From March to May, 30 out of a total of 328 miners who were identified and screened through the Enhanced Coal Workers' Health Surveillance Program had evidence of pneumoconiosis an occupational lung disease caused by the inhalation of coal mine dust with 11 of them having advanced cases, as revealed in the Aug. 25 edition of CDC's Morbidity and Mortality Report.
All 11 miners with advanced cases met radiographic criteria for rapidly progressive pneumoconiosis. All reported at least one respiratory symptom, the most common being dyspnea (shortness of breath).
In 1969, the Federal Coal Mine Health and Safety Act established a mandatory limit of 2 milligrams of dust per cubic meter on breathable dust exposure, which was intended to eliminate advanced forms of pneumoconiosis among coal miners.
Although data from the surveillance program documented reductions in the prevalence of black lung disease among active coal miners after dust levels were lowered, clusters of progressive pneumoconiosis were identified among miners in eastern Kentucky and western Virginia from 1996 to 2002.
In this report, Dr. V.C. Antao, from the National Institute for Occupational Safety and Health (NIOSH), and the rest of his team concluded that out of the 11 advanced cases, nine had not worked before the 1969 limit came into effect.
The authors estimated that 5.5 cases of advanced coal workers' pneumoconiosis would be expected if dust levels had not exceeded the current limits. In contrast, 11.9 cases would be expected if miners' exposure averaged double the limit.
NIOSH concluded in 1995 that the current limit was too high and established a recommended exposure limit of 1 milligram per cubic meter. The authors suggested in the report that NIOSH's recommendations should be followed.
In addition, the report's authors said NIOSH will expand medical surveillance activities in southwestern Virginia and elsewhere and continue collaborations with MSHA to increase protection of coal miners. These activities, according to the report, will help NIOSH make appropriate recommendations to MSHA and other agencies and improve ongoing surveillance and intervention measures.