1948

Donora Death Fog

The history of industrial chemistry has not been an unbroken string of successes. A little-remembered incident from 1948 showed what could happen when not enough attention was paid to the environment surrounding chemical plants. In late October of that year, a temperature inversion trapped air around the valley town of Donora, Pennsylvania, for four days. Large steel and zinc works in the town regularly emitted a variety of toxic fumes, and though the zinc plant was also responsible for killing all the vegetation for a half mile around it, people didn’t complain very much. But during this weather pattern, which essentially formed a lid over the valley, the poisonous exhaust fumes were trapped in the town at ground level. A toxic brew of sulfur dioxide, hydrogen fluoride, and fluorine, among other pollutants, combined with the smoke from the factories to make a nearly impenetrable smog. The residents of the town began coughing and having trouble breathing, and (remarkably, by today’s thinking) many thought some sort of asthma epidemic had been triggered.

But the yellow “death fog” was doing more harm than that to the citizens of Donora. The Donora fire department depleted its supplies of oxygen, going from house to house helping distressed residents, and the Red Cross set up an emergency center to coordinate the work of the town’s doctors. By the time rainstorms cleared out the clouds on the fifth day, twenty people and hundreds of animals had died, seven thousand more residents were ill, and surely many more would have succumbed had the weather not changed. The survivors had lingering health problems for years, and the entire incident, which got national attention, helped to make the country aware of the perils of air pollution.

Over the next decades, legislation and public pressure forced a huge change of attitude regarding factory emissions and air pollution. By now, the idea of a valley full of metalworking plants spewing out untreated waste for the inhabitants to breathe seems almost barbaric, but unfortunately it still occurs in many places around the world.

A nurse wears a surgical mask while making her rounds during the deadly Donora smog incident.