In 1948, the Air Over a Pennsylvania Town Turned Lethal

On October 26, 1948, the sky over Donora, Pennsylvania, stopped working. A temperature inversion locked five days of sulfur dioxide and hydrogen fluoride from two U.S. Steel plants directly over a valley town of 14,000 people. The smog turned yellow-gray and thick enough that residents couldn't see their own outstretched hands. A high school football team ran the ball all game because no one could see far enough to throw a pass.

Twenty people died within days. Somewhere between 5,900 and 7,000 more fell ill, nearly half the town. Some accounts comparing mortality rates in the weeks that followed put the true toll closer to 50 to 70 excess deaths. Elevated death rates in Donora persisted for a full decade.

The steel company called it an Act of God. Many residents, terrified of losing their jobs, underreported their own symptoms. The town had a zinc works that had left a mile-wide dead zone around it since 1915, vegetation gone, ground stripped clean, and people were still weighing that against a paycheck.

What broke the inversion was Halloween rain. What followed was the first large-scale federal epidemiological investigation of an environmental health disaster in American history. Donora fed into Pennsylvania's 1955 Clean Air Act and, along with London's Great Smog of 1952, into the landmark federal Clean Air Act of 1970. The Donora Smog Museum's sign reads: "Clean Air Started Here."

The museum opened in 2008. The dead zone where nothing grew opened in 1915.

Read the full story at National Geographic, October 27, 2020

Hot Take: The company blamed the weather for the deaths, technically true in the same way a locked door kills someone in a fire. The smokestacks wrote the instructions and the atmosphere only carried them out, which makes "Act of God" the least accurate sentence in the company's file.