Section 7981 Of Chapter 2. Gassy And Extrahazardous Tunnels From California Labor Code >> Division 5. >> Part 9. >> Chapter 2.

. An escape chamber or alternate escape route shall be maintained within 5,000 feet of the tunnel face or areas being used to excavate material in an underground mine classified as gassy or extrahazardous. Workers shall be provided with emergency rescue equipment and trained in its use.