The yellow fog arrived five days before Halloween in 1948 , swaddling the Pennsylvania city of Donora and the nearby village of Webster in a nearly impenetrable haze . Citizens attending the Donora Halloween parade squinted into the streets at the ghostlike figures rendered nearly invisible by the smoke . The Donora Dragons played their habitual Friday night football game , but , their vision obscured by the fog , ran the ball rather than throwing it . And when terrified residents began calling doctors and hospitals to report difficulty breathing , Dr . William Rongaus carried a lantern and led the ambulance by foot through the unnavigable streets .
On Saturday October 30 , around 2 a . m ., the first death occurred . Within days , 19 more people from Donora and Webster were dead . The funeral homes ran out of caskets ; florists ran out of flowers . Hundreds flooded the hospitals , gasping for air , while hundreds more with respiratory or cardiac conditions were advised to evacuate the city . It wasn ’ t until the rain arrived at midday on Sunday that the fog finally dissipated . If not for the fog lifting when it did , Rongaus believed , “ The casualty list would have been 1,000 instead of 20 .”
The 1948 Donora smog was the worst air pollution disaster in U . S . history . It jumpstarted the fields of environmental and public health , drew attention to the need for industrial regulation , and launched a national conversation about the effects of pollution . But in doing so , it pitted industry against the health of humans and their environment . That battle has continued throughout the 20th century and into the 21st , with short-term economic interests often trumping long-term consequences . Donora taught Americans a powerful lesson about the unpredictable price of industrial processes . The question now is whether the lesson stuck .
Before Carnegie Steel made its way to Donora , the town was a small farming community . Located on the Monongahela River some 30 miles south of Pittsburgh , Donora sits nestled in a narrow valley , with cliff walls rising over 400 feet on either side . Webster , meanwhile , is situated nearby , across the Monongahela . By 1902 , Carnegie Steel had installed a facility in the immediate region , complete with more than a dozen furnaces ; by 1908 , Donora had the largest volume of railroad freight traffic in the region ; by 1915 , the Zinc Works began production ; and by 1918 the American Steel & Wire Company paid off its first fine for air pollution damage to health .
“ Beginning in the early 1920s , Webster landowners , tenants , and farmers sued for damages attributed to smelter effluent — the loss of crops , fruit orchards , livestock , and topsoil , and the destruction of fences and houses ,” writes historian Lynne Page Snyder . “ At the height of the Great Depression , dozens of Webster families joined together in legal action against the Zinc Works , claiming air pollution damage to their health .” But U . S . Steel rebuffed them with lengthy legal proceedings , and plans to upgrade the Zinc Works ’ furnaces to produce less smoke were set aside in September 1948 as being economically unfeasible .