October 1948: That’s what Donora, a Monongahela River valley mill town, looked like when a heavy fog blanketed the Washington County community in October of 1948.
For five days, a thick, acrid smog blanketed Donora and nearby Webster. The thick stew of sulfuric acid, nitrogen dioxide and fluoride pollution was pumped into the air by U.S. Steel Corp.’s zinc and steel mills and trapped over the valley by a weather inversion.
The smog killed 22 people and sickened half of Donora’s 13,000 residents. A year later, in 1949, Allegheny County adopted a smoke control ordinance and the U.S. Air Pollution Control Act of 1955 was the first federal law to recognize pollution as a problem.
This image shows the smog settling over Donora. The blanket of deadly air did not stop a woman from hanging out laundry. She is standing to the left of the railroad tracks.
On Oct. 31, 1948 , the Donora Zinc Works shut down its furnaces, just a few hours before rain finally dispersed the smog.
