Assessment of respiratory exposures during gilsonite mining and milling operations.

An industrial hygiene study of the entire United States gilsonite industry was done by the National Institute for Occupational Safety and Health (NIOSH) to evaluate the potential for occupational health problems resulting from exposures to gilsonite and its constituents. Gilsonite is a solidified hydrocarbon substance mined only in northeastern Utah to Colorado. Industrial hygiene samples were collected at four gilsonite mining companies including nine mines and three mills. Gilsonite workers had no measurable exposures to polynuclear aromatic hydrocarbon (PNA) compounds, asbestos fibers, or hydrogen sulfide gas. Several organic gases/vapors and metals were detected in the airborne samples; but, none exceeded the current exposure standards/health criteria of the Mine Safety and Health Administration (MSHA), the American Conference of Governmental Industrial Hygienists (ACGIH), or NIOSH. Gilsonite workers in some job categories were exposed to high levels of dust, exceeding ACGIH nuisance dust recommendations. These dusts, comprised largely of aliphatic hydrocarbons, had a large aerodynamic size distribution with average mass median aerodynamic diameters (MMAD) above 30 microns.

Respiratory health status of gilsonite workers.

Gilsonite, a solidified hydrocarbon used in the manufacture of automotive body seam sealers, is mined only in the Uinta Basin of Eastern Utah and Western Colorado. Health effects of gilsonite dust exposure have not previously been published and exposure to gilsonite dust is not regulated. To examine potential respiratory health effects associated with gilsonite dust exposures, this cross-sectional study surveyed the 100 current male employees who had been exposed to gilsonite dust at 3 existing gilsonite companies. Total dust exposures up to 28 times the nuisance dust standard were found, and 5 of 99 (5%) workers had chest radiographs consistent with pneumoconiosis of low profusion. Increased prevalences of cough and phlegm were found in workers with high-exposure jobs, but no evidence for dust-related pulmonary function impairment was noted. To prevent pulmonary health effects, we recommend reducing dust exposures for those workers in jobs currently characterized by relatively high dust exposures.

Effect of spirometer temperature on measurement of FEV1 shift changes.

Spirometric parameters are generally obtained at ambient (spirometer) temperature pressure saturated (ATPS) and then converted to body temperature pressure saturated (BTPS) by multiplying each observed value by a BTPS correction factor. At ambient temperatures of 23 degrees C or higher, the accepted practice of using a constant BTPS factor introduces a relatively small error in forced expiratory volume in one second (FEV1), but as the temperature decreases below 23 degrees C the error in FEV1 increases. A dynamic BTPS correction factor model has recently been developed to reduce this error. Analysis of across-shift spirometry data from a recent survey indicates that, with an increase in temperature over a work shift of greater than 3 degrees C, 27.1% of 302 subjects were classified as having a greater than or equal to 5% FEV1 drop over the shift using the dynamic BTPS factor model, compared with 41.4% when the standard BTPS correction factor was used (P less than .005). These results indicate the importance of correcting for ambient temperature differences when analyzing for shift changes in spirometric parameters.

Occupational exposure to coke oven emissions from 1979-1983.

Breathing zone samples of benzene soluble fraction of total particulate matter (BSFTPM) were obtained for coke oven workers at a selected steel plant from 1979-1983. Analysis of the 1622 samples, collected for compliance with the 1976 OSHA coke oven emissions standard, indicated that there were significant differences in exposures to BSFTPM among the following variables: job classifications, batteries where the employees were stationed, shifts during the work day, and years and quarters of the year when samples were collected. In comparison to studies conducted prior to 1976, exposures to BSFTPM in the current study are consistently lower for every job classification. However, even in 1983, a large percentage of the workers in many of the sampled job classifications had BSFTPM concentrations that were above 0.150 mg/m3, indicating that current engineering controls and work practices are not sufficient to provide exposure levels below the recommended standard.

Respiratory symptoms and pulmonary function in welders of mild steel: a cross-sectional study.

Pulmonary function measurements, respiratory symptoms, smoking history, and occupational history were obtained from 91 male welders of mild steel, with mean welding exposure of 108 months, and 80 male factory controls. Nonsmoking welders compared to nonsmoking controls reported higher frequencies of respiratory symptoms and the differences were statistically significant for two symptoms: phlegm, and episodes of cough and phlegm. In comparisons of smoking welders and smoking controls, no significant differences were found in the prevalence of respiratory symptoms. Nonsmoking welders and smoking welders, compared to respective controls, did not have significantly decreased mean values of forced vital capacity or forced expired volume in 1 sec. Mean mid-expiratory flow rates and forced expiratory flow rates at 75% of forced vital capacity were lower, but not significantly different, for welders, compared to controls. These decrements in peripheral flow rates could be trivial or they could represent the initial stages of chronic obstructive pulmonary disease. Long-term follow-up, provided by a large prospective study, is needed to make this distinction.