Clinical and immunological responses to occupational exposure to alpha-amylase in the baking industry.

alpha-Amylase is a starch cleaving enzyme often used in the baking industry as a flour additive. It is usually of fungal origin, produced by Aspergillus oryzae. One previous report has shown IgE antibodies and positive skin prick test against alpha-amylase in asthmatic bakers. This paper describes four alpha-amylase sensitised index cases with occupational asthma or rhinitis and the results of a cross sectional study of 20 workers from the same factory who were also exposed to alpha-amylase powder. Air sampling detected airborne alpha-amylase at a concentration of 0.03 mg/m3. Significantly more work related symptoms such as rhinitis and dermatitis were found among the alpha-amylase exposed workers compared with referents. A skin prick test to alpha-amylase was positive in 30% (6/20) of the exposed workers. Most of the persons showing a positive skin prick test had work related symptoms and were also skin prick test positive to common allergens. Nasal challenge tests with amylase were performed in selected cases and validated three cases of alpha-amylase induced rhinitis. Two non-symptomatic workers had precipitins to alpha-amylase. Specific IgG antibodies were shown by two further serological techniques. The nature and relevance of these antibodies are currently being studied. It is concluded that alpha-amylase powder is a potent occupational sensitiser. Precautions should be taken when handling this allergenic enzyme.     

Clinical and immunological responses to occupational exposure to alpha-amylase in the baking industry.

alpha-Amylase is a starch cleaving enzyme often used in the baking industry as a flour additive. It is usually of fungal origin, produced by Aspergillus oryzae. One previous report has shown IgE antibodies and positive skin prick test against alpha-amylase in asthmatic bakers. This paper describes four alpha-amylase sensitised index cases with occupational asthma or rhinitis and the results of a cross sectional study of 20 workers from the same factory who were also exposed to alpha-amylase powder. Air sampling detected airborne alpha-amylase at a concentration of 0.03 mg/m3. Significantly more work related symptoms such as rhinitis and dermatitis were found among the alpha-amylase exposed workers compared with referents. A skin prick test to alpha-amylase was positive in 30% (6/20) of the exposed workers. Most of the persons showing a positive skin prick test had work related symptoms and were also skin prick test positive to common allergens. Nasal challenge tests with amylase were performed in selected cases and validated three cases of alpha-amylase induced rhinitis. Two non-symptomatic workers had precipitins to alpha-amylase. Specific IgG antibodies were shown by two further serological techniques. The nature and relevance of these antibodies are currently being studied. It is concluded that alpha-amylase powder is a potent occupational sensitiser. Precautions should be taken when handling this allergenic enzyme.     

Determinants of inhalable dust exposure in the European carbon black manufacturing industry

A large study to investigate the respiratory health effects of occupational exposure to carbon black in the European carbon black manufacturing industry commenced in 1987. During the study, a large amount of personal occupational exposure data was collected. This article describes the empirical models used to study the determinants of inhalable dust exposure, using data from 16 factories collected in the third and last cross-sectional phase of this study. Information on activities during the measurements was collected using short job category-specific questionnaires. In addition, questionnaires were completed by factory representatives on the implementation of control measures and changes in production process since the first cross-sectional phase. Mixed effects analyses of variance models were used to identify determinants of exposure, while taking into account the within- and between-worker (random) variance components. The results of these models show that, for any job category, factory is a strong predictor of exposure in this industry. These differences could not be explained entirely by factors such as age of the factory or the control measures implemented since the first phase of the study. Surprisingly, implementation of local exhaust ventilation systems had an effect that was counterintuitive; for example, in warehouses where local exhaust ventilation systems had been implemented, higher dust exposure levels were found compared to those where such control measures had not been installed since the first cross-sectional survey. Season appeared to have some effect on exposure for some job titles, with generally relatively low exposures being found in the summer. Finally, a number of activities were identified that caused higher levels of dust exposure, most notably "changing of filters" and "clean-up of carbon black spills."     

Variations in exposure to inhalable wood dust in the Danish furniture industry. Within- and between-worker and factory components estimated from passive dust sampling

Variability of exposure to wood dust at large factories in the Danish furniture industry was studied. Three repeated exposure measurements of 292 workers at 38 factories were included in the study. The measurements were carried out by use of personal passive dust monitors. The components of variance were estimated by means of a random effects ANOVA model. The ratio of within- to between-worker variance was 1.07. Based on this result, and three repeated exposure measurements, the observed relation between health outcome and exposure will be attenuated to 74% of the true value. Grouping by factory showed very poor exposure contrast, as the contrast in exposure level among factories was as low as 0.15.     

