The Triangle Shirtwaist Factory fire of 1911 in New York City killed 146 garment workers, mostly young immigrant women. The fire was caused by a cigarette left in a scrap bin and spread quickly due to accumulated scraps and lack of safety measures in the factory. It revealed the unsafe conditions many workers endured, such as locked doors, and led to major reforms regulating workplace safety and the establishment of unions. The tragedy served as a turning point, improving conditions for industrial workers through new laws and organizations in the decades after. However, unsafe factories still exist today in other parts of the world.