Okla. Stat. tit. 45, § 45-519: Mines to be kept free from gas

All mines generating fire damp shall be kept free of standing

gas in all working places and roadways. No accumulation of

explosive gas shall be allowed to exist in the worked-out or

abandoned parts of any mine. It shall be removed as soon as

possible after its discovery, and no miners or other persons who are

not employed in the removal of the dangerous accumulation, shall be

allowed to remain in any mine, or part of mine, during the time that

a dangerous accumulation of explosive gas is being removed from any

part of the mine, and the entrance or entrances to be worked out and

abandoned places shall be properly fenced off and cautionary notices

shall be posted upon said fencing to warn persons of danger.