30 CFR §57.5046
Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
Where radon daughter concentrations exceed 10 WL, respirator protection against radon gas shall be provided in addition to protection against radon daughters. Protection against radon gas shall be provided by supplied air devices or by face masks containing absorbent material capable of removing both the radon and its daughters.