Whenever an access shaft is used as the normal means of entrance or exit to an underground mine or tunnel, it shall be constructed of fireproof material or fireproofed by chemical or other means.
Ca. Lab. Code § 7964
Whenever an access shaft is used as the normal means of entrance or exit to an underground mine or tunnel, it shall be constructed of fireproof material or fireproofed by chemical or other means.
Ca. Lab. Code § 7964