Speculator Mine Fire Kills 168 Workers: Anaconda Safety Failures Trigger Butte Strike and Repression

On June 8, 1917, a fire broke out 2,400 feet underground in Butte, Montana’s Speculator Mine when an assistant foreman’s carbide lamp ignited the frayed insulation on an electrical cable. The fire spread rapidly through the mine’s timber supports and ventilation system, trapping hundreds of workers. 168 miners died, making it the deadliest hard-rock mining disaster in American history.

The disaster exposed catastrophic safety failures by the Anaconda Copper Mining Company. Bulkheads meant to seal off fire areas were never installed. Concrete-lined escape routes mandated by state law were ignored. Safety equipment was inadequate or absent. The mine’s sole escape route became an inferno as fire raced through connected tunnels. Workers were found dead where they had written farewell messages on walls as smoke filled the passages.

The tragedy sparked a strike of 15,000 Butte miners demanding safety improvements, union recognition, and the removal of the rustling card system that blacklisted organizers. The Anaconda Company refused all demands and recruited strikebreakers. On August 1, IWW organizer Frank Little, who had come to support the strike, was lynched. Montana’s governor declared martial law, and federal troops occupied Butte. The strike collapsed by year’s end with no concessions. The Speculator disaster illustrated how completely regulatory capture protected corporate interests: despite clear evidence of criminal negligence, no Anaconda official faced prosecution, and the company resumed operations with minimal safety improvements. The subsequent repression showed that even mass worker death could not overcome corporate-state collusion.