Exposure to inhalable dust, wheat flour and alpha-amylase allergens in industrial and traditional bakeries

This study was designed to characterize exposure to inhalable dust, wheat flour and alpha-amylase allergens in industrial and traditional bakeries. The study included 70 bakeries from the northern part of Belgium. Based on the degree of automation and a clear division of individual job tasks, four bakeries were identified as industrial and the remaining 66 were identified as traditional ones. Personal, as well as stationary, samples of inhalable dust were collected during full shift periods, usually 5-7 h. The portable pumps aspirated 2 l/min through Teflon personal dust samplers (Millipore, pore size 1.0 microm) mounted in PAS-6 sampling heads. In the collected samples the inhalable dust, wheat flour and alpha-amylase allergens were determined. Wheat flour allergens were measured using enzyme-linked immunosorbent assay inhibition and an antiwheat IgG4 serum pool. The alpha-amylase allergens were measured using a sandwich enzyme immunoassay with affinity-purified polyclonal rabbit IgG antibodies. In total, 440 samples (300 personal and 140 stationary) were processed. The highest inhalable dust exposure was observed in traditional bakeries among bread [geometric mean (GM) 2.10 mg/m3] and bread and pastry workers (GM 1.80 mg/m3). In industrial bakeries the highest dust exposure was measured in bread-producing workers (GM 1.06 mg/m3). Similar relations were observed for wheat flour and alpha-amylase allergens. Bread baking workers in traditional bakeries had the highest exposure to both allergens (wheat flour GM 22.33 microg/m(3), alpha-amylase GM 0.61 ng/m3). The exposure to wheat flour and alpha-amylase allergens in industrial bakeries was higher in bread baking workers (wheat flour GM 6.15 microg/m3, alpha-amylase GM 0.47 ng/m3) than in bread packing workers (wheat flour GM 2.79 microg/m3, alpha-amylase GM 0.15 ng/m3). The data presented suggest that, on average, exposure in the Belgium bakeries studied-industrial as well as traditional-is lower than or similar to bakeries in The Netherlands, Canada, Sweden, the United Kingdom and Finland. Furthermore, the exposure levels in traditional bakeries seem to be higher than in industrial bakeries.     

Enzyme exposure and enzyme sensitisation in the baking industry.

OBJECTIVES: To assess the exposure to enzymes and prevalence of enzyme sensitisation in the baking industry. METHODS: A cross sectional study was conducted in four bakeries, one flour mill, and one crispbread factory. Sensitisation to enzymes, flours, and storage mites was examined by skin prick and radioallergosorbent (RAST) tests. 365 workers were tested. The workers were interviewed for work related respiratory and skin symptoms. Total dust concentrations were measured by a gravimetric method, and the concentration of alpha-amylase in air was measured by a catalytic method. An immunochemical method was used for measuring cellulase and xylanase in air. RESULTS: Total measured dust concentrations were from 0.1 to 18 mg/m3, with highest values in dough making areas of bakeries. The alpha-amylase concentrations generally followed the total dust concentrations and reached the highest values < 6.6 micrograms/m3 in the same areas. Cellulase and xylanase varied with concentrations < 180 ng/m3 and < 40 ng/m3, respectively, in the flour mill and the crispbread factory. No cellulase, but concentrations of 1-200 ng/m3 xylanase, were found in the bakeries, probably indicating the natural xylanase activity of wheat. 12 workers (8%) in the bakeries, three (5%) in the flour mill, and four (3%) in the crispbread factory were skin prick positive to enzymes. The corresponding percentages of positive reactions to flours were 12%, 5%, and 8%. CONCLUSIONS: The study confirmed that industrial enzymes in baking used as additives in a powdered form pose a risk of sensitisation. The no effect air concentrations for industrial enzymes are not known. Based on present knowledge, however, lowering exposures and eliminating short and high peaks by technical measures would lower the risk of sensitisation. This would be most effectively accomplished by shifting to non-dusty products.     

Occupational exposure to inhalable and total aerosol in the primary nickel production industry.

