CFR › Title 30 › Part 57 › §57.2222030 CFR §57.22220Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗Copy linkAir that has passed by or through unsealed abandoned or unsealed inactive areas and contains 0.25 percent or more methane shall—(a)Be coursed directly to a return airway;(b)Be tested daily for methane by a competent person; and(c)Not be used to ventilate work places.