With the 1970 passage of the Occupational Safety and Health Act (OSHA), federal regulation reached the American workplace. Given the newness of the legislation, any firm conclusion on its effectiveness seems premature. However, there is ample evidence on federal safety regulation of a specific workplace: the coal mine. The federal government has been directly involved in coal mining safety for over 35 years, operating under three major pieces of legislation, enacted in 1941, 1952, and 1969. Opposing opinions regarding the effect of this legislation can be grouped into three categories: radical, reactionary, and reformer. A multiple interrupted time-series analysis indicates that, in fact, the 1941 and 1969 regulations significantly reduced the fatality rate in coal mining. Certain conditions seem related to the effectiveness of this safety legislation: birth order, provisions, enforcement, target population, and goals. The first two conditions would appear to work for the success of the OSHA, the latter three conditions to work against it.