An evaluation of short-term exposures to metalworking fluids in small machine shops.

In a study of 23 small machining shops using metalworking fluids (MWFs), real-time air monitoring using an aerosol photometer was performed to investigate the temporal nature of the exposure and to examine the relationship between the instrumental measurements and traditional sampling methods. Time-weighted averages were calculated from the aerosol photometer data and the results were compared to collocated thoracic and 37-mm closed face cassette samplers. The filter samples were analyzed for total mass and the solvent extractable fraction. Depending on the averaging period used, short-term MWF concentrations exceeded 2.0 mg/m3 in 13 to 39% of the plants studied. High short-term exposures were as likely to be found in plants with average concentrations below 0.4 mg/m3 (thoracic-gravimetric) as those above. Regression analyses indicated that the aerosol photometer most closely matched the data obtained from the thoracic fraction of the total mass. In general, the aerosol photometer overestimated the levels determined using the thoracic cyclone and filter, especially when measuring concentrations of water-based fluids. Use of a calibration factor of 0.7 for straight oils or 0.5 for water-based fluids may assist in the interpretation of aerosol photometer measurements if field calibration data are not readily available. Several approaches to determining the calibration factor from field data were evaluated; more complex calibration techniques improved the accuracy of the measurements.

Metalworking fluid exposures in small machine shops: an overview.

Sampling was conducted in 79 small machine shops to assess airborne exposures to metalworking fluids (MWFs). Measured exposures were compared with data from the literature and exposure criteria currently recommended by the National Institute for Occupational Safety and Health and the Occupational Safety and Health Administration MWF Standards Advisory Committee. Sixty-two percent of 942 personal samples collected were less than the recommended exposure limit (REL) of 0.50 mg/m3 for total particulate. However, at least 1 sample exceeded the REL in 61 of the 79 facilities studied; 100% of the samples collected in 10 shops were greater than the REL. Similar trends were found for thoracic particulate exposures where 75% of 238 samples were below the thoracic particulate REL of 0.40 mg/m3. The ratio between thoracic and total particulate for 238 paired samples was 0.55 (r2=0.73). Workers exposed to straight fluids had the highest exposures (GM=0.67 mg/m3) when compared with workers exposed to other classes of MWFs. The highest exposures were measured for grinding and hobbing (GM=0.67 and 0.60 mg/m3, respectively). Measurements using personal impactors indicated that particle size distributions of MWF aerosols had an average mass median aerodynamic diameter of 5.3 microm. Straight oils and soluble fluids tended to be associated with larger particles than were other fluid types; grinding and turning produced the largest particles, whereas hobbing resulted in the smallest. In general, exposures were similar in magnitude and particle size to those previously reported in large automotive plants. Therefore, workers in these small shops may have risks of adverse health effects similar to those demonstrated in the automotive industry.

[Occupational exposure to inorganic lead in a printing plant in Mexico City]. / Exposición ocupacional a plomo inorgánico en una imprenta de la Ciudad de México.

OBJECTIVE: To describe occupational lead exposure and its biological indicators in workers in a printing company. MATERIAL AND METHODS: An epidemiological and industrial hygiene research was undertaken. Lead was measured in the air of work environment and on the hands of the participants; additionally, subjects underwent a venous blood samples for the determination of whole blood lead by atomic absorption spectrophotometry; and a bone lead measurement using a spot-source 109Cd K-X-ray fluorescence instrument. Also, a standardized questionnaire was applied. We obtained information on demographic and life styles factors, work history, type of work, position and activity within the company. RESULTS: Of the 209 workers, 117 agreed to participate and 90 (83.3% males and 16.7% females) completed all phases of the study. The average lead concentrations were: in air samples, of 0.94 microgram/m3; in hands before washing, of 6,802 micrograms/m2; in hands after washing, of 194 micrograms/m2; in whole blood, of 12.3 micrograms/dl; and in tibia and fibula, of 25.9 and 43.3 micrograms Pb/g of bone mineral, respectively. Important variations in these measurements were observed according to the workers post. CONCLUSIONS: Worldwide, lead exposure levels have been used to evaluate acute exposures being in the workplace. The higher lead levels find in the bone of the workers in this study are similar to other occupational studies in the United States of America and suggest that the accumulated metal in bone may be an important endogenous exposure source, and here its measurement importance. However in developing countries because its high costs per application, the measurements in bone lead become limited to epidemiological research, although not as an instrument for occupational epidemiological surveillance. In Mexico, there are no reliable studies of occupational lead exposure, which would allow the establishment of both, maximum permissible ambient and biological levels. This study is intended to contribute to blood lead standard setting, which is being discussed in Mexico.

Elevated blood lead levels in children of construction workers.

OBJECTIVES: This study examined whether children of lead-exposed construction workers had higher blood lead levels than neighborhood control children. METHODS: Twenty-nine construction workers were identified from the New Jersey Adult Blood Lead Epidemiology and Surveillance (ABLES) registry. Eighteen control families were referred by workers. Venous blood samples were collected from 50 children (31 exposed, 19 control subjects) under age 6. RESULTS: Twenty-six percent of workers children had blood lead levels at or over the Centers for Disease Control and Prevention action level of 0.48 mumol/L (10 micrograms/dL), compared with 5% of control children (unadjusted odds ratio = 6.1; 95% confidence interval = 0.9, 147.2). CONCLUSIONS: Children of construction workers may be at risk for excessive lead exposure. Health care providers should assess parental occupation as a possible pathway for lead exposure of young children.

