Between 1864 and 1869, approximately 15,000 Chinese immigrants (90% of the Central Pacific Railroad's workforce) were hired due to a critical labor shortage in the American West. Most white workers were either fighting in the Civil War or lured away by the Nevada gold and silver strikes. Initially hired as an "experiment" by Charles Crocker, Chinese laborers proved so disciplined, healthy (due to their habit of drinking boiled tea), and efficient that the railroad began recruiting them directly from the Guangdong province. These men were fleeing the poverty and violence of the Taiping Rebellion. Despite their essential role, they were paid 30% less than white workers, forced to pay for their own food and lodging, and assigned the most dangerous tasks—such as hand-tunneling through the solid granite of the Sierra Nevada Mountains using unstable nitroglycerin. Their sacrifice was pivotal in connecting the US, yet they were largely excluded from the "Golden Spike" celebrations and faced the Exclusion Act shortly after.