30 C.F.R. § 57.5042 Revised exposure levels.
Title 30 - Mineral Resources
If levels of permissible exposures to concentrations of radon daughters different from those prescribed in 57.5038 are recommended by the Environmental Protection Agency and approved by the President, no employee shall be permitted to receive exposures in excess of those levels after the effective dates established by the Agency.
Title 30: Mineral Resources
PART 57—SAFETY AND HEALTH STANDARDS—UNDERGROUND METAL AND NONMETAL MINES
Subpart D—Air Quality, Radiation, Physical Agents, and Diesel Particulate Matter
Radiation—Underground Only
§ 57.5042 Revised exposure levels.

