Eric Reyes-Barriga

It depicted a worker starting a deadly fire by mindlessly tossing a match onto the floor.

The outrage over Triangle didn't let up.

Activists pushed lawmakers to shift responsibility for safe workplaces onto companies.

In the years after the fire, New York State passed over two dozen new laws related to working conditions.

Employers became responsible for providing safer buildings to work in and for following building fire codes, including leaving doors to exit stairwells unlocked.

By the 1930s, Frances Perkins, who had witnessed the fire, was appointed Secretary of Labor by President Franklin D. Roosevelt.

She was the first female cabinet secretary and brought her agenda to the job.

Many of the New York state reforms passed after the Triangle Fire were soon made federal law.

Employers were put on notice.

When we come back from the break, another public tragedy again raises the question of how to keep workers safe, but this time from a different kind of threat.

As the federal government began to regulate workplaces in the 1930s, another tragedy was about to grab the public's attention.

This time, it wasn't a fire or an accident.

It was a disease.

Silicosis.

Here's historian Gerald Markowitz again.

Near a town called Gawley Bridge in West Virginia, thousands of workers were hired by chemical company Union Carbide to drill a tunnel through a mountain.

It was called Hawk's Nest Tunnel.

Later estimates have put the death toll from this disaster at over 700.

Some even put it at 1,000.

We'll likely never know the real number of dead.