EPA Region 10 King County Seattle
7th Congressional District Other Names:
Last Update: May, 2010
Harbor Island is a 400-acre industrial island located in Puget Sound at the mouth of the Duwamish River on the southern edge of Elliott Bay. The island was created around 1905 from sediments dredged from the Duwamish Waterway. Since 1912, the island has been used for commercial and industrial activities, including secondary lead smelting, shipbuilding and repair, bulk petroleum fuel storage, metal fabrication, and containerized cargo shipping. Warehouses, laboratories, and other buildings are located on the island. There are no residences on Harbor Island, but approximately 10,000 people live within one mile of the site. All these residents receive their water from the Seattle public water supply system. Fishermen use the waters around Harbor Island for shellfishing, crabbing, and fishing.
Site Responsibility: This site is being addressed through federal, state and potentially responsible parties' actions.
NPL Listing History
Threats and Contaminants
Media Affected:Groundwater, Soil & Sludges, Sediments, Environmentally Sensitive Area
The groundwater contains benzene, ethylbenzene, xylene, mercury, cadmium, lead, and zinc. However, groundwater under Harbor Island is not used as a source of drinking water. The soils are contaminated primarily with heavy metals, polychlorinated biphenyls (PCBs), and petroleum. Sediments near the island are contaminated with heavy metals, polycyclic aromatic hydrocarbons (PAHs), tributyl tin (TBT), and PCBs. There is potential for individuals to be exposed to site contaminants through direct contact or incidental ingestion of soils, seafood, or sediments. The site is located in an estuary, an important habitat for wildlife.
EPA has divided the Harbor Island site into four project areas: 1) Soil and Groundwater; 2) Lockheed Shipyard; 3) Petroleum Tank Facilities; and 4) Marine Sediments. EPA has delegated the Washington State Department of Ecology (Ecology) as the lead agency for the petroleum tank facilities because the primary contaminant is petroleum, which is not addressed under EPA's Superfund law. Below is a summary of the cleanup progress for the four project areas. EPA is currently doing a five-year review of the entire Harbor Island site to ensure that the cleanup continues to protect people and the environment.
Project Area # 1- Soil and Groundwater: Contaminants include arsenic, lead, mercury, benzene, PAHs, PCBs, and total petroleum hydrocarbons. The Record of Decision (ROD) for this project area requires: 1) treatment or off-site disposal for petroleum-contaminated soil hot spots; 2) off-site hazardous waste disposal for PCB-contaminated soil hot spots; 3) removal of floating petroleum product at Todd Shipyards; 4) asphalt capping of soil with contamination exceeding cleanup goals; and 5) long-term monitoring of groundwater quality. Under an August 1996 consent decree with thirty-eight potentially responsible parties, identified hot spots have been addressed and cleaned up. The Port of Seattle's redevelopment project for this area included removal of PCB "hot spots" and environmental capping for the final surface. This project completed the environmental capping requirements for nearly all of the island. The remaining action is at Todd Shipyards, where petroleum product is being removed from the ground. In addition to removing the petroleum product to cleanup levels, EPA and Todd are currently working on designs for removing the remaining contaminated soil. Following these efforts, longterm groundwater monitoring for benzene and other constituents will take place. Long-term groundwater monitoring for the perimeter of the island is currently on-going.
Project Area #2 - Lockheed Shipyard: Lockheed Martin completed cleanup activities for the shipyard in the fall of 1995. Cleanup included excavating petroleum hot spot soil and treating it by thermal desorption, capping other soil contaminated above cleanup goals, and long-term monitoring of contaminant concentrations in the groundwater. Soil sampling and analysis show no significant risk to public health or the environment from residual contamination in the soil. Following a public comment period, EPA deleted the Lockheed Shipyard soils, in 1996, from the National Priorities List of highly contaminated sites. Lockheed Martin sold this property to the Port of Seattle, which uses it for industrial purposes. The Port is working on managing and treating storm water, as well as making routine repairs to the asphalt cap.
