In any extrahazardous tunnel or underground mine smoking by employees or open flame shall be prohibited. Welding or cutting with arc or flame underground in other than fresh air shall be done under the direct supervision of qualified persons who shall test for gas and vapors before welding or cutting starts and continuously during such an operation. No cutting or welding shall be permitted in atmospheres where any concentration of gas or vapor reaches 20 percent of the lower explosive limit or more while a probe hole is being drilled or when the tunnel face or material from a mine is being excavated.

(Added by Stats. 1972, Ch. 1430.)

Terms Used In California Labor Code 7978

  • Face: means the head of the tunnel where soil is being removed, or that area in a mine where digging is underway. See California Labor Code 7951
  • Lower explosive limit: means the lowest concentration at which a gas or vapor can be ignited or will explode. See California Labor Code 7951
  • Mine: means any excavation or opening above or below ground used for removal of ore, minerals, gravel, sand, rock, or other materials intended for manufacturing or sale. See California Labor Code 7951
  • Tunnel: means an underground passageway, excavated by men and equipment working below the earth's surface, that provides a subterranean route along which men, equipment, or substances can move. See California Labor Code 7951
  Previous section
Next section  
 Chapter 2 Contents