In the 1970s, the air in Ohio's cities was so dirty that people had to use headlights to drive in the daytime.
Laundry hanging outside to dry would be stained with pollution from blast furnaces, and people brushed soot off their cars with snowbrushes.
In 1975, 44 air pollution alerts forced facilities to stop production until the air cleared. Ohio has had no air alerts for decades.
Today, facilities operate with sophisticated air pollution control equipment and Ohio EPA operates one of the largest air monitoring networks in the country.