Elevated lead contamination in homes of construction workers.

National Institute for Occupational Safety and Health investigators studied lead exposures among 37 families of construction workers; 22 neighborhood families with no known lead exposures were included for comparison. Workers were identified as having blood lead levels at or above 25 micrograms/dL. This article reports the levels of lead contamination on hands and interior surfaces of homes and automobiles of study participants. Results indicate that the hands of lead-exposed workers were seven times more contaminated with lead compared with control workers; no difference was found between exposed and control family members' hands. Surface lead contamination was significantly higher in automobiles driven by the lead-exposed workers; some locations, such as armrests, were 10 times more contaminated for the exposed group. High lead loadings in lead workers' automobiles were found on the driver's floor (geometric mean [GM] = 1100 micrograms/m2), driver's armrest (2000 micrograms/m2), and passenger's armrest (1200 micrograms/m2). Surface lead concentrations were significantly higher for exposed homes compared with control homes in rooms where work clothing was changed (GM = 370 versus 120 ppm; p = 0.005). While environmental sources of lead were also evaluated, study results strongly suggest that construction workers' occupational exposures together with poor hygiene practices were the primary causes of lead contamination. Requirements intended to prevent "take-home" lead exposures were reported by workers in this study to be infrequently followed by employers. These findings may be limited in representativeness since only highly exposed workers were selected from a specific geographic area. Regardless, targeted education and enforcement efforts are necessary to help ensure that preventive measures are adequately practiced throughout the construction industry.

Respirable dust exposures in U.S. surface coal mines (1982-1986).

Exposure of miners to respirable coal mine dust and to respirable quartz silica at surface coal mines in the United States during 1982-1986 were evaluated by job category using data collected by coal mine operators and Mine Safety and Health Administration (MSHA) inspectors. Average coal mine dust concentrations were usually well below the MSHA Permissible Exposure Limit (PEL) for all job categories, but at least 10% of the samples obtained from some coal preparation plant job areas and most drilling job areas had concentrations that exceeded the 2.0 mg/m3 limit. In contrast, a very high proportion of samples from surface mine driller areas exceeded the quartz PEL. Of all samples collected for highwall drill operators and helpers, 78% and 77%, respectively, were greater than the 0.1 mg/m3 quartz exposure limit (average concentrations were .32 and .36 mg/m3, respectively). Although MSHA compliance data may not be entirely adequate for assessing chronic exposure to quartz, these data and the results of other NIOSH studies nonetheless indicate excessive exposure to silica in a group of surface coal miners.

Medical and industrial hygiene characterization of the cotton waste utilization industry.

We studied 260 workers in the cotton waste utilization industry and 310 "blue-collar" control workers from nondusty industries in the same geographic area of the United States by respiratory symptom questionnaire and by pre- and postshift spirometry. We excluded 75 cotton workers and 75 control workers from statistical analysis because of prior hazardous occupational exposures. Plant-wide, 8-hour time-weighted average exposures ranged from 0.28 mg/m3 to 7.80 mg/m3. The overall prevalence of symptoms compatible with byssinosis was 5.9% in cotton workers and 4.7% in the controls. Cotton workers with less than 2 years of employment had a significantly greater prevalence of bronchitis than their control counterparts. The cotton workers with 2 years or more of employment had significantly greater prevalences of bronchitis, shift decrement in forced expiratory volume in 1 second (FEV1) of greater than or equal to 10%, and FEV1/FEV1-predicted less than 80%, than their control counterparts. Regression analysis showed that for matched cotton and control workers, the percentage decrement in FEV1 over the shift was significantly greater for cotton workers; and that in all cotton workers, longevity in industry had a negative effect on the before-shift forced vital capacity (FVC). This study suggests that there are both acute and chronic effects of cotton exposure in the cotton waste utilization industry.

Characterization of airborne cotton dust concentrations in the non-textile cotton industry.

Workers in the "non-textile" cotton industry breathe a dust which is similar to the dust in the cotton spinning and weaving or "textile" industry. This exposure prompts the question of byssinosis prevalence and other respiratory disease in the non-textile cotton industry. NIOSH has completed a cross-sectional medical and environmental study evaluating the prevalence of byssinosis in five segments of the non-textile cotton industry. A total of 92 non-textile cotton facilities were evaluated, including cotton gins, cotton classing offices, cottonseed oil mills, cotton compress-warehouses, and waste utilization plants. This paper presents the results of the measurements of cotton dust levels and particle size distributions in these segments. Average elutriated dust concentrations for individual plants ranged from 101 to 2050 micrograms per cubic meter of air (micrograms/m3) in 35 cotton gins, 81 to 376 micrograms/m3 in 13 classing offices, 502 to 2041 micrograms/m3 in 18 cottonseed oil mills, 39 to 831 micrograms/m3 in 13 compress-warehouses, and 237 to 3968 micrograms/m3 in 13 waste utilization facilities. Results tend to be lower than those reported in the literature for non-textile operations.