This story was originally published on February 18, 2009.

In 1948, news from a small town in western Pennsylvania shocked the world when pollution-laced smog killed 20 people and sickened thousands. The culprit was toxic smoke from a zinc plant. A thick yellow smog hung over the valley for five straight days and left the town with a trail of bodies.

Town councilman Don Pavelko says when he was growing up, nobody talked about what happened. “It was sort of a black eye to Donora. I always heard, ‘Let it die, let it die.’” But Pavelko and some other townspeople want the world to remember the environmental disaster and the good that has come from their great loss. In 2008, they opened the Donora Smog Museum. Outside of the museum hangs an orange sign that reads, “Clean Air Started Here.”

LISTEN: The Smog Museum. Clean Air Started Here.

The Donora smog tragedy — one of the worst air pollution disasters in U.S. history — let the public know that industrial pollution could kill and led to stronger air pollution laws. Before that, people in mill towns like Donora lived under blankets of dirty air. A photograph in the window of the museum shows mourners at the grave site of one of the victims of the smog. Smoke from the zinc plant and steel mill continues to plume above them. Charles Stacey, who spent the past year assembling old newspaper clippings and maps for the Smog Museum, remembers when scenes like these weren’t ironic. “Many times, we walked to school, we could barely see where we were going. But we didn’t pay that much attention because it happened all the time.”

An unidentified nurse administers oxygen to Frieda Van Kirk, 66, October 30, 1948 in Donora, Pennsylvania. She was rushed to the emergency room after being overcome by heavy smog in this town. Unidentified members of her family look on. Photo: AP

An unidentified nurse administers oxygen to Frieda Van Kirk, 66, October 30, 1948 in Donora, Pennsylvania. She was rushed to the emergency room after being overcome by heavy smog. Unidentified members of her family look on. Photo: Associated Press

Devra Davis is an epidemiologist who grow up in Donora. Her book When Smoke Ran Like Water tells the story of industrial disasters — including the one that happened in her hometown. She says developing countries can learn lessons from Donora. “When I gave my first talk about this internationally, two young colleagues came up to me — one from China and one from Mexico. They said we have Donoras happening now in China and Mexico. If people understand that this happened to you, then we will be able to do better to help our people.”

Councilman Don Pavelko is proud of his town’s legacy. Inside the museum, he shows a young visitor an old oxygen tank — the same tank a firefighter carried throughout the dark streets of Donora to help citizens survive the smog that put pollution control on the map.

“We here in Donora say this episode was the beginning of the environmental movement,” he says. “These folks gave their lives so we can have clean air.”