Coal workers’ pneumoconiosis prevalence disparity between Australia and the United States

Although rates of pneumoconiosis in coal miners have declined substantially in the United States since the passage of the Federal Coal Mine Health and Safety Act of 1969, new cases continue to occur, including cases of rapidly progressive disease. In contrast, Australia’s underground coal mining industry has reported few new cases of pneumoconiosis for more than 20 years. Mortality from coal workers’ pneumoconiosis in official health statistics and the prevalence of pneumoconiosis among miners screened in X-ray surveillance programs are also lower in Australia. The U.S. National Institute for Occupational Safety and Health (NIOSH) was requested by both industry and labor stakeholders to examine this issue, with the ultimate aim of reducing the rate of pneumoconiosis among U.S. coal miners. A number of factors, including coal dust exposure, silica exposure and coal rank were examined as potential contributors to the above noted differences. Comparison of coal rank data from each country did not illuminate the issue. Air sample data from the coal mining industries in both countries show that coal dust levels in Australian mines are somewhat higher than those reported in similar U.S. mines; however, quartz exposure for Australian miners is lower than for many U.S. miners. If quartz is contributing to the greater number of cases of pneumoconiosis in the United States, more effective dust control measures, as well as an independent exposure standard for respirable quartz in coal mining, should be implemented to reduce this potentially disabling condition. Introduction Australia has an active underground coal mining industry in two states — New South Wales and Queensland — but has maintained a low rate of pneumoconiosis for more than 20 years. By comparison to the United States, mortality from coal workers’ pneu moconiosis (CWP) in official health statistics and the prevalence of pneu moconiosis among miners screened in X-ray surveillance programs are also lower in Australia. Clouding the dif ference in disease rates between the two countries is the fact that the oc cupational exposure standard for the respirable fraction of coal mine dust (RCMD) in the above two Australian states is higher than the regulatory ex posure standard in the United States. The U.S. National Institute for Oc cupational Safety and Health (NIOSH) was requested by stakeholders from both U.S. industry and labor to inves tigate the disparity in pneumoconiosis rates between Australia and the United States. Pneumoconiosis is a disease of the lung parenchyma caused by deposition ­