The St. Mary's River was designated an Area of Concern under the 1987 Great Lakes Water Quality Agreement. Industrial and municipal discharges as well as combined sewer overflows caused impairments of water quality, sediment and biota at the AOC. Priorities for the AOC include restoration of tributaries, cleanup of the Cannelton Tannery Superfund site, sea lamprey control, elimination of combined sewer overflows and remediation of contaminated sediments.