Methods are discussed for evaluating hazards of pneumoconiosis in underground coal mines. Pneumoconiosis hazards are decisively influenced by: content of respirable dusts in mine air at a working place, dust composition, temperature and time of a miner's contact with dusts. The following classification of pneumoconiosis hazards is used in the USSR: low hazards when a miner is endangered by pneumoconiosis after 20 years or more, medium hazards when pneumoconiosis may occur after 10 to 20 years, high pneumoconiosis hazards when a miner is endangered by pneumoconiosis after less than 10 years of contact with dusts. High air temperature in deep coal mines increases pneumoconiosis hazards: when temperature exceeds 26 C a temperature increase of 1 C causes a 10% increase in dust chemical activity. Safety standards which describe the maximum permissible dust level in coal mine air in the USSR, the FRG, France and Poland are compared.