In 1948, 20 people died and 6,000 became sick in Donora, Pa., when a smoke pall hung on the hills. In December 1952, when five days of stagnant air blanketed London, 3,600 to 3,800 people died from complications of breathing bad air. Both cases were mostly caused by soot and noxious gases belched from steel mills. A watershed for the environmental movement in the U.S. then came in 1962 with publication of Rachel Carson's "Silent Spring." The public awakened.
The Clean Air Act of 1970 made the Environmental Protection Agency (EPA) responsible for establishing air pollution limits and enforcing rules and regulations. While created by President Nixon for political purposes to satisfy public demand and to defuse issues advanced by opponents, Congress wanted to gain control of EPA direction. Members of the House and Senate often made outrageous charges to EPA officials to enhance their image and show constituents a "commitment" to the idea of environmental protection. Industry, however, wanted time to understand new rules and develop ways to abide by them, but harbored fears that Congress would change policies, or that EPA would impose restrictions that would destabilize criteria by which pollution control investments were made. The Nixon Administration was concurrently trying to depress inflation, restrict spending in Congress and bolster employment for improved economic prospects. American industry associated with targeted emissions often questioned EPA air quality standards by attacking their scientific credibility. It was an ugly time.