Oct. 27—It was 75 years ago when a deadly smog settled over the Washington County mill town of Donora.
Over five days — Oct. 27-31, 1948 — the heavy smog killed 20 people in Donora and in nearby Webster, across the Monongahela River. In the weeks that followed, the death toll climbed to as many as 70 while several thousand people were sickened.
The disaster brought attention to the ill effects of air pollution and is credited with leading the way to the eventual passage of the Clean Air Act of 1970.
"This is ground zero of the environmental movement in the United States," said Brian Charlton, retired history professor and curator of the Donora Historical Society and Smog Museum. "This is where all of the momentum started."
Investigators identified factors that contributed to the disaster, including emissions from the American Steel and Wire plant and the Donora Zinc Works. They combined with an unusual temperature inversion: cold air became trapped below warmer air and became trapped within the hills surrounding the community.
The Donora museum opened in 2008. Its documentation of the pivotal smog event has attracted researchers from around the globe as well as regular visits from classes engaged in environmental studies at Washington & Jefferson College.
This year, the historical society has marked the anniversary of the disaster with a series of activities including participation in virtual presentations and a riverfront cleanup. It hosted a book-signing by Andy McPhee, author of a recent history of the event, "Donora Death Fog — Clean Air and the Tragedy of a Pennsylvania Mill Town."
"Rumor of Blue Sky," a 2009 documentary about the smog disaster created by Janet Whitney and Andrew Maietta, will be screened at 8:25 p.m. Wednesday at the Row House Cinema, 4115 Butler St., in Pittsburgh's Lawrenceville neighborhood. Admission is $12. Select the Events heading at rowhousecinemas.com/lawrenceville for more information and to reserve tickets.
The film tells the story of the disaster in the words of more than 20 people who lived through it.
"It's history from the bottom up," Charlton said. "A lot of those people have since passed away."
Museum volunteer Mark Pawelec compared the 1948 Donora disaster to the environmental catastrophe that occurred with the February train derailment in East Palestine, Ohio, and the controlled burn of chemicals that followed.
The difference in Donora, he said, was that residents had been exposed to smaller doses of pollution from the local mills for decades before the 1948 disaster.
"It was a double-edged sword," he said. "People immigrated here for a better chance in life. They had jobs in the mills, so they tolerated it."
Jeff Himler is a Tribune-Review staff writer. You can contact Jeff by email at email@example.com or via Twitter .