The derivation of estimated dust exposures for U.S. coal miners working before 1970.
Am Ind Hyg Assoc J 1992 Apr; 53(4):248-255
An analysis of dust exposures of US coal miners working before 1970 was performed to determine exposure response relationships for coal workers pneumoconiosis (CWP) that would be useful for predicting the future incidence of CWP based on the current coal dust standard of 2mg/m3. Work history data collected during the first round of the National Study of CWP from 1969 to May 1971 and gravimetric coal mine dust sampling data collected by the US Bureau of Mines between 1968 and 1969 and by the Mine Safety and Health Administration (MSHA) in 1969 were reviewed. The data were used to estimate cumulative coal mine dust exposures occurring before 1970. Where necessary, MHSA monitoring data obtained after 1970 were used to back extrapolate to obtain pre 1970 coal dust concentrations. Sufficient data existed to estimate exposures for 9054 miners. The mean estimated cumulative dust exposure for pre 1970 miners unadjusted for mine type was 112 gram hours per cubic meter (ghr/m3). The standard deviation was 81ghr/m3. Approximately 95% of the exposures lay between 4 and 250ghr/m3. The estimated exposures were significantly associated with the length of service underground, correlation coefficient 0.85. Dust exposure concentrations obtained by dividing the cumulative exposures by length of service underground, ranged from 0.1 to 8.7mg/m3, mean 3.0mg/m3. Adjusting the cumulative dust exposures for mine type by utilizing empirical factors of 0.4 to 1.4 widened the dispersion by increasing the standard derivation in the distribution to 96ghr/m3.
NIOSH-Author; Coal-miners; Coal-dust; Occupational-exposure; Epidemiology; Job-analysis; Coal-workers-pneumoconiosis; Dust-exposure
American Industrial Hygiene Association Journal