From the National Archives:

Photograph of a Broken Fire Escape after the Triangle Shirtwaist Factory Fire, 03/25/1911

One of the deadliest industrial disasters in United States history, the Triangle Shirtwaist Factory fire in New York City left 146 workers dead in 18 minutes on March 25, 1911.

Locked doors kept the workers from escaping; there was not enough water to put out the flames, and firemen’s ladders were too short to reach the upper stories. Many of the young women and men working there leapt out the windows and fell to their deaths onto the sidewalk outside. Others were crushed in the elevator shaft or when the fire escape collapsed.

The fire led to sweeping reforms in labor laws and safety standards, providing a boost to labor unions, and was a pivotal event in the career of future labor secretary Frances Perkins.