A 2,4,8-trichlorodibenzofuran, a tetrachlorodiphenyl ether, and a trichlorodiphenyl ether have been identified in samples of edible marine organisms and suspended particulate material obtained from Narragansett Bay, RI. Rapid declines in the concentrations of these compounds with increased distance from the highly polluted northern bay strongly suggest an upper-bay source. Comparisons of the characteristics of this contamination with those from known chemical-plant inputs and with those in PCBs, chlorophenols, and wastes from municipal incinerators indicate chemical-plant discharges as the most likely source.