The volume and velocity of the current of air shall be sufficient to dilute so as to render harmless, and to carry away, flammable or harmful gases.
225 ILCS 705/31.01
All active underground working places in a mine shall be ventilated by a current of air containing not less than 19.5% of oxygen, not more than 0.5% of carbon dioxide, and no harmful quantities of other noxious or poisonous gases
Laws 1953, p. 701.
Official source: Illinois General Assembly. Reproduced from public-domain Illinois statutes; confirm against the official source for the current text. Not legal advice.