The Triangle Shirtwaist factory fire happened on this day 122 years ago. And it changed the government’s approach to worker safety ever since. Unrestrained by workplace laws, the factory owners locked the exits to the stairwells so that the workers – mostly young women aged 16 to 23 – could not take unauthorized breaks. The result was the unnecessary deaths of 146 people who couldn’t escape the fire.

The fire led to public outcry against such business practices and helped to convince politicians to enact laws and regulations to protect workers on the job. For a look at the fire and its consequences, check out the well-made video below: