This testimony demonstrates the support of NIOSH for the proposed rule on safety standards for explosives at metal and nonmetal mines as put forth by the Mine Safety and Health Administration. Comments are offered on three areas of the proposed rule. First, the definitions of magazine and powder chest often differ between peoples, particularly in different geographical locations. A definition that standardizes the meaning of the term and describes the function for prospective readers is important. Secondly, NIOSH considers that sections proposing that combustible liquids be stored in a manner that assures drainage will be away from ruptured storage tanks may still allow liquid to flow into shops, mine work areas or transportation routes. The rules should require impervious diked platforms under the storage tanks to contain any spills. The final section for comment concerns the use of video monitors to protect unsuspecting individuals from dangerous blasting and suggests that such use be restricted to remote mine sites where the opportunity for unauthorized miners or persons other than miners to enter the blast area is unlikely.