Project Area #3 - Petroleum Tank Facilities: Ecology has completed most of the cleanup for the petroleum tank farm facilities and is monitoring the cleanup. Ecology is using cleanup goals for fuel product, soil, and groundwater contamination consistent to the goals in the EPA ROD for the soil and groundwater project area.
Project Area #4 - Marine Sediments: Sediments at Todd Shipyards and the Lockheed Shipyard were selected for initial sediment cleanup action because of high concentrations of metals that are toxic to marine organisms. EPA divided the shipyard sediment project area into two smaller units for Lockheed Shipyard sediment and Todd Shipyard sediment. The 1996 ROD required that, based on Washington State sediment quality standards, certain shipyard sediments would be dredged and appropriately disposed of, while other sediments could remain in place and be capped. The ROD also required that the remedy for the under-pier areas be determined based on cost benefit and technical feasibility, and that the marine environment be restored to its most productive condition, to the extent practicable.
Lockheed Martin and Todd completed additional analyses of the nature and extent of contamination and remedial feasibility, after the ROD, to further refine and tailor the remedy for each unit. Based on this additional analysis, EPA issued three Explanations of Significant Differences (ESDs). A February 2002 ESD for the Lockheed unit defined the cleanup in more detail. This ESD required that the pier structure be removed, that sediments in the previous under-pier area be dredged sufficiently to accommodate a cap, and that the sediments in the open-water area be dredged to meet sediment quality standards. A March 2003 ESD required Todd to extend its unit boundaries. Another March 2003 ESD specified a contingency area potentially requiring cleanup by Lockheed, pending additional investigation. Remedial designs for the Lockheed and Todd units were finalized in October 2003 and March 2004, respectively. Demolition of the pier at Lockheed and replacement of the bulkhead started in July 2003. Dredging and capping at Lockheed started in November 2003. Remedial action at Lockheed was completed in March 2005. Remedial action, pier demolition, dredging, and capping in the Todd unit started in July 2004 and was completed in February 2007. Currently the under pier contaminated areas at Todd have been capped. If Todd Shipyard choses to remove the pier, the contaminated sediments underneath may require further cleanup. Monitoring is under way at both Todd and Lockheed to ensure that the cleanups are meeting cleanup goals.
Sediments with the highest chemical concentrations in the West Waterway were designated for cleanup as part of the Todd and Lockheed Shipyard remediation, and then EPA continued to investigate whether the remaining sediments in the West Waterway warranted cleanup. EPA determined that no Superfund action is necessary because environmental investigations and site-specific risk assessments found that the sediments do not pose unacceptable risks to human health or the environment. EPA issued a "no action" ROD for the West Waterway in September 2003. Ecology concurred with this decision. Following the cleanup decision for the Lower Duwamish Waterway, EPA will evaluate whether this no action decision continues to be protective of human health and the environment.
Sediments located in the East Waterway on the eastern side of Harbor Island are also contaminated. For over ten years, the East Waterway has been investigated in conjunction with dredging projects, waterway investigations, and as part of investigations of other areas at the site. In the summer of 2003, the Port of Seattle completed an Engineering Evaluation/Cost Analysis for a cleanup in the East Waterway. As a result, 200,000 cubic yards of sediments contaminated with PCBs, pesticides, and mercury in a 20-acre area offshore of Terminal 30 and Slip 27 were dredged and disposed of in an off-site landfill. Sixty thousand cubic yards of additional sediments were determined suitable for disposal in an open-water disposal site in accordance with the Puget Sound Dredged Material Management Program and were dredged and disposed of accordingly. A 6-inch sand layer was placed on those areas that still did not meet state standards after dredging. Recontamination monitoring has found some places on the sand layer that exceeded state standards.
The Port of Seattle, City of Seattle, and King County are currently working with EPA on a supplemental remedial investigation for the East Waterway, which will ultimately lead to a waterway-wide investigation and cleanup decision. Sampling has been completed for surface sediment and subsurface sediment as well as for tissue from fish, shellfish, and creatures that live in the mud. Contamination sources and pathways are also being evaluated as are the movement of the sediment in the waterway. EPA expects to make a cleanup decision for this waterway in 2013.