OBJECTIVES--This paper describes a study that was carried out in the primary nickel production industry to investigate the levels of personal exposure to aerosols containing nickel and the impact on exposure assessment of introducing new personal sampling techniques with performance consistent with the latest particle size-selective criteria. METHODS--Experiments were carried out at workplaces in mining, milling, smelting, and refining works to investigate the effect of changing from the current method of total aerosol (with the widely used 37 mm filter holder) to the new method of measuring inhalable aerosol (with the Institute of Occupational Medicine (IOM) inhalable aerosol sampler). RESULTS--The results show that inhalable aerosol exposure concentrations--for both overall aerosol and for total nickel--were consistently and significantly higher than the corresponding total aerosol concentrations. Weighted least squares linear regression yielded IOM/37 mm factors ranging from about 1.2 to 4.0. The exposure data for each company process were found to be log-normally distributed. CONCLUSIONS--The results suggest the possibility of generating a single pragmatic factor for each company process for converting current total aerosol exposures to new exposures based on the inhalability concept contained in the latest particle size-selective criteria for aerosol exposure assessment. Such data may be important in determining new occupational exposure limits for nickel.     

Enzyme exposure in the British baking industry

OBJECTIVES: Enzymes are commonly used in the baking industry, as they can improve dough quality and texture and lengthen the shelf life of the final product. There is little published information highlighting exposure to enzymes (other than fungal alpha-amylase) in the baking industry, therefore the purpose of this study was to identify antibodies and develop assays for the measurement of a variety of such enzymes in samples of airborne flour dust. METHODS: Polyclonal antibodies to bacterial amylase, glucose oxidase and amyloglucosidase were identified and developed into ELISA assays. The assays showed limited cross-reactivity with other enzymes commonly used in the baking industry. RESULTS: We measured levels of airborne enzymes in 195 personal air samples taken from a sample of 55 craft baking establishments. We were able to detect amyloglucosidase in 9% (16/184) of the samples, fungal alpha-amylase in 6% (11/171), bacterial alpha-amylase in 7% (13/195). However, we were unable to detect glucose oxidase in any of the samples. Measurements for protease enzymes were not carried out. Median levels in detectable samples of amyloglucosidase, fungal alpha-amylase and bacterial amylase were similar at 10.3, 5.3 and 5.9 ng/m(3), respectively. These figures represent the total enzyme protein (active and inactive) measured. CONCLUSIONS: There are few data in the literature regarding sensitization and exposure-response relationships to these enzymes, and indeed there is often a lack of information within the industry as to the precise enzyme content of particular baking ingredients. As a precautionary measure, all enzymes are regarded as having the potential to cause respiratory sensitization. Consequently, exposures need to be controlled to as low a level as reasonably practicable, and future investigation may highlight the importance of measuring a variety of enzyme exposures and standardizing these methodologies to inform approaches to adequate control.     

Comparison of four methods to assess fungal alpha-amylase in flour dust

The aim of the study was to compare four different immunological methods to analyse fungal alpha-amylase in flour dust samples. Three European research groups have independently developed four immuno assay based methods to measure alpha-amylase in air samples. Three of the methods use polyclonal antibodies and one method uses monoclonal antibodies. Eighty personal samples have been collected during two to three work-shifts in four bakeries. Sampling was performed with PAS-6 inhalable dust samplers and aliquots from each sample were analysed by the three laboratories. The agreement between the four methods was high compared with agreement between immunological methods to measure other allergens in the air, e.g. for rat allergens. For the three methods with polyclonal antibodies the mean differences for individual samples was less than a factor of two. The arithmetic means (AM) of the estimated alpha-amylase exposure were 12.5, 11.3, 8.6 and 25.9ng/m(3) for the respective methods with values ranging from below the detection limit to 192, 215, 207 and 615 ng/m(3). The AM for all samples analysed by the methods with polyclonal antibodies varied by about a factor of 1.5. About one-third of the values were below or at the detection limit for all methods. In a regression analysis the squared correlation coefficients (R(2)) between the methods varied between 0.91 and 0.95 for the log transformed values. For workplace monitoring, results from the methods using polyclonal antibodies will be relatively comparable. High levels of alpha-amylase might differ in absolute numbers with a factor of two or more between the different methods but will anyway be considered as high and should result in preventive actions. On the other hand, this study also shows that despite the relative agreement between methods, there is a clear need for standardization.     

