A study was initiated to examine the ways in which a number of foreign countries classify and regulate metal and nonmetal mines that experience problems caused by naturally occurring flammable gases. Twenty countries were selected for study and useful information was obtained from 16. Nine countries were visited to hold meetings with representatives of government mine regulatory agencies and mine operators and to visit mines encountering methane, carbon dioxide, nitrogen, etc. Seven gassy metal and nonmetal mines in the United States were visited to provide a basis for comparison, and hence the evaluation of both U.S. and foreign gassy mine regulations. In addition to obtaining copies of the mining laws and regulations of a number of foreign countries, nine foreign and seven U.S. gassy mines were documented in as much detail as possible.