Abstract
When did scientists, regulators, and industry first realise that industrial waste threatens the quality of ground-water? The conventional wisdom holds that widespread knowledge of this problem only dates back to the 1970s. In this view, what knowledge did exist earlier was confined to small circles of technical specialists and not generally known in industry. The passage of the Dickey Act, which established California's Water Quality Control Boards in 1949, provides documentation of events and ideas against which this hypothesis can be tested directly. A legislative committee, after lengthy public hearings, produced a detailed scientific report about ground-water and stream pollution. Bitter public controversy then erupted among politicians, industry, regulators and scientists about whether and how to protect ground-water supplies from contamination by industrial wastes. This controversy in the most populous region of the western United States demonstrates that many well-informed policy-makers knew that industrial wastes could pollute ground-water.