Trends in levels of inhalable dust exposure, exceedance and overexposure in the European carbon black manufacturing industry

In an attempt to investigate the relationship between exposure to carbon black and respiratory morbidity, a study of the complete carbon black manufacturing industry in Western Europe was commissioned. As part of this study, a large number of personal inhalable (n=8015) dust exposure measurements was taken during three phases of data collection between 1987 and 1995. Repeated measurements on the same worker were taken in the last two phases, which enabled the estimation of the within- and between-worker components of variance. Simultaneously, the fixed effects of phase and factory were estimated using mixed-effects analysis of variance. The results show that the personal inhalable dust exposure has reduced significantly since the first phase of the study. In addition, the interaction term between phase and factory was significant in most job categories, confirming that the reduction of exposure was not equal across all factories.When all factories were considered together, the probability that the mean exposure of a randomly selected worker (overexposure) or the probability that the exposure on a randomly selected day for a randomly selected worker (exceedance) was higher than 3.5mg m(-3), was 10% or less for all job categories in the last phase. However, when the factories were considered separately, it appeared that the probability of overexposure or exceedance was in excess of 10% for the job categories 'Fitter/Welder', 'Warehouseman' and 'Site crew' for a number of factories. Therefore, even though exposure levels of inhalable dust have dropped considerably across the whole carbon black manufacturing industry in Western Europe, further reductions in exposure levels are required in these areas to make sure that the probability of overexposure and exceedance falls below a level of 10%.     

Occupational exposure to dust in quartz manufacturing industry.

Owing to the abundance of a sedimentary rock, 65 small-scale quartz manufacturing enterprises, employing 650 workers, have been established in the region studied. Quartz powder manufacturing involves various processes and operations, such as manual handling of quartz stones, crushing, grinding, sieving, screening, mixing, storing and bagging. Results demonstrate that each of these operations generates high concentrations of airborne 'total' dust and respirable dust, which contain a very high percentage (> 75%) free silica. The estimated average exposure to airborne 'total' dust was 22.5 mg m-3 (Permissible Limit of Exposure 1.08 mg m-3), and respirable dust 2.93 mg m-3 (PLE 0.36 mg m-3). This shows that 'total' dust exposure was 7.7 times higher than respirable dust. Since the present work systems and practices may pose a serious health risk to the workers, public and the environment, suitable preventive and control measures have been suggested for improvement in the workplace.     

Assessment of bioaerosols and inhalable dust exposure in Swiss sawmills

An assessment of wood workers' exposure to airborne cultivable bacteria, fungi, inhalable endotoxins and inhalable organic dust was performed at 12 sawmills that process mainly coniferous wood species. In each plant, samples were collected at four or five different work sites (debarking, sawing, sorting, planing and sawing cockpit) and the efficiency of sampling devices (impinger or filter) for determining endotoxins levels was evaluated. Results show that fungi are present in very high concentrations (up to 35 000 CFU m(-3)) in all sawmills. We also find that there are more bioaerosols at the sorting work site (mean +/- SD: 7723 +/- 9919 CFU m(-3) for total bacteria, 614 +/- 902 CFU m(-3) for Gram-negative, 19 438 +/- 14 246 CFU m(-3) for fungi, 7.0 +/- 9.0 EU m(-3) for endotoxin and 2.9 +/- 4.8 g m(-3) for dust) than at the sawing station (mean +/- SD: 1938 +/- 2478 CFU m(-3) for total bacteria, 141 +/- 206 CFU m(-3) for Gram-negative, 12 207 +/- 10 008 CFU m(-3) for fungi, 2.1 +/- 1.9 EU m(-3) for endotoxin and 0.75 +/- 0.49 mg m(-3) for dust). At the same time, the species composition and concentration of airborne Gram-negative bacteria were studied. Penicillinium sp. were the predominant fungi, while Bacillus sp. and the Pseudomonadacea family were the predominant Gram-positive and Gram-negative bacteria encountered, respectively.     

