30 C.F.R. § 56.6904 Smoking and open flames.
Title 30 - Mineral Resources
Smoking and use of open flames shall not be permitted within 50 feet of explosive material except when separated by permanent noncombustible barriers. This standard does not apply to devices designed to ignite safety fuse or to heating devices which do not create a fire or explosion hazard.
Title 30: Mineral Resources
PART 56—SAFETY AND HEALTH STANDARDS—SURFACE METAL AND NONMETAL MINES
Subpart E—Explosives
General Requirements
§ 56.6904 Smoking and open flames.

