Inversion occurs when the air near the ground is cooler than the air above it, a reversal of normal atmospheric conditions. When that happens, manmade pollutants are trapped, resulting in smog. The physical conditions around Los Angeles, for example, lead to frequent inversion layers over the basin. That, combined with heavy automobile pollution, consistently gives L.A. the worst air quality in the country.

But L.A. has never seen anything quite like that one week in Pennsylvania, in what became known as the Donora air inversion or, more dramatically, the “Donora Death Fog.”

In Donora, an industrial town about 20 miles south of Pittsburgh, pollution from the nearby U.S. Steel smelting plants and Donora Zinc Works was the main culprit. Trapped in a temperature inversion, the pollutants blanketed the town during the night of Oct. 26.

The companies connived with the U.S. Public Health Service to cover up the facts of the incident and succeeded in doing so for half a century. Whistle-blowers were silenced; records disappeared. It wasn’t until 1994 that a full accounting of what happened in Donora was finally published.

To Philip Sadtler, an industry consultant sent to evaluate the disaster and who tried without success to expose the corporate cover-up, U.S. Steel was guilty of murder:

“The directors of U.S. Steel should have gone to jail for killing people,” Sadtler said shortly before his death in 1996.

In the end, 40 percent of Donora’s population of 14,000 became ill as a result of the “death fog,” and the town joined a growing list of other places hit hard — and harder — by industrial pollution.

Source: Various

Photo: Donora Zinc Works of the U.S. Steel Corporation is dimly seen through fume-laden smoke and fog.
Bettmann/Corbis

This article first appeared on Wired.com Oct. 26, 2007.

See Also:

• Nov. 11, 1856: Bessemer Becomes the Man of Steel
• Aug. 13, 1913: Great Alloyed Victory for Stainless Steel
• Gallery: Attack of the L.A. Smog Archives
• Smog Musicians Turn Pollution Data Into Jagged Melodies
• Olympic Organizers Give All Clear To Beijing Air, Despite Smog
• California Smog Police Turn to Stealth
• March 17, 1948: William Gibson, Father of Cyberspace
• June 3, 1948: Interesting Idea, But Will It Fly?
• June 14, 1948: TV Guide Prototype Hits N.Y. Newsstands
• June 21, 1948: Columbia's Microgroove LP Makes Albums Sound Good
• July 28, 1948: IG Farben Explosion Punctuates Nuremberg Trial
• Sept. 7, 1948: Where the Rubber Is the Road
• Oct. 26, 1992: Software Glitch Cripples Ambulance Service

Authors: Tony Long

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