Exposure levels and determinants of inhalable dust exposure in bakeries

The study's objectives were to measure full-shift exposure to inhalable dust in bakeries and define the determinants of full-shift exposure. Inhalable dust was measured gravimetrically. Ninety-six bakery workers, employed in seven different bakeries, participated in the study. Two side-by-side full-shift inhalable dust samples were obtained from each study participant on a single occasion. Samples were collected on 18 days selected at random. During the entire sampling period, bakers were observed and information on 14 different tasks was recorded at 15 min intervals. Other production characteristics were also recorded for each sampling day. These task and production variables were used in statistical modelling to identify significant predictors of exposure. The mean full-shift inhalable dust exposure was 8.2 mg/m³ (range: 0.1–110 mg/m³). A regression model explained 79% of the variability in exposure. The model indicated that tasks such as weighing, pouring and operating dough-brakers and reversible sheeters increased the exposure, while packing, catching and decorating decreased the exposure. Bread and bun production lines were associated with increased full-shift inhalable dust exposure, while cake production and substitution of dusting with the use of divider oil were associated with decreased exposure. Production tasks and characteristics are strong predictors of personal full-shift exposures to flour dust among bakers; these can be altered to reduce exposure levels.     

Scientific principles and pragmatic solutions for the measurement of exposure to inhalable dust

In order to understand and control the risks presented by inhalation of dust at work, research over many years has been focused on understanding how dust present in the air enters the human nose and mouth during the act of breathing. For health-related dust exposure monitoring, sampling devices are needed that collect the same 'inhalable fraction' of dust as the human head. Mark and Vincent's 1986 paper presented a study that has contributed more than any other to the practical realization of this inhalable dust concept. The authors developed a simple solution--the IOM personal inhalable dust sampler--to what we now know is an extremely complex problem. Although scientific understanding has grown in the years since this paper was published, very few other dust sampling instruments have emerged as being able to meet both the scientific criteria and the practical need for inhalable dust measurement. Both authors have continued to build on this work and have made further contributions to our theoretical and practical understanding in this field.     

Occupational exposure to inhalable wood dust in the member states of the European Union

The aim of this study was to estimate occupational exposure to inhalable wood dust by country, industry, the level of exposure and type of wood dust in 25 member states of the European Union (EU-25) for the purposes of hazard control, exposure surveillance and assessment of health risks. National labour force statistics, a country questionnaire (in 15 member states, EU-15), a company survey (in Finland, France, Germany and Spain), exposure measurements (from Denmark, Finland, France, Germany, The Netherlands and the United Kingdom) and expert judgements were used to generate preliminary estimates of exposure to different types of wood dust. The estimates were generated according to industrial class (six wood industries, four other sectors) and level of exposure (five classes). These estimates were reviewed and finalized by national experts from 15 member states. Crude estimates were generated also for 10 new member states (EU-10). The basic data and final estimates were included in the WOODEX database. In 2000-2003, about 3.6 million workers (2.0% of the employed EU-25 population) were occupationally exposed to inhalable wood dust. Of those, construction employed 1.2 million exposed workers (33%), mostly construction carpenters. The numbers of exposed workers were 700,000 (20%) in the furniture industry, 300,000 (9%) in the manufacture of builders' carpentry, 200,000 (5%) in sawmilling, 150,000 (4%) in forestry and <100,000 in other wood industries. In addition, there were 700,000 exposed workers (20%) in miscellaneous industries employing carpenters, joiners and other woodworkers. The numbers of exposed workers varied by country ranging from <3,000 in Luxembourg and Malta to 700,000 in Germany. The highest exposure levels were estimated to occur in the construction sector and furniture industry. Due to limited exposure data there was considerable uncertainty in the estimates concerning construction woodworkers. About 560,000 workers (16% of the exposed) may be exposed to a level exceeding 5 mg m(-3). Mixed exposure to more than one species of wood and dust from wooden boards was very common, but reliable data on exposure to different species of wood could not be retrieved. This kind of assessment procedure integrating measurement data, company data, country-specific data and expert judgement could also serve as one model for the assessment of other occupational exposures.     

Field comparison of two inhalable samplers used in Italy to measure the wood dust exposure

Background: Particle size affects the performance of personal air samplers used to measure dust exposure in the workplace. Few field studies have been conducted for comparing the performance of personal inhalable samplers.

Objective: To compare wood dust sampling with two inhalable samplers: IOM (Institute of Occupational Medicine) and Italian cone.

Methods: 136 Italian cone/IOM paired samples and 136 passive IOM samples were collected in 30 Italian woodworking industries. The valid number of sample pairs was 114. Ultra-large particles were collected by passive IOM. The sampling membranes were weighed and the size particles were measured. Mass differences in active and passive IOM samples were calculated (IOM-Δ).

