Deadly 1948 Donora Smog Launched the U.S. Clean Air Movement

Donora smog, pollution
The smog that blanketed the small town of Donora, Pennsylvania in October 1948 caused at least 21 deaths and ultimately resulted in the passage of the Clean Air Act of 1963. This photo shows 9 of the 10 spelter stacks of U.S. Steel's Donora Zinc Works. Donora Historical Society

In Donora, Pennsylvania, about 30 miles (48 kilometers) by car south of Pittsburgh along the Monongahela River, what used to be a Chinese restaurant is now the home of the Donora Historical Society and Smog Museum.

Over the years, scholars from academic institutions all over the world have made their way to the humble local volunteer-run institution to peruse its archive of documents, blueprints, microfilm, scientific studies and film footage, according to volunteer curator and researcher Brian Charlton, who notes with amusement that he also doubles as the janitor. "I was just mopping before I returned your call," he explains one recent Saturday morning.


There's continuing interest in the museum's collection because it documents one of the worst pollution catastrophes in U.S. history, a toxic smog that enveloped Donora in late October 1948 and killed more than 20 residents, in addition to sickening thousands more. Many credit the disaster with awakening the American public to the dangers of air pollution, and stirring an outcry that eventually led to enactment of the first federal clean air laws in the 1950s and 1960s.

In the words of a historical study published in April 2018 in the American Journal of Public Health, Donora's killer smog "changed the face of environmental protection in the United States."

Today, Donora is an out-of-the-way town of just 4,000 inhabitants, without even a gas station or a grocery store, But back in 1948, Charlton explains, it was several times larger, a bustling center of industry that was home to both a zinc works with 10 smelters and a steel mill that used the zinc to galvanize its products. While the zinc works provided thousands of residents with good-paying jobs, there was a major downside. Workers were paid a full day's wage for just a few hours of work, because too much exposure to the zinc could make them ill. "The layman's term was the zinc shakes," Charlton explains.

The plant also continuously released billowing emissions into the local sky, laden with a soup of pollutants that included "hydrogen fluoride, carbon monoxide, nitrogen dioxide, multiple sulfur compounds, and heavy metals within fine particulate matter," according to the AJPH study.

In the neighboring village of Webster, the pollution from Donora had a devastating effect on local farmers' orchards. "It just destroyed their way of life," Charlton says. In Donora, the pollution killed vegetation, denuding hillsides and causing so much erosion that a local cemetery became an unusable wasteland of rocks and dirt.


It Crept Up Slowly

But nobody imagined that the pollution would turn deadly. Then, in the last week of October 1948, the Monongahela-Ohio valley experienced an unusually severe temperature inversion, a weather phenomenon that in Donora trapped smoke from the plants at ground level.

Donora resident Charles Stacey, who in 1948 was a 16-year-old high school senior, recalls that several days before the deaths began, the smog that enveloped the town was so thick that when he walked to school in the mornings and evenings, it was difficult to see the traffic signals. "You had to be careful stepping off the curb," he says.


At first, he and his friends didn't think anything of it. "We thought the smog was something that had to be," he says. "It was part of our heritage."

But older people and those with chronic respiratory conditions weren't faring as well. By the end of the week, close to 6,000 had taken ill, as federal researchers later determined. Charlton, who has combed through county death certificates for that weekend, says that he's documented 21 deaths from respiratory causes between noon that Friday and 6 a.m. the following Monday. More probably died in the weeks that followed, he believes.

With nearby hospitals filling up and funeral directors overwhelmed, the old Donora Hotel became an improvised infirmary and morgue, Stacey recalls. The hotel's street level was filled with sick people, while the lower level was for the dead.



In the aftermath of the horrific event, state and federal public health investigators descended upon the town. But as U.S. Public Health Service official Dr. James Townsend noted in this 1950 account, some residents — fearful of incurring the wrath of their employer (the Zinc company) — tried to minimize the illnesses they'd suffered during the smog. Others, though, "were more angry than afraid."

Eventually, dozens of local residents filed lawsuits against the company that owned the zinc works — which, in its defense, asserted that the smog had been an Act of God for which it was not responsible, according to a 1994 article by Lynn Page Snyder published in Environmental History Review. In order for families to participate, the court required an autopsy of the person who'd died, which probably kept many more from participating, Charlton says.


Eventually, the families ended up settling the case for $250,000. "They were afraid they were going to end up with nothing," Charlton explains.

But the lives lost in Donora did lead to change. As Townsend wrote, the federal investigation ultimately found that the smog's harmful effects probably were caused by a combination of pollutants, rather than one single chemical culprit. But they also discovered "considerable evidence" of previous smog events in which the death rate had soared. The Donora investigation "has shown beyond doubt "that the combination of gases and particulate matter in emissions could have an adverse effect upon health, Townsend concluded. He recommended more research on pollution's effects and urged industry to work on cutting the amount of pollution emitted.


The Clean Air Act of 1963

As this 2012 article by Arthur C. Stern in Journal of the Air Pollution Control Association details, slightly more than a year after the Donora Smog, President Harry S. Truman ordered the creation of a government committee to study the air pollution problem. It was the start of a research effort that ultimately led to passage of the Clean Air Act of 1963. (Congress further strengthened that law with the Clean Air Act of 1970.)

By then, the Donora zinc works was gone. "People thought it was because they had said bad things about the plant," Charlton says. "They believed for years that it was their fault." In reality, though, the 1957 closure was just a business decision, the result of an English company developing a more efficient process that made Donora's smelters obsolete.


The demise of the zinc works — followed by the demise of the nearby steel mill a decade later — started Donora on a gradual economic decline from which the town is still trying to recover, Charlton said. But Donora's residents can rightfully be proud of their town's historic role in the fight against pollution.

"One of our tag lines is 'Clean Air Started Here,'" Charlton says. "Everyone looks to us as the ground zero of the environmental movement, of making sure that industry doesn't get out of control."