This Act shall not be construed to prohibit the breaking down of coal while men are in the mine if such breaking down is accomplished by compressed air or by some mechanical or chemical-mechanical device which does not emit spark or flame and if in any place where men are working, the total concentration of carbon monoxide or other noxious gases is within established safe limits when ventilation is as specified under Article 31 of this Act.
225 ILCS 705/27.03