Results: Statistical analysis of all 114 Italian cone/active IOM paired results showed a significant mass difference (P < 0.05) and no significant mass difference for sanding and cutting woodworking processes. The Italian cone/IOM-Δ paired results consistently showed no statistically significant mass differences in any woodworking processes. Both samplers performed similarly when ultra-large particles mass contribution was not considered.

Conclusions: These findings confirm the presence of ultra-large particles in woodworking. The Italian cone and IOM samplers can be used interchangeably for personal wood dust exposure assessment, when the wood activities produce small-size particles.     

The impact of a change to inhalable occupational exposure limits: strontium chromate exposure in the U.S. Air Force

The American Conference of Governmental Industrial Hygienists has announced its intention to replace all total particulate threshold limit values (TLVs) with size-selective TLVs. Because the U.S. Air Force has adopted the TLVs as its occupational exposure limits, the impact of this change is of interest, specifically for hexavalent chromium. This article reviews historical strontium chromate sampling data in the Air Force and the impact of its reinterpretation in comparison to an inhalable TLV. Based on the measured conversion factor between the 37-mm cassette and the IOM inhalable sampler, inhalable strontium chromate exposures will continue to exceed the TLV during all aircraft priming and most sanding procedures. In addition, inhalable exposures are expected to exceed 1000 times the TLV, greater than the highest currently assigned protection factor for airline respirators, during 25% of priming procedures. Without a change in the value of the current TLV time-weighted average of 0.5 microg/m(3), the Air Force will need to reduce strontium chromate levels, either by incorporating work practices that decrease worker productivity or considering a change to nonchromated primers.     

Personal inhalable dust and endotoxin exposure among workers in an integrated textile factory

Abstract

The aim of this study was to determine personal exposure to inhalable dust and endotoxin levels among workers in an integrated cotton-processing textile factory and exposure variability across the different work sections. Full shift measurements were carried out using inhalable conical samplers with 37?mm glass-fiber filters. Personal inhalable dust was determined gravimetrically, and endotoxin levels were analyzed by kinetic chromogenic Limulus Amebocytes Lysate assay. The geometric means of personal dust and endotoxin concentrations were 0.75?mg·m^?3 and 831 EU·m^?3, respectively. The highest dust and endotoxin concentrations were observed in carding section (1.34?mg·m^?3 and 6,381 EU·m^?3, respectively). Altogether, 11% of dust and 89% of endotoxin samples exceeded workplace exposure limits. This study showed a moderate correlation between inhalable dust and endotoxin (r?=?0.450, p?<?0.001). Our findings indicate that low dust exposure does not guarantee a low exposure to endotoxin.     

Driver exposure to combustion particles in the U.S. Trucking industry

A large study of combustion particle exposures for drivers of diesel-powered trucks was conducted in collaboration with an epidemiologic study of lung cancer outcomes for workers in the trucking industry. Three components of diesel exhaust combustion particles (PM(2.5), elemental carbon, and organic carbon) were measured inside the driver cabs of diesel-powered trucks from 36 different trucking terminals across the United States between 2001 and 2005. In-cab particle exposures for drivers assigned to both short and long distance trips were observed, as well as information on the smoking status of the driver, truck characteristics such as age and model, and weather conditions during the sampling session. This article summarizes these findings and describes the relationship between exhaust particles and various determinants of exposure. The results suggest that in-cab particle exposures are positively related to smoking, ambient particle concentrations, truck age, and open windows, with other significant modifying factors such as weather. This study represents the largest and most comprehensive exposure assessment of drivers in the trucking industry, encompassing a 4-year period of observations on diesel and exhaust particle exposures nationwide. The results are relevant not only to the occupational group of truck drivers being examined but also to the general population that live, commute, or work within proximity to diesel-fueled traffic or trucking terminals.     

Long-term cotton dust exposure in the textile industry

A three-year survey was conducted in six cotton-yarn manufacturing mills and one mill processing synthetic polyester fibers as part of a longitudinal epidemiologic investigation of the health experience of workers employed in the textile industry. A total of 1324 elutriated and total dust samples were collected during the three years of the study. The results indicate that the average elutriated dust concentrations in the surveyed mills were generally at or below the current OSHA standard and they ranged from 0.069 to 0.396 mg/m3, 0.089 to 0.391 mg/m3, and 0.106 to 0.210 mg/m3 for the first, second and third year surveys, respectively. Introduction of modern automated yarn processing equipment and elimination of some of the classic processes were associated with a decreasing trend in airborne dust concentrations in these mills.