In the Granite Mountain/Speculator Mine disaster of June 8, 1917, an electric cable was being lowered into the Granite Mountain mine as part of a fire safety system. At this time, the Butte, Montana copper mines were at full wartime production. When the cable fell and was damaged, a foreman (approximately 2,500 feet below the surface) with a carbide lamp went to inspect the damage, and the oil-soaked cloth insulation on the cable was ignited by the flame from his lamp.