Section 57.22234 - Actions at 1.0 percent methane (I-A, I-B, III, V-A, and V-B mines)(a) If methane reaches 1.0 percent in the mine atmosphere, ventilation changes shall be made to reduce the methane. Until such changes are achieved-(1) All persons other than competent persons necessary to make the ventilation changes shall be withdrawn from affected areas;(2) Electrical power shall be deenergized in affected areas, except power to monitoring equipment determined by MSHA to be intrinsically safe under 30 CFR part 18 ; and(3) Diesel equipment shall be shut off or immediately removed from the area.(b) If methane reaches 1.0 percent at a main exhaust fan, electrical power underground shall be deenergized, except power to monitoring equipment determined by MSHA to be intrinsically safe under 30 CFR part 18 , and all persons shall be withdrawn from the mine.(c) If methane reaches 1.0 percent at a work place and there has been a failure of the main ventilation system, all persons shall be withdrawn from the mine.52 FR 24941, July 1, 1987, as amended at 53 FR 9615, Mar. 24, 1988