ENVIRONMENTAL ASPECTS OF THE ARCO ANCHORAGE OIL SPILL, PORT ANGELES, WASHINGTON1

ABSTRACT On December 21, 1985, the tanker Arco Anchorage ran aground in Port Angeles Harbor. Approximately 5,960 bbl (239,000 gal) of Alaska North Slope crude oil were released from two gashes in the ship's hull. Weather conditions permitted the effective operation of containment booms and skimmers. Once the vessel was secured, first priority during the response was protection of environmentally sensitive areas to the east of the spill site, including a National Wildlife Refuge with large populations of marine birds, fishes, and invertebrates. Heaviest shoreline contamination was on Ediz Hook in Port Angeles Harbor, but oil was observed as far east as Dungeness Bay and as far west as Neah Bay. Approximately 2,000 seabirds were known to be oiled during the spill. Removal of oiled debris was a successful cleanup strategy for all beaches except Ediz Hook, and concentrations of oil in the sediments returned to background levels within weeks. Oil penetrated into coarse sediments at the most heavily oiled sites on Ediz Hook. A unique cleanup method incorporating a combination of physical agitation and high-pressure water jets was devised to remove most of the entrained oil. Concentrations of oil in these sediments and biological recruitment are being monitored. Recommendations are made to further reduce the environmental impacts of such incidents.