The health activities fulfilling NIOSH responsibilities under the Federal Coal Mine Health and Safety Act of 1969 are reported for the calender year 1974. The extensive medical examination services coordinated at the NIOSH Appalachian Laboratory for Occupational Respiratory Diseases (ALFORD) in Morgantown, West Virginia processed 46,896 chest x-rays of active underground coal miners by the end of 1974. Although this second round of examinations which began in 1973 is not complete, 5,714 (over 13%) x-rays showed some evidence of coal workers' pneumoconiosis and progressive massive fibrosis was seen in 239 cases. By the end of 1974, 1,059 physicians had demonstrated competence in the use of the official clsasification systems for x-rays. Preliminary results from the second round of the National Study of Coal Workers' Pneumoconiosis in which 4,072 underground coal miners were examined showed significantly lower prevalence of pneumoconiosis compared with the results from the first round completed in 1971, but this is considered to reflect change in miner sample rather than general improvement in total miner health. The National Coal Workers' Autopsy Service had accepted 628 post mortem examinations during 1974. Coal mine health research during 1974 included community surveys, biochemical techniques for diagnosis and early detection, and study of the mechanism by which lung function is altered by pneumoconiosis as well as genetic aspects, infectious diseases, and cellular and tissue reactions to coal dust.