A prospective case-control study was undertaken to assess respiratory disability 
in 133 former coal miners who were claimants for "black lung" benefits. 
Consecutive assignment was made to either case or control group based on their 
chest radiograph having shown coal workers' pneumoconiosis or no coal workers' 
pneumoconiosis. A respiratory occupational survey was completed with physical 
examination that placed special emphasis on the cardiorespiratory systems. 
Subjects underwent pulmonary function testing while 92 of these also received 
arterial blood gases to assess respiratory disability and pulmonary 
insufficiency. Arterial blood gases were superior to spirometry in assessment of 
pulmonary insufficiency/disability. Smoking interacts with coal workers' 
pneumoconiosis to cause pulmonary insufficiency. The most frequent spirometric 
pattern was obstructive. Disability was caused by occupational injuries and 
comorbidities, both of which occurred with greater frequency in miners with coal 
workers' pneumoconiosis than in controls. Pulmonary insufficiency appears to be 
a better discriminator than respiratory disability in coal miners, suggesting 
that arterial blood gases replace spirometry in their evaluation. Greater 
emphasis on smoking intervention among coal miners should be given.