Forced expiratory volume and expiratory flow rate in Black miners and in a control group

The peak expiratory flow rate and the forced expiratory volume and 1 second were measured in 772 Black miners who did not have pneumoconiosis, tuberculosis or chronic bronchitis. The same tests were done in 164 non-mining workers. It was found that exposure to dust associated with the miners' work had no effect on the results of these tests.