The U.S. Environmental Protection Agency has completed its investigation of the Gowanus Canal Superfund site in Brooklyn, N.Y. The investigation confirmed the widespread presence of numerous contaminants in the canal and identified the sources of contamination. The investigation also identified characteristics of the canal that will influence future plans for a cleanup. A companion human and ecological risk assessment found that exposure to the contaminants in the canal poses potential threats to people’s health and the environment. The Gowanus Canal was originally built to allow access for industrial needs by bulkheading and dredging a tidal creek and wetland that had previously been fished for oysters. After its completion in the 1860s, the canal quickly became one of the nation’s busiest industrial waterways, home to heavy industry including gas works, coal yards, cement makers, soap makers, tanneries, paint and ink factories, machine shops, chemical plants, and oil refineries. It was also the repository of untreated industrial wastes, raw sewage, and surface water runoff for decades, causing it to become one of New York’s most polluted waterways. Although much of the industrial activity along the canal has stopped, high contaminant levels remain in the sediments.