samples, taken as far as 50 yards from the firing line, and 10 (67%) of 15 personal breathing zone air samples exceeded the current Occupational Safety and Health Administration (OSHA) standard for occupational exposure to airborne lead (50μg/m3). Blood lead levels (using a t-test) were found to increase significantly in all cadets after day 2 ( p &lt; 0.0001) and day 5 ( p &lt; 0.0007) of firing conventional, nonjacketed, lead bullets. None of the blood level values exceeded the OSHA standard of 40 μg/dl. A strong positive correlation ( r = 0.92; p &lt; 0.000001) existed between personal-breathing-zone air lead levels and the number of rounds fired by the cadets. A positive correlation also existed between blood lead levels and cumulative personal breathing zone air lead levels ( r = 0.85; p &lt; 0.02), as well as the total number of rounds fired ( r = 0.84; p &lt; 0.02). Based on environmental and medical data, it was concluded that a potential health hazard may exist due to inorganic lead exposure to cadets at this covered outdoor range during firing exercises.

An analysis of exposure to styrene in the reinforced plastic boat-making industry.

To evaluate patterns of occupational exposure to styrene monomer in the boat-building industry, we conducted industrial hygiene surveys in seven fiberglass-reinforced plastic boat-fabrication plants. A total of 397 personal breathing zone air samples were collected on workers in four key job categories: gel coating and hull, deck, and small-parts lamination. We found that exposure to styrene in 234 (59%) of the personal samples exceeded the NIOSH-recommended time-weighted average (TWA) standard of 50 parts per million (ppm), and 96 (24%) of these samples exceeded the OSHA eight-hour TWA permissible exposure limit of 100 ppm. From highest to lowest average exposure potential, the job categories ranked in the following order: hull lamination (range 2-183 ppm, mean 78 ppm), deck lamination (range 12-160 ppm, mean 73 ppm), gel coating (range 5-94 ppm, mean 48 ppm), and small-parts lamination (range 9-130 ppm, mean 45 ppm). The former two categories composed a higher-exposure group, and the latter two tended to form a lower-exposure group. Exposures in these jobs appear to be proportional to resin consumption. Statistical analyses indicated that the parameter that most affects exposure potential is job category. Within a job category, part size, configuration, and surface area are important determinants of exposure. The principal reason for high exposures was the absence of control technologies and, in particular, the absence of adequate ventilation.

Failure of enzyme encapsulation to prevent sensitization of workers in the dry bleach industry

BDE added to dry bleach have been associated with immunologic sensitization and development of clinical allergic disease in detergent workers and occasionally in consumers. However, improved dust control and modification of the manufacturing process through encapsulation of enzyme were believed to have reduced or eliminated these problems. To determine whether or not immunologic sensitization could still develop in the detergent industry, we studied employees of a dry bleach manufacturing plant that incorporated encapsulated BDE into a consumer product. We performed air sampling for enzyme dust and total particulates, administered questionnaires, conducted physical examinations, and spirometry in 13 currently exposed, two previously exposed and nine nonexposed, employees. To assess sensitization status, RAST and ELISA were performed. Air concentrations of enzyme dust ranged from 0.002 to 1.57 μ/m 3; all of these levels were below the TLV of 3.9 μ/ 3. Positive BDE—specific RAST results (3.4%, 4.4%, and 8.0% binding) were obtained in three of 12 currently exposed workers. Results of personal breathing—zone air sampling indicated that these workers had high dust-exposure levels. Specificity of RAST was verified by RAST inhibition with BDE. BDE-RAST binding was not significantly elevated in the nonworkers (range: 0.6% to 1.4% binding). Positive results for specific IgG by ELISA were obtained in four of 12 currently exposed and in one of two previously exposed workers but in none of the nonexposed workers. We conclude that immunologic sensitization can develop after occupational exposure to encapsulated BDE in the dry bleach industry. We have not proved, however, that this immunologic reactivity is related to clinical sensitivity.